[RobM2]

Curious what tire pressure people are running?

The recommended pressure is 32/32 PSI front/rear but I've been running a bit more and the car feels more planted. My M2 came from the factory with 42/42 and I've toyed with lower pressures but still over 32.

The manual also recommends 39/44 front/rear if going over 100 mph. A staggered pressure makes sense.

What do folks do? Curious for both daily driving and sport use.

[NewToM]

I was previously between 32-34 but recently had new wheels put on. They put the pressure at 36/36. Don’t notice much difference between the two.

[JMcLellan]

I have been running 32 to 33 on both on my all season and summer tires.

[yash27]

Originally Posted by rlove

The manual also recommends 39/44 front/rear if going over 100 mph. A staggered pressure makes sense.

I don't understand why THAT much of an increase in tire pressure makes sense for over 100 mph. Doesn't higher speed = higher tire temperature = higher PSI? Isn't that why tire pressures decrease when it's really cold outside and increase when it is hot outside?

[RobM2]

Not sure it matters, but I have the Pirelli P Zeros as OE, where I am preferring the slightly higher PSI.

Will probably change to Michelin PS4S when I need to swap.

[RobM2]

Originally Posted by yash27

I don't understand why THAT much of an increase in tire pressure makes sense for over 100 mph. Doesn't higher speed = higher tire temperature = higher PSI? Isn't that why tire pressures decrease when it's really cold outside and increase when it is hot outside?

I don't know either. I've seen higher pressures recommended for sporty driving in general but not specifically higher speeds.

[apez]

I keep the backs a couple PSI higher. Usually 32/34 cold or if doing a lot of highway maybe 34/36 cold. On track I also try to keep it around 32/34 hot, but I also watch for rollover and adjust as warranted.

I do this stagger because I think it should help understeer, but I am just some guy on a forum that has limited driving experience or expertise.

[aerobod]

2.4 bar all around.

[sacowich]

32/32

[JABCAT]

Whatever the door jamb sticker says, MPS4S.

[beren]

I'm with JABCAT.

[RockCrusher]

Originally Posted by rlove

Curious what tire pressure people are running?

The recommended pressure is 32/32 PSI front/rear but I've been running a bit more and the car feels more planted. My M2 came from the factory with 42/42 and I've toyed with lower pressures but still over 32.

The manual also recommends 39/44 front/rear if going over 100 mph. A staggered pressure makes sense.

What do folks do? Curious for both daily driving and sport use.

I generally adhere to what the sticker on the door jam calls for. Think the pressure is 32psi. This pressure suits my usage which involves just mundane daily driver duties with the occasional spirited drive on interesting roads. Spirited but in no way approaching the usage the car would receive on the track.

As an aside -- and without bothering to check the car's owners manual -- for track usage I'd probably inflate the tires to their high speed usage pressure. While the car won't spend much time at >100mph on the track it will experience much higher loading.

That your car came with the tires inflated to 42psi suggests during the pre delivery inspection of the car the tech failed to adjust/lower the tire pressures. Word is the factory policy is at the factory to inflate the tires to close to or to their max pressure to avoid flat spotting the tires from all the sitting a car might experience before it is sold.

For high speed usage -- driving at speeds >100mph -- with some cars it is common to have the recommended tire inflation pressure higher.

At the higher pressure the tire deforms less which means less tire heating at speed which is a good thing. The tires will still get hot but less so.

[Jett2835]

MPS4S here.

Dealer had them set at 36/36 when I collected the car.

They are currently at 32 all around.

[BroDoze]

32lbs sounds low, honestly.

[Carefree]

Wide tires generally require less pressure. If I recall my physics from long ago it’s called hoop stress, the force applied to the tire's cylinder walls. It increases with wider tires. I read (forgot source) the new Z06 tires are inflated to 29-30psi.

Conversely, high pressure is found in those very skinny racing bicycle tires; many are upwards of 100+psi.

[BroDoze]

I guess I meant that sounds low compared to BMW's recommendation pressures..

[Carefree]

Originally Posted by BroDoze

I guess I meant that sounds low compared to BMW's recommendation pressures..

Yeah, I was surprised when I saw 32 all around on the door plate.

