I had a loaner RX with the 235/65/18 wheels, much better ride with the 65 profile tires compared to the 235/55/20 f sport wheels, especially living in NYC with these roads. What a shame because I love the looks of the f sport wheels. Is there ANY way to make the ride more comfortable by putting 235/60/20 tires? Will it mess anything up like the alignment? I’m sure it’s not going to be perfect if Lexus didn’t design it this way but I’d love to have thicker tires

 

i think it will just make your speedometer inaccurate.

 

Yes you can, they have very similar circumference. I have stock 235/55/20 and 235/65/18 for my winter tires. And I do find that the 18" is smoother that the 20". You will feel though that the handling in curves is better with the 20".

 

I know in previous cars I’ve had if you go larger then stock wheels it can sometimes throw off the alignment, which is why lexus chose the thinner tires to compensate for the larger rims. I know the speedometer was the main purpose of that but I just need to hear someone say they put thicker tires on their 20” rims with no negative effects for me to take that risk. Has to be someone out there

 

Yup noticed that right away when I get my car back it definitely handles and turns better with the larger rims. I’m saying would it be possible to put 60-65 profile tires on the 20” F sport rims?

 

Oh! on the 20" wheels! No that you cannot.

The tire is going to be much larger!

 

Damn not even 60 tires instead of 55?

 

From that site: it introduces an error of 3.1% on the odometer. But it would seem that it would require a rim of 6.5 inches while your rim is actually 8 inches.

https://www.wheel-size.com/calc/?whe...cl=30mm&sr=0mm

 

I could care less about the odometer reading. My only concern is if it will drive differently in a bad way. There has to be a reason lexus didn’t go with that tire

 

I don't think it won't be any different than the 18 inch format which have a larger side wall...

The issue is this tire size availability. Quick search and I found only a Continental that make a 235/60R20, I did not find any 235/65R20.

There is a possibility to go narrower that 235 though.

Good luck in your search!

 

The simple answer yes as I have done that multiple times with other vehicles but Not the RX350 YET.

I will do 255/55/20 when it's time to change tires. This has similar circumference to your 235/60/20 while little wider and little less sidewall. Also, there are plenty of tires in that size.

 

Ignoring introducing odometer error and possible alignment issues, I would not expect much ride improvement going to only slightly taller rubber (going from a 55 to a 60 profile) as the only change. The difference you noticed between the two cars might also be related to the different suspension/tunings between the "regular" RX and the Sport version, and not so much the tire differences. I think a bigger ride quality variable, easily controllable by you, would be strict adherence to the factory suggested tire inflation. I have noticed a significant ride improvement going from 37-38 psi (cold) to 33 psi (I have the 20" Sport wheels). Related to this, do you know if the tires on both cars you tested were both inflated to factory specs since that would surely impact the ride quality.

 

Another solution for better ride quality and handling is to go with a set of Continental Extreme Contact DWS 06; size 255/50/ZR20. I’ve got a set of these on one of my other cars, and they are outstanding. They significantly improved ride comfort, grip and road noise, and, IMO, much better way to go than changing aspect ratio to something taller.
https://www.continentaltire.com/prod...550zr20-109y/?

 

As terrific as your experience has been with the Conti's in other vehicles, there is no assurance that they will improve the ride of the RX compared to the same size tire that the OP is running now.

 

No guarantees in life.