Not To Beat A Dead Horse...

[bobstoc]

I realize the topic of VIBRATION comes up quite frequently here, but I have one more quick question. After sitting overnight, my '01 Gs430 has a vibration at 60-70mph and the car seems unable to track a straight line (requires minor steering corrections). A short time later, the ride smooths out and the car tracks straight. It has Goodyear gt+4 (225/55/16).

I was told the vibration is from flat spots on the tires. I might believe this if I was running 20's, but does this sound plausible for stock 16 inch tires which simply sit overnight? Or could it be something much more complex. I've had the tires speed balanced, aligned and the wheels are not bent. Thanks.

[Ericok]

I'd vote for flat spotting. You could try and get the tires rebalance at a shop that has a Hunter Road Force balancing machine. That machine can compensate for tire-to-tire interaction and can spot out of round wheels and tires also.

I realize the topic of VIBRATION comes up quite frequently here, but I have one more quick question.  After sitting overnight, my '01 Gs430 has a vibration at 60-70mph and the car seems unable to track a straight line (requires minor steering corrections).  A short time later, the ride smooths out and the car tracks straight.  It has Goodyear gt+4 (225/55/16). 

I was told the vibration is from flat spots on the tires.  I might believe this if I was running 20's, but does this sound plausible for stock 16 inch tires which simply sit overnight? Or could it be something much more complex.  I've had the tires speed balanced, aligned and the wheels are not bent.  Thanks.

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[chuckb]

if it goes away after a few miles it's flat spots from sitting. mine does it for up to 3 miles sometimes. my car even mildly gets them from sitting for an hour or so.

btw-it was even worse when I had my factory 16 inch goodyear gt+4s.

[bartkat]

Flat spotting is not size dependent. It's probably going to be more pronounced in colder weather though. Tires with a nylon belt overlay will be more prone to flat spotting. It it runs out in 3 miles or so, it's normal.

[914lps]

Flat spots will a tire. My wallet has taken that hit over the years. Even on small tires. If the tires can not be balanced on a high speed balancer it is a flat spot. A good tire shop will be able to test for you, If you are lucky and have enough tread left, you may find a tire shop that can shave the tire back to round. You loose tread life like crazy, but it is better then just thowing the tire out.