[nexit]

Just swapped tires from the Bridgestone Alenza 21" RFT to the Michelin Pilot Sport 4s (SuperSport). As most are aware the odd 245 front size does not exist in the 4s, so the tires I settled on are the same tires used on the x3m. This is for the stock 21 inch wheels.

Front: 245/40/21 -> 255/40/21 (4mm taller)
Rear: 275/35/21 -> 265/40/21 (9.75mm taller)
Difference front to rear: ~1%
Speedo error (measured): ~2mph @70mph (68mph via GPS)

Seeing that these same tires are used on the x3m, with practically the same transmission, I did not expect any issues. One caveat is that I do have the m limited slip rear diff. The only other consideration is the wheel width, which is 8.5" and 9.5" on the x3m40i and 9" and 10" on the x3m.

The overall fitment is excellent. Front tire is flush (almost no stretch) and the rear tire has a minimal stretch. The ride is very good. The bounce from the RFT tire is gone and the car feel more planted. I'm still taking it easy as they are new tires, but going into corners does feel a little more planted overall, but you will likely not feel the difference unless you push it much harder. Happy with the swap overall, but do not expect a dramatic change. Considering the other non-RFT "official" option is the Pirelli Pzero, this is a much better option IMO.

[nvestr]

Awesome - I believe you are the first to do this. Been waiting to confirm this as a viable option for when my OEM P-Zeros bite the dust. I will take off the PZeros as they approach the wear limit for lease return and will keep them to return the lease if I keep it to maturity.

Can I ask how expensive they were in those sizes? I remember checking and they were out of stock everywhere with obscene prices - curious if that has changed.

[verysideways]

Thanks for the write up. Keep us updated on how they feel after you have a few more miles on them please

[nvestr]

Curious for some longer term updates to see if you have any issues with tranny, etc. Like you say, I imagine the M sport diff will make a difference as well. Even if you don't have issues doesn't mean I won't without the diff.

[HampshireUK]

Originally Posted by nexit

Just swapped tires from the Bridgestone Alenza 21" RFT to the Michelin Pilot 4s (SuperSport). As most are aware the odd 245 front size does not exist in the 4s, so the tires I settled on are the same tires used on the x3m. This is for the stock 21 inch wheels.

Front: 245/40/21 -> 255/40/21 (4mm taller)
Rear: 275/35/21 -> 265/40/21 (9.75mm taller)
Difference front to rear: ~1%
Speedo error (measured): ~2mph @70mph (68mph via GPS)

Seeing that these same tires are used on the x3m, with practically the same transmission, I did not expect any issues. One caveat is that I do have the m limited slip rear diff. The only other consideration is the wheel width, which is 8.5" and 9.5" on the x3m40i and 9" and 10" on the x3m.

The overall fitment is excellent. Front tire is flush (almost no stretch) and the rear tire has a minimal stretch. The ride is very good. The bounce from the RFT tire is gone and the car feel more planted. I'm still taking it easy as they are new tires, but going into corners does feel a little more planted overall, but you will likely not feel the difference unless you push it much harder. Happy with the swap overall, but do not expect a dramatic change. Considering the other non-RFT "official" option is the Pirelli Pzero, this is a much better option IMO.

Looks good and keen to hear the difference

Is there a reason you did t stick to the stock rear size as they do that in the MPS4S

[nexit]

Originally Posted by nvestr

Awesome - I believe you are the first to do this. Been waiting to confirm this as a viable option for when my OEM P-Zeros bite the dust. I will take off the PZeros as they approach the wear limit for lease return and will keep them to return the lease if I keep it to maturity.

Can I ask how expensive they were in those sizes? I remember checking and they were out of stock everywhere with obscene prices - curious if that has changed.

From tirerack, price was about $1600 shipped.

[nexit]

Originally Posted by nvestr

Curious for some longer term updates to see if you have any issues with tranny, etc. Like you say, I imagine the M sport diff will make a difference as well. Even if you don't have issues doesn't mean I won't without the diff.

The difference between the front and rear is 1%, which falls within the acceptable limit for xDrive in general, regardless of what size the tires are, or what transmission is used. Based on that, at least in theory, this should not pose any difficulties for anyone.

[nexit]

Originally Posted by HampshireUK

Looks good and keen to hear the difference

Is there a reason you did t stick to the stock rear size as they do that in the MPS4S

If you used the 255/40 up front and the 275/35 in the rear, the difference between front and rear is close to 1.5%, which is outside the acceptable range for xDrive. The stock tire, 245/40 and 275/35 have a .5% difference.

