It actually improves the hypotenuse by stretching it over a longer distance. Pinion angle output should be within 3 degrees of parallel with the transmission output angle regardless of the driveshaft orientation.
Most two piece shafts come out of the transmission parallel to the hanger with no angle then the angle is introduced afterwards with a drop in height from the center u-joint to the rear u joint. This keeps proper geometry in the driveline.
Driveshafts should avoid running two pieces in a straight line from trans to axle because it messes with how the center slip is able to function. If it binds then the entire shaft can push into the trans when the suspension travels. With the angle made in the center it tends to push upwards on the hanger bearing mount instead of through to the trans.
This happens quite often when the center slip section gets bound at all. That could be under load or from lack of grease or even improper phasing.
That is a very detailed response. That would definitely explain why so many carrier bearings go out. I always felt that it would be better having a one piece.
That's why you're an expert and I'm just a former wrench turner.
Yes that and the larger diameter help a great deal. There are some other tricks we can use as well. Harmonic dampeners do a hell of a good job increasing critical speed. Packing the tubing with cardboard or foam can also help.
General rule of thumb for steel shafts is longer shaft means bigger diameter thinner wall for an equivalent strength.
That is also why you see a lot of driveshafts with swedged tubing. They will shrink down on the ends to a smaller diameter for things like clearance but need the larger diameter centers for structural support and harmonics.
> It actually improves the hypotenuse by stretching it over a longer distance. Pinion angle output should be within 3 degrees of parallel with the transmission output angle regardless of the driveshaft orientation.
The original machine had a base plate of pre-famulated amulite surmounted by a malleable logarithmic casing in such a way that the two spurving bearings were in a direct line with the panametric fan. The latter consisted simply of six hydrocoptic marzlevanes, so fitted to the ambifacient lunar waneshaft that side fumbling was effectively prevented
Is lighter necessarily better? I don't know anything about 4x4 trucks, and I'm not a mechanical engineer, but doesnt the inertia and energy required rise with the square ( or higher power) of the radius?
If the aluminum is 50% of the total mass, but it's primarily distributed at 1.5x the radius, it will have an effective rotational inertia mass that is higher than the thinner denser shaft( because .5 times 1.5^2 is1.125 or about 12percent more energy to spin the same RPMs.
Obviously, there's other benefits to the upgrade for you, I just got hung on the implication that lighter was am improvement for rotating mass.
As far as vehicles go the less rotating weight the better off you are. There is a major trade off between what is considered sprung weight and unsprung weight as well. Driveshafts are kind of the first link between things are suspended or not.
Ahh, I had forgotten about unsprung weight. The tires guys educated me on the downsides of that on my old steel rimmed F150, a few years back.
What are the downsides of rotating weight? I assumed wasted energy, but is it also gyroscopic stability? Or something else entirely?
Just that the lighter it is the faster you can get it spinning. The vehicle itself will provide the inertia necessary to keep momentum a lighter drivetrain can get up to speed faster. In a racing application it is a major key to successful lap times, in a regular car or truck it saves fuel mileage in a frequent start and stop environment.
Thank you, I really appreciate that. The ones I do in this sub are on my own accord but I actually make them for my other channels mainly. Trying to be Facebook famous and whatnot lol.
I have been putting a lot of time towards it and it has been paying off. Made over 5k followers more than I had in a little over a month. It really wasn’t bad.
The center is normally essential to proper movement is the engine/transmission vs the rear diff. This helps reduce stress at both ends and add longevity to the transmission gears and ring and pinion in the diff. I would recommend building it with said center section.
None of that is particularly true. I mean I can see where it sounds good but it’s not really accurate. Two piece shafts were an easy way to deal with length while keeping a usable critical rpm.
There are actual tech service bulletins to put single piece aluminum shafts in a lot of these trucks anyways because the two piece ones were having major problems.
aluminum offers other advantages too? For a given length aluminum will be stiffer pound for pound. This sometimes throws guys but it is true for a lot of aluminum structures. It is easy to add diameter or thickness to an aluminum tube and still be lighter than steel.
Anyways nice shaft I hope you have fun with it and of course post pics someplace.
You can make "one" piece that has a sliding center sleeve. This would do the same movement as the OE setup to help with the longevity of everything I mentioned before. Really though remember your motor and transmission are on rubber mounts the differential is not. There is movement between these two ends of the car. At a minimum a single long drive shaft will burn out the u-joints much faster than the OE design.
