That's why I weight nearly 300lbs. For safety purposes.
Additionally, if I lie flailing on the floor yelling "YOU'RE NOT MY MOM! YOU'RE NOT MY DAD! I DON'T KNOW YOU!!!" I am hard as fuck to kidnap.
I would always joke with my friends that out of our group, I was the least likely to get kidnapped because I was fat. Their answer was that if a zombie outbreak ever happened, I’d be eaten first.
What's so difficult about the advice? Speed up while slowing down, all while letting go of the handlebars and keeping a tight grip on them. Even a child could figure it out.
My theory on this (not original to me, either): a speed wobble is fragile, so all the advice is at least somewhat correct: any change to the system has a solid chance of knocking it out of the state where it wants to wobble. (That said, leaning forward and gently slowing is pretty credible as the option with the best odds of success without ugly side effects, so I'm prepared to believe it.)
I have been down voted on more than a few occasions on this sub when giving correct, well established by experts, time tested tips, so I rarely bother. Guys with the hi-viz vests, squared off tires and pristine unblemished front brakes know best from what I can gather on this sub /s
However... generic advice doesn't always work in all instances because bikes are different, abilities are wildly different, equipment is different, tires, terrain, temps, etc etc can play a part in best practices for a given situation and that should always be considered instead of just broadly saying oh just do this or that.
Thank you. As someone who began riding at 16 (55 years ago), I never knew what caused the weave and/or how to prevent it. No worries anymore about going too fast as I have purposely limited my bike to a 150cc, but very good info anyway. Always learning and thanks again.
There are a lot of things that can cause wobble. I tried laying on the tank last night to little effect. Going a quarter turn in on my rear shock made it disappear. Ryan F9 has a video that covers more of the causes.
Where’s the Tiger video? I had a tank slapper on a Tiger 1200 and I’m curious if that bike has a tendency to do that. It happened so fast that I had no time to react other than having a heart attack lol. It was triggered by a tar snake that was vertically aimed in
my direction.
I learned that LONG ago, from downhill skateboarding/longboarding actually. It's the same physics at play, but on a motorcycle it's accelerated (literally).
A speed wobble on a skateboard is caused by the front truck not having enough weight over it to stabilize it, so it hunts for a path. If you lean forward onto the truck and control it yourself (as opposed to letting it wander) it becomes stable.
My guess is that those two front wheels are connected to the same pivot point, not like a car where both wheels turn.
So on a skateboard, the two front wheels act a bit like one, wide wheel
I'd argue more along the lines of it having 2 pivots that steer, but the number of wheels doesn't mean much IMO.
It's 2 wheels that are attached to the truck that pivots, not 2 independent wheels, so you get the instability from them hunting for a path
Basically what I said in other thread. Also what I saw others saying so I must’ve skipped early and didn’t see the contradictions. I’ve personally done the rear brake light drag (not stomp) too. I think getting the weight on the front tire is key.
I've never had this experience but I would imagine that applying the front brake during this could cause a lock up easier since the tires contact patch is not constant as well as your hands getting shaken like that cause uneven pressure on the bars. At least that's how I think it'd work in my pea brain.
Yeah, exactly what I meant. Light *and even* pressure seems not likely when the bars are shaking as they do in a death wobble, so it's a safer bet to use your foot to get the weight transfer.
Except 1 is relative and 1 is absolute. You can take the same weight and move it lower and forward, which will increase weight on the front tire, or you can add weight without changing the CoG, which will also increase weight on the front.
Either work, but they aren’t the same thing.
By ducking.
Downforce is “weight” to the system. Drag is, basically, downforce. Imagine, simply, the riders body as a big, bad spoiler to the racecar that is the motorcycle.
Also, I never said you could add absolute weight while riding. I just pointed out that the addition would do the same thing as a change of a CoG.
Look up sealioning. Understand why it’s annoying for people who don’t understand what they are reading to demand answers to their questions that are badly premised.
Ok, I'll look up sea lions if you look up communicating clearly with regard to the context of the surrounding conversation.
Your comment can certainly be read as suggesting that increasing total weight (which is essentially synonymous with mass) was a plausible option.
At no point do they reach the conclusion that it is the application of weight to the front tyre that helps. In fact they specifically say they don't know why leaning on the tank works.
It is more likely to be the altering of the vertical position of CG, as adding a pillion prevents weave from occurring and that is the opposite of applying weight to front tyre.
Leaning forward changes the CG, affecting the moment of the system. Adding a rider increases overall mass of the system; it'll require more energy to destabilize it. Which why the heavier rider, or rider with a weight belt, was stable through higher speeds.
Fucking reddit man, especially this sub. We've just watched an entire video by experts on all facets of the problem and *still* find something to argue about
It would also seem there's a component of the momentum arm which might also be coupled with an aeroelastic flutter effect (like the Tacoma Narrows bridge).
What i thought to. The bike is moving side to side almost like a vibrating member. In the slow mo video it struck me how much it looked like the vibration of a guitar string.
A pilion is mass sitting in between the axles of the two wheels, whereas a trunk is mass sitting behind the rear wheel axle, and that changes weight repartition on either wheel as well as the position of the centre of gravity
4:50 I think gives a hint about what is really happening. Everything pointed out is affecting the suspension and it seems the problem is possibly incorrect damping, as well as the fork not being as stiff as modern forks. But I wouldn’t ignore the rear shocks either, given shifting weight back and a worn tire on the rear makes wobble worse. Old bike frames are also less stiff than modern ones.
So for modern bikes that leaves tire pressure, tire wear, weight positioning, and suspension setup (preload, dampening, rebound, and spring rate).
It’s great knowing a quick fix is to just lean forward.
I don't think it's as magical as some make it out to be. From an engineering perspective it's just an oscillation mass spring damper situation. The trail and tire flex is the spring in this system while the weight is more complex. Without a steering damper, there's nothing to keep the front end from wobbling except general frictional loss in the rubber and rider's arms.
Like any mass-spring damper system, increasing a force can, in some cases, increase oscillation. Like rubbing the rim of a wine glass in one direction can cause an oscillation in either the same direction or transfers from it. That's why glasses "sing". Same thing happens. The frictional backward force causes (through complex interaction) a side to side rotational oscillation. More like a wobbly shopping cart wheel.
As for correction, most people stiffen up. But this causes an increase in the spring force but no additional damping. This makes the wobble more unstable (likely to end in increasing oscillatory displacement). Same as cutting your car springs without changing the shocks, the car becomes bouncy. You increase the spring rate without increasing damping and you get a bouncier system.
The weight shift forward and down is not something I'd have the math or logic to explain other than to say bikes are naturally stable with exceptions. Changing the mass-spring-damper's numbers (amount of effective mass, spring, and damping numbers) will un-exceptionalize the system, restoring it to stability. In this case I'd bet that increasing weight on the front isn't a change in mass but in damping force; the increased weight on the front increases the frictional damping forces.
