SKK

In January, I bought 19" wheels for my BMW 530i M Sport from my local BMW dealer. I was pleased with the purchase as the 19" rims really looked fantatic and suited the car perfectly. I noted that the ride quality had also improved marginally from the 18" runflats I was previosuly running.

To my shame, I didnt bother checking the tyre pressures at all - yes in 10 months....

I was driving back from a work party last night and the idrive came up with a tyre puncture warning. I stoped, checked all the tyres and they all looked good. I was only three miles from home so I decided to risk it and drive home (thinking I probably had a slow puncture of some sort). Reached home safely and in the morning I checked all the tyres again and still no sign of a puncture.

I decided to check the tyre pressures at my local petrol station. The idrive was still pinging warnings at me about the puncture. Readings were as follows -

Driver front - 43psi
Passenger front - 45psi
Rears - 48psi

WTF is all that about? Those numbskulls at the garage had massivley overinflated all the tyres !!!!!
Anyway I bought the pressures down to 32psi for the fronts and 37psi for the rears and reset the idrive. The puncture sign has now gone away but what an improvement in ride quality !!!!
To think I have driving around for over 9 months in substantially overinflated tyres just makes me depressed. It's my fault for not checking the pressures as soon as they installed the wheels.

You guys probably already do this but if you give your car in to a dealer, please always check the pressures after it's been handed back to you.

olli_535d

looks too high, but wheel tyre combo of 19" and bigger are recommended to being run at the higher end of the pressure field.
Mine (19) are on 38/42 standard and are perfectly fine. Longer trips with the family, I even put a little more in.

SKK

The sticker on my drivers side doorwell states 2.2 (fronts) and 2.6 bar (rears) when on 19" wheels and with a maximum of 4 passengers. Thats approx 32 and 37 psi.

pinguhk

My 19" is 36F/40R

colejl

Remember you must check the pressures when the tyres are cold - it's surprising how quickly they warm up, even with a short drive, and read well over! If you checked them warm and then sent them down to 32/37 you might actually find they're well under...

Just something to bear in mind...

Personally, I have mine set higher than the minimum recommended as I prefer the small sacrifice in ride quality for the sharper handling - experiment between the guidelines... The heavy diesel front seems to prefer a bit more pressure. Plus I've lost the runflats so I reckon a bit more than 'standard' is worth it too! I'm running 37F/38R on 18" staggered.

OliverB

Check your pressures at least every month. But it's better every 2 weeks. Of course, ckeck BEFORE starting to drive, when the tyres are still cold !
Pressures are advised by BMW so that the car is "easy" (understeering at the limit), and adapted to the set up (camber, toe...). If you prefer to have a more dynamic handling, you can inflate 0.2 bar more (Not too much, because the tyre may then wear more on its center). You'll also use less fuel...