01-26-2021, 09:38 AM | #1 |
Private First Class
9
Rep 102
Posts
Drives: M550I/X6M50I/G83
Join Date: Apr 2019
Location: NYC
|
275/45/r21vs 275/40/r21 --question . . .
The standard for the 21 rims will be 275/40/R21 in the front
if i wanted more sidewall bumping it to 275/45/R21 - how much of a difference is that really going to make? has anyone seen less problems going up by 5 ? |
01-26-2021, 10:06 AM | #2 |
Major General
4593
Rep 8,559
Posts
Drives: eVeRyOnE mAD!
Join Date: Dec 2020
Location: neither here nor there...
|
you'll have slight speedometer discrepancies (reading about 1-3 miles faster as you increase speed). Maximus2002 is happy running that tire size.
|
Appreciate
0
|
01-26-2021, 10:44 PM | #3 |
Brigadier General
4350
Rep 4,246
Posts |
You'll also need to change the rear to an equivalent rolling diameter.
OEM front 275/40R21 = rear 315/35R21 = 29.7" rolling diameter. 275/45R21 = 30.7" with 656 revs per mile which is 3.3% larger in diameter compared to the OEM 315/35R21 rear which will F'up xDrive. You'll want the front and rear diameters to be within 1%, necessitating rear sizing 315/40R21 which is 652 revs per mile or 0.6% / 0.3mph less than your planned 275/45R21 size change.
__________________
Current BMWs - '20 X5 xDrive40i M Sport, '20 BMW M550i | Past BMWs - '03 E39 540iT M Sport, '06 E53 4.8is, '11 E70 M Sport LCI
|
Appreciate
0
|
01-27-2021, 08:20 AM | #4 |
Private First Class
9
Rep 102
Posts
Drives: M550I/X6M50I/G83
Join Date: Apr 2019
Location: NYC
|
I was wondering that, & you answered my question
much appreciated !! |
Appreciate
0
|
Post Reply |
Bookmarks |
Thread Tools | Search this Thread |
|
|