Vibration at 75mph, Not rims or tires, no vibration in steering wheel

If the vibration seems to occur only while accelerating, you most likely have a bad inner CV axle joint, either left, right, or both sides. If it occurs under any power condition above 75 mph, you may have an out of round axle hub in front or stub hub in back. Check all four hubs with a dial indicator for any type of runout - lateral or radial. If one has clearly more runout than the others, ithat hub is the most likely culprit.

Toyota MDT in MO

I forgot to add that the rear tires were replaced about 3K ago becase of uneven wear. The tires showed signs of cupping!

I had a similar issue with a sunroof open and NO windows open. (not at 75 though)

"Wind buffeting"

A cupped tire isn't round and will definitely vibrate. However, a tire that vibrates is likely to cup. (Sounds like Catch 22.)

Was there any suggestion as to why the tires were cupped? Are they rotated regularly? (Rotation every 5,000 miles or so will reduce cupping.) Is the rear suspension in good shape? No worn shocks? Has the car been in an accident, or have one of the wheels hit a curb? Are the rear wheels tracking true?

If the cupping was caused by vibration, it sounds like the problem was never fixed, and you may soon be due for another pair of rear tires.

Dan

(This account is not used for email.)

Yes, it would indicate a rear vs. front--if one end is the culprit. Assuming so, check the rear tires for *out of round*; remember, a box can be installed onto an axle, spin-balanced, and rotate smoothly--and yet it definitely won't ride smooth! Check them yourself by raising them just an inch or so above ground. Lay an oil bottle squarely on its side and up close to a tire. Carefully spin the tire, by hand, and watch how close the tire approaches the stationary bottle as it rotates. High spots will narrow the gap, and low spots will widen the space(DUH!). If found out of round, have them trued and then balanced, and enjoy the quiet, smooth ride Lesabres are capable of. HTH, s