[SoftShoe]

Tire pressure can really affect how a car handles, and I’m betting these numbers are going to vary more than some of us expect.

My ‘19 RWD M240i lists 38-45 for 18”s

That doesn’t match anything I found in the owners manual that came with my car.
(And I’m currently running 35f-36r)

[TAZ007]

Originally Posted by SoftShoe

Tire pressure can really affect how a car handles, and I’m betting these numbers are going to vary more than some of us expect.

My ‘19 RWD M240i lists 38-45 for 18”s

That doesn’t match anything I found in the owners manual that came with my car.
(And I’m currently running 35f-36r)

I don't have a pic, but just topped off last night and my door sticker is 40/42 (f/r) I hold 40-42 all around and enjoy the light rolling resistance.

[KennyFSU]

My '16 xdrive that came with 225 RFT states 33 F and 38 R.

[Ajowhan]

m '18 RWD has the Michelin PSS states 33/38 as well...

I dont know if its the original tire... What a mess

[dradernh]

2017 M240i w/155 MPH top speed, delivered with 225 & 245 PSS: 35 psi front, 39 psi rear.

The car has RWD, a MT, and no sunroof. Maybe BMW tweaks pressure specs based upon curb weight?

[WolfGTI]

Same as my car - also a 2017 M240i 6 spd with no sunroof and staggered tires from the factory.

Originally Posted by dradernh

2017 M240i w/155 MPH top speed, delivered with 225 & 245 PSS: 35 psi front, 39 psi rear.

The car has RWD, a MT, and no sunroof. Maybe BMW tweaks pressure specs based upon curb weight?

[Sportstick]

Originally Posted by SoftShoe

Tire pressure can really affect how a car handles, and I’m betting these numbers are going to vary more than some of us expect.

My ‘19 RWD M240i lists 38-45 for 18”s

That doesn’t match anything I found in the owners manual that came with my car.
(And I’m currently running 35f-36r)

Just confirming that the purpose of the sticker and the values shown are clear. That is the GVWR information (gross vehicle weight rating). Note it starts at the top with the maximum weight of cargo and passengers. The tire pressures shown are for that GVWR condition, not for typical driving for a driver alone or one other person. The pressures on this label are usually too high for normal, daily usage, although sometimes they are similar to recommended normal load pressures. Let the owner's manual be your guide unless you've loaded up the car to the maximum permissible weight.

[SoftShoe]

Originally Posted by Sportstick

. The pressures on this label are usually too high for normal, daily usage, although sometimes they are similar to recommended normal load pressures. Let the owner's manual be your guide unless you've loaded up the car to the maximum permissible weight.

That’s my understanding (the book even includes a picture of all the people and baggage you’ll have stuffed in for those pressures), but I’ve found most generic shops and my dealer will set for what’s on the door. One shop even claimed they “had” to set it to the door specs (and I could change it later if I wanted to).

The race shop that installed my LSD set it lower and that’s how I prefer it.

Finally, a trip to the track/autocross section shows a lot of people running ~34 at each corner.

What does yours list and what do you run?

Here’s my owners manual:

[Sportstick]

Originally Posted by SoftShoe

That’s my understanding (the book even includes a picture of all the people and baggage you’ll have stuffed in for those pressures), but I’ve found most generic shops and my dealer will set for what’s on the door. One shop even claimed they “had” to set it to the door specs (and I could change it later if I wanted to).

The race shop that installed my LSD set it lower and that’s how I prefer it.

Finally, a trip to the track/autocross section shows a lot of people running ~34 at each corner.

What does yours list and what do you run?

Here’s my owners manual:

My door jamb GVWR sticker is no longer relevant as it was for the original 18" tires and I changed to 17" PS4S tires. I run a square setup at 34psi cold, although I back off in the summer here with triple-digit ambient temperatures when normal driving can add +4 -5 psi. 99%+ of my driving is just me along in the car.

[msej449]

2016 M235i Convertible, RWD, MP LSD, Sports Auto

Front: 7.5Jx18 ~ 225/40 R18 92Y = 36psi (41psi if fully-loaded)
Rear: 8.0Jx18 ~ 245/35 R18 92Y = 36psi (46psi if fully-loaded)

[SoftShoe]

Originally Posted by dradernh

2017 M240i w/155 MPH top speed, delivered with 225 & 245 PSS: 35 psi front, 39 psi rear.

The car has RWD, a MT, and no sunroof. Maybe BMW tweaks pressure specs based upon curb weight?

