Vibrations At Highway Speeds

[vista4u2]

I have 92 LS 400 with 200k miles. It is in exceptional condition considering its age and mileage. But something is going on that's kind of irritating - at about 60 MPH up to about 75 MPH, a vibration/shutter starts happening. It comes and goes, but mostly comes and stays, and totally deminishes from my enjoyment of the smooth and quite Lexus ride. I had my tires re-balanced and it helped little. Can I assume that this problem isn't all that uncommon on older models, and somebody out there has some good advise? Please let me know. Thanks!

[monarch]

Could be out of round tires, or tires with irregular tread wear, could be warped brake rotors (due to overtightening of the wheel lug nuts) , could be a bent wheel rim (from driving with a flat tire). Age of the car doesn't hardly matter. If there is no vibration when braking then the rotors might be OK and a shop with a Hunter road force balance machine might be able to cure the vibration by balancing the tires better.

[1990LS400]

I would not rule out wheel balancing yet. My 00 LS had a similar wobble on its summer wheels at 60 - 70 mph since I bought it in 2003 -- and the OEM wheels were new/replaced under warranty and used for the first time in spring 2004 with brand new Dunlop 5000's.

I had these wheels balanced a total of six times in two years but the wobble remained - really disgusting to feel the vibration through the steering wheel.

Two weeks ago I discussed the problem with a Lexus dealer service writer who led me to their balancing guy to discuss the issue. The mechanic (hey, I'll call him that) explained to me how he would use a combination of tape weights and rim weights (only on the inner rim edges) to solve the problem. He told me he could balance the wheels properly using only the dynamic feature of his machine and that it was doubtful that he would need to use the road force feature.

He showed me how he could "tell" his balancing machine exactly where to put the tape weights so that they would not hit the brake calipers.

I had very low expectations.

The service writer came into the waiting room about one hour later and told me that the job was done and that he had personally road tested the car on I-435 next to the dealership.

Frankly, I did not believe the problem had been solved and I paid the $50 and drove away.

My car drove like a dream - no vibrations at all at any highway speeds and no unsightly wheel weights showing on the OEM chrome wheels. Normally I stay away from dealerships but this was the best 50 bucks I have spent on this car -- I will return to the dealership next time I need a wheel balance.

[vista4u2]

Well, frankly I am relieved to be hearing more focus on tires than on ujoints, ball joint and the other related parts. I will take your advice and shop around for someone with a high grade balancer, express my concerns and expectations and go from there. Thank you guys very much.

[swordfish]

i had vibration -not in steering, but u can feel it thru your seat back from 60-65 mph. goodyear tyre centre said rear balance was not out enough to cause the vibrations and i should look at other cause.I thought otherwise cos i have had same prob b4. sure enough go on highway over easster, and its fixed! The rears are very sensitive to correct balance, i think because of those bushes in the bottom of the up rights that go soft .

cheers