[Lancelot]

Hi everyone

Just wanted to share a recent experience with my m550i:
I had recently started to feel jerking/stuttering on hard acceleration as well as at the lowest speeds, while braking, when you let the car go with zero throttle.

I thought my transfer case was going bad.

Decided to try to switch to my 19 wheels set i had in the garage and suddenly all issues gone!

When checking wheel rolling length on the 20in set, i got a front/back 2% difference; and thread depth showed 2.5mm difference front/back (back wearing out more)

Bottom line, 20in wheel specs already start with a 1% difference out of the box, and things only get worse from there, as rear wheels wear out quicker since they handle 75% of the torque.

I’ll go for 285/30/20 size on rear next time! At least starting with exact same rolling radius!

But i can’t help but wonder what in the world were they thinking when speccing 275/30/20 rear wheels! This is already maxing out the Xdrive tolerance!

[tjbuggy2b]

OEM 20" tire size should start at 1%. 245/35r20 & 275/30r20.

https://www.wheel-size.com/calc/?whe...cl=50mm&sr=0mm

[Lancelot]

Exactly my point : they start already at the end of the tolerance window

[AirbusPilot]

My new 2023 M550i has 275/35x20” Rear, 245/40x20” Front. Zero issues at 10k miles, but the aspect ratio is larger than yours.

[admranger]

Originally Posted by Lancelot

Exactly my point : they start already at the end of the tolerance window

I get a slight shudder as well under heavy load, like deciding to pass someone quickly when you're already moving. When my tires get worse I'm going to go up on the aspect ratio to make the wheels live slightly longer and make the speedo read closer to the real speed number. Keeping the circumference closer is a goal as well.