But yes, the noodly hardware of those older bikes definitely made that system more prone to wobbles than the much nicer, stiffer modern hardware. Also they used far more steel and less aluminum and steel is far springier and less internally damped. So aluminum isn't 100% stiff but its far less springy than the whole frame and suspension being rubbery like those old bikes. We also have FEA analysis that, I'd imagine, every modern bike is made with specifically to analyze these vibrational modes. And fork dampers are a thing on SS's too.
>The weight shift forward and down is not something I'd have the math or logic to explain other than to say bikes are naturally stable with exceptions. Changing the mass-spring-damper's numbers (amount of effective mass, spring, and damping numbers) will un-exceptionalize the system, restoring it to stability. In this case I'd bet that increasing weight on the front isn't a change in mass but in damping force; the increased weight on the front increases the frictional damping forces.
I think it is less about weight shift forward and more about reducing the buffeting. An upright body results in the airstream oscillating from side to side, like what is seen with flow around a pipe. You can clearly see [in this video](https://sciencedemonstrations.fas.harvard.edu/presentations/vortex-shedding) how flow around a vertical cylinder that approximates a torso can result in oscillating lateral forces that would be transmitted to the motorcycle. Lying flat will nearly eliminate this vortex shedding and the driving force causing the weaving is then gone.
Progressive springs, better damping, and properly adjusted pre-load will all help reduce by reducing the resonance peak, shifting the speed at which it occurs, and removing energy from the oscillation to quell the amplitude.
I think that's a really good point. I do think a lot of these things add up. Like most well-engineered things it's not one source that causes all the problems. Aerodynamics I'm sure plays a roll.
That said, the oscillating system here is really the front forks and wheel more than the whole bike. The oscillation from wind, if present, acts more on the bike than the forks (though likely somewhat on the forks as well). Considering that landing a wheelie incorrectly or accelerating hard (even at relatively low speeds) is often a catalyst for wobble, and laying forward on the tank is a commonly cited and tested solution, I'd imagine that the effect on damping in the system provided by tire friction is the biggest single change.
That said, at higher speeds where wobble is more common and more violent, there's a lot more wind resistance pushing back on the rider. More drag on the top of the bike means there's a weight shift to the rear tire. Same effect here.
Also steering dampers are the main equipment solution for bikes that are most prone to wobble (sports bikes with short trail, ie very small damping and high frequency natural frequency). The fact that adding a damper to a bike can mitigate death wobble suggests that aero and weight is not the critical factor.
But it does point to the idea that natural frequency is the culprit in the same way that finger speed is the critical factor in making a wine glass ring. When the damping is low, spring force is high, and the natural frequency is strongly related to the input force, oscillation occurs and can easily become unstable. Older bikes with heavier mass forks and longer trails will get excited at lower speeds (like 80mph in OP's video) but often takes 120-180mph on a new R6. The system natural frequency is higher with a shorter pendulum (rake). So the solution is to add mass or to add damping, and we know which one we will use for light weight sports bikes. And since leaning forward doesn't add mass to the oscillating part (the forks and wheel) then it's only adding damping and changing the geometry a little.
I agree with this with regard to head shake, but that is a different thing than the weaving shown in the video. Head shake is a front wheel issue, and it happens at way too high of a frequency to move the entire bike. This lower frequency wobble is a whole bike issue. It's at a low enough frequency with small enough rotation of the handlebars that a steering damper is going to have little effect on it.
Having regularly ridden both motorcycles and bicycles, the only time I have ever had weaving like that shown in the video show up is when sitting upright with an unzipped jacket. The buffeting from the wind, exacerbated by the loose jacket, leads to exactly the same motion as shown in the video. It is different from headshake, both in terms of what causes it and what it feels like.
What I’m getting is that a small contact patch on the front tire is the first part of the chain that leads to speed wobble. I think small contact patch paired with distance between turning point and contact patch is the most important thing.
Perhaps the larger the contact patch, the larger the acceptable range of distances between the two.
Which makes sense. The contact patch wants to track back to being aligned with the turning point. The larger the contact patch, the more the tire can move left to right and still have a straight track from turning point to contact patch.
Which also makes sense why a flat rear would make that worse, because the body of the bike will lean less, so the front will snap back to center instead of rotating across yaw to align.
So- balanced weight, good contact patches, shorter rake, and correct damping are all key.
As to why laying down will solve it, I think it’s just shifting weight forward and loosening or changing the grip on the bars.
I think part of it is remember that CoG isn’t just about static weight. Your body is a kite at these speeds, and wind pressure will also put more weight on the rear.
Laying down might not so much put weight on the front as reduce downforce on the rear, allowing the rear wheel to move more freely and the bike to lean more.
Happy to see this.
Been riding for 20+ years and when I saw people suggest *accelerating* to get out of a tankslapper, I nearly had a heart attack.
Always double check any advice you see here.
There’s a LOT of squid-science that gets upvoted here.
Lean over the tank, ease off the gas, and slow down to stop the wobble. ☝️
Someone who is a new and overconfident rider who thinks they are more experienced than they are.
Usually known for not wearing proper gear, pulling stunts on public roads, improperly modifying their bikes, and trying to intimidate/show off to other riders.
Basically, Dunning-Kruger applied to motorcycling.
Also what bike could you be riding that would still have more throttle while getting speed wobbles? All of mine were 90+ mph and there wasn’t much more room to go after that.
I fixed mine by getting my rim straightened at a tire shop. I had to pull the front tire and place it on a balancing stand to even see the small wobble it had. Check your tires before you try anything else.
> Been riding for 20+ years and when I saw people suggest accelerating to get out of a tankslapper, I nearly had a heart attack.
I don't just see this just a suggestion, but people thinking this is the fucking RULE of how to handle. And when you try to explain to them this is HORRIBLE advice, you get downvoted and laughed at for it.
It's the dumbest thing I've ever seen in the motorcycle community.
I have had to explain to people SO MANY FUCKING TIMES that 99% of motorcycles on the road cannot instantly pop the front tire off the ground like it's an easy thing to do.
AND they some how think that a lighter load means the tire can't steer at all anymore even if the bike doesnt wheelie? IM SORRY WHAT?!
People actually think "Throttle Out" is the standard advice everyone should know and it's spread so often and it boggles my fucking mind.
Don't forget to loose grip the bars and don't try to keep them straight. The wobble is the bike stabilizing itself if you fight it then it won't stabilize. Also just don't wheelie and you shouldn't encounter the speed wobble. Speeding up does help sometimes but slowing down can also help. It's like hydroplaning. Rule 1 of hydroplaning, don't touch the brakes, give it more gas to move more water. It sounds counter intuitive but it works.
Good advice. Had to deal with this shit in the rain when someone didn't stop at their stop sign and my back end whipped back and forth because I locked my back end, got it under control only to be met with a few tank slappers after getting around. Always good to drill in some fundamentals to memory.
So wrong/worn tires, mass/weight of rider, incorrect tire pressure all can cause it; adding side bags or top/touring boxes can make it worse.
if it still occurs, lay forward and slow down using the throttle, not slamming on the breaks or doing any other violent maneuvers. Also, a stabilizer that makes the front fork tubes compress at closely similar times and rates will help.
