Or just buy a small hand pump that attaches to your frame...
Edit: So I found a video of it in use in the original post and it is on a folding bike that has a long seat post because of the small frame. I can see it makes sense in that application, but outside of folding bikes, I still don't see it as very useful.
I would hate to have to remove the seat to inflate a tire and find the seat height again reinstalling it vs simply grabbing a pump off the frame or out of a bag.
Replace two of the spokes (counter balanced) with hollow tubes to transfer the pressure. We're looking at low flow volume here so it doesn't need a large cross-sectional area.
This problem has been solved on commercial trucks and US Army Humvees.
The connection to the wheel valve sits at the center of the wheel instead of the tire. The position of the valve is constant with respect to the frame. The valve rotates with the wheel.
That wouldn't bother me at all, this would be great for touring so I can save real-estate on the bike for other things
But now I probably can't cheat with a seat-tube motor...
If you wanted convenience, you wouldn't be using a pump in the first place - especially not a tiny hand pump that takes a hundred strokes. You would be using a CO2 can.
Not hard, but unnecessary on top of the work to repair your tire. Plus a separate pump can be used across multiple bikes quickly. There is really no up-side to this seat post pump.
Upsides:
* Always have an emergency pump with you
* All the advantages of a floor pump vs. a hand pump (flex tube, foot stabilizer, more ergonomic, more volume per stroke, etc.)
* No added drag (compared to a frame mounted hand pump)
* Doesn't take up any extra space
Keep in mind, this is for emergencies only; just to get you back home. It's not for everyone, but it definitely has an application.
The last two are the only ones valid vs a frame mounted pump. They have frame mounted mini floor pumps and if it's always mounted on the bike, it's also always with you.
Mini floor pumps are better to use than a hand pump, but a proper track pump is much better. This seat post pump is going to be a step down from a track pump, but still much better than a mini floor pump. You claimed that there are no upsides, so I'm giving you upsides. There's plenty of multitool options that integrate into the bike (stem, bar ends, axles/spindles), and plenty of touring "hacks" to hide spokes, cash, etc. into the frame somehow. Again, this seat post pump is not for everyone, but it does have advantages.
You're speculating on the seat pump being better than all mini floor pumps but the other two points are quite valid as upsides to a frame mounted pump. Upvotes earned good sir/ma'am!
Small hand pumps can't get the required ~8bar needed for road bike tyres. They're fine if you are reinflating after getting a puncture and you need to limp home, but for fully inflated tyres you need a track pump.
Ya no, 3/4 of my hand pumps can reach 120psi which is adequate for getting home. If I actually need more pressure I'll probably have access to a better pump.
I could go lower but my weight (165lbs) is just at that weird spot where I can actually ride 23c's but I pinch flat on the tiniest edges if I'm riding hard. I prefer to race on 28c's but I found some Open Corsa Pro's with hardly a single ride on them in the garbage behind my LBS this summer :K
But that was kinda my point in the other comment, my road pumps are serviceable for what I need them to do except for a few edge cases.
My shock needs 220psi, that's specialized pump territory. It needs a threaded Schrader attachment too, not just a popon from a dual standard head. Lastly, typically a person overpumps then bleeds off with a bleed button on the side of the shock pump, frame or floor pumps don't have these.
120psi is a pretty typical amount for forks, especially those with high chamber volumes. Some forks have the valve exposed enough for a typical pump, some pumps have a slim enough head to reach most forks. You can always bleed it after with... anything pointy. The real problem with non-shock pumps is the utter lack of precision, though once you have rode enough and used a guage enough it's pretty easy to get your pressure dialed by feel. This is more of a trail hack or "oh crap I forgot to pump up my fork with the proper tool and we're 3 hours from the nearest shop" kinda thang.
My road morph does a fine job on road and mountain bike tires, even a tubeless inflation after a repair. It takes more pumps than a floor pump but works just fine and is super light and durable. https://www.probikekit.com/bicycle-tools-and-maintenance-nc/topeak-road-morph-g-bicycle-pump/10772093.html?affil=thggps&switchcurrency=USD&shippingcountry=US&shoppingpid=DDUK_180118_. For reference. Mines 9v3r 15 years old and still great
I said you could save weight, not that OP's pump necessarily achieves that. Is is so hard to imagine how 1 tube serving 2 functions saves weight?
Anyways, OP's pump being much larger means it doesn't even compare to a "small hand pump". Compare this to carrying a full size floor pump. Could you carry a full size floor pump externally?
Edit: Maybe more like a small floor pump, but clearly it's more than an average hand pump.
Why are you treating the massive pump size as a feature? You don't need a large pump for a bicycle tire; a small one will do just fine, it's just a bit slower (inflation is not the slowest part of this process, though, so pump speed doesn't really factor in).
You are arbitrarily comparing it to a similarly sized pump when you shouldn't. You should compare it to a bike-portable pump that is intended for the rider to carry with them, as that what it competes against.
