VQT

I asked this question before but did not have enough responses and most answer was not serious.

I have problems with both of my SC400. At first I though it was only my white SC may have rear alignment problem due to the last owner may hurt the car in some ways (accident...).

I like to ask people with original rims size and tires, how long does your rear tire last? I wonder how many SC400 have the same problems like my SC400s.

I have to change the rear tires on my white SC twice this year each time the rear sets lasted less than 18K miles. I don't spin the wheels so don't tell me that is the case. Now I notice that the green SC tire is wear out to the point that needs replacing very soon. We bought the green car last September and drove less than 12K miles; the car has new tires at the time we bought the car. On the white car I have BFgoodrich g-force KDWS 245-50-16 and on the green car we hace GoodYear Eagle RS-A 225-55-16. Both car had their wheel alignment earlier this year and the white car had the wheel alignment again two weeks ago right after the new tire were installed; alignment was perfect???

I know it's not of my driving habit. My 88 Corvette have BFgoodrich Comp T/A ZR have more than 30K miles on and it still have a lot of thred left. If I want to spin the wheels, the corvette would be the one I'll do it in

pcmw

Have you had the car aligned?

How did the tires wear out? Outside first, middle first....what...

Do you have kids? hehe

Do you carry heavy things in the trunk or 4 passengers alot?

Why don't you rotate them front to back?

You need to GIVE more INFO if you want better answers.

MW

ChrisK

iTrader: (1)

Last year I managed to put about 24K miles on my Dunlop SP5000s (UTQG - 340 AA A). Mine wore out pretty evenly, no bad alignment. I did rotate them only once though.

UTQG on BFgoodrich g-force KDWS 245-50-16 is 300 AA A and on GoodYear Eagle RS-A 225-55-16 is 260 A A. To me this means that both tires are pretty soft, and that would mean that they would wear out quicker.

VQT

The tire wear out evenly, the right rear does wear out faster than the left rear.

No kids.

I did carry heavy stuff in the white SC, but nothing on the green so that's not the answer. Plus, on other car when I travel with a lot of thing in the trunk the rear tires don't wear out like that.

Yes, I do rotate them. Tire rotation is to eliminate the out side wear for the front tires, that is if you take alot of fast turn with the tire squeal...

ChrisK

iTrader: (1)

It's normal that the right rear wears out faster than the left one, because it delivers power to the ground.

VQT

ChrisK,

24K miles is not that good but still better than mine.

What is UTQG sstand for anyway? what is the UTQG for BFgoodrich Comp T/A ZR? How come I still have at least 4~5 mm left on the tread even after 30,000 miles? I know that the tread rating for the Comp T/A ZR is 100 while the KDWS is 400

ChrisK

iTrader: (1)

UTQG - Uniform Tire Quality Grade labeling system that establishes ratings for treadwear, traction, and temperature resistance.

UTQG rating for BFgoodrich Comp T/A ZR is between 180 A A - 220 A A, depending on the size of the tire.

UTQG on BFgoodrich g-force KDWS 245-50-16 is 300 AA A

PERRYinLA

I bought my SC 5 years ago with new Goodyear Eagle GS-D's installed by the dealer, and they are pretty much shot now after about 35K miles. Since it hasn't rained in LA since March, I am still using them. All 4 tires are slick and treadless on the inside edges, the rears slightly worse than the fronts. Rotating them did no good, since no matter how you rotate them, the inner part remains inside. I've never had the wheels aligned.

Once the rains start in November, I'll put on the set of all-weather Dunlops I bought on eBay a year ago. They are 245-50s rather than the stock 225-55's, so I'm looking forward to the slightly wider look they'll have.

vaki2

My experience with this is that, not all alignments shops are created equal. Unless they can do a alingment, with the new digital machine, it is never correct. I had several cars, and the only place, so far, that was able to get the alignment dead on, was firestone. I have 18", so it is very important for them to be properly alignent properly.
Talking to a tech one day, he said that some shops uses inches of variation, other use degree. Even though, both are within spec, the one that uses a machine that alignes with degree, will be dead on. I will find out from the alingment shop what machine they use. This is my experience

vaki2

London Bill

Last week I needed to get my geometry reset as we had just finished working on the front end, I could not get into the specialists (two month wait - he must be good), so I went to a local tyre shop.

