BMW Style 68 Rims staggered but all 4 tires are same sizes

[wingzee]

Hi all,My ride is currently on style 68 staggered M-Sports rims.

Front width 7.5j, rear width 8.5jBut I just realized that all 4 wheel sizes are the same ie. 225/45/17.I have read that the rear rims are supposed to be fitted with 245/40/17 tires.Will my current setup (same tire sizes for all 4 wheels) pose any problems or affect the ride & handling in any way?

 

[Iylia H]

Stretching narrow tires over a wide rim may stress the shoulder of the tire, leading to premature wear and or possibly a blow out. Also, the load rating of the tire may also be affected since the shoulder of the tire is not sitting "square" on the rim, i.e. the bead of the tire (that mounts on the rim) is "stretched", while the actual tread of the tire remains the same. This makes the tire look slightly slanted from the bead to the tread.

There is likely little to no handling gains as the shoulders of the tire are not able to flex the way they were designed to, which could cause loss of traction - which is likely why the drifters like this set up; the drifters can easily induce oversteer with this set up.

 

[wingzee]

Thanks for the detailed explanation. The setup came together with I bought the ride recently and never actually thought the rims are staggered until I bump across someone discussing about it in some other forum. 245/40/17 sounds like an odd size tyre to me. Any idea where to source for them? Called up few shops & none of them actually carries it. :/

 

[polaris78]

go to klang tyre shops, various brands are available

 

[Iylia H]

jalan kapar, klang... the best place to look for tyres.

 

[Iceduke]

hi bro wingzee...

I realise the same is on my soon-to-arrive Msport 318i (JSpec) too...perhaps the previous owner changed to the same due to unavailability of the size or coz its very much expensive. I was told the rears of that size is considerably more due to its rarity.

Hope this helps.