[merlin3e9]

Hello everyone,

I'm new to this forum and have a question concerning a set of 640M wheels I'm looking at buying for my 2020 430i Gran Coupe. These wheels were on an M2 and have winter tires 255/40-18. The size are 18x8.5 ET27

I plan to use them as winter tires this year, but switch over to summer tires and use my original 397 (I think) wheels as my winter setup. Size 18x8 ET34

My car is all original with no suspension modifications.

I've searched the forums and online for pictures or comments if they'll fit, but have found mixed results.

So, I thought I'd ask here to see if anyone has any pictures of these wheels mounted to an F36 or any knowledge if they'll fit without rubbing or sticking out too far.

Thank you

[alohasurftoad]

at ET27, the outer shoulder of a 255/40/18 will probably rub the front fenderwell liner while turning at full lock.

a tire size of smaller diameter and/or less width will mitigate the problem.

[merlin3e9]

Okay, thank you. I've been looking for a while for some authentic BMW wheels that are a little wider than what I have now. Almost all the used ones have curb rash. These are like new.

I went to the 'Will it Fit' to verify and below is what was calculated when I entered my original specs compared to this new set:

--- Compared to your existing wheel, this new wheel will have an inner rim which is 0.7mm further away from the suspension strut. The outer rim will poke out 13.4mm more than before.

13.4 mm equates to roughly 1/2 inch. As I understand this, the inner rim is pushed further away from the strut and the outer rim is pushed 1/2" further out.

Any other thoughts?

[alohasurftoad]

increasing the scrub radius causes the tire to swing through a bigger arc at full lock. add the increased girth of the 255/40 and it will likely rub at full lock.

peeps run 18" and 19" M3/M4 wheels with 255 at ET29 up front and some graze some don't. it depends on the girth of the particular brand and model of tire, as they're not all exactly the same size and shape. ET27 is 2mm further out, not much but sometimes that is all the difference between rubbing and not.

if it rubs, it should be just a grazing whatever it's contacting. let us know how it works out

[J555]

Are you sure all wheels are the same 8.5" wide? I'm that case, you would have four front wheels, as 640m come as staggered.

There shouldn't be any issues with the fitment of the wheels, they are less aggressive than e.g. the much popular 437m (19x9" ET29). However, the tires bulge a bit (as 255 is really wide for 8.5"), resulting in tire poking more than some wants (especially in winter makes car more dirty and more risk of stone chips). See: https://f30.bimmerpost.com/forums/sh....php?t=1212756

I suggest to double check, what exact wheels/tires it is. If I am not mistaken, 640m off M2 should be 235/40 8.5x18" ET27 front & 255/35 9x18" ET29 rear. 640m off M3/M4 are the same (staggered) rims, but 255/40 square tires.

[merlin3e9]

Thanks for the input everyone! I've decided not to purchase the 640m wheels because of fitment issues. I don't want to front sticking out that much and I definitely don't want any rubbing.

Did more looking over the past few days and I found a set of BMW 442 M Double Spoke wheels & tires for a very good price. Benefits of living in Germany...LOL The wheels have some minor curb rash and oxidation, but overall very good condition...especially for the price. There's a wheel restoration shop not far from me if I choose to fix any defects.

Tire/Wheel Specs:

225/40-19, 8" ET36
255/35-19, 8 1/2" ET47

The wheels currently have winter tires on them so I'll keep them this way until spring, then switch over to summer tires. My OEM 397 wheels will then become my winter wheels and I'll run the OEM 225/45-18 tire size for winter.

[merlin3e9]

Pictures of the 442M wheels: