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      12-03-2013, 01:12 AM   #1
bornadog335i
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Tyre Pressure - What do you set yours to?

Quote:
6. What tyre pressure should I use?
BMW/Manufacturers in general will suggest 30-32psi, which gives a more 'supple' ride.
This comes down to a matter of personal preference but most people will tend to run high 30s all around. This will see longer tyre life, better fuel economy and sharper handling. Don't overinflate your tyres though - this can decrease traction significantly and cause uneven wear patterns.
Try this out:
Front: 38psi
Rear: 38 psi.

Advanced drivers might tweak the tyre pressure on each axle to finetune their handling
A slightly lower front tyre pressure may reduce understeer, but again, many variables and recommended for advanced drivers only.

It's also worth nothing these are 'cold' temperatures, as a rule of thumb, when the tyres are hot and you go to check their pressures after some street driving they will gain +4psi.

If you look at the centre of your tread pattern, and notice wear occurring there and not on your sidewalls, this indicates overinflation
If the shoulder of your tyres wear quicker than the inside, this indicates under inflation.

Tracking & Tyre Pressures
Street tyres will get very hot on the track and as such they will inflate a fair bit temperature wise over what you think you've set it at. It's hard to say set it to xx psi as there are many variables to consider.
(or slightly lower than your street setup OR equal to OE spec) and going out for a few laps. After that, check your pressure to see what it's at, it might be 40psi, which would bring us to our ideal range of 38-42 for most tyres and applications.
When tyres get hot, naturally they'll start to lose a bit of stickyness and you'll feel the car squirm around a bit.
Do:
- start your first session with a lower tyre pressure
- check them constantly
- inspect the sidewalls for signs of underinflation

Don't
- use your street tyre pressure of 40+... many tyres will have a max of 50psi and on the track, you could easily gain 10psi which would post a safety threat
Reading through Sturt's thread he has suggested somewhere around 38psi front and rear but does have a few options depending on the situation.

What tyre pressure do you guys maintain? Does it matter what size wheels you have?
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      12-03-2013, 07:02 AM   #2
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Quote:
Originally Posted by bornadog335i View Post
Reading through Sturt's thread he has suggested somewhere around 38psi front and rear but does have a few options depending on the situation.

What tyre pressure do you guys maintain? Does it matter what size wheels you have?
OEM P zeros

Fronts Kpa 260
Rears Kpa 280

When it really warms up drop 5 Kpa off each.
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      12-04-2013, 12:11 AM   #3
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With PS2 RFT before
Front 38
Rear 40
I thought the ride was still too hard at those pressure

With Super sport Now
Front 39
Rear 40
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