Bad Vibration
 

My dad just got a 2001 SL2 with 89,000 miles on it. But when we get on the freeway the car vibrates quite a bit between 55 to 75 mph and you can feel the vibration a lot on the steering wheel. It has new aftermarket wheels and tires. Could it be an alignment issue or something needs to be fixed on the suspension components??

I'd start with wheel balancing in the front

Aftermarket wheels sometimes are waaaay outa balance ...

Did it vibrate like that before the new wheels and tires? If not, there's your answer.

Almost all aftermarket wheels require a hub adapter. If you did not get the proper hub adapter, then the only thing centering the wheels are the lug nuts and if the lug nuts were not put on with the greatest of care, the wheel will not be centered.

Most tire shops use an impact wrench to install the wheels and that is NOT the greatest of care. Once the lug nut hole is distorted by the impact wrench, it cannot be re-centered without the proper hub adapter.

My dad just bought the car and didn't vibrate like it does now. The wheels are still original size as the stock ones from what i can tell and so are the tires. Well where ever they took it should have balanced them, right? Will take the car to Discount Tire to have them checked.

Yep, they should have balanced them, but who knows? They need to be spin balanced on the car if at all possible. Bubble balancing has always just pissed me off.

OK, you clearly didn't understand my last post. Saturn wheels have a 4x100 bolt pattern with a 57.1mm hub. You may have put on 14x6" rims with 185/65-14 tires, that would be the same as the stock wheels, but the hub can be quite a bit larger than the 57.1 mm for your car.

Aftermarket wheel manufacturers want to keep down the total number of wheels their distributors have to stock, so most wheels are made with either 8 holes for the lug nuts or 10, depending on whether it has a 4 lug hub or a 5 hub lug. On a 14" wheel with 4 lugs, 4 of the holes will be on 100 mm (3.94") centers and the other 4 will be on 4" centers.

The hole in the center will be quite large and will not fit snugly around your hubs. This is where the hub adapter comes in. It fills the gap between your hub and the wheels hub cutout. Its a simple ring, but without it, no amount of balancing is going to solve your vibration problem. BTW, they don't cost very much.

Your wheels could be used on a Ford Escort because the Ford also uses the 4x100 mm lug pattern, but its hub is only 54.1 mm so it would need a different hub adapter.

Keith has a very valid point, especially if you bought "generic fit" wheels. Those things can be a royal pain in the keester if you don't have the right adapters.

Well Martin did you locate the problem? Did it turn out to be tire balance, a hub centric ring problem or both? Let us know what you found if anything. If you have anything else we can help you with speak up. Do a little posting and add some pictures of your ride to your intro post. We all like pictures.

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