bam

My mom has a 2004 gs430 and all four tires are cupped. The car is all stock and when I originally asked my service technican about the problem, he said it was due to underinflation of the tires. after doing a little more research, the forums are saying that it's due to bad shocks/struts. i actually mentioned that i think the left rear strut is bad and he's had the mechanics check it a few times, and they keep saying it's fine.

The tires have 25k miles on them and the car has even been aligned once since we've bought it but i'm still thining that the strut is leaking or something. Anybody have any suggestions of what else may be causing this if he claims that the struts are not leaking.

The tires will need to be replaced soon and the last thing I want to do is replace the tires for 1k and then have the new ones cup too. The thing that is throwing me off is that it's ALL FOUR TIRES! Please help.

Any suggestion would be appreciated. Thanks!

e-man

Cupping is usually a sign of bad struts. But, if the car is an 04 with only 25,000 milies being driven mostly on California roads, I highly doubt that the shocks are bad (although they could be). You indicated that your technician said it was due to underinflated tires. Would you happen to know what PSI the tires have been at most of the time?

AZDesertGS

iTrader: (4)

I'd be curious about the psi that has been running also. I would question about the tires not being rotated at all as well.....or another is that you have some crappy Bridgestones (assuming that they are the factory ones)

bam

They've been balanced and rotated, i think, twice at the service intervals. I think the psi was about 30 or 29.

Any suggestions as to what else I can have them check?

e-man

Hmmm. Well, they certainly weren't under-inflated. Here's something to think about -- the fact that you got 25k miles out of the stock Bridgestone Potenzas is a feat in and of itself. I never had the tires, but I've heard GS owners replacing those tires often between 15k and 20k miles. The fact that your mom got 25k out of them is pretty good. Is it possible that there's nothing wrong with the car and it's just time to get new tires? How does the car ride? Does it bounce down the road as if the shocks are shot? It sounds like your mom needs new tires anyway, regardless whether there's anything else wrong. Why not get a new set of tires and keep a close eye on them. Rotate them frequently and have them inspected/checked for uneven wear. I wouldn't go and get new struts at this point (unless the dealer is paying for them).

salimshah

If the wear pattern is smooth, then it is due to under-inflated tires. If the tire has scalloped pattern, then shocks can be the culprit.

As others have pointed out, 25K is great milage, I only got 17,000 but the realiztion to replace them came at 14,000 miles.

Salim

bam

It's definitely not wearing smoothly. Unless I don't understand what "cupping" is, it's definitely cupped. The best way I can describe it is to say that if you look at one tread block on the tire, one part of it is wearing less than another part, like it's got a little bump on the single tread. This is on the outside and inside of the tire.

I know that the tire has lasted a lot longer than it really should but that doesn't mean that the cupping is excusable. Cupping shouldn't happen, period. I have an is300 and i just changed my dunlop sp sport 9000 after about 40k miles. That is definitely a lot longer than they normally last and they never cupped or had any problems. I've never had bridgestone tires and I'm wondering if maybe bridgestone tires require a little more attention to keep them wearing evenly? I prefer to have a tire that has no more maintenance requirements except rotation, balance, and tire pressure checks. I've always used michelin and they've been great. I just replaced the sp sport 9000 on the IS with michelin pilot sports.

I guess i'll just askt he service tech to keep looking to make sure that all suspension parts are good to go. maybe that should include everything from the tire rods to the bushings. does anybody have any other suggestions as to what they should check?

thaks in advance for all of your help.