[Charlie (Wessex)]

I swap non RFT PS4S to CrossClimate (as my winter tyre) and there is quite a noticeable difference. More so when putting the PS4S on. Grip is much better, and it is all a little noisier but that much more alive. But having said that, when it gets chilly, the CrossClimate feels less skittish than the PS4S as well as giving a softer ride.

[peelerec]

Originally Posted by andbrads

I’ve just fitted PS4Ss coming off Bridgestone RFT or whatever the standard fitment RFT is for an M340i.

Controversially, I am slightly disappointed. I can’t feel any difference, or very very minor. I haven’t had the opportunity to drive the car with some intent yet so should perhaps reserve judgment but in my previous M240i, when I changed from the standard RFT to Michelin Pilot Sport (not S) it was a dramatic difference which was perceptible driving just 20 feet. The car felt lighter, I immediately had way more steering feel, the ride was better and the front end bite in a different league. I didn’t get any of these first impressions this time around.

I reduced the pressures down to 37 psi all around.

I run 35-36 PSI HOT while on track.
If street driving, I’ll bump them up to 36-38 HOT.
As far as comfort goes, I felt minimal difference. Grip however, wayyyy up. Take a turn at moderate speed and note the difference.
Steering may feel vague as compared to the RFT because the run flats have a stiff outer wall.

[paulockenden]

Don't forget that not all RFTs are created equal. Goodyear Eagles, as has been reported here by several people, feel *almost* (not quite, but almost) like a non-RFT tyre. I have them on the 330e, with adaptive suspension, and the combination of smooth ride, driving 'feel', and good grip/cornering is just about spot-on.

[AndyTo]

Went in for a service today and my tyres pressures were 36PSI (MPS4s), only just had the fronts changed and Kwik Fit put them on at 36PSI.
Noticed the TPMS had been reset, so looked at pressures and they were all now at 44PSI, that's after it'd been sat for 2 hours.

I really noticed the difference, was quite hard and a bit more jarring than I'm used to, it wasn't really bad but hitting a cats eye was noticeably harder, dropped them back down to 36 and all feels normal again.

When I picked the car up from new, a popular car salesman did recommend dropping pressures slightly, and to me anyway, the car feels a bit nicer when under 40PSI

Having said all that, I did only change the fronts as I'd chewed the sides bald when I still had 2.5mm of tread, still got 35k miles out of them.

[ramparts]

From the Michelin Website (after digging around).

19 inch pilot sport 4s (star marked).

Standard Usage - 2.7 bar (39PSI)
"Highway" (read high speeds aka autbahn) Usage - 3.2 bar (46PSI)