[shakham]

I get this funky vibration around 55mph lasting up to about 65mph. It doesn't seem to bother passengers but it irks me. My steering vibrates and the car doesn't feel tight.

I originally thought it was tire pressure. They were perfect at 36 so it wasn't that.

I then though wheel balance. Did those and it got a little better but didn't go away.

I'm running Kumho Ecsta Supra in the rear (275) and...Firestone Firehawk (or something like that) up front (stock size).

What's next? Could it be flat spot on the tires or something like that?

Should I try a different tire pressure??

I appreciate any help...it's embarassing having a nice sports car with a stupid problem like this.

later,
Amir

 

[James Kwon]

I'm not absolutely sure but you may need an alignment. The same symptons happened on my other car and an alignment fixed it.

james

 

[wizard_of_oz]

Not all places do the same quality of wheel balancing. Make sure they use a dynamic balancer.

You could also have a problem with a tire (ie, flat spot or slipped belt) or a bent rim.

Really excessive caster can cause the fronts to shake more, but I doubt that's your problem. You'd be fighting to keep the wheel from snapping back to straight when you're in a turn.

 

[meggleto]

Another thing to inspect is the tie rods. When they get worn the steering linkage can vibrate in relation to the knuckle. You can check this by raising the entire front end up off the wheels and wiggling the tires in/out at the top/bottom and then at the front/rear of the tire. The tires should not wiggle. If they do you'll need to replace the tie rods that are loose in their sockets.

 

[SdSupraTT]

It can also be brakes...watch for warped rotors...Also if someone over tightened the lugnuts that can cause problems as well...at least it did for my old t-bird.

 

[R*Rocket]

Driveshaft?

Driveshaft could need to be balanced?

 

[Josh///M3]

Get the car an alighnment from a GOOD shop with preferably a hunter alignment machine (the neat one with the lasters would be cool). That should do it.

Lates,
Josh

 

[bwill]

There is a newer type of wheel balancer that you may want to try and find. I believe Hunter is one of the manufacturers. The machine has a roller on it so your tire is loaded and it spins on the machine. Supposedly it can locate the stiffest part of your tire sidewall and can find where on your wheel it is (for lack of a better word) flat. It matches your stiffest sidewall point of the tire with the "bad" spot on your rim to round out your wheel/tire combo the best.
Barry H.