Revolution USA Made Front Axle Shaft Installation

Chris said:
That would be interesting to hear. I know @toximus is running 37s whereas you and I are running 35s, so it would be interesting to see how your number differs from the 45° he came up with.
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Axle width, tire size and backspacing will play a role. The maximum achievable angle would be measured at ride height. From there, other interferences like the body and full tire stuff/steering lock would need to be reconciled.

I have future plans for mine that also might matter, but that's a discussion for the build thread. :)
 
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Chris said:
Okay, so there is some truth to this, it just depends on the build, right?

It would be interesting to test this out with my current TJ. How did you go about doing this test? Did you do it while cycling the suspension?
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If you can turn 35's with 4" backspaced rims until they hit the frame, lower control arms, and sway bar arms, do you need any more turning angle?

If you drop the back spacing to get more turning angle, are you willing to live with shit steering, 'cuz that's how you get shit steering.
 
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I am only curious. I had heard others say that RCVs don’t bind like regular axle shafts, but I don’t have enough experience with these things to know if that’s just bullshit or if it’s true.

I can’t imagine you would be using Revolution shafts with u-joints if that were the case, so I’ve essentially answered my own question. Just trying to learn however 👍
 
Chris said:
I am only curious. I had heard others say that RCVs don’t bind like regular axle shafts, but I don’t have enough experience with these things to know if that’s just bullshit or if it’s true.

I can’t imagine you would be using Revolution shafts with u-joints if that were the case, so I’ve essentially answered my own question. Just trying to learn however 👍
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Semantics. The CV part of RCV is constant velocity. The transfer of motion happens smoothly without the speeding up and slowing down that a u-joint has when operated at an angle.
 
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here's to hoping I never have to refer back to this thread for the procedure :ROFLMAO:, but I was curious as to what you did. After looking at the photos of the stock vs. superior vs. RGA shafts I went out to look at mine, I had never noticed the 'Foote' stamp on there & I couldn't find it. Came back in & checked my receipt & sure enough I paid for RGA 30 spline chromoly USA made shafts so I was starting to wonder if I got screwed... I do remember when I got the TJ back after installation noticing the U-joints & entire assembly that's visible looked much bulkier than stock but never looked any closer. Anyway I ended up squirting some simple green on there & rubbing the filth off & sure enough there it was:

Foote 2.jpg


that was a relief but the paranoia lingered so I measured the u-joint as best I could & they appear to be 3 & 5/8ths which is the 1350 width, but it looks like they use those for the 27 & 30 spline shafts so I tried to measure the shaft itself to confirm I have 30 spline shafts. I don't have any good way to measure the shaft so I spun a pair of vice grips until the teeth hit the shaft on opposing sides & adjusted it until it was tight popping it on & off the shaft then measured the gap at 1.5 inches, which can't be right, as far as I know the shaft diameter is 1.31 inches at least for the rear. The shafts do flare out as they join the end so maybe I'm just measuring too close for an accurate measurement.
 
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Chris said:
That would be interesting to hear. I know @toximus is running 37s whereas you and I are running 35s, so it would be interesting to see how your number differs from the 45° he came up with.
Click to expand...

This is quick and dirty. RGA USA made shafts with a Spicer 1350 u-joint. These are installed to get full steering lock each direction. No extension washers. The front tires are off the ground. A stick is tied to the tire. A plumb bob is hung from each end of the stick. The steering is turned to full lock each direction. Both ends of the stick are recorded on the cardboard.
20200830_121605.jpg


Connect the four points and we get a full sweep of about 68° or 34° each way from zero.
20200830_122349.jpg


However, the tires do hit the front control arms at the very end of the turn, so there is a very small amount of movement not recorded on the cardboard. I'm doing this without a helper to hold the steering wheel so the sweep is actually closer to 70°.

And for some bonus fun, I also just demonstrated the scrub radius of a 3.75" backspaced wheel on a factory TJ axle.
 