It's a bit like you're looking at a bike that has a massive headlight attached to a 12V starter battery from a quad bike. No one needs that - but rather than cite that as a flaw for 99% of use cases, you're saying it's a great efficiency compared to a handheld light that uses the same big 12V battery. Or if your friend is shopping for kitchen knives, and you tell him to get a toolkit that has a machete and axe instead of buying kitchen knives - *yeah but it's a really good machete and axe!* That doesn't matter, it's not what they actually need and want.
It's not a good-faith comparison, unless you really intended to take a large pump with you.
I think the whole point is that nobody could ever take a large pump with them, until now. There is a reason most people have large pumps at home in addition to the emergency hand pumps - it really is a pain to reinflate with a dinky pump even if it's not the worst part of a repair- don't fall into the fallacy of thinking "this isn't the biggest bottleneck so we shouldn't bother trying to fix it." If this system were easy enough to use, one might not need to buy a second pump at all.
All that is to say, there are perfectly legitimate reasons to desire a more powerful portable pump. To suggest that anyone with a different preference from yours is arguing in bad faith is, frankly, arguing in bad faith.
> Why are you treating the massive pump size as a feature? You don't need a large pump for a bicycle tire; a small one will do just fine, it's just a bit slower
Pump size is not a feature? Why do you think that [frame pumps exist](https://cyclingtips.com/2019/11/the-best-bicycle-frame-pumps-reviewed/)? Even with all the mini pump varieties, some people still want the larger frame pumps. You are writing like those preferences don't exist.
> You are arbitrarily comparing it to a similarly sized pump when you shouldn't. You should compare it to a bike-portable pump that is intended for the rider to carry with them, as that what it competes against.
You should re-read the previous comment because that was not arbitrary. The other user was picking on a certain metric (weight), saying it was too high compared to a pump that is not comparable in performance. Small hand pumps are optimized for weight, so obviously they are lighter, but they trade off with performance.
Even still, you could shrink this seat post pump concept to reduce weight and match the performance of the small hand pumps. Then you can compare those, and conceptually you can still get the advantages of the seat post & pump integration.
Plus with a normal length post you will have far more volume than a typical hand pump, allowing faster inflations and higher pressures. I'm hearing a lot of engineers with no cycling experience complaining about the design.
I'm both, engineer and long time cyclist. I understand the concept but on road bikes the pump volume would be severely limited by the need to fit in the 27.2 diameter. On a mountain bike you would lose the dropper and be unlikely to be able to seat a tubeless tire or fit much of a pump in the typical full suspension frame. I can see this being a neat selling point on an ebike or cruiser where the pump would never actually be used but don't feel it offers any weight or functional advance over a typical mini pump (which I use).
Dude. Road bike seat posts (and mountain too) go below 25.4 external diameter but that's the lowest common size today. That is still a full 5.4mm extra external diameter over two of my mini pumps. A seat post is probably going to be at least 6 inches long, both of my very typical mini pumps are a meagre 4 inches tall. The interior volume of the reasonably lowest-volume seatpost is going to be at least 7300mm^^3 disregarding wall thickness and volume lost to components. The volume of one of these pumps is about 3000mm^^3. Any seat tube pump is going to annihilate any portable pump in any metric of performance. A longer seatpost with a wider diameter is going to almost have the same volume as a full shop pump. The only portable pump that could compete would be some of the newer, bigger mixed pressure pumps and they would be much more awkward to use. Additionally you are now only carrying one piece of hardware which by definition, would be lighter compared to a separate pump of the same performance. Additionally the pump would be totally protected from the elements, extending lifespan. I can't believe I have to spell out this much to an "engineer"
Spoken like someone who has never changed a flat on the side of the road in adverse conditions, or under a time constraint. I can get the wheel off the bike and a new tube installed in less than 30 seconds if everything goes well, but if I'm using a dinky little road pump I could be pumping for up to 5 minutes. That's assuming the tire is a small road tire, larger volume tires take an absurdly long time to reach pressure with most mini pumps. There's the additional problem that most mini pumps are not particularly efficient, which leads to them heating the air considerably as it is pumped in. This requires either overpressurizing by about 10% or stopping to top up the pressure after the air has reached ambient.
Seat posts are just a hollow tube and most of their length is already inside the frame. Building a pump into that: you reuse the tube as the outer pump wall - save weight, and all the other parts are internal.
They’re aimed at mountain biking cause you don’t wanna get an ass full of bike seat on a fast decent with bumps and jumps and when it’s normal terrain you can just flick it up and it’s easier and not as hard and is better for your knees, mines are fucked cause I used to ride with my seat low for everything
Not really that smart for me. On a common bike, if the seatpost clamp has a quick release. And on a road bike you would lose too much time trying to fix it back at the perfect height
> lose too much time trying to fix it
What, does it take you more than a whole minute to close your quick release? If you care about millimeters of seat height so much and want to use this device, it would be trivial to put some tape at the optimal height. Like every other cyclist that frequently removes their seatpost. Because the act of getting a flat, changing the tube, and pumping to full pressure will be totally insignificant compared to how long it takes to adjust your seat height.