I wonder what it is.
Mine’s a rwd auto with sunroof … that hopefully doesn’t weigh 15% more than yours, but it’s also two years heavier (I mean, younger).
Do we really differ by >350lbs?

They could be car-specific, accounting for:
high speed vs not
runflat vs not
Square vs staggered
Xdrive vs rwd
Vert vs not
And a pile of potential packages/extras
Plus slightly different tire sizes

My door lists 38/45
The book has 38/44
… so maybe they added a psi for my cf spoiler and cargo net?

[Nickies]

Specs on my sticker are 38/45 and I keep them accordingly. Below that, the car doesn't handle well. I have PSS 4S.

[SoftShoe]

Originally Posted by Nickies

Specs on my sticker are 38/45 and I keep them accordingly. Below that, the car doesn't handle well. I have PSS 4S.

Love this.

... Because our stickers are the same and I keep mine lower. Above that, the car doesn't handle well. I have PSS 4S.

Ooh, and I found this picture of us!

[vballer]

My 2018 M240i vert came with Michelin PSS front 225 / rear 245 that require front 33 psi / rear 41 psi which matches the owner’s manual for tire inflation pressures up to 100 mph/160 km/h. Above that the manual recommends 39 psi / rear 46 psi.
My car has RWD, an MT and the increased top speed limiter.

[Udayan]

Originally Posted by msej449

2016 M235i Convertible, RWD, MP LSD, Sports Auto

Front: 7.5Jx18 ~ 225/40 R18 92Y = 36psi (41psi if fully-loaded)
Rear: 8.0Jx18 ~ 245/35 R18 92Y = 36psi (46psi if fully-loaded)

Hi,

My car is a M240i Convertible Auto and I have the same door labelling than you.

Taking into account that an overinflated tire wears more in the center and that an underinflated tire wears more on the sides, and based on measurements of tread depth on the sides and center of the tires, it seems that the appropriate pressures are around 2,7 bars/ 39 PSI Front and Rear.
These values are for a car that is mostly used with the driver and 1 passenger.

Udayan

[cristo]

2020 M240i F23 6MT A/S RFT

[ehosca]

here you go...

[SoftShoe]

Originally Posted by cristo

2020 M240i F23 6MT A/S RFT

At one point, I’d casually assumed that my pressures are listed higher because my car is heavier.

Now I notice that the max combined weight of passengers and cargo
is 785 for my F22. If my car is heavier, why can it carry 133 lbs more extras than your F23?

…Likely because there’s more to it than that.

[USA-RET]

Originally Posted by dradernh

2017 M240i w/155 MPH top speed, delivered with 225 & 245 PSS: 35 psi front, 39 psi rear.

The car has RWD, a MT, and no sunroof. Maybe BMW tweaks pressure specs based upon curb weight?

2017 M240i coupe no sun roof, square run flats (f) 35 psi and (r) 39 Psi 225/40 R18 P7 Cinturato Pirelli

[aerobod]

I normally follow the EU 2.4/2.4bar (35PSI all around) pressures for my 2017 M240i with 2 passengers in it. Typically the door placard for North American cars seems to just follow the pressures for a fully loaded car, which tends to safe understeer from a handling perspective, but also prematurely wears out the centre of the rear tyres.

[SoftShoe]

Originally Posted by aerobod

I normally follow the EU 2.4/2.4bar (35PSI all around) pressures for my 2017 M240i with 2 passengers in it. Typically the door placard for North American cars seems to just follow the pressures for a fully loaded car, which tends to safe understeer from a handling perspective, but also prematurely wears out the centre of the rear tyres.

Your ‘17 has the same occupants and cargo never exceed weight as my ‘19 (785 lbs). I’d have thought that suggests that our cars weigh the same, which would then suggest that they’d have the same tire pressures listed. But the pressures are different…

[aerobod]

Originally Posted by SoftShoe

Your ‘17 has the same occupants and cargo never exceed weight as my ‘19 (785 lbs). I’d have thought that suggests that our cars weigh the same, which would then suggest that they’d have the same tire pressures listed. But the pressures are different…

Depends on other factors, too, such as high speed tuning option, partial vs full load, tyre manufacturer recommended pressures and likely in the US legal implications of under inflated tyres.

The EU spec is more consistent over the years by the looks of it and more aligned with performance driving with a less understeer related pressure spec.