I own a 2003 sc430 with 195,000 miles the tires I have on the car are 255/35/20 sumitumo . The front tires are fine,but it seems the the rear tires always wear on the inside and after a while the inside of the tires develop small cracks on the inside of the sidewalls and the tires eventually will have to be replaced. I was purchasing tires online but now I’m buying them locally. I’m replacing the rear tires and I was wondering what I could do to resolve this problem .

After I purchased the rear tires the technician tried to align the car he said the front was fine but he was having problems with the rear. What can I do to resolve this problem.

Thanks in advance.

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This is what I received from the alignment technician

 

The SC430's basic suspension setup has a lot of negative camber even when set to stock spec. Inner tire wear is very common.

The negative camber is made even worse by the natural drooping of old struts. The lower the ride height, the more negative the camber. Pretty quickly the technician runs out of camber adjust range on the SC430's.

Measure suspension heights and verify car has not sagged down more than a few mm.
a. Front vehicle height from ground to center of lower control arm mounting bolt. (std is 9.13 inch or 232 mm)
b. Rear vehicle height from ground to center of lower control arm No. 2 mounting bolt (std is 8.22 inch or 209 mm)



If ride height is too low, your struts may need replacement before camber can be adjusted properly. Just 1/2 inch of extra drop can make a large difference in camber adjustment range.

For those who intentionally drop ride heights, negative camber can be combatted with after market camber adjustment blocks, but that requires more mechanical work.

EDIT wow your tech made the rear alignment worse than when he started!

 

The car is not lowered it’s at stock height how can I correct this problem?

 

Same Problem here
Do you think New Bushings are needed? Or will that SPC Camber Kit help? I think it adds 1 degree of extra adjustment and requires you to bore out the LCA hole to install it.
I know my bushings are bad. I see them cracking.
Do you think affordable after market is acceptable to stop inner tire wear?
Like 1A Auto
I know Moog is supposed to be decent.
Then I saw some Figs PU for much more than any of the others and it requires a press to install.
I think rubber is supposed to last longer but PU is better?
Id like my vehicle to run well and I do not plan to do any major mods or street race.
Any Suggestions.
Thank You all in advance.

 

What I'm getting at is the stock setup becomes effectively lowered as it ages. Can you measure the ride heights so we can rule that in/out?

Also, realized you are running larger diameter and wider tires and wheels than OEM. Yours are 1.3 inches larger diameter than OEM.
OEM 245/40 R18 = 25.7" diameter
255/35/ R20 = 27.0" diameter

Your measured suspension bolt heights should be 0.65 inches higher than the spec value for OEM wheels.

The wider tires are also increasing how badly negative camber is creating inner tread wear.

 

Forgot to add.. the car has wheel spacers on the rear wheels don’t think they affected my alignment before

 

I have a question to anyone who has used the SPC rear camber kit 67510 to help improve negative camber. I just put new OEM shocks and springs on all four corners (Megazip). However my new rear camber alignment results are -1.9 degrees. The SPC 67510 kit is suppose to give me plus 1.0 degrees of additional camber. That should get me to -0.9 degrees. I really would like -0.5 degrees.



This is my plan. Seeing that I have to elongate the slot used by the oval cam adjustment bolt in the lower control arm to make room for the 67510 why not elongate the slot even further than required and then spot weld the 67510. In other words, if I have to elongate the slot ½ inch just to fit the 67510, why not elongate the slot an extra ¼ inch to gain another 0.5 degrees of positive camber adjustment. What are your thoughts?

 

@Ken52 , this thread's a few years old. But secondly Photos or a sketch would help a lot. I'd generally advise against cutting and welding brand new suspension components just to make up a 0.4 degree difference.

 

I totally understand your position. That is kind of my position too. However I am tired of spending $1400 every year on back tires. I already ordered the SPC kit. I am going to first install it without making the slot any bigger than needed for the kit. Then I will bring it down to Firestone for an alignment just to see how much of that +1.0 degrees I get. Once I know how much slot size increase was necessary to get to the +1.0 degrees I will then make the final decision if to increase it more. As far as possibly decreasing the strength of the LCA due to the increase slot size I believed that welding the SPC kit to the LCA will actually make the LCA stronger than stock

 

Sorry to revive an old thread, but how did this work out?

I've had a lot of negative camber on my '07 and was wondering if this would help.

Thanks

 

The SPC kit helped but not enough. In addition due to the limited improvement in camber I now had to buy aftermarket adjustable toe-in arms. (https://coiloverdepot.com/collection...e-control-arms) Those aftermarket toe-in arms have a wider range of adjustment. If I had it to do over I would have just purchased aftermarket LCA that provided much more adjustment than the SPC kit. (https://coiloverdepot.com/collection...ar-camber-arms) So now I purchased UCA to get the camber totally done. (https://coiloverdepot.com/collection...ar-camber-arms)

Now on to the next problem, the idiots that do the alignments. The "book" allow for a certain amount of time to do the job. If the idiot gets it done sooner than the "book" value he still gets paid for the "book" time. So he is in a rush to do your car. As soon as the alignment machine shows GREEN that alignment is done The alignment machine allows for the rear camber to be within -.67 to -1.67 The mechanic doesn't care if its -1.67 or -.67 Anything in the middle is GREEN. Asking for -.1 to -.4 is something strange to these guys. I purchased the lifetime tire adjustment. (Firestone) Its twice the price of the one-time adjustment. But you will be going back several times as you work on getting your tires right.

 

Thanks.

I've got an appointment with a locally owned shop on Monday, and I hope the tech won't be in a hurry. I guarantee that's what happened at Discount Tire.

Cheers

 

Your Discount Tire does Alignments? The Discount Tires in Washington ST only do tires.

 

From what I gather it's very limited. My store is in Williamsburg, VA.

I wouldn't use them for an alignment again. They wouldn't let me talk to the tech, only showed me a note that said the car had been lowered too much and the camber was the best it could get.

Looking at it when I got it home, one of the camber adjusters was still on the mark I made when I changed the coilovers.

Thus the appointment at a real shop.

I'll post when I have them look at it on Monday.