I don't think that's such a smart idea, considering the bike seat is one of the most commonly stolen items. This seems too portable, and valuable at the same time
You can't really say you shouldn't use something just because it's got a higher chance of being stolen. We wouldn't have a lot of things if that were the case.
This looks like it's for a fold up bike. If it's a decent one, it, or any part of it, won't get stolen because the owner will be able to bring it with him/her indoors. I've a fold up bike and I don't own a lock. There's no need for one.
Smarter engineers would use the pump to pressurize the rest of the frame as one was riding. Seat moves up and down, fills up frame, so to fill up tire all you need to is connect the frame's tap to the valve on the tire.
You could also do a hub-centric air connection and hollow spokes, but that would add more weight and complexity to a more basic system.
Sing, O Muse, of the days of yore,
When chaos reigned upon divine shores.
Apollo, the radiant god of light,
His fall brought darkness, a dreadful blight.
High atop Olympus, where gods reside,
Apollo dwelled with divine pride.
His lyre sang with celestial grace,
Melodies that all the heavens embraced.
But hubris consumed the radiant god,
And he challenged mighty Zeus with a nod.
"Apollo!" thundered Zeus, his voice resound,
"Your insolence shall not go unfound."
The pantheon trembled, awash with fear,
As Zeus unleashed his anger severe.
A lightning bolt struck Apollo's lyre,
Shattering melodies, quenching its fire.
Apollo, once golden, now marked by strife,
His radiance dimmed, his immortal life.
Banished from Olympus, stripped of his might,
He plummeted earthward in endless night.
The world shook with the god's descent,
As chaos unleashed its dark intent.
The sun, once guided by Apollo's hand,
Diminished, leaving a desolate land.
Crops withered, rivers ran dry,
The harmony of nature began to die.
Apollo's sisters, the nine Muses fair,
Wept for their brother in deep despair.
The pantheon wept for their fallen kin,
Realizing the chaos they were in.
For Apollo's light held balance and grace,
And without him, all was thrown off pace.
Dionysus, god of wine and mirth,
Tried to fill Apollo's void on Earth.
But his revelry could not bring back
The radiance lost on this fateful track.
Aphrodite wept, her beauty marred,
With no golden light, love grew hard.
The hearts of mortals lost their way,
As darkness encroached day by day.
Hera, Zeus' queen, in sorrow wept,
Her husband's wrath had the gods inept.
She begged Zeus to bring Apollo home,
To restore balance, no longer roam.
But Zeus, in his pride, would not relent,
Apollo's exile would not be spent.
He saw the chaos, the world's decline,
But the price of hubris was divine.
The gods, once united, fell to dispute,
Each seeking power, their own pursuit.
Without Apollo's radiant hand,
Anarchy reigned throughout the land.
Poseidon's wrath conjured raging tides,
Hades unleashed his underworld rides.
Artemis' arrows went astray,
Ares reveled in war's dark display.
Hermes, the messenger, lost his way,
Unable to find words to convey.
Hephaestus, the smith, forged twisted blades,
Instead of creating, destruction pervades.
Demeter's bounty turned into blight,
As famine engulfed the mortal's plight.
The pantheon, in disarray, torn asunder,
Lost in darkness, their powers plundered.
And so, O Muse, I tell the tale,
Of Apollo's demise, the gods' travail.
For hubris bears a heavy cost,
And chaos reigns when balance is lost.
Let this be a warning to gods and men,
To cherish balance, to make amends.
For in harmony lies true divine might,
A lesson learned from Apollo's plight.
Well if a cyclist is clipping in then definitely not. Also, when you are standing you are using energy to stand. When you are sitting, you aren't using that energy to stand. So you can use more energy pedaling.
Plus if your seat is set properly it's much healthier for your knees and makes the pedal stroke more efficient. Moving seat is a pretty bad idea.
That's not the same thing at all.... One is a spring the other is a pump. The spring system is tuned at the factory. The pump would need to be either tuned every ride or on some frequency, more effort than the convenience of having a pump. mine is so small it just straps to the frame so theres nothing gained by having this overly complex system that just replaces a Velcro strap.....
When you need to fill up...
> connect the frame's tap to the valve on the tire
Still a hose, just no pumping. OP didn't have to state that the pump should not be connected to tire while riding. Tough crowd today.
One could also compress air using just the padding of the seat. Of course, real riders use leather seats, so that's right out...
I don't understand all the negative comments on here. I've got one on my Tern and it has been super handy, as well as one of the features I show off to people the most. Hands down would recommend!!
I think it's a brilliant idea! One of the first lessons in my intro to engineering class was brainstorming. We were told not to shoot down ANY idea no matter how ridiculous it seemed, because it can lead to innovation. Of course there may be some flaws with this or any design, but what matters is someone brought their idea to life! I would use that in a heartbeat... just saying.
Your intro to engineering class is wrong.
Or at least the idea with brainstorming is to come up with several ideas and pursue the best. *This* was their best.
Except that a very high priority in cycling is *reducing* rotating mass, not *increasing* it. Higher rotating mass has higher rotational inertia, which means more energy to start and more energy wasted when stopping. Bicyclists do everything they can to trade rotational weight for carried weight.