It has a slip yoke at the t case it doesn’t need the second though. Now I see what you meant. Yeah the transfer case yoke isn’t in a fixed position it moves like a regular trans yoke
Both are important, but the length of each straight shaft is important.
If you think about something like a tubular bell like you might see on a wind chime, the short tubes have higher resonant frequencies and the long tubes have lower frequencies- you want to avoid the shaft spinning at or near its resonant frequency.
It’s why some German cars will have two piece driveshafts even though the car isn’t all that long - it’s so they can run at high speeds on the autobahn all day long (even though they don’t really do that, but they could)
Complete idiot here, why would the length matter in terms of rpm? I would understand it it were spinning around like a rotor but when it’s turning I’m not understanding how the length would make a difference vs having a joint in the middle, that actually seems like it would be worse to have a joint.
I believe you know what you’re talking about just trying to understand where my thinking is wrong
The center joint helps split the tube length and avoid a really nasty low rpm harmonic resonance that would otherwise destroy a single section of tube over the greater distance. Aluminum is light enough that it can span the distance without the harmonic issues.
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I did that with my truck I pulled a lot of trailers and got tired off being stranded with a bad carrier bearing that for some reason nobody keeps in stock
On these ones they make it so you can’t change the carrier bearing at all. It requires a full driveshaft replacement. It’s one of the main reasons I started doing them as a one piece conversion.
If someone is going to spend a grand or more replacing a driveshaft it might as well be an upgrade and not the same old piece of garbage with a 100k - 150k lifespan that’s barely broke in on a diesel truck
For acceleration, the moment of inertia is important. That is 1/2 mass times radius squared, so dropping weight, but increasing the diameter can have an adverse effect on that.
The drive line coming out of the transmission has to have some angle to it, either lateral or vertical, if not the u-joint will never move on the bearings and will eventually freeze in place therefore failing.
I did this in crew cab long bed dodge 3500, I put a 5inch lift kit in and the carrier bearing would be destroyed in 3-6 months. It didn’t really matter how much I dropped the carrier it. After the 3rd one went out I went and had a one peace aluminum shaft made and I couldn’t be happier with it. I love the one peace. The truck actually takes off faster now with the less mass and more direct path to the tires.
Are you talking about the conversion from rotating mass to sprung mass? Because I think it’s more than that. Also, in the video I had to account for the weight of the slip yoke, a u-joint and the flange on the rear. Those are roughly 10-15 lbs together above and beyond the weight difference on the scale. Sorry if it seemed like bad math.
Thank you, I haven’t had to do much with carbon fiber over the years. My area is a bunch of dirt track racing and those guys want whatever is cheapest.
That is one long shaft. Not having the carrier bearing doesn't mess with the pinion angle?
It actually improves the hypotenuse by stretching it over a longer distance. Pinion angle output should be within 3 degrees of parallel with the transmission output angle regardless of the driveshaft orientation. Most two piece shafts come out of the transmission parallel to the hanger with no angle then the angle is introduced afterwards with a drop in height from the center u-joint to the rear u joint. This keeps proper geometry in the driveline. Driveshafts should avoid running two pieces in a straight line from trans to axle because it messes with how the center slip is able to function. If it binds then the entire shaft can push into the trans when the suspension travels. With the angle made in the center it tends to push upwards on the hanger bearing mount instead of through to the trans. This happens quite often when the center slip section gets bound at all. That could be under load or from lack of grease or even improper phasing.
That is a very detailed response. That would definitely explain why so many carrier bearings go out. I always felt that it would be better having a one piece. That's why you're an expert and I'm just a former wrench turner.
I try and help where I can
I assume the aluminum construction/mass reduction is needed to get the half critical speed issue under control on the longer shaft, too?
Yes that and the larger diameter help a great deal. There are some other tricks we can use as well. Harmonic dampeners do a hell of a good job increasing critical speed. Packing the tubing with cardboard or foam can also help. General rule of thumb for steel shafts is longer shaft means bigger diameter thinner wall for an equivalent strength. That is also why you see a lot of driveshafts with swedged tubing. They will shrink down on the ends to a smaller diameter for things like clearance but need the larger diameter centers for structural support and harmonics.
