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[Diver]

My 2012 135i with PPK has 11,000 miles on it. The rear Dunlop run flats are almost worn out which is pretty bad, IMO. The car has not been tracked or abused. Where did the rubber go?

I am thinking about going 225/40x18 front, 245/35x18 rear on stock M-Sport wheels. No suspension or other mods are planned or desired. My thinking is the slightly larger front tires will reduce understeer a bit, although it is not noticeable on the street. However, I feel the 215's simply are not up to the load.

I am thinking about going with Michelin PSS. Suggestions for other tires are welcome with objective of having no rubbing, stiff sidewalls and something resembling decent tread life. Summer tires are fine, because it never snows where I live. The car will not be tracked.

[128Convertibleguy]

Originally Posted by Diver

I am thinking about going with Michelin PSS. Suggestions for other tires are welcome with objective of having no rubbing, stiff sidewalls and something resembling decent tread life. Summer tires are fine, because it never snows where I live. The car will not be tracked.

Summer tires can be greasy just in cool temps, starting as warm as 40F. It's why I'm thinking about Michelin A/S 3s. They're basically PSS with a rubber compound that can handle cool temps.

[Diver]

It rarely gets as cold as 40F here.

[Freon]

BFG Rivals and Dunlop Z2 are the typical ones for street tires with maximum grip but still practical in terms of not being dangerous in wet and lasting at least 15k miles (i.e. not an R-comp). They're very popular among street-tire class autocrossers, which is very telling. If you really ride them hard they will wear very fast, though. I think I barely got 20k on my Dunlop Z1 while autocrossing regularly, but their grip was great.

Michelon PSS may not be bad either, trading some grip for better life. Michelon would like you to believe they're competitive with the above, but Tirerack does not classify them in the "extreme summer" category, and they're not common among autocrossers.

225/40/18 and 245/35/18 means the front is a bit taller, but it's probably close enough.

[Diver]

Freon, I don't autocross. If anything the choice would be between the A/S 3 and PSS rather than going with tires offering more grip.

I am also undecided on whether to stick with the stock size front tire or go up to a 225. Anyone want to expound on the advantages/disadvantages of this choice. Remember, this is for a non motor sports driver. Sorry if that is too boring.