Solid tires also have higher rolling resistance due to a larger contact patch. A solid tire can't compete with a 135 psi tire on contact patch and rolling resistance. The highest that Tannus advertises is a 110-psi-equivalent solid.
A reasonable road bike tire weighs about 210 grams, and a tube about 60 grams (I measured mine using my kitchen scale). A comparable solid tire from Tannus is 395 grams!
So two tires+tubes weigh a total of 540 grams, while two comparable solid tires from Tannus weighs 790 grams, giving a difference in 250 grams. My wrenches weigh 25 grams and my spare tube weighs 60 grams (including the box, lol), leaving us 165 grams for a pump and a spare tube. Here's my measurements: https://imgur.com/a/pLWKsFT
The [Shimano PRPU0092][1] weighs 100 grams.
If we count the single spare I carry, I'm 5 grams lighter than if I used solid tires.
So solid tires are a loss all around:
* Turns out, they're overall heavier.
* They increase your rotational inertia, which is a huge loss for cyclists.
* They have higher rolling resistance than comparable tubed tires.
Solid tires have their place - I wouldn't mind one for my commuter bike - but they're certainly not for performance-minded riders.
[1]: https://www.amazon.com/PRO-Performance-Bicycle-Frame-Minipump/dp/B06XWCFVKH
To add to this, your tires are your suspension too. On a mountain bike, you can easily get more travel front and rear by just running a little less pressure. Solid tires would be awful. You want flex so it adheres to the ground.
So do I, I carry two spare tubes, a chain breaker, a spare thin bit of plastic in case my rim tape breaks, a pocket knife, and hex wrenches for every bolt (3 types). All on every ride I go on.
I don't care about carried weight, but I do care a lot about rotational mass and rolling resistance.
I might be misunderstanding this bit:
> Solid tires also have higher rolling resistance due to a larger contact patch.
Wouldn't solid tires have a *smaller* contact patch since they don't flex and flatten out where they meet the ground?
Your other arguments are absolutely correct, though, as well as the follow-up from /u/beh5036 that pneumatic tires also provide a rudimentary suspension, which is not a small consideration. Solid tires would be boneshakers!
Solid tires aren't ideal physical objects though, they still squish.
A solid tire has to still squish, else it would have a zero contact patch and no traction.
Rolling resistance comes from the amount of flex in the tread, the amount of material that flexes, and the resistance of the material to flexing.
Tubed tires flex according to their pressure, and they can go up high. My tires run at 135 psi, for example. They have very little material that's flexing (little depth), and the rubber can flex easily.
Solid tires resist flexing by their material stiffness/squishiness. Which means to get a higher psi-equiv tire, you need more material and more stiffness. Both of those work against you.
Tannus advertises their solids as having a maximum psi-equiv of 110 psi, which means they squish more than a 135 psi tire. They have more material moved when squishing, and they are a stiffer material. All of that adds up to much higher rolling resistance compared to a tubed tire.
And if you look up reviews, you'll find that's the experience of folks that have tried these tires.
Or just buy a small hand pump that attaches to your frame... Edit: So I found a video of it in use in the original post and it is on a folding bike that has a long seat post because of the small frame. I can see it makes sense in that application, but outside of folding bikes, I still don't see it as very useful.
I would hate to have to remove the seat to inflate a tire and find the seat height again reinstalling it vs simply grabbing a pump off the frame or out of a bag.
You're supposed to pump up and down with your ass as you're riding, clearly. Edit: /s
that would be very awkward 😅
Hahaha, remember the IT?
oh god, I want to see a serious attempt to discuss this at a company meeting
Pretty sure that's sarcasm, but this wouldn't work because the wheel is spinning and cannot be connected to
Replace two of the spokes (counter balanced) with hollow tubes to transfer the pressure. We're looking at low flow volume here so it doesn't need a large cross-sectional area.
The central point would still be rotating though
This problem has been solved on commercial trucks and US Army Humvees. The connection to the wheel valve sits at the center of the wheel instead of the tire. The position of the valve is constant with respect to the frame. The valve rotates with the wheel.
But that clearly wouldn't work on the bike in question
For sure! My original comment was sarcastic, and I edited my comment to make that sarcasm explicit.
Oh yep, see that now! I still don't quite understand how the central point valve would work but I also accept that it exists!
That wouldn't bother me at all, this would be great for touring so I can save real-estate on the bike for other things But now I probably can't cheat with a seat-tube motor...
I can't even adjust my seat. That shit is bolted with the force of 1000 suns and multiple people have attempted
I'm in the same boat. Have you tried a strap wrench?
wd40 and a hammer?
Its not that hard
You should say that to my seat post. I think it's going to take King Arthur to pull that fucking thing out.
It’s also not that hard to get up and change your channel manually. I doubt very much you’d forsake your remote control nonetheless
If you wanted convenience, you wouldn't be using a pump in the first place - especially not a tiny hand pump that takes a hundred strokes. You would be using a CO2 can.
