[fe7565]

I know this is trivial and the answer depends on various factors like:

- street use?
- ambient temps
- tire brand/model/type
- car loading
- etc.

I have a basic factory F30 2012 328i and just mounted non-flat 235/50/15 Pirelli P7 All Season Plus 3 tires.

I keep them at 33psi cold since it worked out well for my 225/50/17 PIRELLI CINTURATO P7 AS tires for the last 5 years with even wear on them.

[BaconDouble]

I use the "high-speed over 100 MPH" inflation pressure on the sticker inside the driver's door.

That's generally about 5-7 psi more than normal. It's 37-38 psi front and 41-42 psi rear for me on my heavy F34 Gran Turismo.
225/45/R19s (factory wheels and factory size tires)

[fe7565]

Thank you. I have to admit I only noticed the cold tire pressure on the label, but will look closer. That should allow to dial in about 35psi then for 70-80mph speeds. Last time I drove over 100mph was many years ago in Germany

[thatgarrett]

I typically run 34 F and 38 R, I’m on the same runflats you just got rid of and notice a significantly harsher ride on them if they are closer to 30-31, and with colder weather I inflate them a little higher so they won’t get down that low on the colder days. The dealer once had me at 42F and 46R when they put those tires on, you could feel every little crack in the road and I heard more cabin rattles and wasn’t a fan of that- but since you aren’t running run flats you won’t have the overly harsh affect of the lower tire pressures, since they won’t be resting on the tire structure instead of the air.

TLDR, 34-38 and pretty even wear and good mileage for the tires that are on there (should get around ~35k out of the C7’s)

[fe7565]

I have non-run-flats, so the pressure probably needs to be a bit lower than run-flats. Yes, I experienced the same thing as far as harsh ride when I had my tires changed two weeks ago. They put 39psi in them. Every gap in the pavement I hit pinged...

Will go with 34/34 cold during the winter. The F30 is 50/50 weight distribution.

[RobotDoctor]

My F36 came with run flats so it is 32 psi (front) and 38 psi (rear). I am running a squared set up on 18" rims (225/45 r18). This is what the sticker in the front door jam recommends. I am not exactly clear on the exact reasoning for this as I was taught from previous cars that all the tires should be the same pressure.

Be that as it may, my next set of tires will be non-run flats and 245/40 r18. Is it recommended to follow the 32 psi/38 psi rule or would a more balanced pressure set up work best?

[fe7565]

Originally Posted by RobotDoctor

Be that as it may, my next set of tires will be non-run flats and 245/40 r18. Is it recommended to follow the 32 psi/38 psi rule or would a more balanced pressure set up work best?

Just looked this up, and I am still digesting the info in that thread:

https://f30.bimmerpost.com/forums/sh...5&postcount=10

[fe7565]

So I was just reading that changing to a wider tire, in my case from 225/50/17 to 235/50-/17, the pressure should be lowered to maintain the same contact area. Seems counterintuitive...still checking this out.

EDIT: there is a calculator for metric tire sizes for psi:

https://tiresize.com/pressure-calculator/


OEM Size (225/50R17 SL) Load Capacity: 1336 lbs. @ 32 psi.

New Size (235/50R17 SL) Load Capacity: 1345 lbs. @ 30 psi.


So wondering, if going by the factory 32psi cold for all 4 tires as in my case, I should drop the pressure by 2psi....since I added 235 wide vs 225 wide OEM tires? I think I would still not like to run them under 33psi cold.

The new 235/50/17 tires I have on with 400 miles on them, seem to feel much more softer and less precise in cornering. As if hydroplaning slightly even though I am on dry road.

[quakerroatmeal]

I go by what the door jamb says cold inflated typically.

[sspade]

33 up front and 34 rear... set first thing in the morning. Adjust as the seasons change.