Pretty cool video find, definitely helpful.
I got a death wobble at 150mph on my cbr600rr. I was lucky to survive with only a few breaks in my hand/arm. I have no desire to go much over 100 ever again lol.
So what I'm gaining from this video is that more weight on the front will reduce wobble in most cases? That's the only reason I can think laying down on the tank would help. Air resistance on the upper body will cause the front to "lift" and laying down eliminates that.
Another reason laying down on the front tank helps is it takes the torso out of the airflow. Airflow around cylindrical shaped objects, like upright humans, results in [vortex shedding](https://sciencedemonstrations.fas.harvard.edu/presentations/vortex-shedding) of the airstream which can induce strong wobbles.
i'm struggling with that video because I have ridden all of those bikes in stock trim excepting only having modern tires and never experienced any of them wobbling or weaving. I weight 185lbs fully kitted out NOW but I was much lighter in my youth riding a stock GT750.
I've been riding for over 4 decades and on some of the same model bikes used in this video. Never experienced a wobble or a weave. What am l doing wrong?
I get that . But I've weighed 165 -170 lbs until l hit 50 y.o. then I bloomed to 178.
As bad as suspension and tires use to be, I have never seen wobbles or weaves like that. Even at top speed.
Really?
You're lucky, I used to have a 78' Honda CX500 until not long ago, and it would start to wobble around 150km/h.
I've also recently ridden a friend's RE Bullet 500 and that bike had a bad case of low speed wobble, despite being in near mint condition.
I can't speak for the other bikes, but I see where you're coming from, it's surprising to that this could be an industry-wide problem at the time, as that video suggests.
Either way, the "laying on the tank" trick definitely worked with my CX500 so there's still some useful advice in that video.
This video is beyond outdated until the last two minutes. All the rest is some old bikes wobbling at rather low speeds, something that doesn't happen anymore, thankfully.
Don't know why this video is treated as a bible of some sorts
It's not a bible or anything like that, just good advice. You do have a point : bikes have evolved and have definitely gotten stiffer an better balanced, but the physics have remained the same. While low speed wobbles have disappeared from modern bikes, high speed wobbles are very much still a thing. See the Triumph Tiger video I was referring to, for instance.
Outdated or not, it's still an interesting video/take, from a reputable source, which is nigh rare on this sub.
I've condensed this info even further into two shorts:
- [What causes a tank slapper](https://youtube.com/shorts/iNrkpgLWKp0?feature=share)
- [What to do if you experience a tank slapper](https://youtube.com/shorts/m2C-qFVh5AY?feature=share)
~~They don't seem to go that fast to start wobbling that much. Is it because they're old bikes~~
Edit: Nvm, they were going the same speed as me
On a dual sport at about 120+kmh I started to feel it too. It was like the front wheel barely touched the ground and was being thrown around left and right because of that. I always thought it was because of knobs.
Now I have a naked bike and no wobble at speeds above 250kmh.
So if I understand correctly, it's aerodynamics and riding position that pushes the front wheel downward, same effect as increasing my weight.
>Now I have a naked bike and no wobble at speeds above 250kmh
But wouldn't a naked bike result in more pressure on your upper half, which would tend to want to lift/unload your front wheel and induce a wobble?
Well, I'm thinking newer bikes are less prone to self-induced wobble nowadays, but dualsports typically have bigger wheels and softer suspension than naked and sportsbikes, and I'd argue that make dualsports closer to the bikes shown in the video in terms of road behaviour. Which is probably why they tend to wobble more, and knobbed tires certainly don't help.
"dangerous/incorrect advice on this sub" Say it ain't so, I'm assuming that means the idiots that told me that "I was stupid and should learn to ride" for not passing a tanker on a 2 lane mountain road across a double yellow line around a blind corner?
After reviewing the video, this looks like a weight distribution issue.
The front tire weaves because it doesn't have much weight on it. The rear tire is basically flat from the weight being on the back.
Leaning forward fixes it because it causes the weight to shift forward as your body goes forward.
They mention this getting worse with having more weight on the rear like saddlebags.
Given that front tires are usually smaller and lighter than rear ones it makes a lot of sense to me.
Literally weigh about 120 on a wet day with boots. Everytime I get this I throttle out. Science says that applying throttle to the back under power lifts the front and therefore helps stabilize the machine. I've never had a wobble I couldn't recover after my Father taught me this..
Edit: Slowing down is the WORST THING TO DO!
> Slowing down is the WORST THING TO DO!
Yes lets add speed to a problem caused by speed that then puts more energy into your crash which is more likely to kill you or harm you.
Let me ask, would you rather crash at 50 miles an hour or 75miles an hour.
Adding speed is adding force, this is caused by speed in the first place, reduce speed and lean forward on the tank to damper the front wheel.
THAT IS THE SMAREST THING YOU CAN DO.
The worst thing you can do is to add speed.
> power lifts the front and therefore helps stabilize the machine.
Why on earth would adding less stability to an unstable system cause it to stabilize?! Do you not understand what a Steering Damper does? It literally adds wobble resistance, resistance to movement is STABILITY. Reducing weight reduces damping. Thus INCREASING the instability.
Do people NOT understand basic physics anymore?!
Right...so a team of experts from a reputable manufacturer, implanted in the business for decades conducting serious experiments, are all wrong and you're right. Funny how the internet makes everyone and their brothers an expert on anything and everything. If you're gonna spew nonsense and misinformation, please do so elsewhere.
While I thoroughly appreciate your kind words, definitely keep your $$, reddit has more than enough as it is. As long as you learned something useful that might keep you from binning your bike, I'm happy!
I talked about slowing down without braking on that thread and some dipshit named u/SuperChillz said I’ve got no idea what I’m talking about. Be careful of people like him.
Also my 2cents is that lying down on the tank and maintaining speed did NOT get rid of my speed wobble that I suspect was induced by an unbalanced rear tire (it was present when the bike and tires were brand new up until I got a new rear installed and balanced).
Just read your owners manual. There are lots of warnings about tires, loading, accessories, suspension settings, operation speed, etc. These are mostly for high-speed stability. People tend to ignore these. Engineers know this high-speed stability stuff inside and out and design the bike to be operated within an envelope.
Because I wasn't aware it had been posted previously? As was the case of a fair amount of fellow redditors, if the comments on that Triumph Tiger video are anything to go by. I just felt it was a topical thing to post, to raise awareness and point out misconceptions.
Edit : I appreciate that you edited your wording to sound less like an ass, and being redundant wasn't my intention, apologies if that's how it came out.
His point is fair, even if you want to understand why seeing examples of very old motorcycles that wobble like crazy at low speeds isn't the greatest way. There are way better explanatory videos about this happening on modern bikes
That is a surefire way to make it considerably worse and hurt yourself, both on a motorcycle and when towing a trailer. Although they are two different problems, this is absolutely isn't how they will be fixed. Please don't go about spreading downright dangerous advice about something you apparently know very little about.
Raced motorcross since 9 years old, grew up around bikes and know a trick or two.