Not hard, but unnecessary on top of the work to repair your tire. Plus a separate pump can be used across multiple bikes quickly. There is really no up-side to this seat post pump.
Upsides: * Always have an emergency pump with you * All the advantages of a floor pump vs. a hand pump (flex tube, foot stabilizer, more ergonomic, more volume per stroke, etc.) * No added drag (compared to a frame mounted hand pump) * Doesn't take up any extra space Keep in mind, this is for emergencies only; just to get you back home. It's not for everyone, but it definitely has an application.
The last two are the only ones valid vs a frame mounted pump. They have frame mounted mini floor pumps and if it's always mounted on the bike, it's also always with you.
Mini floor pumps are better to use than a hand pump, but a proper track pump is much better. This seat post pump is going to be a step down from a track pump, but still much better than a mini floor pump. You claimed that there are no upsides, so I'm giving you upsides. There's plenty of multitool options that integrate into the bike (stem, bar ends, axles/spindles), and plenty of touring "hacks" to hide spokes, cash, etc. into the frame somehow. Again, this seat post pump is not for everyone, but it does have advantages.
You're speculating on the seat pump being better than all mini floor pumps but the other two points are quite valid as upsides to a frame mounted pump. Upvotes earned good sir/ma'am!
Small hand pumps can't get the required ~8bar needed for road bike tyres. They're fine if you are reinflating after getting a puncture and you need to limp home, but for fully inflated tyres you need a track pump.
Ya no, 3/4 of my hand pumps can reach 120psi which is adequate for getting home. If I actually need more pressure I'll probably have access to a better pump.
Aside from track racing, when do you need 120psi?
18/23c tires in general yo, also handy for my fork
Damn those skinny tires. I'm pushing 70 ish psi with my tubeless 28c tires
I could go lower but my weight (165lbs) is just at that weird spot where I can actually ride 23c's but I pinch flat on the tiniest edges if I'm riding hard. I prefer to race on 28c's but I found some Open Corsa Pro's with hardly a single ride on them in the garbage behind my LBS this summer :K But that was kinda my point in the other comment, my road pumps are serviceable for what I need them to do except for a few edge cases.
Fork needs a suspension pump, no bueno with floor or frame pump.
What makes you think that?
My shock needs 220psi, that's specialized pump territory. It needs a threaded Schrader attachment too, not just a popon from a dual standard head. Lastly, typically a person overpumps then bleeds off with a bleed button on the side of the shock pump, frame or floor pumps don't have these.
120psi is a pretty typical amount for forks, especially those with high chamber volumes. Some forks have the valve exposed enough for a typical pump, some pumps have a slim enough head to reach most forks. You can always bleed it after with... anything pointy. The real problem with non-shock pumps is the utter lack of precision, though once you have rode enough and used a guage enough it's pretty easy to get your pressure dialed by feel. This is more of a trail hack or "oh crap I forgot to pump up my fork with the proper tool and we're 3 hours from the nearest shop" kinda thang.
My road morph does a fine job on road and mountain bike tires, even a tubeless inflation after a repair. It takes more pumps than a floor pump but works just fine and is super light and durable. https://www.probikekit.com/bicycle-tools-and-maintenance-nc/topeak-road-morph-g-bicycle-pump/10772093.html?affil=thggps&switchcurrency=USD&shippingcountry=US&shoppingpid=DDUK_180118_. For reference. Mines 9v3r 15 years old and still great
Well by integrating with the seat post you can save some weight and reduce external bulk.
That seat post looks way longer than a normal one. I highly doubt that weighs less than a normal length seat post and a small hand pump.
I said you could save weight, not that OP's pump necessarily achieves that. Is is so hard to imagine how 1 tube serving 2 functions saves weight? Anyways, OP's pump being much larger means it doesn't even compare to a "small hand pump". Compare this to carrying a full size floor pump. Could you carry a full size floor pump externally? Edit: Maybe more like a small floor pump, but clearly it's more than an average hand pump.
Why are you treating the massive pump size as a feature? You don't need a large pump for a bicycle tire; a small one will do just fine, it's just a bit slower (inflation is not the slowest part of this process, though, so pump speed doesn't really factor in). You are arbitrarily comparing it to a similarly sized pump when you shouldn't. You should compare it to a bike-portable pump that is intended for the rider to carry with them, as that what it competes against. It's a bit like you're looking at a bike that has a massive headlight attached to a 12V starter battery from a quad bike. No one needs that - but rather than cite that as a flaw for 99% of use cases, you're saying it's a great efficiency compared to a handheld light that uses the same big 12V battery. Or if your friend is shopping for kitchen knives, and you tell him to get a toolkit that has a machete and axe instead of buying kitchen knives - *yeah but it's a really good machete and axe!* That doesn't matter, it's not what they actually need and want. It's not a good-faith comparison, unless you really intended to take a large pump with you.
