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Hello all! I hope this is the right forum for this question. I'm hoping to get your thought on what could potentially be wrong with my M235i RWD. I acquired this vehicle about a month ago from a relative who passed away. He purchased it brand new in 2016 and only put 17k miles on it. I drove it from Tampa FL to Boston, straight shot. I was thinking to myself how fun of a vehicle it is. I own a 2018 M3 ZCP with 3k miles on it, and I noticed some similarities in the behavior of its little baby cousin the M235i. The day after I get home I walk outside and notice it has a flat time. I check under the car to see if maybe there was a nail or something and I see the insides of both tires were worn down to the metal! First of all i'm super lucky they didn't give out while doing 120mph on my way home, but then I thought that it was also odd for a car with 17k miles, driven by an 80 year old man would need tires. I also found it odd that only the inside edge of the tires were so warn down vs them wearing evenly.
I'm not sure if i'm going to keep the M235i or not. Partially because I live in New England and this not exactly rear wheel drive convertible territory, AND I already own an F80, and 2 F30s. So I picked up 2 cheap tires (nexus or some brand like that). I had them installed and I put the wheels back on the vehicle. I immediately notice that the vehicle feels different. It's hard to describe but it feels like the rear end is swaying side to side when I try and change lanes at highway speeds. Almost like the rear tires are only at 20lbs pressure. I email the company I ordered the tires from and they agreed to take them back. I had to send them a video of me taking an easy on ramp at 40mph and my traction control light flashing at me.
I purchased 2 michelin sport AS3 tires for the rear and while the problem was greatly reduced, I can still feel that swaying/unstable sensation. The vehicle originally came with super sports, and I'm at the point where I don't know if putting super sports on it will solve the issue or if there is something else going on.
It was a clear night and day difference from what it felt like on the 1200 mile trip from Florida to the time I got the new nexus tires installed.
Can this issue be because I'm not using super sport tires? I've read other posts where people have installed sport AS3's and not ever mentioned that the vehicle didn't handle correctly afterwards. I'm really hoping someone here can help me out. I'm ready to purchase the super sports but i'd be basically throwing money away again if that's not what the issue is.
Thanks!
 

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Middle wear is a sign of over-inflation. Misalignment can make the car feel twitchy. Brand new tire don't have all their grip in the first few hundred miles, because of lubricant used to keep them sticking from the mold during the manufacturing process. Tires of a lower load rating will feel "swervy."

Tires are the only thing that connects the car to the road, and isn't a place to save money with a performance car.
 

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Discussion Starter · #4 ·
Middle wear is a sign of over-inflation. Misalignment can make the car feel twitchy. Brand new tire don't have all their grip in the first few hundred miles, because of lubricant used to keep them sticking from the mold during the manufacturing process. Tires of a lower load rating will feel "swervy."

Tires are the only thing that connects the car to the road, and isn't a place to save money with a performance car.
Thanks so much for this! I just went out and checked on the load rating because it's definitely a "swervy" feeling. The fronts (which are still the stock Michelin Super Sports) are 88Y. The rear are the new Sport AS3 and they are 92Y. Could that be the reason i'm getting that swervy feeling when changing lanes? It's also causing the traction control light to come on during on/off ramps with very little acceleration.
 

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It's probably the (lack of) quality of the new tires. The PSS's are a good as it gets. Nexens***8230; not so much. Even mixing old and new good tires can cause problem. I had an M3 that when through three sets of rear tires and two sets of front tire. When I had two tires on one end and old tires on the other end, I had massive oversteer or understeer.
 

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Years ago I had a Porsche 356 that was very sensitive to tire inflation pressures. An inexpensive experiment would be to over-inflate the rear tires by 4 psi above placard values. That decreases over-steer, which may be your swaying feeling. If that works, the explanation is that the front Michelins are stiffer, with what is called a low slip angle. Putting more flexible tires on the rear as you did means that the rear is loose, or swinging wide in the corners. Increased inflation will stiffen the tires. Don't underinflate the front tires--that can lead to excessive heat build-up and blow-outs. If higher pressure in the rear solves the problem, putting matched tires front and back will also solve it--or you may want to save the front tire money and invest in 4 snow tires for our New England winters.
 

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I know this is a late bump - but...

I just bought a 2016 M235i (50k miles) and after reading all the raves about the handling and steering - I feel the same experience when changing lanes at high speed, something I've never felt in any of the BMWs I've ever owned, an e30 325i cab, E34 328i Saloon, a Z3, or the 2020 M4 cabrio comp package I also currently own. At higher speeds, even in a straight line, it feels like the back end wants to follow a different track than the front end, occasionally. It is very composed and really has tighter steering than the M4 at lower speed - but during hard acceleration at higher speeds, lane changes sometimes feel very unstable and even going in a straight line I feel like the rear end shimmies or sways from side to side. Again - it is like the rear of the car is tracking different than the front. It almost feels like trailer sway... a tail wagging the dog sensation - or driving a live rear axle car like an older Mustang.

My E30 would top out at 137 and despite those having a skittish rear end - it felt more planted and confident than the M235i. They're both cabrios and of very similar dimensions so I don't think it is related to body flex. The dealer did swap out two tires according to the carfax during prep (same make and manufacturer, Pirellis).
 

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Even later reply: Do not mix summer tires and all seasons. Match all four tires.
This.

The OP drove from Florida to Boston on top end summer performance tires, then switched to super cheap tires on the back and couldn't understand why the back got squirrelly. Then, he flipped to all-seasons on the back, resulting in a situation where the front end is solidly planted with a less sticky rear end. This is a less than ideal situation.

Addressing the inner tire wear question, yes, these cars will eat rear tires if you stay with the factory alignment setup, which emphasizes performance over tire life, especially with summer tires. 15,000 mile life on PSS tires isn't at all unusual. In fact, if you have a staggered setup (rear tires wider than the front), Michelin's tire warranty is only 15,000 miles for the PSS. The choice here is to keep the standard alignment setup (and the very responsive handling that goes with it) or have a competent tire shop adjust the rear camber closer to zero.

And, no matter what, all 4 tires need to match.
 

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So...

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? :)
 
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