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Login to post Forums » Grassroots Motorsports » Rubbing causing invisible damage to tires?

July 28, 2009 11:49 p.m. TreoWayne New Reader

I have a 1995 Lexus SC400 that is lowered on gixxer_drew coilovers and has a set of bigger rotors and four-piston calipers from a 95-99 LS400.

The bigger brakes necessitate the use of 15mm hubcentric spacers for my 17" GS400 wheels to clear the big calipers. With the spacers and the suspension drop the tires occasionally rub when the steering wheel is near full lock.

All four of my tires are Bridgestone Potenza RE050A Pole Positions. I also have a set of Blizzaks mounted to 95-99 LS400 16" wheels that clear the big brakes without spacers and therefor do not rub.

I put the big brakes on the car during winter, so I was running the Blizzaks. Ever since I put the summer wheels & tires back on the car the car shimmies/vibrates at high speed. I had the tires balanced at Wal-Mart and the problem persisted.

The other night I put two winter wheels on the front and the 60+ mph shimmy was gone. I took the two front summer tires to a well-respected local tire shop to check the balance. They said the tires were nearly perfectly balanced.

If I put either of the trouble tires on the car at any corner the shimmy returns.

Could the occasional (maybe once a day for 1-2 seconds) cause this problem? I don't think so because the shimmy started as soon as I mounted the summer wheels. Also, there weren't any strange marks or cuts on the tires. The tire shop said the tires were balanced, look fine, and didn't do anything strange on the balancing machine. They think something is wrong with one of the tires. My testing indicates there is something wrong with both of the tires.

Any experience with similar issues? I plan to raise the car a little bit and do a little bit of fender liner trimming to eliminate the rubbing entirely, but this may not happen until after I have at least a new pair of tires installed.

I've had these tires for a little over three years but I have driven this car less than 10,000 miles in that time. I don't think heat cycles or improper storage ruined them because the other two tires seem to be just peachy.

Here is a picture of the car.
July 29, 2009 6:46 a.m. skruffy Dork

There's something wrong with the tires or the wheels are a bit out of round or bent.
July 29, 2009 7:00 a.m. 93celicaGT2 SuperDork

You'd have to be rubbing a CRAPLOAD off those tires to have it affect them enough to disrupt your balance to the point that you notice it.

My car before i rolled the fenders took veritable chunks out of my tires, and still drove smooth as ever.
July 29, 2009 7:01 a.m. jrw1621 HalfDork

I had similar issues with my old '88 MR2. I went from traditional tread tires to v-shaped tread Kuhmos. The Kuhmos were fine when on my Miata but when switched to my MR2 (on the same rims) the MR2 would vibrate.

The culprit was worn front suspension bushings on the MR2. I switched the MR2 back to traditional tread and never was bothered by it again (still on old bushings.) I placed the V-treads onto the Miata and drove them for years with no issue.
July 29, 2009 8:00 a.m. Spinout007 Reader

Man that's a sharp looking car...
July 29, 2009 8:19 a.m. minimac Dork

Have you checked the tires for shifted/damaged belts? I would have thought to check the front end, except you don't have the problem with the Blizzaks. That would indicate to me a problem with the tires(most likely) or a bent wheel.
July 29, 2009 8:23 a.m. TreoWayne New Reader

The wheel would have to be visibly bent to be a problem, right?

The thing that gets me is that these tires were fine when I took them off the car late last fall.

Thanks for the compliment spinout007. The car is dirty and doesn't have the big brakes or the spacers in that picture.

The car is 15 years old and has 213k miles and it still in very good shape with lots of life left in it. The vibration in the front end is a discredit to how nice the car is. It still even manages to ride well with coilovers and +1 wheels.
July 29, 2009 8:26 a.m. Bobzilla HalfDork

I'm guessing whoever you had balance the tires A.) didn't have a road force machine or 2.) didn't know how to use it. A Road Force balancer will find the bad tire. I would suggest finding a local shop that uses a road force machine (hunter 9700 is a great one) and have them check out the two suspect tires.
July 29, 2009 9:01 a.m. minimac Dork

One other cause could be a warped rotor. If the garage monkeys use an impact and bang away, instead of torquing, it can warp the rotors. You wouldn't necessarily have to see a damaged wheel for it to be bent slightly, but I'd bet dollars to donuts it's the tires.
July 29, 2009 9:11 a.m. xci_ed6 Reader

I bet your getting the shimmy from the spacer, not from the wheel & tire. Try the spacer with your winter wheels.

Also, you could just fix the rubbing, grab an old wood bat and bend that lip up a smidge.
July 29, 2009 9:40 a.m. daytonaer Reader

xci_ed6 wrote:

I bet your getting the shimmy from the spacer, not from the wheel & tire. Try the spacer with your winter wheels.

Also, you could just fix the rubbing, grab an old wood bat and bend that lip up a smidge.

That makes allot of sense. Are you running the spacer with the winter tires?

