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[Bamaben]

I'm pretty set on the rf ps2's. Tirerack dude said they don't but a friend says when he went non rf there was.

[ceb]

Originally Posted by Bamaben

I'm pretty set on the rf ps2's. Tirerack dude said they don't but a friend says when he went non rf there was.

In theory the non-runflats have a softer sidewall so the non-runflats would increase body roll.

[Bamaben]

Yeah, I said this to tirerack but he disagreed and said 85% switch to non rf so it must be better. I told him I don't want to sacrifice the flat cornering so I want to hear from people who can share their experience.

[the_doctor]

I use non-RFTs in the winter - the fact that they are non-RFTs AND being 17" (as opposed to 18 in the summer) make the car to have noticeably more body roll.

[John_01]

Non runflats just need a couple of PSI more air pressure that RFT.

[cb4]

I didn't notice any difference in "body roll" when going from rft to good tires. I am not sure how a tire can affect this. Doesn't the suspension control body role?

[Tom K.]

When switching from a summer touring RFT Goodyear NCT5 to a performance all-season non RFT Conti DWS, I immediately noticed an increased "mushiness" on initial turn in. However, since cornering traction was not adversely affected, I simply increased the pressures by 2~3 psi and continue to enjoy the improved ride.

But if you insist on an absolutely "flat" cornering feel, stick with an OEM performance RFT such as the Bridgestone RE 050A RFT or Michelin PS2 RFT.

And I'd agree with CB4 that this is not "body roll", it is a difference in cornering feel due to sidewall stiffness.

Tom

[Bamaben]

Originally Posted by cb4

I didn't notice any difference in "body roll" when going from rft to good tires. I am not sure how a tire can affect this. Doesn't the suspension control body role?

It can, but so do tires . I think BMW softened the suspension in 07 due to complaints in 06 about the rough ride w/ runflats. If that is the case then it makes sense that regular (less stiff) tire would be really soft with a suspension setup for run flats. I just want some first hand experience

[Atsnow]

Hands on experience here,
E90 330i Sport pkg with Staggered 18s
Switch to General UHP staggered 19s same psi , no roll but felt the softer
sidewall

E90 335xi
Switch to General UHP 19s same as my 330i

E92 335xi Sport pkg with Staggered 18s
Switched to Hankook V12s ,less body roll , extremely responsive
Changed that to Bilstein/Eibach combo same tires and

If you want increase comfort and good sidewall stiffness go with Pilot SS, you wont regret it

[rmkearbey]

Just changed from rfts and I noticed immediately that the car has more of a "roll" feel instead of the flat cornering feel it had with stock tires. Thought I was crazy at first and I'm glad others have validated this feeling.

Track day in two weeks will be the real test!

[Dereks435Coupe]

Originally Posted by cb4

I didn't notice any difference in "body roll" when going from rft to good tires. I am not sure how a tire can affect this. Doesn't the suspension control body role?

from rft to "good tires"

I think that statement says it all.