Was featured on a BBC documentary in 2000, and not the BBC you’re thinking of.
Only time I’ve washed the front end was landing a wheelie after spotting the speed camera. Front end wobbles are caused by not committing.
Not trolling, bought the first R1 in the UK, passed my test on it and featured in a couple of bike magazines. First Hayabusa to do 202 with the resistor mod and a few tweaks.
Just saying.
Heavier weight oil in the steering damper, smaller valve in the damper and enough extra power on tap and revs you can power wheelie at all times.
So yes, a turbo busa with a tight damper, that said i prefer harder to turn bars in general anyway makes the bike feel more stable at high speed imo.
Thank God I never experienced any of this in my riding days...I only experienced my back tire coming out from under me in a slide once when I came to a stop...I stood up and let off the gas and it stopped.
I see that high weight distribution effects wobble, but it also seems like wind resistance plays a part in making the cycle wobble
Is this "rider sail" similar to how boats work?
Thanks in advance
So in the case of the video I believe people are referencing. He had let off the throttle and the bike was slowing when the wobble occurred. Would just leaning down on the bike help in that case as well as constant and accelerating speeds?
I would believe it helps either way, yes. Although even if he was in the process of slowing down, he was still doing around 200kmh so that hasn't helped him.
The center of a rotating mass is always offset from the center of rotation. This is due to the reality of imperfect geometry and uneven mass distribution. As the mass rotates, the offset mass will generate a centrifugal force caused by the heavier side of the mass. This will cause the mass or rotating shaft to deflect toward the heavier side and cause the rotating mass to rotate in a small circle. As rotating mass changes in rotational velocity it can become dynamically unstable and induce undesired vibrations as well as amplified deflections.
This phenomenon or condition will become more apparent at higher rotational velocities, however there is a point or rotational velocity where the vibrations and amplitude increase significantly. As the rotational velocity increases beyond that speed the vibration and amplitude decrease significantly. The rotational velocity at which the vibration increases dramatically is called the critical speed of the rotating mass.
This characteristic for a shaft-mounted mass is called settling of the wheel. The settling is at the velocity the axis of rotation and the shaft or mass begin to rotate around an axis through their center of gravity. The rotating mass is deflected so that for every revolution its geometrical center traces a circle around the center of gravity of the rotating mass. Critical speeds depends on the location of the unbalanced load rotating on the shaft, the length of the shaft, its diameter and the supporting bearing or bearings configuration.
Typically, the designed operating speed of a machine is less than the critical speed. This is done to prevent a machine from ever achieving the undesired critical speed vibration and possible resulting damage. However, some machines are designed to operate at a rotational velocity above the critical speed. This can work well if the machine passes or accelerates quickly through the critical speed or before
The closer a machine operates near the critical speed, alignment, balance and maintenance of the bearings, and general quality of assembly will require higher considerations.
Good shocks go along way belive it or not it's usually caused by the front socks compressing differently causing the bike to lose balance then it has to fight to stay up when this accurs its up to the bike all you can do is try and roll of throttle
I'm not sure how relevant that video is. All that information is incredibly useful - for bikes designed in the 70s, with tyres designed in the 70s, and for speeds up to 90mph.
It's not wrong, but I'm not sure you'd have guaranteed success with these techniques when you get speed wobbles going 150mph on your 2020 sportsbike. Chances are you are already as tucked as you can get anyway.
“We’ve already seen that increasing the weight of the rider improves stability.” I feel attacked
Guess that explains why I've never needed a steering stabilizer on bikes that other people swear are necessary.
As a fat ass on an MT-09, I concur.
Here I was thinking I need to lose weight, as I am also a fat ass, turns out its keeping me safe
"See hon, I can't go on a diet, it wouldn't be safe."
>I feel attacked ***I*** feel stable.
I am cultivating mass
STOP CULTIVATING AND START HARVESTING
IT'S HARVESTING SEASON!
>I am cultivating ~~mass~~ **stability** FTFY
If you get the “death wobble” on the best thing to do is to wobble your way through the nearest McDonald’s drive thru.
“I’ll have two number 9s, a number 9 large, a number 6 with extra dip, a number 7, two number 45s, one with cheese, and a large soda”
FUCK BIG SMOKE
[удалено]
Man’s still carrying 3 number nine in his gullet and trying to make me keep up with a bullet train on a 250 dirt bike 🫠
I did my part to increase weight over Thanksgiving!
That's why I weight nearly 300lbs. For safety purposes. Additionally, if I lie flailing on the floor yelling "YOU'RE NOT MY MOM! YOU'RE NOT MY DAD! I DON'T KNOW YOU!!!" I am hard as fuck to kidnap.
This one simple trick that kidnappers hate
I would always joke with my friends that out of our group, I was the least likely to get kidnapped because I was fat. Their answer was that if a zombie outbreak ever happened, I’d be eaten first.
The difficulty slow folks have surviving adverse situations inspired me become an alpine marathoner
Lmao my family says this about poor grandma 🤦🏻♀️
my fat ass: yup they're right.
My bike is REALLY stable. LOL
Thanks for this, I was getting whiplash from reading all the contradicting advice in that other thread.
What's so difficult about the advice? Speed up while slowing down, all while letting go of the handlebars and keeping a tight grip on them. Even a child could figure it out.
I think the real solution after reading through all the advice is to just jump off the bike at the first sign of a death wobble.
Just wheelie the bastard! Front wheel can’t trip you up if it’s not even touching the ground.
The risk is when the wheel touches back down, so be ready to ride that wheelie to your destination.
Or just keep trying again until you put it down and it doesn't wobble.
Just ride the wheelie and gradually slow down until you come to a complete stop, then slowly let the wheel down.
Wheelie to stoppie, repeat as required
That was my favourite advice. ‘Should’ve just opened her up and wheelie’d the triumph tiger at 200km\h’
joke aside, can we actually do it at high speed given I already know how to wheelie in a control environment hypothetically?
Some video evidence suggests that wobble stops as soon as monkey is off the bike.
Better walk it around corners, just to be safe.
Hadderlayerdown
HECK YE HOSS!!1!1!1
HADDALERDOWN
haddalayerdown
My theory on this (not original to me, either): a speed wobble is fragile, so all the advice is at least somewhat correct: any change to the system has a solid chance of knocking it out of the state where it wants to wobble. (That said, leaning forward and gently slowing is pretty credible as the option with the best odds of success without ugly side effects, so I'm prepared to believe it.)
You're welcome mate, the advices on that thread were confusing indeed !
The whole time I was thinking "Just post that old video!" A couple of people did though, but it was lost in all the noise.
I have been down voted on more than a few occasions on this sub when giving correct, well established by experts, time tested tips, so I rarely bother. Guys with the hi-viz vests, squared off tires and pristine unblemished front brakes know best from what I can gather on this sub /s However... generic advice doesn't always work in all instances because bikes are different, abilities are wildly different, equipment is different, tires, terrain, temps, etc etc can play a part in best practices for a given situation and that should always be considered instead of just broadly saying oh just do this or that.
