Re-check your wheel balance too! Maybe your wheels are bent. When I re balanced my wheel I noticed that they were bent while spinning even though they didnt look like they were bent stationary. Even after balancing them back to 0.00 they still vibrate at a certain speed.

 

at 160K+ my 92sc400 was vibrating after 35 mph due to:

1. Worn/Broken Transmission mount
2. Worn Front and Rear Rubber Coupling/Bushing on the Drive Shaft ($200 each for parts at dealer ) ended up changing the whole drive shaft for a used one at a much cheaper price ($180 for whole drive shaft )

got those taken care of and rides pretty good now at 190K (almost a yr)
except for some vibration caused by need for

3. New Shocks/Springs all around

 

thanks for the details ill be bringing it in when im free this weekend

 

Had the same exact problem. Got front wheels rebalanced...hit 80+ with no shake

 

Def. check the front wheel alignment. Also, look at your tires. I had mine aligned on "old" tires and the vibrations didn't go away. Got new tires and balance, now it's smooth as it can be.

Ed

 

I know exactly what that is. Your front brake rotors are warped. You will need to have them resurfaced or replaced.

Excessive heat is the culprit, they got over heated.

 

My car just came out of the shop for total re-doing of the entire power steering system and i had my mechanic check the vibration, i felt it at 40mph and it quit after 60mph he told me i needed to have the drive shaft balanced so that might be your problem too, if any one knows where the hell you take your car to do this i would really appreciate the info, is there a specialty drive shaft place, under what do i look in the yellows and what the average cost of this would be, i am in coral springs, florida if anyone has a shop i can do this at.

 

that could be it easwooth

 

balancing the drive shaft was a problem for me too. Apparently the shop that installed my drive shaft didn't balance it, so the vibration returned. I had to have it done at another shop costing me more money . So if anyone has theirs done make sure to ask them to balance it too which they are supposed to do. If I remember correctly it cost me ~$250

 

wheel spacer can also be the cause. try to rebalance the wheel with Road force.

 

That was a song. The only ones I know of are NO VIBS.

This may date me but "back in the day" those of us that were serious had our tires shaved round and balanced on the car. You can balance an out of round tire but it will NEVER stop vibrating. They used to spin the tire on the car with a special machine and run a knife like device into the tread ever so slowly and when the tire was cut all the way around it was a "round tire. This mated the particular tire to that rim and they were never separated and the tire was marked so that it could be reinstalled to the exact position. The balance was done on the car also. The fronts were spun with a machine and the balance was checked with accelerometers(vibration sensors). Usually a long process, the tire was finally spun for your inspection, without any attachments, and it would be absolutely vibration free at 100 mph and every speed below. The rears were done without the spinner drive as the engine was used. Same process. If they used those big balancing wheels you had those removed for the final test.

Spin each of your rear wheels by lifting one and leaving the other on the floor. 50 mph on the speedometer equals MPH on the spinning wheel if one tire is held. You can kill people with an exploding tire and the things GROW an inch at 100 so get it high enough to start with. If you check all of your tires like this you can select the ones that are running smooth and not pay for needless work or RISK THEM UNBALANCING a good tire. I can't find any shop around here in Eugene that speed balances tires and I guess many of you are in the same shape. I miss southern California for lots of stuff. I have had many tires rebalanced by reputable shops and all I had to do was point and say "you spin it and tell me that is balanced". Twice I got a new tire for that position and I have no doubt that I would have chased that vibration for the life of the tires and been ticked off the entire time. Tires seem to be of higher quality today but my last set of Conti's were balanced three times and my Toyo's were balanced twice and the shops are reputable.

Watch the tire as it spins slowly. Does it weave from side to side? Does it bounce? Have the car aligned and after a quick blitz down the freeway measure the tire temperature across the face of the tire. Hot center...to much air. Hot one side...CAMBER. If camber is on...BAD TIRE. I have had each and every one of these problems and I don't buy cheap tires. Mich is the KING for round and "no weights needed". They are not the only tire brand I buy, though.

Then there is "radial tire pull". A tire will resist rolling more than the tire opposite it on the car. Car pulls to one side. They reverse the position and the problem goes away OR it pulls in the other direction. I wouldn't believe this if I hadn't seen it so many times. Still confuses me though...why doesn't it pull the other way every time?....why didn't I have this problem BEFORE you aligned the car?....and on and on. Can't argue with success though.

Just some thoughts

Good luck

John