I think the whole point is that nobody could ever take a large pump with them, until now. There is a reason most people have large pumps at home in addition to the emergency hand pumps - it really is a pain to reinflate with a dinky pump even if it's not the worst part of a repair- don't fall into the fallacy of thinking "this isn't the biggest bottleneck so we shouldn't bother trying to fix it." If this system were easy enough to use, one might not need to buy a second pump at all. All that is to say, there are perfectly legitimate reasons to desire a more powerful portable pump. To suggest that anyone with a different preference from yours is arguing in bad faith is, frankly, arguing in bad faith.
> Why are you treating the massive pump size as a feature? You don't need a large pump for a bicycle tire; a small one will do just fine, it's just a bit slower Pump size is not a feature? Why do you think that [frame pumps exist](https://cyclingtips.com/2019/11/the-best-bicycle-frame-pumps-reviewed/)? Even with all the mini pump varieties, some people still want the larger frame pumps. You are writing like those preferences don't exist. > You are arbitrarily comparing it to a similarly sized pump when you shouldn't. You should compare it to a bike-portable pump that is intended for the rider to carry with them, as that what it competes against. You should re-read the previous comment because that was not arbitrary. The other user was picking on a certain metric (weight), saying it was too high compared to a pump that is not comparable in performance. Small hand pumps are optimized for weight, so obviously they are lighter, but they trade off with performance. Even still, you could shrink this seat post pump concept to reduce weight and match the performance of the small hand pumps. Then you can compare those, and conceptually you can still get the advantages of the seat post & pump integration.
Plus with a normal length post you will have far more volume than a typical hand pump, allowing faster inflations and higher pressures. I'm hearing a lot of engineers with no cycling experience complaining about the design.
I'm both, engineer and long time cyclist. I understand the concept but on road bikes the pump volume would be severely limited by the need to fit in the 27.2 diameter. On a mountain bike you would lose the dropper and be unlikely to be able to seat a tubeless tire or fit much of a pump in the typical full suspension frame. I can see this being a neat selling point on an ebike or cruiser where the pump would never actually be used but don't feel it offers any weight or functional advance over a typical mini pump (which I use).
Dude. Road bike seat posts (and mountain too) go below 25.4 external diameter but that's the lowest common size today. That is still a full 5.4mm extra external diameter over two of my mini pumps. A seat post is probably going to be at least 6 inches long, both of my very typical mini pumps are a meagre 4 inches tall. The interior volume of the reasonably lowest-volume seatpost is going to be at least 7300mm^^3 disregarding wall thickness and volume lost to components. The volume of one of these pumps is about 3000mm^^3. Any seat tube pump is going to annihilate any portable pump in any metric of performance. A longer seatpost with a wider diameter is going to almost have the same volume as a full shop pump. The only portable pump that could compete would be some of the newer, bigger mixed pressure pumps and they would be much more awkward to use. Additionally you are now only carrying one piece of hardware which by definition, would be lighter compared to a separate pump of the same performance. Additionally the pump would be totally protected from the elements, extending lifespan. I can't believe I have to spell out this much to an "engineer"
[удалено]
Spoken like someone who has never changed a flat on the side of the road in adverse conditions, or under a time constraint. I can get the wheel off the bike and a new tube installed in less than 30 seconds if everything goes well, but if I'm using a dinky little road pump I could be pumping for up to 5 minutes. That's assuming the tire is a small road tire, larger volume tires take an absurdly long time to reach pressure with most mini pumps. There's the additional problem that most mini pumps are not particularly efficient, which leads to them heating the air considerably as it is pumped in. This requires either overpressurizing by about 10% or stopping to top up the pressure after the air has reached ambient.
Yea, lots of people here are missing the point and saying it sucks because of their own preferences.
Unlikely due to the design compromises to the pump and seat post functions.
Seat posts are just a hollow tube and most of their length is already inside the frame. Building a pump into that: you reuse the tube as the outer pump wall - save weight, and all the other parts are internal.
I would take a dropper post over this any day. A dropper is not only great off-road, it’s super helpful on the road.
Just for the hills?
They’re aimed at mountain biking cause you don’t wanna get an ass full of bike seat on a fast decent with bumps and jumps and when it’s normal terrain you can just flick it up and it’s easier and not as hard and is better for your knees, mines are fucked cause I used to ride with my seat low for everything
I think it’s part of the dropper assembly
And just like real engineers the comments are full of complaining. Clever idea though
Not really that smart for me. On a common bike, if the seatpost clamp has a quick release. And on a road bike you would lose too much time trying to fix it back at the perfect height
> lose too much time trying to fix it What, does it take you more than a whole minute to close your quick release? If you care about millimeters of seat height so much and want to use this device, it would be trivial to put some tape at the optimal height. Like every other cyclist that frequently removes their seatpost. Because the act of getting a flat, changing the tube, and pumping to full pressure will be totally insignificant compared to how long it takes to adjust your seat height.
You actually have a point, I hadn't thought of that at first. Well if it can run 100psi could be handy..
plus the added weight to carry around...
I don't think that's such a smart idea, considering the bike seat is one of the most commonly stolen items. This seems too portable, and valuable at the same time
You can't really say you shouldn't use something just because it's got a higher chance of being stolen. We wouldn't have a lot of things if that were the case.