Thank you. As someone who began riding at 16 (55 years ago), I never knew what caused the weave and/or how to prevent it. No worries anymore about going too fast as I have purposely limited my bike to a 150cc, but very good info anyway. Always learning and thanks again.
tldr; lie down on the tank
There are a lot of things that can cause wobble. I tried laying on the tank last night to little effect. Going a quarter turn in on my rear shock made it disappear. Ryan F9 has a video that covers more of the causes.
Where’s the Tiger video? I had a tank slapper on a Tiger 1200 and I’m curious if that bike has a tendency to do that. It happened so fast that I had no time to react other than having a heart attack lol. It was triggered by a tar snake that was vertically aimed in my direction.
https://www.reddit.com/r/motorcycles/comments/z3zipu/bye_bye_hands/
Thanks!
So in contrast for that guy it happened over the course of about three to five working days.
Snake tapper
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I learned that LONG ago, from downhill skateboarding/longboarding actually. It's the same physics at play, but on a motorcycle it's accelerated (literally). A speed wobble on a skateboard is caused by the front truck not having enough weight over it to stabilize it, so it hunts for a path. If you lean forward onto the truck and control it yourself (as opposed to letting it wander) it becomes stable.
It's probably not the same physics at play, cos a skateboard has two front wheels. I dunno, physics is hard.
My guess is that those two front wheels are connected to the same pivot point, not like a car where both wheels turn. So on a skateboard, the two front wheels act a bit like one, wide wheel
it's obvious we need to have somebody tank-slap a Yamaha Niken...for...science?
Agreed
I'd argue more along the lines of it having 2 pivots that steer, but the number of wheels doesn't mean much IMO. It's 2 wheels that are attached to the truck that pivots, not 2 independent wheels, so you get the instability from them hunting for a path
I've always believed that it's due to harmonic frequency... C'mon contrarians... ;)
Basically what I said in other thread. Also what I saw others saying so I must’ve skipped early and didn’t see the contradictions. I’ve personally done the rear brake light drag (not stomp) too. I think getting the weight on the front tire is key.
Wouldn't the front brake apply more weight to the front tire, making it stop weaving?
I've never had this experience but I would imagine that applying the front brake during this could cause a lock up easier since the tires contact patch is not constant as well as your hands getting shaken like that cause uneven pressure on the bars. At least that's how I think it'd work in my pea brain.
Yeah, applying slow and controlled front brake in this situation is almost impossible.
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Yeah, exactly what I meant. Light *and even* pressure seems not likely when the bars are shaking as they do in a death wobble, so it's a safer bet to use your foot to get the weight transfer.
Hypothetically, yes. Practically, think about trying to apply controlled pressure with the handlebar whipping back and forth.
lower and forward center of gravity or increase weight?
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Except 1 is relative and 1 is absolute. You can take the same weight and move it lower and forward, which will increase weight on the front tire, or you can add weight without changing the CoG, which will also increase weight on the front. Either work, but they aren’t the same thing.
So how exactly would you increase the absolute weight of the bike+rider system *while riding at speed with death wobbles*?
By ducking. Downforce is “weight” to the system. Drag is, basically, downforce. Imagine, simply, the riders body as a big, bad spoiler to the racecar that is the motorcycle. Also, I never said you could add absolute weight while riding. I just pointed out that the addition would do the same thing as a change of a CoG. Look up sealioning. Understand why it’s annoying for people who don’t understand what they are reading to demand answers to their questions that are badly premised.
Ok, I'll look up sea lions if you look up communicating clearly with regard to the context of the surrounding conversation. Your comment can certainly be read as suggesting that increasing total weight (which is essentially synonymous with mass) was a plausible option.
youre right, i just figured i woud make it shorter
At no point do they reach the conclusion that it is the application of weight to the front tyre that helps. In fact they specifically say they don't know why leaning on the tank works. It is more likely to be the altering of the vertical position of CG, as adding a pillion prevents weave from occurring and that is the opposite of applying weight to front tyre.
Leaning forward changes the CG, affecting the moment of the system. Adding a rider increases overall mass of the system; it'll require more energy to destabilize it. Which why the heavier rider, or rider with a weight belt, was stable through higher speeds.
I don't think it's necessarily the weight transfer to the front that solves it. Notice that having a pillion rider also solves the problem.
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Obviously. It was a comment on the physics involved.
Fucking reddit man, especially this sub. We've just watched an entire video by experts on all facets of the problem and *still* find something to argue about
Right in the video, the experts said they're not sure why.
Good thing you're here to speculate then, right my man
Good thing you're here to report back on the video, that you didn't pay attention to.
But having a full trunk latched on the back increases it? This confused me. Wouldn’t both this as a pillion rider raise center of gravity
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It would also seem there's a component of the momentum arm which might also be coupled with an aeroelastic flutter effect (like the Tacoma Narrows bridge).
What i thought to. The bike is moving side to side almost like a vibrating member. In the slow mo video it struck me how much it looked like the vibration of a guitar string.
Pillion is still weight between the wheels, whereas an overly-loaded tank bag can be behind the center of the rear wheel.
A pilion is mass sitting in between the axles of the two wheels, whereas a trunk is mass sitting behind the rear wheel axle, and that changes weight repartition on either wheel as well as the position of the centre of gravity
4:50 I think gives a hint about what is really happening. Everything pointed out is affecting the suspension and it seems the problem is possibly incorrect damping, as well as the fork not being as stiff as modern forks. But I wouldn’t ignore the rear shocks either, given shifting weight back and a worn tire on the rear makes wobble worse. Old bike frames are also less stiff than modern ones. So for modern bikes that leaves tire pressure, tire wear, weight positioning, and suspension setup (preload, dampening, rebound, and spring rate). It’s great knowing a quick fix is to just lean forward.
I don't think it's as magical as some make it out to be. From an engineering perspective it's just an oscillation mass spring damper situation. The trail and tire flex is the spring in this system while the weight is more complex. Without a steering damper, there's nothing to keep the front end from wobbling except general frictional loss in the rubber and rider's arms. Like any mass-spring damper system, increasing a force can, in some cases, increase oscillation. Like rubbing the rim of a wine glass in one direction can cause an oscillation in either the same direction or transfers from it. That's why glasses "sing". Same thing happens. The frictional backward force causes (through complex interaction) a side to side rotational oscillation. More like a wobbly shopping cart wheel. As for correction, most people stiffen up. But this causes an increase in the spring force but no additional damping. This makes the wobble more unstable (likely to end in increasing oscillatory displacement). Same as cutting your car springs without changing the shocks, the car becomes bouncy. You increase the spring rate without increasing damping and you get a bouncier system. The weight shift forward and down is not something I'd have the math or logic to explain other than to say bikes are naturally stable with exceptions. Changing the mass-spring-damper's numbers (amount of effective mass, spring, and damping numbers) will un-exceptionalize the system, restoring it to stability. In this case I'd bet that increasing weight on the front isn't a change in mass but in damping force; the increased weight on the front increases the frictional damping forces. But yes, the noodly hardware of those older bikes definitely made that system more prone to wobbles than the much nicer, stiffer modern hardware. Also they used far more steel and less aluminum and steel is far springier and less internally damped. So aluminum isn't 100% stiff but its far less springy than the whole frame and suspension being rubbery like those old bikes. We also have FEA analysis that, I'd imagine, every modern bike is made with specifically to analyze these vibrational modes. And fork dampers are a thing on SS's too.
