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Wheeler

Too much scrub radius.

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My car (280z with ls1,az lca, coil overs, azcar 5 lug conversion) is finally out on the road and running pretty well. But now the process of dialing it in little begins. The biggest issue I am seeing is that the car is very sensitive to bumps in the road and will pull hard to the side of road in which the bump occurs. This is coupled with a lot of steering feedback, more than I would like. I don't believe this is bump steer (I have some of that too, but not too bad). I think it is excessive scrub radius causing this. I recently got the car aligned....

 

Caster 3.125 degrees

Camber -1.5 degrees

SAI 22 degrees

 

I am running 225/50R16 tire on -38 rims.

 

What am I missing? There are many on this forum running more offset which should increase scrub more than I have. What can be done to reduce this? Any thoughts

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Initial thoughts: bad tie rod ends (inner or outer), bad TC rod bushing, excessive toe out, loose wheel bearing? Lots of guys here like toe out, but i toe in per stock spec-i like a car that goes straight unless i turn the wheel. Most z-cars want to follow grooves in the road with a square edge tire. After my last alignment several lock nuts were left loose but I found them on inspection. Re torque ALL your hardware.

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Make sure all the components in the steering and suspension are in good shape. The S30 has a lot of bump steer at either end of the front suspensions range of travel. If your car is lowered to where the front LCAs are parallel to the ground you're in that high bump steer zone. Vertically adjustable tie rod ends are the easy fix. You can also raise the steering rack (much harder to do). Relocating the inner mount for the LCA helps.

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Thanks for the suggestions. The front suspension is all new parts / bushings and feels tight (no slop) so I don't think wear is to blame. The front lca are not quite horizontal, I relocated the inner pivot outward and upward per the suggestions elsewhere on this forum (may have come from you John). Heavy, interesting thought, I did not put this back in. What does it do, prevent the rack from sliding lateraly?

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Heavy,  I put in the rack stopper, test drive in the morning.  

 

Monkey,  Here is a picture from this summer, it is a little more complete now, have to do the interior yet.  How is yours coming along?

 

 

Edited by Wheeler

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Well I put the rack stopper back in and took it for a drive. What a difference! There is still some feedback into the wheel over bumps but it is much better. The stopper bumper is about 1/16 away from the x-member when mounted, I think if I adjust it so it is tight against the x-member it may be even better.

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