They use a Hunter 410, nice peice of kit but the operator did not have a clue on how to setup the PC for my specific settings (TT Soarer was not available but the SC300/400 was), I had to help them enter the new settings and used 10seconds tolerance for all settings (the default tolerance for all settings was 45seconds which I feel is far too much).

Actually resetting the camber/castor was quite simple, look at the screen, rotate the adjuster cams and watch the reading go in/out of range, at one stage we had to close the workshop doors as a slight breeze made the display waver.

They jacked up both front & rear to get the wheel plates underneath, the rear was held on the jack to attain the correct ride height but the front end was sitting about an inch too high even though we tried to "settle" the suspension by bouncing the car (to no avail).

I will be going to the specialist's next month, they spend 2or3 hrs on each car unlike the 30mins at my tyre shop.

pcmw

I think you are just pedal happy if the tires wear out that fast.

300rated tires are not all that soft. They should easily last more than 18k miles.

Also, just because a shop bought a fancy computer alignment machine, it doesn't mean that you will get a good alignment. On a fully stock height car with stock wheels and fairly new shocks/springs. Yeah. On anything modified.....no. The reason you enter the make/model into those computers is so that they can put the car BACK to the factory settings. Not gonna help on a modified car. Old line front end shops are tough to find but worth the cash. First hint that they do a GOOD job is that they dont jack the car UP...tough to align a car that you just drove up a ramp or unsettled with a lift. Second, is if they look to the computer to figure out your camber.

I feel lucky that where I live we have a great shop in town. These guys are such perfectionist, they called up Yokohama to warranty out two of my tires for FREE because the TIRE pulled right on its own. Yokohama rep said that if any other alignment shop had called, "no way". But this shop had the reputation.

MW

VQT

I guess you didn't read my original post. I don't spin the tires on my SC400. If I do spin the tires, it would be my Corvette but my corvette tires are still good even after 30,000 plus miles. As I wrote before, my car is stock, no modification. I also had two different places aligned my car. One in Philadelphia earlier this year and the other in Pomona (near LA) CA.

I like to know if this is a common problem to early SC400 or not. It is wierd to have both of my SC rear tires to wear out in the rear like that. Either way, I will need to visit a alignment specialist to see what's wrong with my car.

strongsail

I have a '93 SC4, stock wheels and tires (for now) - have put 10K on it in the 4 months I've owned it (whoof!), rotated the Toyo Proxes Whatevers once, just got a close look at 'em while the car was on the lift for an oilchange, treadwear is moderate (maybe 60-70% remaining) and wear is nice & even.

I don't do stoplight launches, but I drive it hard & fast on curvy roads, that's where I get my jollies. 33psi front & rear.

I will be getting less boring wheels soon, but keeping the 50mm offset and staying very close to oem rolling radius, and will pay very close attention to alignment after I get wider wheels. I don't plan to lower the car (love the ride) and will have alignment done by a pro performance shop that deals with modded cars every day.

Have a look at the LSOC site and read their "editorial features" section, with much good stuff on wheels, tires and suspension setups written by their resident performance guru, Iain Wiltshire - ain't that right, London Bill?

And Bill, I think you meant minutes not seconds when talking about alignment tolerances - 60 minutes in a degree, 60 seconds in a minute - we don't need to be *that* precise -

London Bill

Spot on there Strongsail I was getting a bit ahead of myself using seconds instead of minutes for the geometry tolerance, having said that 45Minutes (3/4 of a degree) is far too much tolerance for the geo settings.

Iain Wiltshire (LSOC) has published his own settings, this is his preference and it may not suit most, some have said the lack of self centering unnerved them although I drove his car recently and it was not an issue to me, personally I went for the factory settings which seem fine and others agree.

Taller rims & lower section tyres or less offset will give more steering feel but replacing worn front lower arm bushes will make a world of difference.

Toan Nguyen

It might be your rear suspension bushes being worn out. (Very common to older models). When you accelerate, the rear of the car drops a bit and if your bushes are worn/disintergrated there is more travel in the camber angles of the tires as the bushes compress. So when doing a wheel alignment, it would show up as normal as there is no pressure/load on the rear, but when you take off, the bushes will deform and shoot the camber way out. It's just a thought, but might be worth looking into. I know for a fact that alot of the older soarers in Aus (91-93 models) have needed to replace the rear and front bushes control arm bushes due to creaking or tramlining issues as they were worn down.

Just a thought tho. I replaced my bushes 2 years ago when i got my car, so dont really know if it makes any real difference.

Toan.