[Izyrela]

I recently picked up a 2018 340i M Performance Edition and it came with 20' 405m wheels. The tires on the rims are super stretched and don't have a good amount of sidewall. I just got my first flat today with the car by hitting a pothole and its making me worried about the future. Would upgrading to a 235 or 245 be a good idea down line? or would downsizing to the 437m (M3/M4 Wheel) be a better idea?

[khanmohammed]

Originally Posted by Izyrela

I recently picked up a 2018 340i M Performance Edition and it came with 20' 405m wheels. The tires on the rims are super stretched and don't have a good amount of sidewall. I just got my first flat today with the car by hitting a pothole and its making me worried about the future. Would upgrading to a 235 or 245 be a good idea down line? or would downsizing to the 437m (M3/M4 Wheel) be a better idea?

Hi there I have the same wheels as you on my MPE 340 and it comes with 255/30/20 rear and 225/35/20 front. I hated the run flats so I changed them out for Michelin Pilot Sport 4S's and it's so much better overall. I'm using 235/35/20 front and 265/30/20 rear and don't have any issues, sidewall amount is perfect too.
What size do you have on right now?

[Izyrela]

Originally Posted by khanmohammed

Hi there I have the same wheels as you on my MPE 340 and it comes with 255/30/20 rear and 225/35/20 front. I hated the run flats so I changed them out for Michelin Pilot Sport 4S's and it's so much better overall. I'm using 235/35/20 front and 265/30/20 rear and don't have any issues, sidewall amount is perfect too.
What size do you have on right now?

I have 225/35/20 in the front and 255/35/20 rear. and the tires are soo stretched it makes me uncomfortable driving them around. I'm gonna get the shop the car is at to order the PS4S in the spec you have. I had the PS4S on my S4 and they were amazing.

[khanmohammed]

Originally Posted by Izyrela

I have 225/35/20 in the front and 255/35/20 rear. and the tires are soo stretched it makes me uncomfortable driving them around. I'm gonna get the shop the car is at to order the PS4S in the spec you have. I had the PS4S on my S4 and they were amazing.

Yep they're great! They're also two types of PS4S, one has a tire sidewall rim protector and one has no rim protector but instead it has sound insulation in the tire. Whichever one you prefer go for it.

[F36Vader]

Originally Posted by Izyrela

I recently picked up a 2018 340i M Performance Edition and it came with 20' 405m wheels. The tires on the rims are super stretched and don't have a good amount of sidewall. I just got my first flat today with the car by hitting a pothole and its making me worried about the future. Would upgrading to a 235 or 245 be a good idea down line? or would downsizing to the 437m (M3/M4 Wheel) be a better idea?

I have the 20inch 624m on my f36 they are basically identical in fitment to the 405m, I have Michelin ps4s as well
r: 255/35/20 f: 225/35/20



Michelins tend to have a fatter sidewall. so far the driving experience has been phenomenal, do remember it being pretty harsh on the stock RFTs when I initially test drove the car.

Get the PS4s very worth it. I wouldn't put any other tires on my forged 20s.

Btw you might get some rub in the inner front fender liner when in reverse with the wheels turned at almost full lock with the Michelins even at stock height, at least I do in the f36 and that seems pretty common and harmless.

[Izyrela]

Thanks for your input!

I ended up getting Michelin PSS 245/35/20 in the front and 275/30/20 in the rear. The ride and driving confidence is soo much better after removing the rubber bands that come stock on these rims.

[khanmohammed]

Originally Posted by Izyrela

Thanks for your input!

I ended up getting Michelin PSS 245/35/20 in the front and 275/30/20 in the rear. The ride and driving confidence is soo much better after removing the rubber bands that come stock on these rims.

275 fit in the rear?? I thought the wheel was rated for 255 max and I pushed it to 265

[djacinto]

Agreed I thought so too, especially for 8.5 inch rims. I did see another seller selling 405's with 275 rears and he said he got them from the dealer that way (used car).

Op, could you post a picture of your fitment? I'd love to see how they look. I'm interested in doing the same sizing as well if it works

[Wires]

Originally Posted by Izyrela

Thanks for your input!

I ended up getting Michelin PSS 245/35/20 in the front and 275/30/20 in the rear. The ride and driving confidence is soo much better after removing the rubber bands that come stock on these rims.

Good choice! I'd have to say those aren't the stock tires for those rims though. They are much too narrow for that rim width.