Just clarifying,

X3M Specs fit on M40i...

255/40/R21
265/40/R21 will fit M40I 21 inch wheels

Awesome! I will be going with this tire upgrade as well. Thanks for sharing!

suby01 wrote

So 255 45 20 and 295 40 20 should be similar to your % X drive difference with the 21"?

Sort of...

255/45/20 vs 295/40/20 - dia delta 29" vs 29.3" @ ~ 1% difference

255/45/20 vs 285/40/20 - both dia are 29" hence ~0% difference

For 19" wheels

255/50/19 vs 285/45/19 - dia delta 29" vs 29.1" @ ~ 0.3% difference

Bee Pee wrote

Sort of...

255/45/20 vs 295/40/20 - dia delta 29" vs 29.3" @ ~ 1% difference

255/45/20 vs 285/40/20 - both dia are 29" hence ~0% difference

For 19" wheels

255/50/19 vs 285/45/19 - dia delta 29" vs 29.1" @ ~ 0.3% difference

Cheers. For the reply Im not sure how you stumbled on my post thats 16 months old. But Im already all set with my wheel and tire setup.

12v_dub wrote

I finally upgraded to my old Bridgestone Potenzas RTF's to no RTF Michelin pilot sport 4s in 255/40 and 295/35 on the stock 21" 718M wheels. Mounting was done without any issues and the ride is much smoother and quieter. I really like slightly meatier sidewall especially on the rears. During higher speeds, car feels more planted but I do feel the turning is slightly slower with this staggered set up. Regardless, I wish I have switched long time ago but was worried with fitment issues. I have 0 rubbing at full turn and I am lowered on H&R springs.
With this set up I’m still at .3% difference between front and rears.

After over a year of use, curious how this has gone. Any issues or all good? I'm looking to do the same.

Looks great!

I also have this tire setup. No issues. Tires look a bit chunkier but car rides better and looks better. I might go to Pilot Sport 4 SUV when these wear out as the SUV tire is designed for stronger sidewall as SUVs are typically heavier and roll more than sedans/coupes.

freshxdough wrote

I also have this tire setup. No issues. Tires look a bit chunkier but car rides better and looks better. I might go to Pilot Sport 4 SUV when these wear out as the SUV tire is designed for stronger sidewall as SUVs are typically heavier and roll more than sedans/coupes.

So no issues at all with rubbing on bumps, full wheel turn etc? Is there any danger in doing this? Desperately in need of new tires, and I'm kind of a noob when it comes to this tire stuff. I've had two tire shops as well as the dealer (of course), steer me off both F 255/40/R21 R 265/40/R21, and F 255/40/R21 R 295/35/21.

nav3 wrote

freshxdough wrote

I also have this tire setup. No issues. Tires look a bit chunkier but car rides better and looks better. I might go to Pilot Sport 4 SUV when these wear out as the SUV tire is designed for stronger sidewall as SUVs are typically heavier and roll more than sedans/coupes.

So no issues at all with rubbing on bumps, full wheel turn etc? Is there any danger in doing this? Desperately in need of new tires, and I'm kind of a noob when it comes to this tire stuff. I've had two tire shops as well as the dealer (of course), steer me off both F 255/40/R21 R 265/40/R21, and F 255/40/R21 R 295/35/21.

No issues whatsoever. I also have 15 mm spacers (I think it's 15 if I remember correctly). No issues. The front tire looks chunkier than the rear tire honestly.

FS: new Pirelli P Zero OE 21" Run Flat tires $1000

I really appreciate this discussion, and finally got the answer that I wanted:

Michelin Pilots 255/295 will fit my original 21" 726i rims! (even though, ideally, the rear rims should be at least 10", not OE 9.5)

My car just arrived (Tanzanite Blue). I wanted the 21" 726i wheels, and had to take the run flats, which don't work for me. Luckily, I got the PIRELLI P ZERO tires, instead of the awful Bridgestone Alenza TRUCK tires.

I will sell the new Pirelli's: 245/40/21, 275/35/21 for $1000, you pay shipping from 87507. Please contact me via private email.

Car will be in the shop for PPF and Ceramic for a few days, so the tires will be idle. Here is the Tire Rack info on the tires, $1902 their price


https://www.tirerack.com/tires/tires.jsp?tireMake=Pirelli&tireModel=P+Zero+Run+Flat+%28PZ4%29&frontTire=44YR1PZ4XLRFT&rearTire=735YR1PZ4XLRFTOS&vehicleSearch=true&fromCompare1=yes&autoMake=BMW&autoYear=2022&autoModel=X3%20M40i&autoModClar=

freshxdough wrote

I also have this tire setup. No issues. Tires look a bit chunkier but car rides better and looks better. I might go to Pilot Sport 4 SUV when these wear out as the SUV tire is designed for stronger sidewall as SUVs are typically heavier and roll more than sedans/coupes.

Freshxdough, will this tire setup work on a 2019 X3 M40i with 21" 718 wheels? I hope so. I like the availability of these sizes compared with the lack of same for the standard tire sizes for 2019 X3 M40i 21" wheels.
Are wheel spacers needed for fitment?

