[Paul Moran]

I have opted for the non run flat tyres for my M340i. Are they going to be 225 front and 255 back. I owned a 2018 X3 M40i with run flats and the ride even with the adaptive suspension was hard and unsettling to say the least

[Robtor]

I cannot answer your question however I am intrigued as to how you've managed to remove the run flats as I certainly haven't been able to!

[Airplane]

Originally Posted by Robtor

I cannot answer your question however I am intrigued as to how you've managed to remove the run flats as I certainly haven't been able to!

I thought that M340i is the only model of 3 series that can be ordered with go flat tyres.
Edit : perhaps it is market related.

[xenon]

My 330i came with non-run-flat tyres in 18".

[Tam the Bam]

My car (330i mSport) is now 2 years old but I specified the non run flats (19 inch PS4’S) and it came with the staggered setup.

[Lorcan]

Originally Posted by Paul Moran

I have opted for the non run flat tyres for my M340i. Are they going to be 225 front and 255 back. I owned a 2018 X3 M40i with run flats and the ride even with the adaptive suspension was hard and unsettling to say the least

Yes to your tyre question, although I don't know what that has to do with ride comfort? SUVs need reasonably firm suspension as their C of G is high. Witness the debacle with the X3M.

[Bc2005]

For a US spec M340i in 2021, go-flat 19” tires are staggered, and the spare tire or the mobility kit is mandatory. With the performance tire and cooling option (which increases the max speed limiter) they include the mobility kit, but if you just order go-flat tires they add the spare as a mandatory option. The spare is a cheap option at $150, but takes up a lot of trunk room.

I had both Continental and Bridgestone run-flats on my F30 328i M-sport and I thought the ride was comfortable . My 2021 M340i has Pirelli P7 run-flats and stock suspension, and the ride is much rougher on city streets or any uneven-surface highways. I put up with the ride, but find it uncomfortable. When these wear out I plan to try a different brand of run-flats, probably Michelin, to see if the ride is better.

[AndyTo]

Hit a pot hole, which didn’t feel terribly hard but hard enough to blow the side wall out of the run flat tyre. I had Bridgestones on from factory and wasn’t very impressed with them so wasn’t too upset about the forced change.

Left stranded and ringing round for a tyre in stock all I could find was a pair of non run flat MPS4, which is the tyre I’d buy anyway, what a difference. Less noise, the little bumps are much less noticeable, turn in feels better and the grip feels better giving more confidence.

So will be getting the rears changed out soon as I can even though the bridgestones have at least 5mm of tread. The run flats did get me the 7 miles to ATS but for difference in feel and grip I’m prepared to run the risk of non run flat tyres. I changed out to non-RFT on my F31 and remember the difference being night and day, I was told the latest RFT’s are better, and they are, but still a good non-RFT is far superior, all imho of course.

Without a long winded story, BMW assistance were awful, won’t even bother calling them again.

[Lorcan]

AndyTo you need to pick a camp. Runflats on one axle and non-runflats on the other is not compatible with xDrive and can result in winding up and expensive damage to the transfer case.

If you're changing to proper non-runflat tyres on a xDrive car we recommend Michelin Pilot Sport 4S (not 4) or Conti SportContact6 in the standard sizes. Both of these have less than 1% difference in rolling circumference front to back, which is a requirement of xDrive.

[Paul Moran]

Originally Posted by Paul Moran

I have opted for the non run flat tyres for my M340i. Are they going to be 225 front and 255 back. I owned a 2018 X3 M40i with run flats and the ride even with the adaptive suspension was hard and unsettling to say the least

My M340i has finally arrived with 225 front and 255 rear non run flat 19 inch 792 m wheels. The tyres are Michelin sport 4. The 255 back tyres are HUGE i love them

[Paul Moran]

Originally Posted by Paul Moran

I have opted for the non run flat tyres for my M340i. Are they going to be 225 front and 255 back. I owned a 2018 X3 M40i with run flats and the ride even with the adaptive suspension was hard and unsettling to say the least

Received my M340i with Michelin Pilot Sport 4S non run flat 225 front and 255 back. The back tyres look huge, I'm so happy. Non run flat are way more comfortable then run flats. I had run flats on my X3 M40i and it was too harsh even on small bumps in the road

