7.5" spring over pinion angle

[Darren]

what should the pinion angle be for about 7.5" of lift? i have to do the welding at my work and i won't have my truck there for reference. anyone got a number i could work with?

[DirtyComanche]

If nobody comes up with a good answer for you, I can tell you what I think it should be...

[JeepcoMJ]

...don't even attempt this without the truck as a reference, it's not something you want to screw up

 

just get it under there, set it to within 2 degrees positive (twists under accel), and tac weld it in.

 

then take it in and weld it up

[Oizarod115]

eh, you can always shim it as long as you get it within like 5* or so

[DirtyComanche]

eh, you can always shim it as long as you get it within like 5* or so

 

 

Shims suck. I have shims. I hate shims.

[Oizarod115]

 

Shims suck. I have shims. I hate shims.

just make sure they're not aluminum shims... because steel/aluminum/steel doesn't make a good sturdy sandwich. they tend to break.

 

thats the only PITA thing thats ever happened to me with shims involved

[Darren]

i can't use shims, i have ubolt eliminators

[Darren]

no one wants to give me a number?

[DirtyComanche]

You can still use shims. You don't want to though... If you look at one of my threads there's a bit about how my truck is shimmed (at BOTH ends, total of 8 shims).

 

 

 

I want to say 7* up since nobody else will tell you. It should be ballpark 9* difference between the driveline angle and pinion 0*. You can be ballpark and it'll work if the shaft is balanced well enough... It jsut might vibe a little. Or maybe not...

[Pete M]

I find it hard to comment on pinion angles after I put my rear suspension together with absolutely no regard to proper angles (just used the angle that the Bronco axle had) and have had no problems with it. :dunno: Drove it 3000 miles to Moab and back. I know i shouldn't work like that, so I've been attributing my dumb luck to the rubber-isolator driveshaft and using new U-joints. :nuts: Maybe someday I'll actually go measure the angles. I guess there's a chance they are acceptable, although the Bronco had a CV shaft out back. :roll:

[mjeff87]

the stock pinion angle on the D44 I just put in is 7 degrees, if that helps any....

 

Jeff

[87manche]

mock up the axle under the truck, use the angle finder on the machined surface of the housing to get a number. Then use the angle finder to measure the angle on the perches.

 

Take ti to work, make all the angles the same and weld it in. That's what I did with my first axle swap.

 

for reference:

http://4xshaft.com/images/2joint_angle.gif

 

that's how it needs to look, and be sure that the yokes are in phase.

[DirtyComanche]

That's right if you don't have a double cardon shaft... I sorta assumed he had one since he's going SOA. Kinda should...

 

 

In which case the drive-line is like 2* down and you should align the pinion flat (0*) or something...

[87manche]

cv shaft:

[DirtyComanche]

And to note, those are theoretical. For leaf springs the standard rule is to go 2* low to account for axle wrap.

[mjeff87]

Nate/DC/anyone,

Follow my logic on this, then. For the standard 2 UJ shaft, the driveshaft angles will change consistently at either end when you SOA, so long as the vehicle stays level front to rear, yes? That's the debate that Pat, myself and another guy had when we burned my new perches on top of the tubes in prep for going SOA, and that's why I decided to set the new perches parallel to the factory perches underneath (to keep the same factory pinion angle, which we measured at 7 degrees). Irregardless of the amount of lift, SOA or SUA, both the TC output and the axle pinion are fixed, and will not change, unless you alter the wheelbase. Yes?

 

Jeff

[87manche]

should be.

 

When I setup the first D35 I mirrored the angles on the factory one, worked fine with my 3".

 

When I did the 8.8 I did it the "proper" way and mocked it under the Jeep, at ride height.

 

anyway, I think that your conjecture is correct.

[DirtyComanche]

I agree.

[comanchedude]

If I understand your logic, if you keep the angle the same as stock as you lift the jeep you will increase the operating angel of the U-joints and if lifted enough you will exceed their range to operate ,other than that I agree with you but when lifting you would have to make a small adjustment to reduce the operating angle.

 

I did SOA “net 7.5” and adjusted the rear pinion angle by watching the u-joint operating angle and keep the pinion as low as possible but still having an acceptable u-joint operating angle

On my SB Comanche my rear pinion angle is about 5deg up and that has worked well for me no vibes and u-joints (In service for a year before soa ) are still going strong 1.5 year after SOA. I have long Rocky Road spring perch and spun the overload spring long end forward. Have minimal spring wrap. hope that helps

 

 

 

Nate/DC/anyone,

Follow my logic on this, then. I decided to set the new perches parallel to the factory perches underneath (to keep the same factory pinion angle, which we measured at 7 degrees). Irregardless of the amount of lift, SOA or SUA, both the TC output and the axle pinion are fixed, and will not change, unless you alter the wheelbase. Yes?

 

Jeff

[pingpong]

Like Jeff said.. in a non SYE application the output of the t-case and the pinion angle should be kept the same. When doing it with a SYE you point the pinion at the t-case.

 

As Pete and many others have pointed out U-joints get phased( worked in at an angle) and when you change their working angle they cause vibrations. Most ppl automatically assume that there vibes are caused by driveshaft angle. Most ppl install larger tires at the same time as the lift... they develop vibes.. so they assume it is driveshafts.. from MY experience it often is improperly balanced tires.