Contour Enthusiasts Group Archives Forums General Troubleshooting Strange Front-end Vibration

Hello all,

I've come across what seems to be a strange front-end vibration problem. I'll try and briefly
lay out the scenario...

I purchase used '99 SVT. 22k miles on it.

I have to have the dealer replace the rack under warranty.

I have to take it back a few times cause they can't seem to tighten bolts properly.

I put BAT springs on and everything is fine.

I purchase Loco wheels and feel a little vibration, but figure they just didn't balance them as well
as they should of.

I get my mechanic do some brake work and make sure everything in the front-end is tight. In
doing so he had to dismount the wheels.

I pick up my car and have major vibration in the front-end above 60!

My mechanic says the only thing he had to tighten was one bolt on the inside side of a control
arm about a quarter of a turn. He suggests remounting one front wheel.

I decide I'll just go ahead and get them rebalanced and an alignment check done at a reputable
shop (Tire Kingdom).

They do thier thing and everything seems as it was before the major vibration. Even a bit better
cause it was slightly out of alignment and the wheels were slightly out of balance.

Now it's been a while and it's time to rotate the tires so I go back to Tire Kingdom. They rotate
them and now the major vibration is back!

So I take my mechanics advice and dismount, turn, and remount one wheel. To my amazement
the vibration goes back to a minimum!

At this point I'm baffled as to what the deal is and I don't want to throw parts at it. It may just be
something I have to live with, but it just doesn't make sense to me. To me if the wheels balance
then there shouldn't be vibration like they're not. I'm thinking the after market wheels are making
a problem that was probably already there more noticeable. At this point I have 36k miles on it.

Anyone got any ideas?!

Thanks for assistance,
Jay

sounds like one of your tires may have a radial pull (bend in one of the steel bands in the tire). when the tires are on the rear its not nearly as noticeable, if you put them up front you'll get a nice vibration and possibly it will wander more (would seem to be an alignment problem). either that or you could have a bend in one of your rims.

The vibration was probably cause by one of the rear wheels and when they were rotated, it became a front wheel, where vibration is much more noticeable.

Thanks for the replies, but the problem first came about when my mechanic just dismounted the wheels and then remounted in the same place (no rotation). And I can get the amount of vibration to fluctuate by dismounting, turning a half turn, and remounting one front wheel. No positional movement.

Thanks,
Jay

I suspect that it is a wheel problem. If you can't seem to resolve it with tires, take another good look at the wheels. It is not uncommon for aftermarket wheels to be built a little off center.

But if that were the case, how would they be able to be balanced properly? They all zero out when balanced.

Thanks,
Jay

There are a couple of reasons that balancing may not answer the problem. First, balaicning off the car with a computer balancer is, well, off the car. It does not adress how the wheels attach to the car. Computer balancing is the best though well over 99.99 percent of the time. The other is that it can be perfectly balanced and still be out of round. When that happens you will still get a hop no matter how well balanced it is. Picture a well balanced square wheel as it contacts the road.

I have the same vibration over 70mph but mine is a Mystique GS with around 29k's (2000 year model) but I have stock 14" rims.

any ideas?
thanks
later

It does sound like a bad tire or wheel, at least one of them sounds out of round. Find someone with a Hunter GSP 9700 Road Force
tire balancer, this is the best piece of equipment for balancing tires. Ask for match-mounting, especially if you know what 1 wheel/tire combo is bad. This should do the trick

Sounds to me like maybe a belt has broken in one of your tires. Having the tire dismounted, turned and remounted will help lower the amount of the weights needed to balance it, but if it is a problem with the tire, or the wheel, the balancer will not pick that up. Only if a wheel is bent badly will the balancer pick up on it. I spin the wheel on the balancer before I balance it, that way I can look at it to see if it is bent or not, if it is bent I will let the customer know about it, then mount that wheel on the back and recommend replacing that rim before it tears up the tire. if it is a problem with the tire, rub your hand over the tire, feel for any low or high spots, if you find any, replace the tire, if that doesn't fix the problem you might want to have your suspension checked.

Hope this helps a litttle... TJ