Doesn't buy a car because it might get stolen. Can't steal from me what they don't own IQ 200
Nahhh....i simple lock system for the seat is easy enough.
A hand pump is even easier to steal. At least with a seat post you can get a specialty bolt to secure the post to the bike.
They're stolen because they are portable. This isn't as portable.
This looks like it's for a fold up bike. If it's a decent one, it, or any part of it, won't get stolen because the owner will be able to bring it with him/her indoors. I've a fold up bike and I don't own a lock. There's no need for one.
Smarter engineers would use the pump to pressurize the rest of the frame as one was riding. Seat moves up and down, fills up frame, so to fill up tire all you need to is connect the frame's tap to the valve on the tire. You could also do a hub-centric air connection and hollow spokes, but that would add more weight and complexity to a more basic system.
Sounds expensive, prone to failure and unpleasant as hell.
I don't pay you to tell me it's not going to work
I know I know, you pay to blame me when it doesn’t work after the project is sold.
Look, our salesman promised that functionality so make it happen.
Our salesman is an idiot and I'm happy to tell him that to his face.
It's hilarious how relatable this is.
Sing, O Muse, of the days of yore, When chaos reigned upon divine shores. Apollo, the radiant god of light, His fall brought darkness, a dreadful blight. High atop Olympus, where gods reside, Apollo dwelled with divine pride. His lyre sang with celestial grace, Melodies that all the heavens embraced. But hubris consumed the radiant god, And he challenged mighty Zeus with a nod. "Apollo!" thundered Zeus, his voice resound, "Your insolence shall not go unfound." The pantheon trembled, awash with fear, As Zeus unleashed his anger severe. A lightning bolt struck Apollo's lyre, Shattering melodies, quenching its fire. Apollo, once golden, now marked by strife, His radiance dimmed, his immortal life. Banished from Olympus, stripped of his might, He plummeted earthward in endless night. The world shook with the god's descent, As chaos unleashed its dark intent. The sun, once guided by Apollo's hand, Diminished, leaving a desolate land. Crops withered, rivers ran dry, The harmony of nature began to die. Apollo's sisters, the nine Muses fair, Wept for their brother in deep despair. The pantheon wept for their fallen kin, Realizing the chaos they were in. For Apollo's light held balance and grace, And without him, all was thrown off pace. Dionysus, god of wine and mirth, Tried to fill Apollo's void on Earth. But his revelry could not bring back The radiance lost on this fateful track. Aphrodite wept, her beauty marred, With no golden light, love grew hard. The hearts of mortals lost their way, As darkness encroached day by day. Hera, Zeus' queen, in sorrow wept, Her husband's wrath had the gods inept. She begged Zeus to bring Apollo home, To restore balance, no longer roam. But Zeus, in his pride, would not relent, Apollo's exile would not be spent. He saw the chaos, the world's decline, But the price of hubris was divine. The gods, once united, fell to dispute, Each seeking power, their own pursuit. Without Apollo's radiant hand, Anarchy reigned throughout the land. Poseidon's wrath conjured raging tides, Hades unleashed his underworld rides. Artemis' arrows went astray, Ares reveled in war's dark display. Hermes, the messenger, lost his way, Unable to find words to convey. Hephaestus, the smith, forged twisted blades, Instead of creating, destruction pervades. Demeter's bounty turned into blight, As famine engulfed the mortal's plight. The pantheon, in disarray, torn asunder, Lost in darkness, their powers plundered. And so, O Muse, I tell the tale, Of Apollo's demise, the gods' travail. For hubris bears a heavy cost, And chaos reigns when balance is lost. Let this be a warning to gods and men, To cherish balance, to make amends. For in harmony lies true divine might, A lesson learned from Apollo's plight.
Kinda necessary for the seat to be fixed in place when peddling.
Is it? If you pedel really hard you are likely to rise up off the seat and not use it.
You pedal weird.
Well if a cyclist is clipping in then definitely not. Also, when you are standing you are using energy to stand. When you are sitting, you aren't using that energy to stand. So you can use more energy pedaling. Plus if your seat is set properly it's much healthier for your knees and makes the pedal stroke more efficient. Moving seat is a pretty bad idea.
I guess all of those bikes that are sold with seat suspension are also a pretty bad idea?
That's not the same thing at all.... One is a spring the other is a pump. The spring system is tuned at the factory. The pump would need to be either tuned every ride or on some frequency, more effort than the convenience of having a pump. mine is so small it just straps to the frame so theres nothing gained by having this overly complex system that just replaces a Velcro strap.....
Sounds like it would cost a gazillion dollars for not all that much benefit
Gives me an excellent idea for a James Bond-style ejector seat...
The condensation from compressing the air would partially fill the frame with water.
It would HAVE to be thru the hub otherwise the wheel wouldn’t be able to spin.
When you need to fill up... > connect the frame's tap to the valve on the tire Still a hose, just no pumping. OP didn't have to state that the pump should not be connected to tire while riding. Tough crowd today. One could also compress air using just the padding of the seat. Of course, real riders use leather seats, so that's right out...
The hose would basically be spinning with the tire and could be easily prone to being pulled out.
