Turning Axles up?

[think_07]

Everytime I look at my Blazer I ponder the idea of spinning my axle upwards so I can get a better pinion angle. In all the pics I look at it doesn't seem that anyone does this? Is there any reason for this, I know if I turned it too much my shock mounts would be out of whack, but I would just cut them off and reweld them in a proper location. Thoughts on this?

 

[redneckdude]

Everytime I look at my Blazer I ponder the idea of spinning my axle upwards so I can get a better pinion angle. In all the pics I look at it doesn't seem that anyone does this? Is there any reason for this, I know if I turned it too much my shock mounts would be out of whack, but I would just cut them off and reweld them in a proper location. Thoughts on this?

define "better". for most people, a proper rear pinion angle is a few degrees from being parallel to the ground...its supposed to almost mirror the transfer case output angle if you are running single joints on each end. its supposed to be 2* down from being inline on a cv shaft.

 

[Hogback Fabrication]

Some people turn their pinion up to help driveline vibration (though that's certainly not a guaranteed fix).

I turned my pinion angle up quite a bit to keep the driveshaft and yoke from contacting the rocks as much.

There is a limit to how much angle you can run at the pinion, at some point you will starve the pinion bearings of oil and your diff will fail in short order. I would guess that 10 degrees is the maximum acceptable angle but the axle manufacturers would probably tell you its less than that.

 

[think_07]

Okay that sounds reasonable, how many degrees could i index the front axle before it screws up my castor too bad and i need to cut and reweld my C's

 

[redneckdude]

Okay that sounds reasonable, how many degrees could i index the front axle before it screws up my castor too bad and i need to cut and reweld my C's

on a front axle id worry MUCH mroe about alignment (castor more than anything on a solid axle) than pinion angle...if you have a parttime case and lockouts, the front shaft wont be spinning so vibes will be non existant. the measure will vary from rig to rig, best to measure and see how far out of alignment yorus is and go from there.

 

[Hogback Fabrication]

Okay that sounds reasonable, how many degrees could i index the front axle before it screws up my castor too bad and i need to cut and reweld my C's

Generally the caster on a solid axle front end is ~6 degrees so if you change the pinion angle by X degrees it will change the caster by X degrees.

In short, if you change the pinion angle on a front solid axle (without cutting and turning the inner c's) you will significantly change the caster angle and you will compromise the "return to center" attribute and the control of the steering.

 

[think_07]

Will it really effect the steering on the trail, or more on the way to the trail?

 

[Hogback Fabrication]

Will it really effect the steering on the trail, or more on the way to the trail?

Having a zero degree caster angle will make the steering effort easier.

For a trail only rig you would want the caster to be 0 deg.

The lower the caster angle is, the worse the return-to-center will be and the steering will tend to wander more.

 

[twoslo4five0]

Having a zero degree caster angle will make the steering effort easier.

For a trail only rig you would want the caster to be 0 deg.

The lower the caster angle is, the worse the return-to-center will be and the steering will tend to wander more.

Chris, I have to ask whats your caster angle on your front axle currently? With my offset leaf springs I have negative caster, Id say a 10 degree shim would get me back to zero or maybe a degree or 2 under. Remember im full hydro so what angle would be good for me? Me any kert talked about welding 2 steel shims together if I needed more, remember its a trail rig.

 

[rbgerrish]

 

[K85 Octane]

Yeah, was just going to say what the pictures just did. For the street, there is only a magic degree or two you can run until driveshaft angles are wrong. The front can be changed if you don't run 4x4 on the street, but you get into caster geometry like discussed already.

So maxing out you pinion angle is possible if the hearings are still lubed, but what does that do to the DS? (Unless we're talking about a rig with 15" of lift)