[NightOwl-M340i]

Originally Posted by Paul Moran

Received my M340i with Michelin Pilot Sport 4S non run flat 225 front and 255 back. The back tyres look huge, I'm so happy. Non run flat are way more comfortable then run flats. I had run flats on my X3 M40i and it was too harsh even on small bumps in the road

I plan to switch to michelin pilot sport 4 all season non run flat for my m340i since the run flat tires are super harsh. I was deciding on what size to go in the rear, does 255 fit fine back there? No rubbing or issues with that size? Also this will be on a 19 inch wheel.

[HighlandPete]

Originally Posted by NightOwl-M340i

I plan to switch to michelin pilot sport 4 all season non run flat for my m340i since the run flat tires are super harsh. I was deciding on what size to go in the rear, does 255 fit fine back there? No rubbing or issues with that size? Also this will be on a 19 inch wheel.

Are you also changing the rear rims to a wider width? The OE sizing 255/35 R19 require a minimum rim width of 8.5".

[NightOwl-M340i]

Originally Posted by HighlandPete

Are you also changing the rear rims to a wider width? The OE sizing 255/35 R19 require a minimum rim width of 8.5".

Interesting, didnt know that. Thought if I had 19s I’m all good.

[HighlandPete]

Originally Posted by NightOwl-M340i

Interesting, didnt know that. Thought if I had 19s I’m all good.

I'm assuming you are running a square setup at present, from your posts on other threads. If so then yes, rims are where you start for a staggered tire setup.

[dhock_holiday]

I’m so confused how you were able to get non-run flat staggered tires. I don’t see this option in the configurator.

[xenon]

Originally Posted by dhock_holiday

I’m so confused how you were able to get non-run flat staggered tires. I don’t see this option in the configurator.

This is a UK section of the forum - perhaps not available in the US.

[peelerec]

Well anyone can just install 255 width tires on a 8” wheel, just an FYI. Imo, not optimal, but it does fit.

[HighlandPete]

Originally Posted by peelerec

Well anyone can just install 255 width tires on a 8” wheel, just an FYI. Imo, not optimal, but it does fit.

Are you sure, even for the US market?

Here in Europe it is a "no, no" as the 8" rim is outside ETRTO and DIN standards. For the tire on the 3-series, it is 8.5" - 10", with a 9" measuring rim.

Size chart from Continental.

[peelerec]

Originally Posted by HighlandPete

Are you sure, even for the US market?

Here in Europe it is a "no, no" as the 8" rim is outside ETRTO and DIN standards. For the tire on the 3-series, it is 8.5" - 10", with a 9" measuring rim.

Size chart from Continental.

I agree, I don’t recommend it. But it’s possible. Heck, the other day someone wanted to fit a 265 or 275. It’s physically possible, just not optimal.

[HighlandPete]

Originally Posted by peelerec

I agree, I don’t recommend it. But it’s possible. Heck, the other day someone wanted to fit a 265 or 275. It’s physically possible, just not optimal.

Here in the UK, there are insurance implications when fitting tyres outside of the permitted parameters. British Tyre Manufacturers’ Association, (BTMA) reminds us...

When changing tyre size from the original fit, it is recommended the vehicle's insurers are advised and their agreement obtained, otherwise insurance may be invalidated. Fitting of inappropriate tyres will affect the vehicle's handling, potentially compromise safety and hence render the vehicle illegal.

For example, the 255/35 R19 on an 8" rim, (whether it fits or not), would be an inappropriate tyre.

UK Law (The Road Vehicles Construction and Use Regulations 24 through to 27 deals specifically with tyres), requires that tyres fitted to vehicles running on public roads conform to specific standards of condition and suitability for the type of application.

[peelerec]

I totally agree. And a fine imo is justified.

I’m just letting others know what is physically possible. I wouldn’t dare put anything higher than a 245 on a 8” wheel.

In fact, at one point I was tracking with a 245 on the 791M wheels and did not enjoy the soft feedback nor high tyre slip/angle. Hence why I sized down to 235 for my square 8” wheels.