I have a 2017 LS460L and had the same problem with tire "vibration" at high speeds. I bought the car used (28k mules) and the Toyo Extensa HP tires came with it. I had the dealer rotate and balance them a couple of times but still had the vibration. I could feel it in the steering wheel. So I finally bit the bullet and replace all four tires with Michelins. and amazingly the vibration at any speed went away. Just a thought....

 

I've been having this issue for quite a while now and I have a theory.

The long and short of it is I think that road-force balancing is not always the best option. The best balance I've had on my current set of tires (Falken Sinceras) is from an older dynamic balancer (not road-force). My tires seem prone to slight flat spotting whenever they're not at operating temperature. I feel this as a some vibration and jitter for about the first 1/2 mile of travel. I think this slight flat spotting is picked up on a road-force balancer (assuming the tires aren't immediately taken off the car and balanced while they're still warm). The road-force balancer tries to accommodate for the slight flat spot with added weights somewhere. When the tire's warm and moving, that weight would no longer be needed.

This is just a theory, but it makes sense to me.

Source: I've had my tires balanced numerous times. All road-force except 1 time (mechanic was a smart guy that took his time though too).

 

I own many Lexus and I notice that they work great with brand name tires like Michelin, Continental, Bridgestone. Michelin provides the best ride experience then Continental. I used to put Toyo on my GS and it ran like crap.

 

Could be warped rim... This happened in my 2014, I had the tires rebalanced 3-4 times, they were new tires so back and forth with the tire place, they even replaced the set, and it was still happening. I talked to management they investigated it. They finally pulled me aside and showed me on their machine, they could not balance it.

The tire place did not even know, till I made an issue about it.. They balanced as normal, and they didn't see anything...

I tried to schedule an appointment with a place that will fix the rim but, times I have not met up... scheduling conflicts, I will be getting it fixed soon.

Dam New England pot holes !