Thanks in advance for your response.

I will be mounting Michelin 4S or AS 4, 255/40/21 and 295/35/21 on 8.5 and 9.5 OE 726i rims. Thanks to all of you who tried them, and have reported back that they fit and work.

In addition, I have done "springs and spacers" on almost every BMW I have ever had.

Although this M40i is in many ways a utility car, it certainly will never be an off-road truck, so lowering it and maybe going a little stiffer will just make it that much better as a purpose-built road car.

Ordered today from H&R a sport spring set and 2 prs of 15mm spacers+bolts.
The lowering springs go 1.4" lower in front, and .8" in rear.

https://www.hrsprings.com/application/search/results/4/1995/2022/


I will report thoroughly about how the set up works, and attach pictures. Anyone who has already done that, I would appreciate hearing from you about your experience.

Tanzanite Blue, pretty much off the truck. Goes tomorrow for PPF and Ceramic and Tint. When it gets the H&R springs, big tires and spacers, it should start looking like it should

12v_dub wrote

255/45 wouldn't work, it would be at 3% circumference different. see comparison photo below

Looking at some replacement tires and reading through some threads. Just a point of clarification on this post - he asked about 255-45 20, not 21, which is the exact same diameter as a 255/40/21. So those would work, and I've used that exact size on my X3 in the Continental DSW06 just fine, no rubbing, etc.

Great thread. I am glad to see an alternative tire to these run flats. Terrible tire.

Got rid of the Alenzas and am running 21s with 255 and 295 Pilot 4 AS. Great tire, better ride, far better rubber compound. I actually didn't hate the Alenzas until an emergency brake situation on a twisty wet road…absolute garbage wet traction…dangerous.

Hi Everyone, My first post here. Wanted to give a shout out to those who provided the information on this and other threads which helped me to ditch the RF Alenzas. My set up is as follows:

X4 M40i 2019, 23,000 miles
21" 718 rims
front: 245/40/r21 one tire replaced due to bubble, original one ~4/32 tread left
Rear: 275/35/r21 <2/32 tread left
OE spare

Tires purchased:

Michelin Pilot Sport 4 All Seasons
Front: 255/40zr21 102Y XL BSW
Rear: 295/35/zr21 107Y XL BSW

Just reporting that installation went without a problem. I have driven about 40 miles so far and there is no rubbing. Tried full lock turns, no problem. Just adding two photos of the before/after clearance on the fronts between tire and spring seat. A few other points below I haven't seen mentioned.

- Costco nearly always shows these tires out of stock. I stopped by and was surprised to find out they had the fronts. They ordered the rears and they came in 2-3 days. There is currently a discount of $150 off the price of 4 (in California). My cost including tax was $1,650. This includes a very generous 5-year road hazard and repairs warranty.
- Michelin Pilot Sport A/S 4 have a great 60-day customer satisfaction guarantee. So, presumably, if I am not happy with these tires, I can return them for another set (say the 4S summers)
- I was concerned about bigger rears impacting acceleration but I can't discern a change. I was also concerned about handling. That too isn't an issue though I will need to wait for the break in before commenting.
- Some folks have used chains on the rears in this size. Z6 SZ 435 states that it is compatible. I happen to have that chain and tried it on for fun. It definitely doesn't fit. I think tire socks are a better route for my set up.
- Interesting tidbit: The 22" stock set up for my model (255/35r22) have a 29" diameter which is exactly what my fronts are. therefore, the small clearance in the picture shouldn't be a problem.

Ice9 wrote

I will be mounting Michelin 4S or AS 4, 255/40/21 and 295/35/21 on 8.5 and 9.5 OE 726i rims. Thanks to all of you who tried them, and have reported back that they fit and work.

In addition, I have done "springs and spacers" on almost every BMW I have ever had.

Although this M40i is in many ways a utility car, it certainly will never be an off-road truck, so lowering it and maybe going a little stiffer will just make it that much better as a purpose-built road car.

Ordered today from H&R a sport spring set and 2 prs of 15mm spacers+bolts.
The lowering springs go 1.4" lower in front, and .8" in rear.

https://www.hrsprings.com/application/search/results/4/1995/2022/


I will report thoroughly about how the set up works, and attach pictures. Anyone who has already done that, I would appreciate hearing from you about your experience.

Tanzanite Blue, pretty much off the truck. Goes tomorrow for PPF and Ceramic and Tint. When it gets the H&R springs, big tires and spacers, it should start looking like it should

Starling wrote

Hi Everyone, My first post here. Wanted to give a shout out to those who provided the information on this and other threads which helped me to ditch the RF Alenzas. My set up is as follows:

X4 M40i 2019, 23,000 miles
21" 718 rims
front: 245/40/r21 one tire replaced due to bubble, original one ~4/32 tread left
Rear: 275/35/r21 <2/32 tread left
OE spare

Tires purchased:

Michelin Pilot Sport 4 All Seasons
Front: 255/40zr21 102Y XL BSW
Rear: 295/35/zr21 107Y XL BSW

Just reporting that installation went without a problem. I have driven about 40 miles so far and there is no rubbing. Tried full lock turns, no problem. Just adding two photos of the before/after clearance on the fronts between tire and spring seat. A few other points below I haven't seen mentioned.