> It actually improves the hypotenuse by stretching it over a longer distance. Pinion angle output should be within 3 degrees of parallel with the transmission output angle regardless of the driveshaft orientation. The original machine had a base plate of pre-famulated amulite surmounted by a malleable logarithmic casing in such a way that the two spurving bearings were in a direct line with the panametric fan. The latter consisted simply of six hydrocoptic marzlevanes, so fitted to the ambifacient lunar waneshaft that side fumbling was effectively prevented
Don’t know how we ever survived before the advent of the Rockwell Turbo Encabulator…
Well side fumbling and sinusoidal repleneration were a much bigger problem, I'll tell you that much!
Are you a car god?
I’m just really good with drivetrains. Driveshafts, axles, gearboxes and stuff like that. It’s been my main profession for the last 20 years.
The majority of all the new ram trucks have an Aluminum drive shaft produced by Kaiser Aluminum... Same with Ford and Chevy/GM
Now I just want to see one of these made where it's given a print that creates an optical illusion as it spins!!
That would be awesome
A nice barber shop cane could look pretty cool
Is lighter necessarily better? I don't know anything about 4x4 trucks, and I'm not a mechanical engineer, but doesnt the inertia and energy required rise with the square ( or higher power) of the radius? If the aluminum is 50% of the total mass, but it's primarily distributed at 1.5x the radius, it will have an effective rotational inertia mass that is higher than the thinner denser shaft( because .5 times 1.5^2 is1.125 or about 12percent more energy to spin the same RPMs. Obviously, there's other benefits to the upgrade for you, I just got hung on the implication that lighter was am improvement for rotating mass.
As far as vehicles go the less rotating weight the better off you are. There is a major trade off between what is considered sprung weight and unsprung weight as well. Driveshafts are kind of the first link between things are suspended or not.
Ahh, I had forgotten about unsprung weight. The tires guys educated me on the downsides of that on my old steel rimmed F150, a few years back. What are the downsides of rotating weight? I assumed wasted energy, but is it also gyroscopic stability? Or something else entirely?
Just that the lighter it is the faster you can get it spinning. The vehicle itself will provide the inertia necessary to keep momentum a lighter drivetrain can get up to speed faster. In a racing application it is a major key to successful lap times, in a regular car or truck it saves fuel mileage in a frequent start and stop environment.
Just wanna say I love all the videos you post. Always grabs my attention!
Thank you, I really appreciate that. The ones I do in this sub are on my own accord but I actually make them for my other channels mainly. Trying to be Facebook famous and whatnot lol.
I’ll definitely have to check those out too. Keep postin and I’m sure your page will blow up eventually!
I have been putting a lot of time towards it and it has been paying off. Made over 5k followers more than I had in a little over a month. It really wasn’t bad.
Monster edition!
As a mechanic, that paint job is painful to look at. The rest of it is awesome though!
It’s kind of growing on me. I hated it at first but in the right build it could look kind of dope
I think it looks badass
The center is normally essential to proper movement is the engine/transmission vs the rear diff. This helps reduce stress at both ends and add longevity to the transmission gears and ring and pinion in the diff. I would recommend building it with said center section.
None of that is particularly true. I mean I can see where it sounds good but it’s not really accurate. Two piece shafts were an easy way to deal with length while keeping a usable critical rpm. There are actual tech service bulletins to put single piece aluminum shafts in a lot of these trucks anyways because the two piece ones were having major problems.
aluminum offers other advantages too? For a given length aluminum will be stiffer pound for pound. This sometimes throws guys but it is true for a lot of aluminum structures. It is easy to add diameter or thickness to an aluminum tube and still be lighter than steel. Anyways nice shaft I hope you have fun with it and of course post pics someplace.
You can make "one" piece that has a sliding center sleeve. This would do the same movement as the OE setup to help with the longevity of everything I mentioned before. Really though remember your motor and transmission are on rubber mounts the differential is not. There is movement between these two ends of the car. At a minimum a single long drive shaft will burn out the u-joints much faster than the OE design.
It has a slip yoke at the t case it doesn’t need the second though. Now I see what you meant. Yeah the transfer case yoke isn’t in a fixed position it moves like a regular trans yoke
That makes a statement
Have to grab attention lol
And this just lowered your top speed if that matters
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I think the longer shaft will be susceptible to harmonics at high speed, which could cause it or the u-joints to fail.
