Tom H

Has anyone been able to feel a difference in ride comfort between 34psi and 30psi? My RX350 rides very harsh and sends every bump in the road up my spine. It's also starting to creak and rattle (interior) at every bump with only 1100 miles on the clock. On anything other than new, smooth road surfaces it gets so bad that I just can't stand to drive it anymore for more than 15 ~ 20 minuets. I noticed tonight that all my tires are inflated to 34psi (as delivered from dealer) and the manual recommends 30psi as the ideal pressure. Obviously I will lower them to 30psi and see if I can tell the difference but I'm curious about others opinions on the subject and whether or not you can tell a difference. Lastly, why would the dealer set them to 34psi when Lexus lists 30psi as the target value? I red somewhere that some dealers set the pressure high when the car is on the lot to prevent flat spots from thumping during the test drive. Any truth to that?

jfelbab

You will definitely feel the difference. I keep mine at around 31 psi.

Tom H

Thanks Jim. I'm going to set them at 30 in the morning and see what I find.

cheap_deal

34 is too high for me. 30-32 is ideal.

mandyfig

I have tried 34 and found it too stiff. If you had perfect roads...great. If you have so-so roads...it is annoying. I have settled for 32. Some like 35. If you do mostly highway driving, 34 would be perfect. If local and surface streets, try 30~32.

Lexmex

Some gals and guys like to ride a little high. I have a max of 44 psi on my 235-70-16, Michelin CrossTerrains with my RX300, and set them at 40 psi...harder ride for sure, but better MPG and it makes a world of difference on the track. I haven't worn out the center of the tires as would normally happen. If anything, I have been wearing out my outside corners from the nutty high speed turns I take.

Tom H

Well...I lowered my pressure to 30psi and can't say the car feels like it rides any smoother. I still feel relatively small bumps in the road sending a jolt to my spine. I will have to give it a few days to be sure. It does feel a bit sloppy though as far as handling goes with the lower pressure. Ironically, this is the recommended pressure.

MC Wong

I have my tires inflated at 40psi. I know the manual recommends a lower pressure but I dont feel bumps that badly even on 40psi. But that might just be me. I also thought that if you inflate your tires at a higer pressure they will last a bit longer.

cheap_deal

does the manual give different tyre pressures for the front and rear tyres?
its listed as 32 front and 30 rear in my manual or the other way around.

Tom H

My manual list 30psi, front and rear.

AM1

iTrader: (6)

might want to change the tires. the stock tires are somewhat hard to begin with

The G Man

Tom H, AM1 is right, the tire itself makes a lot of diff. Every tire's sidewall has diff. stiffness. Are you riding on 18" tires or 17" and what brand of tires do you have on the RX.

Tom H

Thanks guys. This is Interesting. I have to admit I'm not tuned in to the effects of tire design on ride comfort and handling. I would be interested in knowing if there is a practical way to basically soften up the ride (substantially) via tires and/or suspension changes. If not, I believe I will need to sell the RX350 as it is becoming too much of a strain on my back to drive.

I am currently running the stock Michelin Energy LX4 tires. 225/65 R17

jfelbab

Here are three tires that top the ratings at TireRack.com. They are all much higher rated in ride comfort than the LX4 tries.

I recently changed to the Bridgestone Alenza and it rides much better than my OEM tires. Goodyear Fortera TripleTred got the nod for comfort but only by 8 hundredths of a point over the Alenzas though. I love my Alenza's.

http://www.tirerack.com/tires/tests/...omCompare1=yes
The RX350 loaner I drove on the Michelins felt very jumpy or bouncy to me. If I had test driven that vehicle with Michelins prior to purchase I'd have passed on the RX.

Losiho

I run 36psi all round in my 225/65/17 Yokohama Geolander HTS G051s.