[Jeef Beef]

Originally Posted by E92325i

Sort of off topic but has anyone here had their tyres filled with nitrogen which is supposedly better for various reasons (although many doubt the benefits) and usually costs around $5/tyre from the usual tyre shops?

People need to remember that AIR is about 78% nitrogen. The main difference is that there is usually no moisture in the nitrogen fillups which brings the main benefit.

[pcockley]

Originally Posted by E92325i

Sort of off topic but has anyone here had their tyres filled with nitrogen which is supposedly better for various reasons (although many doubt the benefits) and usually costs around $5/tyre from the usual tyre shops?

my understanding is this stops the expansion/contraction from cold to hot (could also have something to do with condensation). plane tyres are filled with nitrogen as I understand, so unless you are planning on some high altitude driving sounds like a con. plus what do you do when you get a slow leak etc and need to top up

[johnnydad]

Originally Posted by bmroxm5

recommended pressure like 30psi? That's way underinflated... that's recommended for a nice comfy ride, has a very detrimental affect to fuel consumption, steering crispness and tyre wear

I'd recommend 36-38psi if filling up when the tyres are cold... 40-42 when they're hot.

The tyre placquard on my car suggests 34F/38R. Running 37-38F/38-39R stone cold with a calibrated guage when the car is driven 1-2 up. Any more than that up front reduces grip with PS2s in my size, especially once warm. Ride is good well beyond that.

Because I corner hard, and do a lot of inner urban driving (roundabouts, 90 deg corners) and the occasional track day, I end up sacrificing the sidewalls. C'est la vie

[Jeef Beef]

Originally Posted by johnnydad

The tyre placquard on my car suggests 34F/38R. Running 37-38F/38-39R stone cold with a calibrated guage when the car is driven 1-2 up. Any more than that up front reduces grip with PS2s in my size, especially once warm. Ride is good well beyond that.

Because I corner hard, and do a lot of inner urban driving (roundabouts, 90 deg corners) and the occasional track day, I end up sacrificing the sidewalls. C'est la vie

Get some neg camber happening!

[Stuart@BMRAutowerkes]

Originally Posted by johnnydad

The tyre placquard on my car suggests 34F/38R. Running 37-38F/38-39R stone cold with a calibrated guage when the car is driven 1-2 up. Any more than that up front reduces grip with PS2s in my size, especially once warm. Ride is good well beyond that.

Because I corner hard, and do a lot of inner urban driving (roundabouts, 90 deg corners) and the occasional track day, I end up sacrificing the sidewalls. C'est la vie

haha right o...

Funnily enough when I first put 20s on my 1er I accidentally inflated the tyres to 66psi (dodgy gauge lol) and I thought to myself damn this steering response is lightning quick! The steering was actually very very responsive... then deflated them to 40psi and the steering has returned to slightly less responsive... but the 20s with their low profile (225/30/20) do offer surprisingly good steering feel.

[johnnydad]

Originally Posted by Jeef Beef

Get some neg camber happening!

Short of camber plates, how?

[Jeef Beef]

Originally Posted by johnnydad

Short of camber plates, how?

Exactly what I was referring to

[GT1977]

Originally Posted by pcockley

my understanding is this stops the expansion/contraction from cold to hot (could also have something to do with condensation). plane tyres are filled with nitrogen as I understand, so unless you are planning on some high altitude driving sounds like a con. plus what do you do when you get a slow leak etc and need to top up

Pretty pointless in a road car. As you said, pure nitrogen doesn't expand or contract anywhere near as much as normal air, so regardless of the tyre temperature, your PSI stays the same. That's important for planes (so their tyres don't freeze solid (its cold up there) or for race cars where the tyre pressue is critical to the suspension. As road cars have heaps of suspension travel, the tyre pressure changing by a few PSI as the tyre heats up or gets cold makes hardly any difference. As everyone says, what is important is that tyre pressures are in the correct range to avoid excessive wear.