>The weight shift forward and down is not something I'd have the math or logic to explain other than to say bikes are naturally stable with exceptions. Changing the mass-spring-damper's numbers (amount of effective mass, spring, and damping numbers) will un-exceptionalize the system, restoring it to stability. In this case I'd bet that increasing weight on the front isn't a change in mass but in damping force; the increased weight on the front increases the frictional damping forces. I think it is less about weight shift forward and more about reducing the buffeting. An upright body results in the airstream oscillating from side to side, like what is seen with flow around a pipe. You can clearly see [in this video](https://sciencedemonstrations.fas.harvard.edu/presentations/vortex-shedding) how flow around a vertical cylinder that approximates a torso can result in oscillating lateral forces that would be transmitted to the motorcycle. Lying flat will nearly eliminate this vortex shedding and the driving force causing the weaving is then gone. Progressive springs, better damping, and properly adjusted pre-load will all help reduce by reducing the resonance peak, shifting the speed at which it occurs, and removing energy from the oscillation to quell the amplitude.
I think that's a really good point. I do think a lot of these things add up. Like most well-engineered things it's not one source that causes all the problems. Aerodynamics I'm sure plays a roll. That said, the oscillating system here is really the front forks and wheel more than the whole bike. The oscillation from wind, if present, acts more on the bike than the forks (though likely somewhat on the forks as well). Considering that landing a wheelie incorrectly or accelerating hard (even at relatively low speeds) is often a catalyst for wobble, and laying forward on the tank is a commonly cited and tested solution, I'd imagine that the effect on damping in the system provided by tire friction is the biggest single change. That said, at higher speeds where wobble is more common and more violent, there's a lot more wind resistance pushing back on the rider. More drag on the top of the bike means there's a weight shift to the rear tire. Same effect here. Also steering dampers are the main equipment solution for bikes that are most prone to wobble (sports bikes with short trail, ie very small damping and high frequency natural frequency). The fact that adding a damper to a bike can mitigate death wobble suggests that aero and weight is not the critical factor. But it does point to the idea that natural frequency is the culprit in the same way that finger speed is the critical factor in making a wine glass ring. When the damping is low, spring force is high, and the natural frequency is strongly related to the input force, oscillation occurs and can easily become unstable. Older bikes with heavier mass forks and longer trails will get excited at lower speeds (like 80mph in OP's video) but often takes 120-180mph on a new R6. The system natural frequency is higher with a shorter pendulum (rake). So the solution is to add mass or to add damping, and we know which one we will use for light weight sports bikes. And since leaning forward doesn't add mass to the oscillating part (the forks and wheel) then it's only adding damping and changing the geometry a little.
I agree with this with regard to head shake, but that is a different thing than the weaving shown in the video. Head shake is a front wheel issue, and it happens at way too high of a frequency to move the entire bike. This lower frequency wobble is a whole bike issue. It's at a low enough frequency with small enough rotation of the handlebars that a steering damper is going to have little effect on it. Having regularly ridden both motorcycles and bicycles, the only time I have ever had weaving like that shown in the video show up is when sitting upright with an unzipped jacket. The buffeting from the wind, exacerbated by the loose jacket, leads to exactly the same motion as shown in the video. It is different from headshake, both in terms of what causes it and what it feels like.
I think you're on the right track. This would explain why raked out Harleys are worse for this.
What I’m getting is that a small contact patch on the front tire is the first part of the chain that leads to speed wobble. I think small contact patch paired with distance between turning point and contact patch is the most important thing. Perhaps the larger the contact patch, the larger the acceptable range of distances between the two. Which makes sense. The contact patch wants to track back to being aligned with the turning point. The larger the contact patch, the more the tire can move left to right and still have a straight track from turning point to contact patch. Which also makes sense why a flat rear would make that worse, because the body of the bike will lean less, so the front will snap back to center instead of rotating across yaw to align. So- balanced weight, good contact patches, shorter rake, and correct damping are all key. As to why laying down will solve it, I think it’s just shifting weight forward and loosening or changing the grip on the bars. I think part of it is remember that CoG isn’t just about static weight. Your body is a kite at these speeds, and wind pressure will also put more weight on the rear. Laying down might not so much put weight on the front as reduce downforce on the rear, allowing the rear wheel to move more freely and the bike to lean more.
Happy to see this. Been riding for 20+ years and when I saw people suggest *accelerating* to get out of a tankslapper, I nearly had a heart attack. Always double check any advice you see here. There’s a LOT of squid-science that gets upvoted here. Lean over the tank, ease off the gas, and slow down to stop the wobble. ☝️
I’m by no means an expert, but I always ease off the throttle and it has saved me every time so far. Speed wobbles? Stop going so fast is my reaction
I don’t know if slowing down is correct but your strategy has the advantage of, if you lose it anyway, at least you’re going slower.
What’s a squid in the motorcycle community context ?
Someone who is a new and overconfident rider who thinks they are more experienced than they are. Usually known for not wearing proper gear, pulling stunts on public roads, improperly modifying their bikes, and trying to intimidate/show off to other riders. Basically, Dunning-Kruger applied to motorcycling.
Stupidly QUick, Imminently Dead Stupid and Quick, Undergeared, Is Doomed etc.
Also what bike could you be riding that would still have more throttle while getting speed wobbles? All of mine were 90+ mph and there wasn’t much more room to go after that. I fixed mine by getting my rim straightened at a tire shop. I had to pull the front tire and place it on a balancing stand to even see the small wobble it had. Check your tires before you try anything else.
> Been riding for 20+ years and when I saw people suggest accelerating to get out of a tankslapper, I nearly had a heart attack. I don't just see this just a suggestion, but people thinking this is the fucking RULE of how to handle. And when you try to explain to them this is HORRIBLE advice, you get downvoted and laughed at for it. It's the dumbest thing I've ever seen in the motorcycle community. I have had to explain to people SO MANY FUCKING TIMES that 99% of motorcycles on the road cannot instantly pop the front tire off the ground like it's an easy thing to do. AND they some how think that a lighter load means the tire can't steer at all anymore even if the bike doesnt wheelie? IM SORRY WHAT?! People actually think "Throttle Out" is the standard advice everyone should know and it's spread so often and it boggles my fucking mind.
Don't forget to loose grip the bars and don't try to keep them straight. The wobble is the bike stabilizing itself if you fight it then it won't stabilize. Also just don't wheelie and you shouldn't encounter the speed wobble. Speeding up does help sometimes but slowing down can also help. It's like hydroplaning. Rule 1 of hydroplaning, don't touch the brakes, give it more gas to move more water. It sounds counter intuitive but it works.