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jjvw said:
This is quick and dirty. RGA USA made shafts with a Spicer 1350 u-joint. These are installed to get full steering lock each direction. The front tires are off the ground. A stick is tied to the tire. A plumb bob is hung from each end of the stick. The steering is turned to full lock each direction. Both ends of the stick are recorded on the cardboard.
View attachment 187031

Connect the four points and we get a full sweep of about 68° or 34° each way from zero.
View attachment 187032

However, the tires do hit the front control arms at the very end of the turn, so there is a very small amount of movement not recorded on the cardboard. I'm doing this without a helper to hold the steering wheel so the sweep is actually closer to 70°.

And for some bonus fun, I also just demonstrated the scrub radius of a 3.75" backspaced wheel on a factory TJ axle.
Click to expand...

Thanks for this, that’s more than I could have asked for.

So let me ask you this then, every so often I’ll hear something I’ll hear something about the ears breaking off the outer shafts. What is that about? Is that a case of the steering stops not being adjusted correctly and allowing the wheel to turn to far?
 
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Chris said:
Thanks for this, that’s more than I could have asked for.

So let me ask you this then, every so often I’ll hear something I’ll hear something about the ears breaking off the outer shafts. What is that about? Is that a case of the steering stops not being adjusted correctly and allowing the wheel to turn to far?
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The u-joint gets weaker as the angle increases. Comparing the strengths of the 5-760 and the 1350 at various angles might be the next step.
 
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Chris said:
Thanks for this, that’s more than I could have asked for.

So let me ask you this then, every so often I’ll hear something I’ll hear something about the ears breaking off the outer shafts. What is that about? Is that a case of the steering stops not being adjusted correctly and allowing the wheel to turn to far?
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Too much torque.
 
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Great write up @jjvw ! Take a look at the area circled in blue, doesn’t the stub shaft look like it was cracked for a period of time before it actually failed. Look how dark that area is compared to the final failure areas.

EF5B2BB7-3434-49B0-B773-2956B6EA625E.jpeg
 
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Daryl said:
Great write up @jjvw ! Take a look at the area circled in blue, doesn’t the stub shaft look like it was cracked for a period of time before it actually failed. Look how dark that area is compared to the final failure areas.

View attachment 187035
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Go back to my build thread a few weeks when this happened. I used a file to cut through the bent ear until I could break it off the rest of the way.
 
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Chris said:
Okay, so there is some truth to this, it just depends on the build, right?

It would be interesting to test this out with my current TJ. How did you go about doing this test? Did you do it while cycling the suspension?
Click to expand...

You'd need to use different steering to get more than 37*. Even I got only 40* or so with custom steering.
 
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jjvw said:
Axle width, tire size and backspacing will play a role. The maximum achievable angle would be measured at ride height. From there, other interferences like the body and full tire stuff/steering lock would need to be reconciled.

I have future plans for mine that also might matter, but that's a discussion for the build thread. :)
Click to expand...

It doesn't matter how much flex, ride height, etc... The angle of that axle joint is based on the rotation of the knuckle on the balljoints.
 
i'm gonna have to try that 1. i had to put a couple washers behind my stops to keep my ears from grinding at full turn. i'd like to know what i have left.
 
I had to grind a decent amount on my left shaft to get it able to turn without binding at full lock. It had a good 5-6 degrees less motion than the right side shaft.

Ultimately, I did end up having to add washers for the hydro assist, but even with those washers, I would still have had to grind a good amount.

If you replace the bolts with Grade 10.9 M12 x 80mm hex bolts (not flange bolts or heavy hex), no grinding of bolt heads is required, at least with BMB knuckles.
Part number 91310A736 on McMaster-Carr; $12 for a set of 10.
 
toximus said:
It doesn't matter how much flex, ride height, etc... The angle of that axle joint is based on the rotation of the knuckle on the balljoints.
Click to expand...

It would be a way to solve a problem that neither one of us would pursue.
 
Steel City 06 said:
I had to grind a decent amount on my left shaft to get it able to turn without binding at full lock. It had a good 5-6 degrees less motion than the right side shaft.

Ultimately, I did end up having to add washers for the hydro assist, but even with those washers, I would still have had to grind a good amount.

If you replace the bolts with Grade 10.9 M12 x 80mm hex bolts (not flange bolts or heavy hex), no grinding of bolt heads is required, at least with BMB knuckles.
Part number 91310A736 on McMaster-Carr; $12 for a set of 10.
Click to expand...

Grinding of the factory bolts is likely not needed most of the time anyway.
 
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