This is not a TPMS related thread...

First, I wish there was a way to include this in all the Coupe, Clubman , JCW forums as this question is equally for all... Hope folks interested in any see this. ...Also, a bit of reading but please do if you're interested in the subject of tire pressure and how it affects driving dynamics.

I was very surprised to find tire pressure @ 38psi from the dealer, not realizing yet that's what the manual specs. The R56S manual for coupe & clubman (no JCW specific manual) specifies the runflats w/ 17" rims should be run at 38psi front & back ; 41psi if the car is fully ladened. I read in a recent Modern Mini article however -- in the final page's "Speaking Frankly" article interview with "ex-JCW guru" Tony Franks for a very different tire pressure recommendation...

Because of the +60% of weight over the front, he states you need the high pressure up front, but in the rear "the last thing you need is high pressure that reduces the contact patch, giving you sudden death oversteer when you lift off in a bend". [of this I can attest, having spun, almost putting the rear into a sign-pole, w/about 1 mile on the odo on an increasing radius decreasing elevation left, where all I did was lift off throttle instead of braking into the turn, not knowing the dynamics of the car yet. Lesson Learned!]

He goes on to explain (the very surprising part) ... I'll quote (this is all w/the stock suspension)
Having spent gobs of money to make my last car handle incredibly well [custom suspension hardware w/Penske 8100 dampers @ the heart of it], neutral handling balance is a very very good thing and the goal to strive for be it road or track.

(if you go this far, much thanx for reading!)

I tried this, and I do like how the car feels. I did it slightly different, with 36 up front and 31.5 in the rear. However, a) I'm not happy running 17" rims w/a 24" outer diameter near or under 32psi (in the rear) -- bent rims here I come from low tire pressure w/a thin sidewall (yes, I took the rim+tire insurance) .... and b) my fuel economy has suffered. I couldn't believe how low the real-time OBD estimates were @ 70mph today... then I realized I'd done the PSI change. I will be going to 39 or 40psi up front, and 34 or 35psi in the back. (5psi difference, not 6psi)

...however, it -does- drive real well!

Anyone else try it or run that way?
You wanna give it a try then report back?
Much thanx for playing if you do...

 

Last weekend on the track, I started (Cold) with 45 PSi, frt and back. That was wrong! Went to 40 frt and back, again wrong (lots of over steer as you stated). I spoke with a few people over beers at dinner who were also running 08 MCS's and some who had experience with run flats and found that 34 frt & 34 rear gave me neutral balance. I may try 38 / 34 and see what happens.

 

Don't get this

On all my fw drive cars i've run higher pressures at the back to dial out understeer. On my latest mini ( R56 Stage 1 works ) i have 18" R105's with RF tyres and the JCW rear sway bar. I run 33psi fr and 38 psi rr. I have never had anything other than mild controllable oversteer at best.

We have a lot of roundabouts in the UK

 

netma1000, thanx for sharing your experience.

That sounds like fun japper!

 

Those pressures at the track are probably great, but on the street with the thought of bent wheels dancing in my head, i'd rather stick to the higher pressures