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Run Flats and i4M50?

10276 Views 36 Replies 21 Participants Last post by  niam
Hi. I pre-ordered the i4M50. It’s my first M series. While going through choosing options on the BMW website I noticed that there is no option for run flats. Is there some technical reason that one cannot have run flats on an M?

Thanks for any responses.
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@Jack D , I had run flats on my 135i, they have much stiffer sidewalls (to keep the tire rigid enough without air), and as a result, ride a lot stiffer; they also have a higher unsprung weight, further affecting the ride. All of it conspire to increase the rolling friction as well, so I suspect that BMW wanted to keep the range of the M50 to a reasonable value. Mine were also double the cost of non-run-flats for the same brand and size, probably partially due to more expensive build (they need rubber ridges inside to support the rim without air) but probably also due to lower sales volume (popularity of the type and size). Personally, I'm glad to have non-run-flats, though they don't provide a spare either, but then again, tires these days really don't flat very often.
As above for likely reasoning.

My UK order form has a tyre repair kit, so ’go-flat’ tyres.

Slightly going to miss the ease of runflats after 3 BMW’s on them. My last puncture was I the dead of night on the motorway 100 miles from home. Stopped checked, drove on. Made it home fine. Then drove to work the next day. Tyre replaced in the afternoon.

But, that was about 100,000 miles ago…

Next one tomorrow now…

Many folk switch to go flats for improved performance if you read the forums.
Runflats also make more noise. That also could be a reason not to put them on an electric car.
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Thanks guys. I managed to speak to a salesman. He said that it has to do with the torque generated by M motors/engines. The run flats can’t handle it. Not sure if I believe that. Who believes a car salesperson! 😀
What I have found is a modern 30-40 series tire has a stiff enough sidewall to not roll off the bead if you aren't being silly.

You are going to need a new tire anyway.

I had a wheel crack and catastrophic air loss on my 335i. The tire was a 275/30-19 on a 19x9 wheel. I drove 25 miles on the tire at 35-40 miles per hour.

From the outside the tire looked fine. The inside had rubber dust.

I don't worry about run flats. I just assume they will get me a little more distance but I'm going to need a tire anyway.

Sent from my LE2125 using Tapatalk
They aren't available on the I4e40 either. I asked if there was any combination from the factory that included them and they said no. I like the run-flats. The ride isn't the best but if I hit a pothole or get road debris in my tire I don't have to worry about tire changing equipment, spare tire, or waiting for anyone. For my current car my dealer offered me a 4 year warranty on the tires. Any damage and they replaced the $350+ tire for a deductible of $50. I'll drive the car with the tires it comes with but I will replace them with runflats on the first time they are worn.
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I like the run flats too just to avoid the hassle but it seems I won’t be able to get them so I will have to live with the non run flats. It’s been a long time since I drove with non run flats. I suppose they will give a better ride. I think I have had three BMWs with run flats. The first ones were very rough. They seem to have improved the technology for a smoother ride with each new BMW I got. Anyway, I guess I will have to live with more risk of of a blowout but I won’t lose sleep over it. I put the question to BMW via the website. I don’t know if or when I might receive a reply. So I have gone ahead and placed my order for the i4M50. Should be fun. Thanks for the replies.
So the salesman just got back to me. He contacted BMW. They said that the reason there is no option to choose run flats when configuring the i4 is that there is a shortage of them. It does not have anything to do with technical issues. So, if I want the run flats I have to take delivery of the I4M50 with non run flats and special order the run flats. Also I think my local dealer is desperate. The guy tried to get me to put down $5k deposit. I told him that sounded fishy and that I had already dropped the $1500 to pre-order the i4. He said, “OK then $1000 and reminded me that will be applied to the final deal. I almost laughed at that point. So a special deposit to the dealer without any prediction of when I will take delivery of the vehicle……Whatever. My local dealer pretty much sucks……
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Run flats:
higher rolling resistance
less efficiency
less damping
more noises
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But safer. I know. It’s an M. I’m an old geezer….😁
In the Danish configurator, you can specify Run Flats (258) and according to the price list I have, there is no added cost.

I haven't chosen it myself though.
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That is an interesting data point. Perhaps Europe is better stocked on run flats than US? I wonder why that would be the case.
I noticed no run flat options as well, which is fine, I really do not care for them and have replaced them in all my cars at first opportunity for Michelin Pilot Sport tires. I cant recall having a flat to date. But then I cant recall a lot of things.:oops:
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I had a chance to speak with a product specialist regarding run-flats on the electric cars. He said that the run-flats are extremely heavy and it takes alot more work to being moving every time you hit the gas (rolling resistance is significantly higher). They don't last as long, are harder on the motors, and ultimately will give you significantly less mileage per charge. I'll see how I like what comes stock before making decisions, if the car ever gets here.
Hmm. So I am getting the HK audio in my i4M50; there will be no room for a spare tire. Also I think the battery takes up space in the rear. So with no run flats then you just roll the dice about getting a flat? 🤔
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Hmm. So I am getting the HK audio in my i4M50; there will be no room for a spare tire. Also I think the battery takes up space in the rear. So with no run flats then you just roll the dice about getting a flat?
Mobility kit?
Something catastrophic will have you calling for assistance anyway.

Waiting on my Tanzanite M50!
I believe one of the main reasons is efficiency and consumption. BMW wouldn't be able to claim those fantastic WLTP 590km if the car was being delivered with run flats. In any case, I haven't had a puncture in decades here in Europe (touches wood), so it's not something that worries me specially.
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