A even later, late reply.
I eventually came to kind of enjoy the high-strung, skittish handling of the stock, square Pirelli tires. It gave the car a very "kart" like ride with an eager rear-end that felt like it was trying to get off its leash and teach you who was boss. Made the daily commute on surface streets exciting.
But highway speeds were unnerving. There is a sweeper from the 202 onto the 101 north in Phoenix on the way to Sky Harbor that is a blast to accelerate through. To be honest, I've seen minivans and full size trucks take it at 80 mph... which is generally about the speed I take it at if it is open. In the M235i, at 80 the ASC light was coming on through the whole apex as the original poster experienced. Frequently the flow of traffic in this area is 80-85, and honestly, even if I'm doing ~90, there are regular passenger cars pulling away from me in the diamond lane. (This stretch also tends to have some horrific wrecks). I just didn't have the confidence to drive the M235i at the flow of traffic
on this stretch of highway. That worried me because I wasn't sure I'd be confident enough to react quickly or decisively enough in an emergency maneuver. Even casual driving at or below the flow of traffic, the tramlining was excessive enough that the car felt like it could get away from you if you weren't completely focused. Basically, anything around 70 or faster required both-hands-on-the-wheel complete focus. It wasn't fun to drive on the highway at all.
I shopped around, sent pictures to several wheel guys, and 3 different shops agreed that my wheels were Orbit Grey. So I ordered two replacements, same make, orbit gray, in the 8.5" rears. I had seen Ferric Grey wheels that were much lighter, more "silver" than mine, so I felt pretty secure that Orbit Grey was what I had.
Of course, the weekend before they arrived, I saw a blue M235i at a BMW Drive Event - and the wheels were the same design - but the color was FAR darker than I had on mine. A few days later mine arrived, and sure enough...
The ones that came on the car must be Ferric, not Orbit grey.
So... because of the shipping delays - with one of these wheels shipping from Germany - I didn't want to hassle with shipping the ones I received back - so I ordered two new 7.5" ones for up front.
Bought a set of Michelin Pilot Sport 4s - and it is like a whole new car. 225s up front.... but no one could find the 245 rears. The tire shop told me that 255s were in their fitment guide for these wheels, and once again - with how backed up supply chains are, I decided to go with the 255s. If anyone has any solid
information on fitting 255s to the 8.5" rims - I'm all ears... but I'd like to see sources confirming any tire fitment wisdom that I am bestowed here.
Anyhow, the car handles like a completely different beast. I was afraid there might be something wrong with the front end, alignment or suspension - as the carfax shows two minor accidents in this vehicle's past. I imagine they were contributed to by the Pirelli square runflat configuration. Took that sweeper recently at 80, with no ASC light to be seen, the car doesn't tramline on the highway - even my wife noted "it feels smoother, now..." It is much grippier, and just feels overall better balanced with the staggered Michelins. I also like the Orbit Grey. The Ferric Grey shows every bit of brake dust almost immediately after a wash.
Someone had suggested the very stiff sidewalls of the runflats just really amplify any road imperfection that could cause tramlining - and my experience seems to confirm this - and I think the M235i has enough power at the rear wheels that having wider rear tires probably isn't a bad idea. Not sure why anyone opts for the all-season run-flats. This car started somewhere down South, then lived in the Bay Area for a while, before ending up in Phoenix. I don't think any
of the places it has been driven really necessitated all-season tires. Oh well. I should have paid more attention when I was buying it.
I do have a spare set of 4 Ferric grey 7.5" square wheels with nearly new Pirelli Run Flat rubber on them... anyone here live in a wetter/colder part of the country and need a pair of winter shoes for their 2 series?