[M5stu]

Originally Posted by Nikolov

That's correct, the rears are have Porsche homologation. I'm getting some really inconsistent behavior form the rears. Sometimes they grip just fine, sometimes I can't accelerate at all because the DSC light is on the entire time.

I'm considering slapping a 275/35/20 in the rear too, just not sure how stretched it's going to be and whether that would affect circumference significantly or not (most likely not).

So I've got the following Michelin Alpin PA4
- R20 285 35 104W
- R20 275 35 102W
- Differing patterns as noted earlier
- Winter tyres "other" selected in the tyre settings
And no dramas with the TC.
When I was buying I was advised by BMW service advisor that there could be issues with MO (mercedes) or N (Porsche) rated tyres. The one I have aren't N or MO badged..
So maybe it's the compound of the 104V N PA4's leading to issues for some? Go for the W speed rating without the N, ensure the car knows it's wearing winter rubber and should be fine..

[Nikolov]

Originally Posted by M5stu

So I've got the following Michelin Alpin PA4
- R20 285 35 104W
- R20 275 35 102W
- Differing patterns as noted earlier
- Winter tyres "other" selected in the tyre settings
And no dramas with the TC.
When I was buying I was advised by BMW service advisor that there could be issues with MO (mercedes) or N (Porsche) rated tyres. The one I have aren't N or MO badged..
So maybe it's the compound of the 104V N PA4's leading to issues for some? Go for the W speed rating without the N, ensure the car knows it's wearing winter rubber and should be fine..

I have the exact same tires as you. I don't think the I drive setting for winter/summer tires has anything to do other than tire pressure monitoring.

[M5stu]

Originally Posted by Nikolov

I have the exact same tires as you. I don't think the I drive setting for winter/summer tires has anything to do other than tire pressure monitoring.

No worries. I'm not sure what the tyre setting does - just mentioned it in case it has an effect on TC behaviour. Perhaps there could be more than one version R20 285 35 104W PA4 available then? I've just been to check mine and there's no N Stamp on the sidewall to signify Porsche homologation. I think you said yours are the Porsche ones?

[Nikolov]

Your rears have this thread pattern I presume?

[Rcg412]

Tire setting is just tpms. I have BMW pilot alpin and it doesn’t hold traction well either. I chalk it up to 617hp

[wanesso]

Originally Posted by kdeleon

This is interesting. To add a data point, this will be my second season on Pirelli Sottozeros and I have not see the TC light come on during normal driving. I wonder if the different tread patterns for the Michelin between the front and rear are grabbing at slightly different rates and thus triggering the TC.

Never had any acceleration or other issue with the sotto zeros, second winter in deep snow country

[M5stu]

Originally Posted by Nikolov

Your rears have this thread pattern I presume?

Yep same pattern as your pic. Just checked. No N marking I can see though..

[Nikolov]

Originally Posted by M5stu

Yep same pattern as your pic. Just checked. No N marking I can see though..

The N tires have the same thread pattern. I'm currently exploring options. Trying to find 275/35/20 tires with the same thread pattern as the rears, or find rears with the same thread pattern as the fronts.

If I can't find a suitable tire, I guess I'll go with 275/35/20 in the rear.


P.S. I talked to my tire guy and had him check all 285/35/20 PA4 models - Mercedes homologated, Porsche and the non-homologated (which I have) - he said all 3 tires have the same thread pattern. On the other hand the 275/35/20 also comes in only one pattern, which is different from the 285 tire.

[FSociety]

Originally Posted by brava09

My rear PA4 285/35/20 have the 104W speed and load rating

Lucky you, you're able to find 104W 285/35-20 over here in the states we only have 104V

Originally Posted by F90M5C

that's not true ,you can get the 285 in 104W and it will still have the different pattern. i read once ( cant find it now ) that Michelin developed one of the patterns with Porsche

...

Originally Posted by Nikolov

The N tires have the same thread pattern. I'm currently exploring options. Trying to find 275/35/20 tires with the same thread pattern as the rears, or find rears with the same thread pattern as the fronts.

If I can't find a suitable tire, I guess I'll go with 275/35/20 in the rear.


P.S. I talked to my tire guy and had him check all 285/35/20 PA4 models - Mercedes homologated, Porsche and the non-homologated (which I have) - he said all 3 tires have the same thread pattern. On the other hand the 275/35/20 also comes in only one pattern, which is different from the 285 tire.

Did he say if its ok to run the 285 square instead ?

[Nikolov]

Originally Posted by FSociety

Did he say if its ok to run the 285 square instead ?

Yeah, as long as the front and rears have the same specs/thread pattern it should be fine. I feel like the narrower tire pattern has better grip though and generally you'd want a narrower tire for snow conditions, that's why I'm going with 275 in the rear as well.

[FSociety]

Originally Posted by Nikolov

Yeah, as long as the front and rears have the same specs/thread pattern it should be fine. I feel like the narrower tire pattern has better grip though and generally you'd want a narrower tire for snow conditions, that's why I'm going with 275 in the rear as well.

I have Continental DWS 275/35-20 square but I'm not sure if the lower load in the rear is good or bad lol. I might just go full winters but not sure if that makes sense for 3 months