[neelkc12]

Hello,
My OEMS on my 2011 28i are 245/55/R-17 .
Came across a set of Winter tires and Tirerack sports wheels of size 235/RR/R-17. The only difference I see is in treadwidth . Using
http://www.1010tires.com/tiresizecal...?action=submit revealed



Revs per Mile: 753.3 on 245/55/R-17

Revs per Mile: 765.5 on 235/55/R-17.
-----------
Do i need to be concerned? Appreciate any input. Thanks

[-=DC=-]

Originally Posted by neelkc12

Hello,
My OEMS on my 2011 28i are 245/55/R-17 .
Came across a set of Winter tires and Tirerack sports wheels of size 235/RR/R-17. The only difference I see is in treadwidth . Using
http://www.1010tires.com/tiresizecal...?action=submit revealed



Revs per Mile: 753.3 on 245/55/R-17

Revs per Mile: 765.5 on 235/55/R-17.
-----------
Do i need to be concerned? Appreciate any input. Thanks

235/55/17 are from E83 first generation X3
tire will look small in the wheel arch

so better stick to oem size or go taller by 5pct using 235/60

[brissim]

To answer your specfic question - there should be no problems in using 235/55/17s in place of 245/55/17s. There is only a 1.6% difference in tire overall diameter (27.6" for the OEM tire vs 27.2" for the replacement). Only issue will be your speedo will read 1.6% high - ie when speedo shows 60 mph, you actually will only be going approx 59 mph.

The alternative suggested by DC will also work. I know because thats the tire size I replaced my original OEM 245/55/17s with when I took delivery of our X3 over 12 months ago. For the 235/60/17s, tire diameter is 28.1" or 1.8% larger than the OEM size (in this case the speedo reads 1.8% low).

One other alternative which will let you keep the BMW OEM tire diameter is 225/60/17 (tire OD = 27.6").

Tony

[-=DC=-]

Yes but we need to remember that usually speedometers do not show real speed (go faster) so increasing the diameter will bring us to actual speeds

Have seen x3 with a f10 M5 wheels and 255/40/20 tires that is .... something
Sorry not 17"

[neelkc12]

Originally Posted by brissim

To answer your specfic question - there should be no problems in using 235/55/17s in place of 245/55/17s. There is only a 1.6% difference in tire overall diameter (27.6" for the OEM tire vs 27.2" for the replacement). Only issue will be your speedo will read 1.6% high - ie when speedo shows 60 mph, you actually will only be going approx 59 mph.

The alternative suggested by DC will also work. I know because thats the tire size I replaced my original OEM 245/55/17s with when I took delivery of our X3 over 12 months ago. For the 235/60/17s, tire diameter is 28.1" or 1.8% larger than the OEM size (in this case the speedo reads 1.8% low).

One other alternative which will let you keep the BMW OEM tire diameter is 225/60/17 (tire OD = 27.6").

Tony

Thanks Tony