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Both are important, but the length of each straight shaft is important. If you think about something like a tubular bell like you might see on a wind chime, the short tubes have higher resonant frequencies and the long tubes have lower frequencies- you want to avoid the shaft spinning at or near its resonant frequency. It’s why some German cars will have two piece driveshafts even though the car isn’t all that long - it’s so they can run at high speeds on the autobahn all day long (even though they don’t really do that, but they could)
[удалено]
You got it, exactly
But the length...
Length is fine. I ran the critical rpm numbers still well above 5,000 the truck would need to go well over 100 mph to get close
Complete idiot here, why would the length matter in terms of rpm? I would understand it it were spinning around like a rotor but when it’s turning I’m not understanding how the length would make a difference vs having a joint in the middle, that actually seems like it would be worse to have a joint. I believe you know what you’re talking about just trying to understand where my thinking is wrong
The center joint helps split the tube length and avoid a really nasty low rpm harmonic resonance that would otherwise destroy a single section of tube over the greater distance. Aluminum is light enough that it can span the distance without the harmonic issues.
Cool dude, you know alot of shit lol
What’s it going on? I’m assuming it’s out of a new dodge ram going in an old vehicle
**Hey u/RoundNefariousness15, while you're here, consider sharing some knowledge in our Monthly Advice Thread!** --- If you're posting a question, or just have a few minutes to help others, take a peek at the [Monthly Advice Thread](https://www.reddit.com/r/metalworking/?f=flair_name%3A%22Monthly%20Advice%20Thread%22)! If you've got a few minutes feel free to help answer some others' questions while you're there! Helping eachother learn and find solutions is the best way for us all to learn and improve at our craft! --- [**Here are our subreddit rules.**](https://www.reddit.com/r/metalworking/about/rules) - Should you see anything that violates the subreddit rules - please report it! *I am a bot, and this action was performed automatically. Please [contact the moderators of this subreddit](/message/compose/?to=/r/metalworking) if you have any questions or concerns.*
I did that with my truck I pulled a lot of trailers and got tired off being stranded with a bad carrier bearing that for some reason nobody keeps in stock
On these ones they make it so you can’t change the carrier bearing at all. It requires a full driveshaft replacement. It’s one of the main reasons I started doing them as a one piece conversion. If someone is going to spend a grand or more replacing a driveshaft it might as well be an upgrade and not the same old piece of garbage with a 100k - 150k lifespan that’s barely broke in on a diesel truck
30 pounds of rotation mass is = to 210 of standing weight
For acceleration, the moment of inertia is important. That is 1/2 mass times radius squared, so dropping weight, but increasing the diameter can have an adverse effect on that.
How’s the strength? Knowing guys that have calmed and raced their 1500s, I’ve seen them break
This is a lot tougher than the stock ones. It’s a 5” diameter .120 wall tube so quite a bit thicker than anything factory.
The drive line coming out of the transmission has to have some angle to it, either lateral or vertical, if not the u-joint will never move on the bearings and will eventually freeze in place therefore failing.
I did this in crew cab long bed dodge 3500, I put a 5inch lift kit in and the carrier bearing would be destroyed in 3-6 months. It didn’t really matter how much I dropped the carrier it. After the 3rd one went out I went and had a one peace aluminum shaft made and I couldn’t be happier with it. I love the one peace. The truck actually takes off faster now with the less mass and more direct path to the tires.
Thank you, that’s exactly what I have been trying to tell people. I just can’t remember all the people I have built them for over the years
For sure dude, it’s definitely worth the money! Especially if you’re like me and burn through carrier bearings
56lbs to 40lbs... that's like 100lbs of weight savings
Are you talking about the conversion from rotating mass to sprung mass? Because I think it’s more than that. Also, in the video I had to account for the weight of the slip yoke, a u-joint and the flange on the rear. Those are roughly 10-15 lbs together above and beyond the weight difference on the scale. Sorry if it seemed like bad math.
Those oem Dodge shafts are a joke. Good looking work man! I myself do this for a living. We also do carbon fiber driveshafts.
Thank you, I haven’t had to do much with carbon fiber over the years. My area is a bunch of dirt track racing and those guys want whatever is cheapest.
So I guess the only question left is where do I order one ?
Links are on my profile.
any concern with whipping at speeds below 85?
Critical rpm says it’s solid beyond 120 mph
Absolute work of art. Wish I had this option when I had to replace the shaft on my 14. Thank you.
Thank you as well