Tyre pressures

[M4Hulk]

What the tyre pressures for M3/M4 psi/bar. Just had new rears and tyre check monitor 2.5brs

[Wills2]

The door card says 2.3 rear and 2.2 front IIRC, after about 30 minutes driving they start to change, I've given up worrying about it.

At the moment mine tend to be 2.3 all round (cold) but can be as low as 2.1 when the temp drops 12c vs. 20c etc, I often see 2.5 after a long motorway drive.

I'm not sure how accurate the gauges are.

[JOHNBMWM5]

I run 36PSI all round cold, never had a problem.

= 2.48 BAR

[M4Hulk]

Thanks for info, reason I asked because I did run 2.3brs at the rears and it worn down the tread in the middle of the tyres. I was reading the wrong info on label door frame, now using 2.2 on the new rears as stated.

[G82Dude]

Should be 2.2 all round on 19s...?

[Wills2]

But it never stays at 2.2 and .10 of a bar isn't going to cause premature wear of your tyres, nor is the pump you use or the pressure gauge more accurate than .10 of a bar.

My CSC5P did 27k and when they came off they still had 4mm all round, you can't bugger your tyres for .10 bar.

As do a lot of high speed motorway work they are always around 2.3-2.5 sometimes higher, tyre wear never an issue over 48k in 18 months.

[JOHNBMWM5]

Originally Posted by M4Hulk

Thanks for info, reason I asked because I did run 2.3brs at the rears and it worn down the tread in the middle of the tyres. I was reading the wrong info on label door frame, now using 2.2 on the new rears as stated.

The tyres should not be affected, I put that 36PSI in all my "M" cars never had bad tyre wear.

[gatsojon]

2.2 all round for both 20s and 19s @ ambient temperature, whatever that may be. Tolerance is large, they're not F1 cars

[M4Hulk]

Would put pictures up of old tyres but don't know how too.

[Super Spartan]

The door card says 38 PSI all round for me, but when it's hot or after driving, the PSI jumps by 2 so what I do is, put 36 PSI all round and after driving for a while, they are all at 38 PSI. That's the best way to do it

[JOHNBMWM5]

Originally Posted by Snappy Phoenix

The door card says 38 PSI all round for me, but when it's hot or after driving, the PSI jumps by 2 so what I do is, put 36 PSI all round and after driving for a while, they are all at 38 PSI. That's the best way to do it

I have dropped my M3 CP to 34 PSI cold = 36PSI hot and it's good quieter too.

[DazC]

Mine are 2.2bar all round.

[Wills2]

Originally Posted by gatsojon

2.2 all round for both 20s and 19s @ ambient temperature, whatever that may be. Tolerance is large, they're not F1 cars

Since this thread I've been checking this, depending on the ambient temp the tyres are either 2.1-2.3 (in the morning) during a long drive they rise to 2.3-2.4 depending on the ambient temp and whether it's raining or it's a sunny day.

They never stay at the cold pressure you start off with for obvious reasons.

The car feels just the same within those windows as you say the tolerance is large.