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[BLR]

Hi there,
Is there any wrong effects of more pressure in tires, like from the begining i am keeping 40psi all the way around.
I know the ride is little harder other than this.
Any experience.

[Year's_End]

40psi is too much. are you talking about cold or hot pressure?

[Pyrat 2]

Side effects are:

• Harder ride
• Theoretically more wheel dent protection - don't know that this is significant.
• Theoretically higher gas mileage - don't know that this is significant either.

I run at about 40 all the time except when I am tracking the car. When tracking it I start at about 35 cold as the tires get a little greasy feeling if the hot pressure gets too high.

If you overinflate them you could in principal wear the center sooner than the sides. However, my tires show no evidence of this happening as they are just about due for replacement now and they have worn faster on the edges (probably due to the track time).

[SG333E]

You will wear the center of the tread more rapidly than the outer shoulder. If you took your tires through their entire life that much higher than recommended my guess is you would cord the center.

[-=Hot|Ice=-]

I set mine to 32 in hot and cold, at least that's what the label on the side of the door says.

[Aurora Bearialis]

Originally Posted by -=Hot|Ice=-

I set mine to 32 in hot and cold, at least that's why the label on the side of the door says.

mine too

[John 070]

Originally Posted by mdemange

Side effects are:

• Harder ride
• Theoretically more wheel dent protection - don't know that this is significant.
• Theoretically higher gas mileage - don't know that this is significant either.

I run at about 40 all the time except when I am tracking the car. When tracking it I start at about 35 cold as the tires get a little greasy feeling if the hot pressure gets too high.

Underinflation there's a tendency to ride on the outsides of the treads. Overinflation there's a tendency to ride on the centers of the treads. Not only does that have a detrimental effect on handling (the tires are directional and asymmetrical), but it would cause them to wear improperly. Given the tires could be $350 ea. in the rear, the fuel economy savings attributable to overinflation is offset by the improper wear imho.

[BLR]

The manual says 32 front and 35 rear
32 all the ways i believe too less as one said here.
Is there a problem with the center wearing out soon.

[noro]

Originally Posted by SG333E

You will wear the center of the tread more rapidly than the outer shoulder. If you took your tires through their entire life that much higher than recommended my guess is you would cord the center.

+1 ...

35 all around has worked out very well for me in terms of even wear, ride comfort and cornering response.

[DSXMachina]

Typical arrogant BMW owner. Don't you realize that if everyone in the world did this it would result in approximately an additional 80 billion cubic feet of air being trapped inside tires. Then there'd be less air to go around and baby polar bears will die!

[noro]

Originally Posted by DSXMachina

Typical arrogant BMW owner. Don't you realize that if everyone in the world did this it would result in approximately an additional 80 billion cubic feet of air being trapped inside tires. Then there'd be less air to go around and baby polar bears will die!

Yum yum.. baby polar bear tastes so good... and the fur is so soft.

[Andrew@ET]

never thought about it like that before.

[chaz58]

You want to share why you are doing this?

There are advantages either way. But, if you over inflate, you will wear your tires out earlier, and have less traction. Still, 40PSI isn't too bad. I've had to go up near that for autobahn running with a loaded car.

Actually, I don't think anyone has bothered to check this, but cars delivered from the factory are set at the max - 50 PSI. Probably to make sure people don't overload/over drive their tires on the autobahn

[DrGP]

You might want to check out the second post on this thread. http://www.e90post.com/forums/showthread.php?t=100597.

BTW, the recommended tire pressures are actually higher if you are going to exceed 100 mph. Not that ayone on this forum would ever think of doing that.

[BMWFM]

Fresh from my training at BMW Performance Driving School this week-end.

If you overinflate your tires, you may have

- a smaller section of the tire in contact with the road, leading to less grip (think of it as riding on a bicycle tire). You would have less adherence when driving your car at the limit of grip, DSC may take over earlier to save your life :-)

- Higher wear in the middle of the tire...

- Potentially harsher ride, with less shock absorption and perhaps more prone to tire and rim issues with potholes, etc. Your suspension was tuned to work with the tires inflated at the manufacturer's specifications.

A few PSI over is not that bad. Much better than being under which may create more adherence problems especially in rain or wet conditions.

Hope this helps!

FM

[Year's_End]

Originally Posted by BMWFM

A few PSI over is not that bad. Much better than being under which may create more adherence problems especially in rain or wet conditions.

Hope this helps!

FM

True that. Make sure that the tires are never under-inflated. The stiff sidewalls cause the outer edges of the tread to wear absurdly fast. (happened to me)

[BMWFM]

Originally Posted by Bimmer Loyalist

True that. Make sure that the tires are never under-inflated. The stiff sidewalls cause the outer edges of the tread to wear absurdly fast. (happened to me)

Not only they wear out fast because the car rests on the outer edges, but the water evacuation function of the threads/gutters on the tire may be suboptimal and more water would be trapped in the middle. Hence you may reach the grip limit faster in wet conditions.

(I am just repeating what they told us )

FM

[BK]

Originally Posted by chaz58

Still, 40PSI isn't too bad. I've had to go up near that for autobahn running with a loaded car.

Actually, I don't think anyone has bothered to check this, but cars delivered from the factory are set at the max - 50 PSI. Probably to make sure people don't overload/over drive their tires on the autobahn

I agree 40 psi isn't really that big a deal. I wanted to mention, though, that not all cars are filled to 50 psi at the factory. Mine certainly wasn't, or maybe my dealer took care of that as part of vehicle prep.

FWIW, on the ZSP 330i E90, the recommended psi for the summer RFTs is 32F/36R. Lower pressure in the front tires probably adds a bit of understeer, so some people might go 36 psi all around.

When using 17" 225/45 winter M+S tires, for the ZSP 330i E90, recommended psi is 33F/41R, and this is what I run in the winter. For speeds > 100mph on those tires, recommended psi is 38F/45R.

[dmz]

I always run 38 all around and never had any uneven wear issues. I feel that the front end feels more feedback an grip than the stock spec.

[E90330iS]

for 19" tires should the tire pressure go up?

[mike-y]

typically, you want a little more pressure with bigger wheels and a lower profile tire, but some of that also depends on the type of tire you are running. From what I could tell from reading the manual, the recommended tire pressures increased slightly as rim size went up.

also, if you are worried about wearing out the center part of your tires with them at 40psi, just make sure you corner a bit harder to wear out the edges, then it will even out :-)

[.:bHd:.]

I tried to put 35psi all around and it felt like the car understeered a lot more. So now i have 40 all around. By the way when i put 32psi i get a low tire pressure warning.