- Costco nearly always shows these tires out of stock. I stopped by and was surprised to find out they had the fronts. They ordered the rears and they came in 2-3 days. There is currently a discount of $150 off the price of 4 (in California). My cost including tax was $1,650. This includes a very generous 5-year road hazard and repairs warranty.
- Michelin Pilot Sport A/S 4 have a great 60-day customer satisfaction guarantee. So, presumably, if I am not happy with these tires, I can return them for another set (say the 4S summers)
- I was concerned about bigger rears impacting acceleration but I can't discern a change. I was also concerned about handling. That too isn't an issue though I will need to wait for the break in before commenting.
- Some folks have used chains on the rears in this size. Z6 SZ 435 states that it is compatible. I happen to have that chain and tried it on for fun. It definitely doesn't fit. I think tire socks are a better route for my set up.
- Interesting tidbit: The 22" stock set up for my model (255/35r22) have a 29" diameter which is exactly what my fronts are. therefore, the small clearance in the picture shouldn't be a problem.

You guys still happy with your 255/40/21; 295/35/21 tires on 726i and 718M wheels? Looks like Starling went with Mich PS 4AS, and Ice did you stick with summers or end up with all season too? No issues, would you do it again? No turn in/handling concerns or traction control? The 295 rears haven't fallen off our 9.5 rim lol? Thanks

@freshxdough, I don't mean to beat a dead horse, but WTH I'm doing wrong when calculating these 21" tires sizes?? Everything I've read here says 255/40/21; 295/35/21 work on stock 21" M40i wheels (obviously, you are riding on them as are many others). But how are these OD calculations .3% like noted below in that Thread? Aren't they more like 1.05% front and 1.7% rear, which exceeds the 1% xdrive rule?

New Michelin PS 4S 255/295 on 718M https://x3.xbimmers.com/forums/showthread.php?t=1760448

cehrl7 I tried responding back to your PM, but your mailbox is full. I don't see Michelin offering the PS All Season 4 in 285/35/21

Kief wrote

@freshxdough, I don't mean to beat a dead horse, but WTH I'm doing wrong when calculating these 21" tires sizes?? Everything I've read here says 255/40/21; 295/35/21 work on stock 21" M40i wheels (obviously, you are riding on them as are many others). But how are these OD calculations .3% like noted below in that Thread? Aren't they more like 1.05% front and 1.7% rear, which exceeds the 1% xdrive rule?

New Michelin PS 4S 255/295 on 718M https://x3.xbimmers.com/forums/showthread.php?t=1760448

cehrl7 I tried responding back to your PM, but your mailbox is full. I don't see Michelin offering the PS All Season 4 in 285/35/21

You are not using the calculator correctly. Size 1 is front and size 2 is rear. So 245/275 is the stock setup. 255/40R21 and 295/35R21 is the upgrade setup. Insert 255 as size 1 and 295 as size 2.

Apropos of nothing; I'm going with aftermarket rims for the new ride (here 5 days ago)

20 x 9 front and 20 x 10.5 rear

Michelin 4S 255/40 front and 295/35 rear with a 0.3% difference

Wanted to go 265 up front but chickened out

I considered 21" wheels but roads here are pretty horrible and I didn't want to chance it

Bought the best spacers I could find for the stock wheels but no longer need them

https://x3.xbimmers.com/forums/showthread.php?t=1954393

freshxdough wrote

Kief wrote

@freshxdough, I don't mean to beat a dead horse, but WTH I'm doing wrong when calculating these 21" tires sizes?? Everything I've read here says 255/40/21; 295/35/21 work on stock 21" M40i wheels (obviously, you are riding on them as are many others). But how are these OD calculations .3% like noted below in that Thread? Aren't they more like 1.05% front and 1.7% rear, which exceeds the 1% xdrive rule?

New Michelin PS 4S 255/295 on 718M https://x3.xbimmers.com/forums/showthread.php?t=1760448

cehrl7 I tried responding back to your PM, but your mailbox is full. I don't see Michelin offering the PS All Season 4 in 285/35/21

You are not using the calculator correctly. Size 1 is front and size 2 is rear. So 245/275 is the stock setup. 255/40R21 and 295/35R21 is the upgrade setup. Insert 255 as size 1 and 295 as size 2.

Thank you, Sir:thumbsup:

@cehrl7
So it looks like 255/40/21; 285/35/21 would work too, but again, I don't see where Michelin made a 285/35/21 in PS All Season 4?

Michelin just needs to make us BMW owners happy and start making some OEM all season tires that fit the 21.

They have the Primacy in the stock 21 size but it's not speed rated for the car. Not sure how much that really matters. I'm thinking of getting these tires to maintain the stock size when my Allenzas are done.