But, I follow recommendations for my cars. For instance, our M240i cars are 38 front and 45 rear. Weird difference.

So it seemed odd to see 32 on the M2.

[JABCAT]

Originally Posted by Carefree

Wide tires generally require less pressure. If I recall my physics from long ago it’s called hoop stress, the force applied to the tire's cylinder walls. It increases with wider tires. I read (forgot source) the new Z06 tires are inflated to 29-30psi.

Conversely, high pressure is found in those very skinny racing bicycle tires; many are upwards of 100+psi.

Corvette tires have been 30 psi for decades.
The tires on my Z (285/30/19 & 335/25/20) are 30 psi all around. 32 seems right for the M2. I have 11k on mine and they have 7/32nds left.

[MineralGreyMetallic]

I think mine are 43 right now. I put aftermarket wheels on with very different tire sizes. They came mounted from the wheel manufacturer.

The sizes are

285/30 R20
305/25 R21

Should I lower to 31, and is that cold or hot?

[RockCrusher]

Originally Posted by MineralGreyMetallic

I think mine are 43 right now. I put aftermarket wheels on with very different tire sizes. They came mounted from the wheel manufacturer.

The sizes are

285/30 R20
305/25 R21

Should I lower to 31, and is that cold or hot?

I checked my car's owners manual and the tires you have chosen are not listed. I have not checked the tire pressure label on the driver's door pillar but I don't hold much hope the tire sizes you have chosen are listed.

Thus by choosing to fit wheels/tires not sanctioned by the factory then you are without tire pressure settings recommended by the factory.

Unless the tire maker has some inflation pressure settings not sure how you can arrive at the right inflation pressure.

I would offer a layman's opinion that 32psi (cold) would be the minimum tire pressure because my memory is 32psi is the lowest pressure called for by the factory for its sanctioned tires.

Check/set the tire pressure with the tires cold.

From my M2's owners manual regarding low tire pressure:

A tire with too little or no tire inflation pressure may heat up significantly and sustain damage. This will have a negative impact on aspects of handling, such as steering and braking response. There is a risk of accident. Regularly check the tire inflation pressure, and correct it as needed, for instance twice a month and before a long trip.


And what is considered "cold"...

The tire inflation pressure specifications in the tire inflation pressure table only relate to cold tires or tires at the same temperature as the ambient temperature.

Only check the tire inflation pressure levels when the tires are cold, i.e.:
▷ A distance traveled of max. 1.25 miles/2 km has not been exceeded.
▷ If the vehicle has not moved again for at least two hours after a trip.

[Bret]

MineralGreyMetallic, I'll add a bit, but the bottom line is that you have to know what the tire manufacturer recommends for their tire setup on your car and you have to make sure that the pressure remains that way.

I'll give you an example of how things can go wrong. My father had a GMC truck that came from the factory with a set of tires with a particular speed rating that required the pressure to be set to around 50psi. Once those tires wore out, the manager at the local tire shop suggested that he could put some different tires on the truck which were less expensive and would last longer. However, these tires would have to be pressurized at about 35psi. OK, no problem. My father bought the new tires. They actually made the truck drive better and looked better too. He drove the truck this way for a couple of years without issue. Then I needed to take the truck from Atlanta to Savannah, Georgia and back. This is about a four-hour trip each way. He decided to get the oil changed before I made the trip. I got down there without issue, but on the way back a tire blew to pieces while I was driving on the interstate. I was fortunate that it was a rear tire, so I didn't crash. Unfortunately, it was in the heat of a Georgia summer. I never sweated so much in all of my life while putting the spare tire on. I drank two 32oz Gatorade sport drinks and didn't have to go to the restroom for another four hours. When I check the pressure of the other tires, I found that they were all almost 60psi! It turns out that the monkey at the oil change place checked the tire pressure, compared it to label inside the door jam and decided to inflate all of the tires to 50psi. He never bothered to look at the maximum psi on the tires which was 38psi. So, the bottom line here is that I learned the hard way that if you're going to run tire pressures significantly different than what the car manufacturer recommends, you have to be vigilant about making sure that nobody else adjusts them.

[MineralGreyMetallic]

Max pressure on the tires I listed is 50/51.

I think I’m probably good at 43 cold.