Yet another episode in my Cup wheel saga

I have now tried almost everything to find out why my steering wheel shakes. So today I even tried to run cups in the front and the good old tele dials at the rear. Less shaking, but still there. Put all tele dials back on the car and NO SHAKING. The stupid dealer won't admit that he sold me a crappy trash product. I already told him that it simply has to be the wheels that are not ok, but he then suggested that maybe the balancing wasn't ok and that the tires themselves could be bad. Oh yeah! 4 brand new tires that are bad? I think not. And the balancing was done by a collegue who claims he did it right. I believe him.

SO THINK HARD BEFORE YOU BUY CUP REPLICAS!!!

New tires can be bad! Some could be out of round. Can you limit to one tire or wheel? Did you try spinning the wheels with the backend up to see if there is any runout?

I agree with 89911 about the tires. In fact I am more inclined to think it is the tires and not the wheels. Try mounting them on your old wheels and see if you still have the problem.

Kurt V
72 911E

Try putting your old wheels (and tires) on one-at-time and see if you can isolate the problem to one wheel. From what you have said, I would start with the rears.

'Course you don't want to drive far with a mismatch but it would be okay for a quick test.

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'86 Cab, '77 Targa, '85 toyota 4wd rain mobile http://www.cheaterswayside.com/911/

Mikkel;

I had a new set of tires put on my commuter car at NTB. One of the tires (brand new) had a broken belt!! I figured out which one it was and they put a new one on. THAT one was bad also, and I had to go back again. Then the ride was fine. Point is, it's probably a tire (s) that is causing your grief, not the wheel.

Good luck.

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Clint
73T mfi coupe

Cheap replica wheels are almost always out of round, and balance, by a big margin too.

Tires only rarely are. I've been through a few dozens of tires in the last 2-3 years, and about 6 sets of different rims on my Porsche, and other cars.

I also worked at GoodYear for a period of time.

I'm almost positive, even without seing your car, that it's your wheels. I had a millie miglia cup wheel so far out of balance, I thought it got damaged during shipping or something... You know what else, their offsets aren't that consistent either, you can see them being off a few mm EASY!

It's kinda scary to visualize what kind of RPM they turn, going even 80mph, what if they blow (and they do blow) at 140+? I don't think it'd be pretty!!!

Mine were bought through performance products, it took me about 9 wheels to get 4 that are "acceptable". I do not mean totally straight either. I see factory fuchs with 10s of 1000s of miles on them, still true and straight, brand new cheap replicas are nowhere near!!!

Try to give'em back, if not try to sell them!

Also found a crack in a brand new wheel once, and I don't think their density is that regular either. Finish looks fine when new, not so after you let brake dust sit on them for a couple of days, it'll eat into the polish in no time.

Sorry for the long post, but I lost a lot of time, and money over this before, that's why I feel strongly about it!
Ahmet

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It's all the driver...

Thanks guys

1.2gees I agree with you. I have now talked to various other Porsche owners and they have also had problems with bad cup wheels. It's seems unlikely to me that (both front AND rear wheels shake)4 new tires should be bad at the same time.

The seller is not exactly helpful and he is defenitly not going to take the wheels back. I asked to have them replaced with 4 others but no. "First try to balance them again and try to rotate the tires and....and etc". I think they're trying to tire me. Even when I ensure them that it's NOT my 911 that's the problem they don't trust me. So therefore I'm going to put the wheels on another 911 and see how it reacts.

I can't sell the wheels because a potential buyer will feel the same shaking as I do and come back and complain. So this has cost me a lot of money and I'm still running tele dials on the car. DAMN I'm mad Even if I wanted to buy Fuchs now I can't afford them.

By the way how do I know if a tire is bad?

Hallo

Nobody is perfect

tires can have heavy spots and therfore have an mark showing the heavy point. to make it correct you match the wights by runing the rim without any wights to find the high points.

Today i would say 80% of the aftermarked rims ( here in germany with TÜV approval ) are very unround and way out of factory specs.
Even with the finerst matching you still have a little restvibration that will be very feelable at the light frontaxle.

First to check is if your frontaxle is in good shape ( bearings play correct ? ).

Then remove the tire from the rim and let it run on the bench. use an big plastichammer to aligne the rough spots. mostly the cheap rims will break then and you are lucky you hvnßt use them on the road.

Well said aligment by hamering is normally only allowed at forged wheels not on cast. But if they have passed TÜV they musst outstand much higher forces without breakage. ( Bendage is allowed ).

And Costumer is king, if he likes an rim by design and can´t live or sleep wthout it then you have to give your best.

BTW factory specs for unroundness are in the specs book or in the shop manual.

