Any info or advice on modifying a rear driveshaft double cardan joint for a little more flexibility?

[kmas0n]

Does anyone have any info or advice on modifying a rear driveshaft double cardan joint for a little more flexibility? Do they make a "High Angle" DC? Can you grind a little off the "H" for a tad more clearance? My 12" Foxes are pushing past the limits of what mine can handle.

 

[Jerry Bransford]

Tom Wood makes a high angle version of their driveshaft but first, what u-joints are in your rear driveshaft? That problem is common with the 1350 but not so much with the 1310 or 1330 u-joints.

 

[toximus]

Tom Wood makes a high angle version of their driveshaft but first, what u-joints are in your rear driveshaft? That problem is common with the 1350 but not so much with the 1310 or 1330 u-joints.

Tom Wood's high angle 1310 and 1330 joints are offset. Meaning they likely aren't suitable for his application (assuming he wants to go 30mph+).

 

[kmas0n]

Okay thanks for the info. I'm running 1310 joints.

 

[Mike_H]

Does anyone have any info or advice on modifying a rear driveshaft double cardan joint for a little more flexibility? Do they make a "High Angle" DC? Can you grind a little off the "H" for a tad more clearance? My 12" Foxes are pushing past the limits of what mine can handle.

I think someone does, but they are spendy, like 600 a pop, and they get you a couple extra degrees, tops. How much travel do you sacrifice if you install a limit strap? I think @jjvw had to on his rig.

 

[toximus]

Does anyone have any info or advice on modifying a rear driveshaft double cardan joint for a little more flexibility? Do they make a "High Angle" DC? Can you grind a little off the "H" for a tad more clearance? My 12" Foxes are pushing past the limits of what mine can handle.

Okay thanks for the info. I'm running 1310 joints.

Take a close look at it off the Jeep. The binding is actually happening at the centering ball.

You'll likely need to add in a center limit strap. A light bind is okay as long as you can turn past it, that's caused by the seal binding which gets pushed out of the way as it rotates. The limit of the droop is when you can't turn the driveshaft by hand anymore.

 

[kmas0n]

I think someone does, but they are spendy, like 600 a pop, and they get you a couple extra degrees, tops. How much travel do you sacrifice if you install a limit strap? I think @jjvw had to on his rig.

At full droop I can still line up the ds with the pinion flange by hand (barely) , but at full compression, I have to push it with a good grunt to get it to line up. I'm right at the limits of what this driveshaft can do.

My build is a custom mid arm, the lower links are 24" and the upper is 26". The idea was that at full droop the pinion starts pointing up a little, and it works, but at full compression its still mostly pointing up.

 

[kmas0n]

Take a close look at it off the Jeep. The binding is actually happening at the centering ball.

You'll likely need to add in a center limit strap. A light bind is okay as long as you can turn past it, that's caused by the seal binding which gets pushed out of the way as it rotates. The limit of the droop is when you can't turn the driveshaft by hand anymore.

Good to know. I'm pretty much at where you say the limits are, so it might be okay, I don't spend much time at full compression or droop. I can still spin the shaft by hand at the limits but I can feel it binding

 

[toximus]

I can still spin the shaft by hand at the limits but I can feel it binding

You should be good to go!

 

[kmas0n]

You should be good to go!

Much thnks

 

[mrblaine]

Does anyone have any info or advice on modifying a rear driveshaft double cardan joint for a little more flexibility? Do they make a "High Angle" DC? Can you grind a little off the "H" for a tad more clearance? My 12" Foxes are pushing past the limits of what mine can handle.

Almost everyone with 12" + balanced travel rear shocks has that issue. More so with the Rubi case since they can't be shortened with a different SYE set up to lengthen the rear shaft.

Also, if you look inside the CV while manipulating it, you'll see there is very little that can be done since what generally stops more angle is the seals and caps on the joint.

You may be in modified 1350 area or put a center limit strap on the diff. There are some Toyota parts they can use to build a high angle driveline if you want to throw lots of money at the problem.

 

[toximus]

They are offset but Tom and Shawn wood would be very surprised to read they're unable to go over 30 mph since his axle would not be drooping or stuffed at driving speeds.

Why would they be very surprised to read something they already know?

THIS JOINT WILL CAUSE DRIVE SHAFT VIBRATIONS. It is not compatible with double cardan (cv) assemblies. It should not be used in high speed applications.

 

[kmas0n]

his axle would not be drooping or stuffed at driving speeds.

Challenge accepted.

 

[Jerry Bransford]

Why would they be very surprised to read something they already know?

This was new news to me but upon further research you are correct. I just remember being asked if I wanted to try their new, at the time, offset u-joints when they were making a new driveshaft for me. I declined them in favor of standard Spicer u-joints. I apparently didn't give this enough thought, thanks for the information.

 

[jjvw]

Challenge accepted.

Challenge most likely achieved! Mine has been airborne at least twice.

 

[jjvw]

I think someone does, but they are spendy, like 600 a pop, and they get you a couple extra degrees, tops. How much travel do you sacrifice if you install a limit strap? I think @jjvw had to on his rig.

I put a center strap to protect the drive shaft. As I recall, it stops center droop about 3/4" before the shocks fully extend. 12s split 50/50 at ride height. Articulation is not affected.

The odd thing is that I didn't need a strap on my first DC rear shaft from Tom Wood. But I did after I rebuilt it with a new H yoke even after I did a little bit of clearancing. Then I added the strap. So I believe this is related to casting differences in driveshaft parts.

Now, I have a completely new drive shaft, but I haven't checked to see if I need a strap on this one. I just know I can bolt it up hanging from the strap.

 

[Gollywomper]

What is the Max operating angle of our CV shafts?
High Angle drive lines has a shaft that good up to 42 degrees. I think it is a 1350 joint.

 

[toximus]

What is the Max operating angle of our CV shafts?
High Angle drive lines has a shaft that good up to 42 degrees. I think it is a 1350 joint.

If you follow my engine swap thread, I show how Tom Woods can also get another ~5* out of their 1350 shafts by switching to a flange.

 

[Gollywomper]

If you follow my engine swap thread, I show how Tom Woods can also get another ~5* out of their 1350 shafts by switching to a flange.

As long as the shaft allows for reasonable droop and the strap does not prevent full articulation is there really a downside to using a strap?

 

[toximus]

As long as the shaft allows for reasonable droop and the strap does not prevent full articulation is there really a downside to using a strap?

Not much downside to a center strap. Pretty common for TJs with 12" shocks. The only time it will limit performance vs a pricey high angle driveshaft is if you get the belly hung up just enough that 1/2" more of letting your tires move down would get you traction, or if you're jumping it and want as much travel available as possible (but then you'd likely have straps on each corner so you're not busting the caps on your shocks).