Tyre Pressure Rx400H

[copfprd]

Hi all, I have a rx 400h with 255/55/18s. The handbook says put 32psi all round. This is supported by the sticker in the driver's dorr. However, the local Lexus garage puts 35psi in and so does our local tyre place. Would welcome your views.

[steve2006]

Hello and welcome to the LOC.

I have moved your question from the LS400 forum to the RX400 forum as you may get more answers here.

My LS400 has a range of tyre pressures from 32-36 PSI so it may be the same on the RX.

[copfprd]

OK thanks Steve

[nib4722]

hi , i too run mine at 35psi - i get better mpg as less rolling resistance but i do drop them to 30psi in the snow for better grip,

[copfprd]

great, thanks Nigel

[coolcatshaft]

hmmm

I was told to put in 35psi at the front and 38psi at the rear by Martin Addy, the service manager at Lexus Leicester.

[Farnham Dave]

On 7/27/2012 at 8:24 PM, copfprd said:

Hi all, I have a rx 400h with 255/55/18s. The handbook says put 32psi all round. This is supported by the sticker in the driver's dorr. However, the local Lexus garage puts 35psi in and so does our local tyre place. Would welcome your views.

I know this is an old thread, but I have an old car, so that's ok.

Just had a couple of new tyres fitted to 2006 RX400h. 255s. He reckoned 38psi. I just took out on a spin, and felt like the car wanted to take a literal spin.... Front end feels lose and bumpy under acceleration. I'm going to reduce it down to about 33, and see how it goes. I don't see the point of having 0-60 doable in under 8 seconds of the car just wants to visit the ditch every time.

Any one else has a recommendation of 38?

[BachelorDays]

255s?

Amazing.  I thought given same chassis the spec would be same.  Mine are 235/55/18.

 

[Farnham Dave]

2 hours ago, BachelorDays said:

255s?

Amazing.  I thought given same chassis the spec would be same.  Mine are 235/55/18.

 

Sorry... I meant 235!

[BachelorDays]

Great.

I must say on 32psi my tyres look almost punctured!  I had a valve changed and the tyre guy didn't want to know 32 - he wasn't going to shift from putting in 35psi.

I ran on 35psi for a little while and then decided to try 32psi.  Been on that for a few months.  Several motorway journeys, even a run in France.  Feels comfortable.  Don't know about any affect on mpg, nor, for that matter, how the tyres will fare long term.  I thoroughly enjoyed the drive in France, pushing it most of the time - beautiful ride and did wonder if the correct tyre pressure played its part in it.  Abysmal mpg but worth every (extra) Euro.

[Farnham Dave]

I seem to recall that tyre pressures are finalised by a test driver on a circuit running with ever increasing pressures until the car tries (or succeeds) to leave the track, then the pressure is dialed back. If this is true, being 5 psi over what I suspect is the right pressure is asking for trouble.

Also, I don't want to be improving my mpg by being scared of the loud pedal.

[rich1068]

Ever since I started driving if the people who built the car say it should be xxpsi then xxpsi is what it gets. Not at all concerned about how the tyres "look" with 32psi on a 400h. And tbh I'm a little surprised that some take the word of tyre fitters as gospel.

[Farnham Dave]

7 hours ago, rich1068 said:

Ever since I started driving if the people who built the car say it should be xxpsi then xxpsi is what it gets. Not at all concerned about how the tyres "look" with 32psi on a 400h. And tbh I'm a little surprised that some take the word of tyre fitters as gospel.

This particular tyre fitter has always, up to now, been right. I am going to deflate back down today.

Update: have just taken them down to 32-33. A totally different drive. Solid, precise and a joy. And acceleration doesn't make me feel like I'm going into orbit.

What made it worse... Having recommended 38, he put in 40!

Edited November 15, 2018 by Farnham Dave