Grüsse

I´m surprised about the problems you are having. As you might recall, I have the same wheels in my 3.2 and have experienced no vibration problems at all.

The thing that comes to my mind also is the condition of the suspension and steering. Because these wheels were designed for a totally different offset and then "stretched" to fit earlier cars, they put a lot of stress and leverage on the bearings. (And being so heavy doesn´t help either)

If you can trace the problem to be either the tires or the wheels, you should be able to get a replacement and if not satisfied, then a refund. Consult the consumers advicer office (or whatever that might be in your country )if the seller is unwilling to co-operate.


Best of luck,

Mika

Mikkel:
Very sorry to her about your problems.
I don't know about the consumer protection laws where you live (Denmark?), but in the US you can ask your credit card company to reverse the charge, if you have made a good faith effort to resolve the matter with the vendor. I have done this, and it works.
Do you have an equivalent of Small Claims Court? In the US, companies have to have an attorney go to SCC for them, and if the amount of money is small, it is usually cheaper for them to pay you off rather than go to court. I have done this on 2 occasions when my car was damaged and the other person's insurance company would not accept liability.
Remember the motto of the Animal House fraternity: "Don't get mad, get even."

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John C
1988 Carerra coupe
1957 Speedster replica
1997 A6 Avant

Maybe I am over simplifying this, but shouldn't you be able to see if the wheel is out of round by putting it on a spin balancer without a tire?

Tom

Sometimes, if tires are just a little out of round, and the technician says there should be no problem, you must consider that if more than one tire has a slight out of round problem, they will, at some point, become harmonically out of round and when they are shaking in harmony, that's when you really notice it. I've gone thru that problem a couple of times & found that shaving just a hair off all tires that are even slightly out of round cured the problem.
regards,
jlex.

Well I'm going to try the wheels on another 911 soon. If that one shakes too I'll take off the tires and check if the wheels themselves are out of balance as suggested.

I bought the wheels through my place of work - a car dealership - that way I got a trade discount which was very nice for my bank account, but at the same time it's a trade between "2 professionals" in law language. Therefore I haven't got the usual buyer's protection...

Mikkel, if I were you, I'd go ahead and pull the tires off the rims, to see how far the rims are off being straight.

However, make sure you are sitting down, as the wheel is being spun!

Looking at several of these wheels, I couldn't believe the shaking was not MUCH WORSE than what I felt, with a wheel this far out of straightness, and balance. Also surprising is how the F#CK they could make a brand new wheel to tolerances this loose.

I don't know much about the TUV certification, but I believe it's pretty strict, except if the wheels don't break, they pass. They can bend however much they end up bending...

I've seen these wheels get bent, crack, and have heard about them breaking, but haven't seen that in person. Actually a couple of people I know are using these wheels on highly modified cars, for track events with race rubber.

However I'll be one person who'll stay away from them, although my car looked quite good with them too...
Ahmet

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It's all the driver...

[This message has been edited by 1.2gees (edited 03-17-2001).]

Mikkel, as some of the previous posts have said, it IS possible (and more often than you might think) for new tires to be out-of-round or out-of-balance (they are two different things, though they can be combined in one tire.) I worked as a salesman for a large national wheel and tire company for about a year-I sold thousands of tires and hundreds of wheels, and yeah, we replaced quite a few of both because they weren't within tolerance and unable to be spin-balanced to the customers' satisfaction.

Have the tires removed from the wheels.
Put the wheels on the spin balancer and spin them slowly to check for run-out (wobble), both in the axial and the radial planes (side-to-side and up-and-down).
If all the wheels are nice and straight, then spin them at road speed and check for balance.
If any of the wheels fail any of the tests, then replace it (or them).
If all wheels pass all tests, then mount the tires and spin balance the assemblies, while checking the TIRES for out-of round at the same time (easy to do while they're spinning by holding a tool or piece of chalk against the tread while it spins.) If one tire and wheel assembly is very out of balance before putting any weights on it, have them remove the tire and remount it 180 degrees from the original position on the wheel, and re-balance it-it will usually solve the problem, or at least greatly leesen it.

Finally, make SURE whatever wheel you're using on the car sits FLAT against the hub when it's mounted on the car-many times the wheel and tire are balanced fine, but wobble slightly on the car because of slight interferance between the hub and the back of the wheel, or wheels not being hub-centric to the car. Track the problem down one step at a time, and you'll find it-it's almost always something simple. Good luck.

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Clay McGuill '66 912, '97 Jeep Cherokee www.geocities.com/the912guy



[This message has been edited by ClayMcguill (edited 03-17-2001).]