What's causing my rear tires to wear inside ?

[Jeff P.]

HI EVERYONE,

This car is a "68" L-79 roadster which has a lot of new parts in the rear suspension. My problem is the insides of the rear tires are wearing excessively. Took the car to a dealer for a alignment and they tell me that they can't add any more shims to the inside of the trailing arm and still has a toe-in problem on both wheels ,and the camber is with in spec. Could this car have the wrong stablizer rods or a wrong spring ?? Can't get any info from the previous owner. Any suggestions would be greatly appreciated. New to these independent rear suspensions.

[Paul O.]

Re: What's causing my rear tires to wear inside ?

Jeff

On the trailing arms are they the originals and did you replace the bushings? If they were the bushings may not have been compressed correctly causing a loss in shim allowable dimension. Thus causing a low limit to the amount of shims that can be used for toe in adjustment.

Paul 18046

[Jeff P.]

Re: What's causing my rear tires to wear inside ?

Paul,
Looks like the arms are offset style. They have the poly bushings in the arms.

[Paul O.]

Re: What's causing my rear tires to wear inside ?

Jeff

The Poly bushing are very hard there could be your problem.


Paul 18046

[Joe L.]

Re: What's causing my rear tires to wear inside ?

Paul,
Looks like the arms are offset style. They have the poly bushings in the arms.

Jeff------


You just identified the roots of your problem.

[Jeff P.]

Re: What's causing my rear tires to wear inside ?

Paul, Joe,
Yes i had the same suspicion when i seen these arms. I purchased a complete set from Van Steel (NCRS) approved style. I had another guy tell me probally was the spring. The spring is 9 leaf,looks clean and the car sits level with same gaps at front and rear. Thanks for your replies to this issue.

[Michael W.]

Re: What's causing my rear tires to wear inside ?

Jef,

The spring cannot cause excessive or incorrect toe-in. It has no effect whatsoever on any element of suspension geometry other than ride height. If the stock length of spindles and half shafts are being used then the trailing arms themselves are suspect.

[Bill M.]

Re: What's causing my rear tires to wear inside ?

The analysis by the dealer doesn't make sense. Negative camber can wear inner edge of the tires and toe-out can accelerate that inner edge wear. I would expect in-spec camber and excessive toe-in to wear the outer edge of the tires. I would try another alignment shop.