Getting rid of the run flats

[B21]

If I remember correctly (which I probably don't), Birdgestone run flats have "RFT" on the sidewall somewhere.

 

[warmasice]

I replaced old P-Zeros with 4mm of tread on the rear of my old SL400 because grip was atrocious, I replaced them with MP4S and the difference was night and day, it’s a common problem with P-Zero as they age grip drops significantly.

Agree with your summary of the P-zeros. Had a similar experience and stayed away from them ever since.

 

[jamesgarbett]

If I remember correctly (which I probably don't), Birdgestone run flats have "RFT" on the sidewall somewhere.

Nice - thank you

 

[craigdm]

My fronts need replacing and I was considering upping the ratio to 40 from 35.
Would these fit in the arches?
Would this make any difference to the ride?
Currently have 225/35/R19s fitted.
TIA

 

[tiglon]

My fronts need replacing and I was considering upping the ratio to 40 from 35.
Would these fit in the arches?
Would this make any difference to the ride?
Currently have 225/35/R19s fitted.
TIA

They would probably fit (only slightly larger diameter than the 245/35 that some apparently run with no issues, and also quite a lot narrower), but if you still have the standard 255/30/19 at the back then they'd be significantly different diameters which could be problematic.

 

[craigdm]

My fronts need replacing and I was considering upping the ratio to 40 from 35.
Would these fit in the arches?
Would this make any difference to the ride?
Currently have 225/35/R19s fitted.
TIA

They would probably fit (only slightly larger diameter than the 245/35 that some apparently run with no issues, and also quite a lot narrower), but if you still have the standard 255/30/19 at the back then they'd be significantly different diameters which could be problematic.

Out of interest, why would this be a problem? Are there any readings taken from the rotation of the front wheels on a rear wheel-drive car?

 

[enuff_zed]

My fronts need replacing and I was considering upping the ratio to 40 from 35.
Would these fit in the arches?
Would this make any difference to the ride?
Currently have 225/35/R19s fitted.
TIA

They would probably fit (only slightly larger diameter than the 245/35 that some apparently run with no issues, and also quite a lot narrower), but if you still have the standard 255/30/19 at the back then they'd be significantly different diameters which could be problematic.

Out of interest, why would this be a problem? Are there any readings taken from the rotation of the front wheels on a rear wheel-drive car?

ABS and depending on the year possibly tyre pressure measurement too. Earlier versions did that by measuring and comparing rotational speeds.
I also think putting higher sidewalls on the front may serve to emphasise the hard ride at the rear.