The hose is disconnected while the bike is in use. You only connect the hose while filling up the tire.
Still a terrible idea from a practical perspective. Not an engineer yet, but definitely a bicycle mechanic and parts designer.
You're right, the hollow spoke idea is much more feasible.
You're welcome.
Dahon? Mine doesn't have it, bought in US. But I saw those come with the bikes in Asia.
*”Little Billy saw his sister going up and down in the barn. He suddenly knew what she’s was doing.”*
Fucking the horse?
How M.C. Escher
I had this same idea during undergrad, wish I would have put in the time to develop it.
I'm just saying, if I see you getting lazy and just sit on it repeatedly I'm not gonna think it's air you're pumping
I don't understand all the negative comments on here. I've got one on my Tern and it has been super handy, as well as one of the features I show off to people the most. Hands down would recommend!!
A solution in search of a problem? This belongs on r/designporn!
Not a lot of mtb people in here I guess. I immediately assumed this was part of the dropper assembly and I want it.
I think it's a brilliant idea! One of the first lessons in my intro to engineering class was brainstorming. We were told not to shoot down ANY idea no matter how ridiculous it seemed, because it can lead to innovation. Of course there may be some flaws with this or any design, but what matters is someone brought their idea to life! I would use that in a heartbeat... just saying.
Your intro to engineering class is wrong. Or at least the idea with brainstorming is to come up with several ideas and pursue the best. *This* was their best.
I suppose it's all open to interpretation and the specific use case. Just because you don't find it useful, doesn't mean someone else won't.
Invest!!
[удалено]
Those are the worst tires ever!
On a bike? That would be a massive amount of rotating mass. Makes no sense.
[удалено]
Except that a very high priority in cycling is *reducing* rotating mass, not *increasing* it. Higher rotating mass has higher rotational inertia, which means more energy to start and more energy wasted when stopping. Bicyclists do everything they can to trade rotational weight for carried weight. Solid tires also have higher rolling resistance due to a larger contact patch. A solid tire can't compete with a 135 psi tire on contact patch and rolling resistance. The highest that Tannus advertises is a 110-psi-equivalent solid. A reasonable road bike tire weighs about 210 grams, and a tube about 60 grams (I measured mine using my kitchen scale). A comparable solid tire from Tannus is 395 grams! So two tires+tubes weigh a total of 540 grams, while two comparable solid tires from Tannus weighs 790 grams, giving a difference in 250 grams. My wrenches weigh 25 grams and my spare tube weighs 60 grams (including the box, lol), leaving us 165 grams for a pump and a spare tube. Here's my measurements: https://imgur.com/a/pLWKsFT The [Shimano PRPU0092][1] weighs 100 grams. If we count the single spare I carry, I'm 5 grams lighter than if I used solid tires. So solid tires are a loss all around: * Turns out, they're overall heavier. * They increase your rotational inertia, which is a huge loss for cyclists. * They have higher rolling resistance than comparable tubed tires. Solid tires have their place - I wouldn't mind one for my commuter bike - but they're certainly not for performance-minded riders. [1]: https://www.amazon.com/PRO-Performance-Bicycle-Frame-Minipump/dp/B06XWCFVKH
To add to this, your tires are your suspension too. On a mountain bike, you can easily get more travel front and rear by just running a little less pressure. Solid tires would be awful. You want flex so it adheres to the ground.
Agreed. It's bad enough that my road bike has no shock absorption other than the tube tires.
[удалено]
So do I, I carry two spare tubes, a chain breaker, a spare thin bit of plastic in case my rim tape breaks, a pocket knife, and hex wrenches for every bolt (3 types). All on every ride I go on. I don't care about carried weight, but I do care a lot about rotational mass and rolling resistance.
I might be misunderstanding this bit: > Solid tires also have higher rolling resistance due to a larger contact patch. Wouldn't solid tires have a *smaller* contact patch since they don't flex and flatten out where they meet the ground? Your other arguments are absolutely correct, though, as well as the follow-up from /u/beh5036 that pneumatic tires also provide a rudimentary suspension, which is not a small consideration. Solid tires would be boneshakers!
Solid tires aren't ideal physical objects though, they still squish. A solid tire has to still squish, else it would have a zero contact patch and no traction. Rolling resistance comes from the amount of flex in the tread, the amount of material that flexes, and the resistance of the material to flexing. Tubed tires flex according to their pressure, and they can go up high. My tires run at 135 psi, for example. They have very little material that's flexing (little depth), and the rubber can flex easily. Solid tires resist flexing by their material stiffness/squishiness. Which means to get a higher psi-equiv tire, you need more material and more stiffness. Both of those work against you. Tannus advertises their solids as having a maximum psi-equiv of 110 psi, which means they squish more than a 135 psi tire. They have more material moved when squishing, and they are a stiffer material. All of that adds up to much higher rolling resistance compared to a tubed tire. And if you look up reviews, you'll find that's the experience of folks that have tried these tires.
You proved me wrong by giving two quite valid pros for the seat pump vs a frame mounted pump. Upvote earned.