That being said, I compared the 265 4s and the 275 Alenza and they were almost identical in tread width.

[HampshireUK]

Maybe Goodyear will make the Goodyear Eagle F1 Supersport in the correct 21” wheel size this year. They seem to have excellent early reviews and several owners of the M140i/M240i making the move

Recently installed the Goodyear Eagle F1 Asymmetric SUV on our VW SUV and they are excellent.

[Driving for Charity UK]

Following with interest.

[ClaretFozzy]

Good stuff.

You simply can’t beat Michelin tyres.

[youngdoc1]

Looks nice!

Any winters available for these rims? Trying to plan for a few months down the road... looks like aftermarket 19" or 20" rims would be best.

[Ricarr]

Thanks

[iManu]

Wanted to go with 255/40/21-265/40/21 but they didn't have them in stock until August... I went with 255/35/21-265/35/21. Hope to get them soon!

[comber]

Interesting...thank you for your information.

I have seen on the Michelin website that now they have PS4 SUV, and as it happens with PS4s, it is available in the X3M size but not in the "normal" one, but it could be a very good option as well.

[Replicant]

Very cool. What are you doing in case of flat? I love PS4S / PSS and have them in all my other cars.

[iManu]

Just installed these and wow! They feel less stiff than the runflats and also less road noise and more cornering traction! Also, I get ZERO wheel spin with launch control! Can't wait to go to the 1/4 mile!

[Ilyam5]

Originally Posted by comber

Interesting...thank you for your information.

I have seen on the Michelin website that now they have PS4 SUV, and as it happens with PS4s, it is available in the X3M size but not in the "normal" one, but it could be a very good option as well.

What is that Pilot Sport 4 SUV tire? how is it different from Pilot sport 4S.
I understand 4s is a passenger tire but with the proper load rating should withstand the weight of the SUV.
For x3, x5 type vehicles - i do not see the need to go to Light truck or super High load index tire unless you tow a trailer.

[comber]

Originally Posted by Ilyam5

What is that Pilot Sport 4 SUV tire? how is it different from Pilot sport 4S.
I understand 4s is a passenger tire but with the proper load rating should withstand the weight of the SUV.
For x3, x5 type vehicles - i do not see the need to go to Light truck or super High load index tire unless you tow a trailer.

It seems that the Pilot Sport 4 (PS4) SUV is the natural substitute of the Latitude Sport 3, so it is a Sport tyre adapted to the needs of SUVs, with same pattern and new technologies of the PS4, but less "radical" than the PS4s.

I had the regular PS4 in my previous car and they were simply amazing, so they must work very good in SUVs as well, I'm sure... I think for my 30d PS4 SUV is a better option than the PS4s.

If changing sizes is not a problem for our xDrive system, then my only problem would be losing run flat...and that is what causes me doubt.

[Crassus]

Originally Posted by comber

If changing sizes is not a problem for our xDrive system, then my only problem would be losing run flat...and that is what causes me doubt.

Not all punctures will leave you on the side of the road. Some punctures are slow enough for you to even drive with a nail in a tyre for weeks before having the problem diagnosed.

The benefits of non-rtf in comfort, steering feel and road noise ourweight the fear of standing at the side of the road. Just get a tyre repair kit and you will be up and running very quickly.

[nexit]

As iManu has stated, these tires have been absolutely phenomenal on the car. I'll stress that while it's not a night and day difference, the change is definitely noticeable.

I feel the tires are actually a little stiffer, or perhaps as stiff as the RF's, but in a much more controlled way. As expected, the tires are less bouncy and more forgiving over road imperfections/potholes. Grip is excellent. They feel much more plated in corners, especially when accelerating, e.g. sweeping turn / on-ramp. The biggest change I've noticed, besides performance, is the lack of road noice on the highway. I also have not noticed any significant sidewall flex around tight turns at higher or more aggressive speeds.

Overall review is that these tires do exactly what was expected, with the added benefit of being quieter (for now) as well. I recommend anyone looking to switch to non-RF 21" tires to grab the X3M (255 + 265) tires for the swap. If you're worried about flats, you can always grab a mobility kit or have your aaa card handy

[Aimster82]

Please educate me on tires. I need to replace the tires on my car and there are very few 21" options available on tirerack.

Why doesn't tirerack have this listed as an option? Does it not fit correctly?