[MRPoisson]

Hey guys

Not sure if this has been covered before.

What kind of tyre pressure are you running on 19" 403M's under normal load? (ie, 1/2 people up front, golf bats in the boot..)

I'm currently running 34 psi front and 37 psi back. On the E92, the bridgestone runflats contrary to the door card, were recommended to run at 40+ due to combat the excessive inner wear

[NISFAN]

Personally I would stick with the correct pressures rather than 'better wear' 'better fuel consumption' type pressures. They are the only bits connecting car with road.

[Bjacks]

Would that then explain why the Bridgestones on my old 123d were effectively splitting at the sidewalls when I was fortunate enough to swap them?

Hope the new arrival isn't on those dreaded things!

Cheers

Ben

[MRPoisson]

Originally Posted by Bjacks

Would that then explain why the Bridgestones on my old 123d were effectively splitting at the sidewalls when I was fortunate enough to swap them?

Hope the new arrival isn't on those dreaded things!

Cheers

Ben

Exactly my concern. Had a similar issue with the Bridgestone RE05A Run flats on the E92. I'm told the Bridgestone S001's fitted to the F30 are vastly improved but definately want to keep the pressure correct!

[Bjacks]

That's what they were I think. I couldn't believe it, nor could the tyre fitter.

The sidewall was basically flapping around from the main body, and there were shreds of rubber floating around inside all over the place!

Happened to a friend of mine where it totally separated on the M25, ended up in an insurance claim for him as the tyre fell apart and broke various parts in the wheel arch, from the liner, to suspension components. Then there was the new wheel and tyre on top of that.....

Hope they have improved!

[HighlandPete]

In my experience with RFTs you need to be sure you are running typical working temperatures, as often we will find the setting pressure needs to be up a couple of psi or so, to accommodate a lower than ideal working temperature.

For example, if we drive a lot of short trips from cold, or run a lot in wet conditions the tyres don't warn up enough, certainly need more miles than a normal tyre.

I ran my Bridgestone Potenza RE05A at a higher than plate pressure with BMW Technical suggesting I did, due to the wear pattern, as they too were on the learning curve.

I ran some experiments to show Bridgestone and BMW that the tyres were running not much higher than setting pressure even after 12 miles, (most of the time), rather than increasing by 3 - 5psi as we'd normally expect from a working tyre.

I run my current 535i at higher than the lower plate pressure, even for just me in the car, due to the same reasoning, more critical in winter(ish) temperatures than in mid summer.

There are additional reasons why RFTs wear badly, it isn't all poor geometry or hard driving.

HighlandPete

[JOHNBMWM5]

36 PSI front 38PSI rear, I carry golf gear in the boot most of the time, no issues with bumps/noise etc.

[MRPoisson]

Originally Posted by johnbmw6

36 PSI front 38PSI rear, I carry golf gear in the boot most of the time, no issues with bumps/noise etc.

Thanks, might nudge mine up a psi or 2.

[MRPoisson]

Upped the PSI in the tyres today to 36 front and 38 rear . Interestingly they had dropped to 35 back and 32 front in 1.5k miles

[stefan4]

yes, they'll do that. I think its because there's so little air in there that small losses/changes in ambient temp result in losing/gaining a PSI or 2. I checked my tyres yesterday - first time since I collected the car - 39 and 37.5 on the fronts! and 35.5 on the rears.

I've set them all now to 36 and 38 - much happier now

[jimboss]

Somewhat related, i have the 18inch m sport wheels. Went to have a look at tyre pressure on the door...it states the pressure for a 255/40 R18 rear tyre is 3.1 bar whilst the fronts 225/45 R18 should be 2.2 bar. Thats a big difference. Is this correct or have i missed something?

[JOHNBMWM5]

Originally Posted by jimboss

Somewhat related, i have the 18inch m sport wheels. Went to have a look at tyre pressure on the door...it states the pressure for a 255/40 R18 rear tyre is 3.1 bar whilst the fronts 225/45 R18 should be 2.2 bar. Thats a big difference. Is this correct or have i missed something?

Just run them at 36 PSI front 38 PSI rear, all will be good.