Owl Vans Grenadier Steering Box Upgrade

[Dokatd]

Yep. I came back here to point @Dokatd to that post and procedure. It's what was in my mind when I mentioned thrust angle above.

Except you cannot modify the axle thrust angles. You would have to have cam bolts on the upper links as well.

On the rear axle you only have a single cam bolt on each lower arm. You could attempt to load the rubber bushings I suppose, but you cannot twist the axle housing so thrust angles cannot be adjusted. Even if you loaded the bushings you still won't change the thrust angle. Same applies to the front axle. The upper arms are static and the lowers have a single cam bolt per arm. Maximizing wheelbase via front axle is simply adding maximum caster. Adjusting the rear is just changing the pinion angle.

What I will concede is that preloading the links with the cams may reduce some squirm from differences in torque from being under power and alternatively engine braking.

But that's not correcting thrust angle but rather loading suspension like a nascar so it behaves correctly on each track.

 

[Clark Kent]

Except you cannot modify the axle thrust angles. You would have to have cam bolts on the upper links as well.

On the rear axle you only have a single cam bolt on each lower arm. You could attempt to load the rubber bushings I suppose, but you cannot twist the axle housing so thrust angles cannot be adjusted. Even if you loaded the bushings you still won't change the thrust angle. Same applies to the front axle. The upper arms are static and the lowers have a single cam bolt per arm. Maximizing wheelbase via front axle is simply adding maximum caster. Adjusting the rear is just changing the pinion angle.

I understand the geometry. But apparently there is enough in it to solve crabbing so that's a tweak of the front and rear thrust angles. Have a read of the procedure. If you find your thrust angle is out it may be something that can only be corrected by replacing parts. That sounds like warranty.

 

[Dokatd]

I understand the geometry. But apparently there is enough in it to solve crabbing so that's a tweak of the front and rear thrust angles. Have a read of the procedure. If you find your thrust angle is out it may be something that can only be corrected by replacing parts. That sounds like warranty.

View attachment 7912334

Yeah, I read it and followed it from Zimm when he originally posted.

The document is likely just misworded or it accidentally solves the problem with the act of trying to precision align the back axle resulting in enough bind to reduce the rear bushings compliance. It's certainly possible the bushings are just overly compliant.

 

[C-Mack]

For sure whatever adjustments are possible it’s certainly very minimal and enough in some instances to correct a slight crabbing issue it would seem. How the procedure has you loosening three of the attachment points on each side of the axle including the upper link suggests they are counting on there being enough tolerance stack or free-play at each non-eccentric attachment bolt when you turn the eccentric some very slight longitudinal fore and aft adjustment of the axle can be made.

I bet in many instances there probably isn’t enough movement to correct the thrust angle fully but perhaps enough to mitigate a small issue. Other than that any other fore and aft movement of either side of the axle is simply being taken up by the compliance in the bushings and at that point you’d have to wonder how long the alignment would actually last as the bushing go about their business and flex under load?