I have had tires with broken belts, ride like crap but balance ok.
July 29, 2009 9:48 a.m. Gimp Dork

In reply to xci_ed6:

+1 You said you aren't running the spacer on the winter wheels, but are running them on the summer. That's gotta be it.
July 29, 2009 9:50 a.m. audifan New Reader

couple of things to check, are the wheels hubcentric (originally designed for the specific car you have them on?) if not do you have the correct hub centering rings on the car?, are you using the correct lug nuts/bolts (is the taper correct I.E. some are a 45 degree angle and others are a rounded taper called an acorn taper) if any of theses is also not correct it can cause vibrations. And lastly go somewhere other than walmart where they hire the people that could not make it thru 9th grade auto shop class. spend the money you have a nice car find a reputable shop and go there they will also be able to tell you if you have a bent tire or a shifted belt causing the problem as well. good luck!
July 29, 2009 10:16 a.m. iceracer HalfDork

Gimp wrote:

In reply to xci_ed6:

+1 You said you aren't running the spacer on the winter wheels, but are running them on the summer. That's gotta be it.

Beat me to it. 15 mm spacer is a lot. It has increased the scrub radius significantly.
July 29, 2009 10:42 a.m. audifan New Reader

also make sure the spacer isn't some 20$ set of crap from the local speed shop invest in some real spacer from eibach or H&R they will run you over 200$ but they wont cause you any issues either.
July 29, 2009 12:59 p.m. TreoWayne New Reader

The winter wheels don't NEED the spacers, but I have them on the car anyway for the recent experimentation. With the two sketchy tires off and all four spacers in place no vibration.

I don't remember what brand the spacers were, but it was about $200 for all four and they are the type that bolt to the hub and then the wheel bolts to the spacer.

I don't need any hub rings since all the wheels are Lexus wheels and all have the same center bore as the hub.
July 29, 2009 2:31 p.m. xci_ed6 Reader

move the vibey wheels to the back, and the back wheels to the front.
July 29, 2009 3:15 p.m. TreoWayne New Reader

I did that too. They vibrate whether front or back. If either of the skeezy tires is at any corner of the car it vibrates.

I dropped the tires off at Firestone to have them road force balanced, we shall see what happens.
July 29, 2009 6:32 p.m. aussiesmg Dork

I would bet on a broken belt, probably a belt that runs the circumference not side to side, I had one recently and the vibration comes and goes, I tested the balance and it was all good.
Aug. 11, 2009 6:02 p.m. TreoWayne New Reader

I had the tires road force balanced, everything checked out OK. I decided to start all of my testing over. The only way the car doesn't vibrate is with the winter wheels/tires and no spacers.

OK so its the spacers I decide. I sell the 17" wheels and tires that need the spacers and buy a set of 17" wheels that fit without spacers plus a set of new tires.

The car doesn't vibrate with the snows and STILL VIBRATES at speed with the brand new 17" wheels and tires. This whole scenario is driving me nuts. Any other ideas?
Aug. 11, 2009 6:04 p.m. mad_machine UberDork

gotta be the spacers... can you drive at all without them?
Aug. 11, 2009 6:21 p.m. TreoWayne New Reader

I have new 17" wheels that fit without spacers.

They have +40mm offset instead of +50mm of the OEM Lexyota wheels.

Still vibrates.

The only combo that doesn't vibrate is the 16" snows with no spacers. The new 17" wheels with new tires and no spacers still vibrates.

I'm taking it in for alignment tomorrow we will see what happens.
Aug. 11, 2009 7:46 p.m. Hal HalfDork

TreoWayne wrote:

I have new 17" wheels that fit without spacers.

They have +40mm offset instead of +50mm of the OEM Lexyota wheels.

Still vibrates.

My math may be off in which case the suspension experts will correct me.

The stock wheels have a +50 offset which means the centerline of the wheel is moved inward 50mm from the mounting face. When you put in a 15mm spacer you moved the center line out 15mm giving +50mm - 15mm = +35mm offset.

Your new wheels have a +40 offset so you only changed the offset by +5mm. Which is not very much at all.

Some of the suspension experts on here can explain much better than I how this would affect scrub radius and some other things.
Aug. 12, 2009 9:18 a.m. TreoWayne New Reader

40mm - 0mm spacer (40mm) 50mm - 15mm spacer (35mm)

Are both fairly large departures from 50mm.

I took it in for alignment this morning. They said the camber was whacked out side to side but toe was pretty even. I think that is probably accurate.

They set zero toe and got the camber evened out side to side, but couldn't get the camber set to factory spec (which is fine, a little extra negative camber never hurt anyone who takes corners with aggression).

We'll see how she takes to the highway later today.
Aug. 13, 2009 1:38 p.m. Jake HalfDork

Could stiffer/shorter sidewalls on the bigger wheels be causing you to notice a vibration that is always there with the winter tires, just soaked up by them (aren't winter tires pretty much balloons with treads?)? I'm thinking of a messed up suspension bushing, loose tie rod etc. still.

So you've so far eliminated the tires and spacers as a problem: something is loose or worn or broken in there somewhere.

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