[cyam]

Yes, I know there have been a lot of threads on this, but I don't understand some of the pressures ya'll are running.

I have non RFT PS4S* staggered with adaptive suspension.

My tire placard say 39psi all around.

I hear people running much lower - low to mid 30's.

How are you doing that and not getting the outside edges of your tires wearing out?

I ran 40psi on all four over the entire life of one set of tires, and when it came time to replace the tires my rears were worn very evenly, the fronts though, the outside edges were worn completely, yet center still had a few mm.

When I thought about it, it made sense. The car has a 50:50 weight distribution. So same weight on both axles. Yet the front tires are 225 and rears are 255. The narrower the tire, the higher pressure you need to hold the same weight.

So it makes sense the fronts wore the outside edges.

This is also similar to my Alfa 159, its much heavier in the front than rear yet has same tire size all around. Tire placard said 41F 39R, yet over hundreds of thousands of miles, I ran 46F, 41R to get even tire wear and balanced handling.

Now on the new tires I have (done a lot of miles already) they are wearing evenly across the tread on both front and rear - but I am running 44psi on front and 40psi on rears.

This also helped handling, esp on the track (track being cold and wet so temps didn't rise much). Front stuck down better and was a tad more tail happy.

But how are those of you running much lower pressures getting even tire wear?

I know that many will lower pressures for "comfort" - I don't care about that, I drive in Sport by default (coded it like that) and even with 44psi on the front, I am happy with the firmness and feel. If I wanted a soft-ass ride, I wouldn't buy a performance car.

[BottomGear]

I have the same staggered PS4S tires with non adaptive suspension. I run 36psi cold which warms up to a nice 40psi.

My rears are at 4/32", 5/32", and 6/32" respectively from inside to outside.

So mine aren't exactly wearing evenly but I'm happy with how it wore after 19k miles. I've done a couple burnouts and I kick the tail out every single time I drive.

It wears evenly enough for me.

[peelerec]

OP, my theory is because you have adaptive suspension, you may not be feeling how rough of a ride it is at 40psi on PS4S. I know our vehicles are not maximized for optimal comfort, but at 40psi, my take is the tires over overinflated and don’t grip well. That’s my subjective experience when street driving and also feedback I’ve seen online and in person from those running similar setup.

[hrf]

I ran factory recommended 38/39 and it feels okay. Also I tried different gauges and looks like displayed pressure is 1PSI higher than what I have with 3 different gauges.

[snekjumpr]

My door jam recommends 39/44 cold. Currently running non run flat 235/40/19s, PS4 all seasons on all 4 corners. I run them cold at about 34/36.

One thing I don’t get is my dealer service technicians insist that even with 235 non run flats, I should still be running them at 39/44 cold, which would get me close to 50 PSI on certain days, depending on outside temperature changes. So that’s what they inflate them to if I bring it in for anything. That just makes no sense for these tires or this car.

[peelerec]

Originally Posted by snekjumpr

My door jam recommends 39/44 cold. Currently running non run flat 235/40/19s, PS4 all seasons on all 4 corners. I run them cold at about 34/36.

One thing I don’t get is my dealer service technicians insist that even with 235 non run flats, I should still be running them at 39/44 cold, which would get me close to 50 PSI on certain days, depending on outside temperature changes. So that’s what they inflate them to if I bring it in for anything. That just makes no sense for these tires or this car.

The door jamb is meant for run flat tires since your car was equipped with them from factory, as was mine. I would tell dealer to not inflate that high. It’s dangerous as your tire could rupture.

[hrf]

Mine came with non run flats, staggered summer tires and door jam recommended is 38/39

[cyam]

Originally Posted by peelerec

OP, my theory is because you have adaptive suspension, you may not be feeling how rough of a ride it is at 40psi on PS4S. I know our vehicles are not maximized for optimal comfort, but at 40psi, my take is the tires over overinflated and don’t grip well. That’s my subjective experience when street driving and also feedback I’ve seen online and in person from those running similar setup.

I've tested on the track, mind you at cold ambient temps and in the wet and 44/40 PSI cold gave me the best grip and handling balance.

But I ain't taking about that. I'm taking about tire wear and the evenness across the width of the tread.

[peelerec]

Originally Posted by cyam

I've tested on the track, mind you at cold ambient temps and in the wet and 44/40 PSI cold gave me the best grip and handling balance.

But I ain't taking about that. I'm taking about tire wear and the evenness across the width of the tread.