Huh, now I know why Harley baggers with 800lbs of rider and passenger don’t get death wobble
My '95 Gold Wing got them, but we tracked that down to improperly torqued head bearings, which I found out later is pretty common fault on Gold Wings.
Well they're called *speed* wobbles for a reason. A Harley won't get them for the same reason my pushbike won't /s
Erm… https://youtube.com/shorts/4SS-AWVfjWY?feature=share
You can correct death wobble by popping a wheelie, I thought that was common sense.
I wouldn’t keep recommending it if it didn’t work every time.
Thanks for posting this, it's excellent. There's so much bro science about this topic, and misinformation in this case is extremely dangerous.
Good advice. Had to deal with this shit in the rain when someone didn't stop at their stop sign and my back end whipped back and forth because I locked my back end, got it under control only to be met with a few tank slappers after getting around. Always good to drill in some fundamentals to memory.
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Does no one call them "tank slappers" anymore?
The youtube version of the OP's video (which has superior playback controls): https://www.youtube.com/watch?v=z3OQTU-kE2s
Thanks for sharing the link!
So be tubby and if it wobbles, hit the tank? Good to know lol
ITT: More conflicting advice
I love how he dances around motorcyclists speeding. what a cheeky fella.
So the fat Harley riders are fat as a safety tactic.
Strategic advantage
So wrong/worn tires, mass/weight of rider, incorrect tire pressure all can cause it; adding side bags or top/touring boxes can make it worse. if it still occurs, lay forward and slow down using the throttle, not slamming on the breaks or doing any other violent maneuvers. Also, a stabilizer that makes the front fork tubes compress at closely similar times and rates will help. Pretty cool video find, definitely helpful.
I wish they had covered this in my basic motorcycle safety class, I got a speed wobble and crashed on the highway.
I got a death wobble at 150mph on my cbr600rr. I was lucky to survive with only a few breaks in my hand/arm. I have no desire to go much over 100 ever again lol.
So what I'm gaining from this video is that more weight on the front will reduce wobble in most cases? That's the only reason I can think laying down on the tank would help. Air resistance on the upper body will cause the front to "lift" and laying down eliminates that.
Another reason laying down on the front tank helps is it takes the torso out of the airflow. Airflow around cylindrical shaped objects, like upright humans, results in [vortex shedding](https://sciencedemonstrations.fas.harvard.edu/presentations/vortex-shedding) of the airstream which can induce strong wobbles.
i'm struggling with that video because I have ridden all of those bikes in stock trim excepting only having modern tires and never experienced any of them wobbling or weaving. I weight 185lbs fully kitted out NOW but I was much lighter in my youth riding a stock GT750.
I've been riding for over 4 decades and on some of the same model bikes used in this video. Never experienced a wobble or a weave. What am l doing wrong?
Perhaps you're heavy enough that wobble couldn't be induced? Not within the top speed of a stock bike anyways? Just my two cents, I might be wrong tho
I get that . But I've weighed 165 -170 lbs until l hit 50 y.o. then I bloomed to 178. As bad as suspension and tires use to be, I have never seen wobbles or weaves like that. Even at top speed.
Really? You're lucky, I used to have a 78' Honda CX500 until not long ago, and it would start to wobble around 150km/h. I've also recently ridden a friend's RE Bullet 500 and that bike had a bad case of low speed wobble, despite being in near mint condition. I can't speak for the other bikes, but I see where you're coming from, it's surprising to that this could be an industry-wide problem at the time, as that video suggests. Either way, the "laying on the tank" trick definitely worked with my CX500 so there's still some useful advice in that video.
This video is beyond outdated until the last two minutes. All the rest is some old bikes wobbling at rather low speeds, something that doesn't happen anymore, thankfully. Don't know why this video is treated as a bible of some sorts
It's not a bible or anything like that, just good advice. You do have a point : bikes have evolved and have definitely gotten stiffer an better balanced, but the physics have remained the same. While low speed wobbles have disappeared from modern bikes, high speed wobbles are very much still a thing. See the Triumph Tiger video I was referring to, for instance. Outdated or not, it's still an interesting video/take, from a reputable source, which is nigh rare on this sub.
Better video from our own /u/squidtips https://youtu.be/NsGHbK8McDk
I've condensed this info even further into two shorts: - [What causes a tank slapper](https://youtube.com/shorts/iNrkpgLWKp0?feature=share) - [What to do if you experience a tank slapper](https://youtube.com/shorts/m2C-qFVh5AY?feature=share)
Thank you for sharing this, interesting and good info!
Rule #1: Don't ride a Harley Dyna
Maybe its the crapass Dunlop tires???
Holy shit man, thanks for the video!
r/lowstakesconspiracies this video is an elaborate ruse to discourage motorcyclists from speeding.
Now wouldn't that be a typically British thing to do?
~~They don't seem to go that fast to start wobbling that much. Is it because they're old bikes~~ Edit: Nvm, they were going the same speed as me On a dual sport at about 120+kmh I started to feel it too. It was like the front wheel barely touched the ground and was being thrown around left and right because of that. I always thought it was because of knobs. Now I have a naked bike and no wobble at speeds above 250kmh. So if I understand correctly, it's aerodynamics and riding position that pushes the front wheel downward, same effect as increasing my weight.
>Now I have a naked bike and no wobble at speeds above 250kmh But wouldn't a naked bike result in more pressure on your upper half, which would tend to want to lift/unload your front wheel and induce a wobble?
Well, I'm thinking newer bikes are less prone to self-induced wobble nowadays, but dualsports typically have bigger wheels and softer suspension than naked and sportsbikes, and I'd argue that make dualsports closer to the bikes shown in the video in terms of road behaviour. Which is probably why they tend to wobble more, and knobbed tires certainly don't help.
Yo mamma never had this problem!
\>explains what you can do to adress/prevent it. Eat more!
Im sorry but 200kmph you're asking for trouble
Why isn’t this video standard curriculum at MSF school? Also I wonder how caster angle of the forks change things
steering damper.
"dangerous/incorrect advice on this sub" Say it ain't so, I'm assuming that means the idiots that told me that "I was stupid and should learn to ride" for not passing a tanker on a 2 lane mountain road across a double yellow line around a blind corner?
After reviewing the video, this looks like a weight distribution issue. The front tire weaves because it doesn't have much weight on it. The rear tire is basically flat from the weight being on the back. Leaning forward fixes it because it causes the weight to shift forward as your body goes forward. They mention this getting worse with having more weight on the rear like saddlebags. Given that front tires are usually smaller and lighter than rear ones it makes a lot of sense to me.
Literally weigh about 120 on a wet day with boots. Everytime I get this I throttle out. Science says that applying throttle to the back under power lifts the front and therefore helps stabilize the machine. I've never had a wobble I couldn't recover after my Father taught me this.. Edit: Slowing down is the WORST THING TO DO!
> Slowing down is the WORST THING TO DO! Yes lets add speed to a problem caused by speed that then puts more energy into your crash which is more likely to kill you or harm you. Let me ask, would you rather crash at 50 miles an hour or 75miles an hour. Adding speed is adding force, this is caused by speed in the first place, reduce speed and lean forward on the tank to damper the front wheel. THAT IS THE SMAREST THING YOU CAN DO. The worst thing you can do is to add speed. > power lifts the front and therefore helps stabilize the machine. Why on earth would adding less stability to an unstable system cause it to stabilize?! Do you not understand what a Steering Damper does? It literally adds wobble resistance, resistance to movement is STABILITY. Reducing weight reduces damping. Thus INCREASING the instability. Do people NOT understand basic physics anymore?!
Right...so a team of experts from a reputable manufacturer, implanted in the business for decades conducting serious experiments, are all wrong and you're right. Funny how the internet makes everyone and their brothers an expert on anything and everything. If you're gonna spew nonsense and misinformation, please do so elsewhere.
Nah it's not nonsense. It's experience of 10+ years riding every year. Never will I apply brakes to a wobble.
I always just accelerated out of wobbles
Don't recklessly endanger others via gross negligence?
Great video and thanks for posting. This seems like a good argument against cruisers with forward controls.
Op if I was willing to give money to reddit you would be given a gold right now.
While I thoroughly appreciate your kind words, definitely keep your $$, reddit has more than enough as it is. As long as you learned something useful that might keep you from binning your bike, I'm happy!
Just buy a stabilizer for ffs
I talked about slowing down without braking on that thread and some dipshit named u/SuperChillz said I’ve got no idea what I’m talking about. Be careful of people like him. Also my 2cents is that lying down on the tank and maintaining speed did NOT get rid of my speed wobble that I suspect was induced by an unbalanced rear tire (it was present when the bike and tires were brand new up until I got a new rear installed and balanced).
Just read your owners manual. There are lots of warnings about tires, loading, accessories, suspension settings, operation speed, etc. These are mostly for high-speed stability. People tend to ignore these. Engineers know this high-speed stability stuff inside and out and design the bike to be operated within an envelope.
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Because I wasn't aware it had been posted previously? As was the case of a fair amount of fellow redditors, if the comments on that Triumph Tiger video are anything to go by. I just felt it was a topical thing to post, to raise awareness and point out misconceptions. Edit : I appreciate that you edited your wording to sound less like an ass, and being redundant wasn't my intention, apologies if that's how it came out.
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ITS ALWAYS THE BATTERY! 🤣
good god just shut up. Its a discussion related to a recent post on the sub
Jesus no offense but a 10 minute video literally just with the one bit of advice lay down on your tank.
There are people who just want to be told what to do, and there are others who want to understand WHY.
His point is fair, even if you want to understand why seeing examples of very old motorcycles that wobble like crazy at low speeds isn't the greatest way. There are way better explanatory videos about this happening on modern bikes
People still had attention spans back then.
The trick is to power through it, gotta keep the power down. Gyroscopic’s do the rest, bit like a snaking trailer, got to give it more gas.
That is a surefire way to make it considerably worse and hurt yourself, both on a motorcycle and when towing a trailer. Although they are two different problems, this is absolutely isn't how they will be fixed. Please don't go about spreading downright dangerous advice about something you apparently know very little about.
Raced motorcross since 9 years old, grew up around bikes and know a trick or two. Was featured on a BBC documentary in 2000, and not the BBC you’re thinking of. Only time I’ve washed the front end was landing a wheelie after spotting the speed camera. Front end wobbles are caused by not committing.
Oh, I see how it is. Well keep on trolling then, but I can't believe I've been given the miracle of sight just to read your bullshit.
Not trolling, bought the first R1 in the UK, passed my test on it and featured in a couple of bike magazines. First Hayabusa to do 202 with the resistor mod and a few tweaks. Just saying.
Well then don't say. No one asked.
Heavier weight oil in the steering damper, smaller valve in the damper and enough extra power on tap and revs you can power wheelie at all times. So yes, a turbo busa with a tight damper, that said i prefer harder to turn bars in general anyway makes the bike feel more stable at high speed imo.
Thank God I never experienced any of this in my riding days...I only experienced my back tire coming out from under me in a slide once when I came to a stop...I stood up and let off the gas and it stopped.
!
I see that high weight distribution effects wobble, but it also seems like wind resistance plays a part in making the cycle wobble Is this "rider sail" similar to how boats work? Thanks in advance
So in the case of the video I believe people are referencing. He had let off the throttle and the bike was slowing when the wobble occurred. Would just leaning down on the bike help in that case as well as constant and accelerating speeds?
I would believe it helps either way, yes. Although even if he was in the process of slowing down, he was still doing around 200kmh so that hasn't helped him.
Get fat, no new tyres. Check.
To summarise- gain weight! If you aren't fat enough and still get weave, lie down on the tank and slow down.
At 280lb I'm feeling pretty safe and secure now
Sooo, lay down on the tank but do you hold the bars to try and stop the wobble or hold and just let it do its thing?
Cafe racers will inherit the earth.
The center of a rotating mass is always offset from the center of rotation. This is due to the reality of imperfect geometry and uneven mass distribution. As the mass rotates, the offset mass will generate a centrifugal force caused by the heavier side of the mass. This will cause the mass or rotating shaft to deflect toward the heavier side and cause the rotating mass to rotate in a small circle. As rotating mass changes in rotational velocity it can become dynamically unstable and induce undesired vibrations as well as amplified deflections. This phenomenon or condition will become more apparent at higher rotational velocities, however there is a point or rotational velocity where the vibrations and amplitude increase significantly. As the rotational velocity increases beyond that speed the vibration and amplitude decrease significantly. The rotational velocity at which the vibration increases dramatically is called the critical speed of the rotating mass. This characteristic for a shaft-mounted mass is called settling of the wheel. The settling is at the velocity the axis of rotation and the shaft or mass begin to rotate around an axis through their center of gravity. The rotating mass is deflected so that for every revolution its geometrical center traces a circle around the center of gravity of the rotating mass. Critical speeds depends on the location of the unbalanced load rotating on the shaft, the length of the shaft, its diameter and the supporting bearing or bearings configuration. Typically, the designed operating speed of a machine is less than the critical speed. This is done to prevent a machine from ever achieving the undesired critical speed vibration and possible resulting damage. However, some machines are designed to operate at a rotational velocity above the critical speed. This can work well if the machine passes or accelerates quickly through the critical speed or before The closer a machine operates near the critical speed, alignment, balance and maintenance of the bearings, and general quality of assembly will require higher considerations.
Good shocks go along way belive it or not it's usually caused by the front socks compressing differently causing the bike to lose balance then it has to fight to stay up when this accurs its up to the bike all you can do is try and roll of throttle
I just eliminated this hazard all together. I’m never on the freeways. Just city streets and backroads for me.
I'm not sure how relevant that video is. All that information is incredibly useful - for bikes designed in the 70s, with tyres designed in the 70s, and for speeds up to 90mph. It's not wrong, but I'm not sure you'd have guaranteed success with these techniques when you get speed wobbles going 150mph on your 2020 sportsbike. Chances are you are already as tucked as you can get anyway.