That doesn’t make sense. Not attacking you but it just doesn’t make sense. On track, I run 34-36 psi HOT. No way you have optimal grip above 40 psi hot. These street tires get greasy that high psi with heat in them.
My tires wear down fine running 36-38 psi HOT during street driving, and with frequent rotations 3-5k miles.

[peelerec]

Originally Posted by cyam

My car was equipped from factory with Michelin PS4S*. Non run flats fitted with factory tire repair kit.

The door jams are specifically for the factory setup which is exactly what I am still running. That has never changed.

Irrelevant point anyway, I am taking about evenness of tire wear across the tread width. And I never said dealer put those pressures in my tire, I did. And it is a ridiculous, niave idea that they would rupture with 44psi.

That comment was directed towards snekjumpr.
Just an FYI PS4S max psi is 50.

[peelerec]

Originally Posted by hrf

Mine came with non run flats, staggered summer tires and door jam recommended is 38/39

This makes sense
cyam is it possible your door jamb was equipped with incorrect decal.

[cyam]

Originally Posted by peelerec

That doesn’t make sense. Not attacking you but it just doesn’t make sense. On track, I run 34-36 psi HOT. No way you have optimal grip above 40 psi hot. These street tires get greasy that high psi with heat in them.
My tires wear down fine running 36-38 psi HOT during street driving, and with frequent rotations 3-5k miles.

I've said on a cold, wet track. I tested various pressures.

I had EXCESSIVE tire wear on both outside and inside edges on the front running 40psi cold for the life of the tire. So this is what I find weird IF you are running staggered Michelin PS4S*

[peelerec]

Originally Posted by cyam

I've said on a cold, wet track. I tested various pressures.

Again, not the point, I am taking about EVENNESS OF TIRE WEAR a Ross the width of the tread. That is all.

Besides tire pressure, suspension and how the car is being loaded under weight and load, also contributes to tire wear. I have no issue with even wear street driving, which I drive the speed limit, nice and slow.

[cyam]

Originally Posted by peelerec

This makes sense
cyam is it possible your door jamb was equipped with incorrect decal.

Nope mine says for my 225/40/19 front, unloaded - 39 psi, and same for my 255/35/19 rears - both Michelin PS4S* from factory.

[cyam]

Originally Posted by peelerec

Besides tire pressure, suspension and how the car is being loaded under weight and load, also contributes to tire wear. I have no issue with even wear street driving, which I drive the speed limit, nice and slow.

Yes driving style will make a difference. I drive very aggressive, very hard all the time.

So I'd expect outside edges to wear faster, but the fronts both the outside AND inside edges wore off first. That's not driving style, that's under inflation. And I checked pressures weekly, alignment regularly checked also

[cyam]

Anyway I find it interesting. But these pressures are working great for me now, so I'm fine, was just curious.

Every car I have ever owned I drive very hard and I play around with tire pressures until I get the handling I want with the most even treadwear.

Every car it usually about 10% over the door jam for me.

[bavarianride]

mine is 330i non-M with Driveguard+ RFT, I just did a tire rotation and the 4 tires were each measured as 7/32(inner), 7/32(middle), 7/32(outer). I think these started as 9/32, and I had 6k miles on them.

I usually keep all 4 around 37-38psi cold.

[Portimao Blue M440ix]

My door placard on my 2022 G22 M440i Michelin PS4S staggered setup says 39f/36r

[cyam]

Originally Posted by Portimao Blue M440ix

My door placard on my 2022 G22 M440i Michelin PS4S staggered setup says 39f/36r

Ok well that's interesting. You have same setup, slightly different car. And it says what I found - more pressure in front. And my usual formula of ending at around 10% above tire placard works out (44/40). Although my tire placard just says 39 all around.

[zazzau]

Staggered non runflat PS4S on M340i. Door tag calls for 38 all round but I run 39f/42r.

It should be noted that the sticker number for the U.S market is at MAX load. I'm a solo driver 80% of the time.

[JJKiii]

Originally Posted by zazzau

Staggered non runflat PS4S on M340i. Door tag calls for 38 all round but I run 39f/42r.

It should be noted that the sticker number for the U.S market is at MAX load. I'm a solo driver 80% of the time.

That's correct, numbers are for Max load. Wondering why you are running higher than recommended rather than lower?

[zazzau]

Originally Posted by JJKiii

That's correct, numbers are for Max load. Wondering why you are running higher than recommended rather than lower?

Good question. I am using that number from someone's door tag in the EU (for a load of 3.) Have been using that since day 1; changed my tires at around 20K and they all wore evenly.