[benoitch2]

Hi, been searching and reading though a lot, but could not find some examples confirming that setup.

OEM tires/wheels: 225-45-18 in 8" rims
2014 F30 335 xDrive with M Package

Anyone tried and succeeded in upgrading to

245-40-18 SQUARED ?

The reason is that I find the 225 a bit narrow on the M-Package'd car. I just bought a used one and they need to replace a faulty tire in the back. And they are winter tires also. I want to take the opportunity to upgrade the tires (paying for the difference for the front tires) and get better ones and SUMMER ones. The car is NOT staggered, hence on 18" / 8" rims. I could go for 225/45 in front and 245/40 in the back, but i'd like to have it SQUARED this time. My past 2 cars were staggered (225 front and 255 back). Not the best for rotation.

I'm just afraid it might look too wide in front. What about car behaviour ? Clearance in front ? Remember it has M Package, if it makes any difference (I dunno).

Thanks in advance for your feedback if any of you did that move.

PS: I should get the car in the next 2 days.

[alohasurftoad]

http://f30.bimmerpost.com/forums/sho...mmmm+new+tires

[MacklinUSOB]

Originally Posted by benoitch2

Hi, been searching and reading though a lot, but could not find some examples confirming that setup.

OEM tires/wheels: 225-45-18 in 8" rims
2014 F30 335 xDrive with M Package

Anyone tried and succeeded in upgrading to

245-40-18 SQUARED ?

The reason is that I find the 225 a bit narrow on the M-Package'd car. I just bought a used one and they need to replace a faulty tire in the back. And they are winter tires also. I want to take the opportunity to upgrade the tires (paying for the difference for the front tires) and get better ones and SUMMER ones. The car is NOT staggered, hence on 18" / 8" rims. I could go for 225/45 in front and 245/40 in the back, but i'd like to have it SQUARED this time. My past 2 cars were staggered (225 front and 255 back). Not the best for rotation.

I'm just afraid it might look too wide in front. What about car behaviour ? Clearance in front ? Remember it has M Package, if it makes any difference (I dunno).

Thanks in advance for your feedback if any of you did that move.

PS: I should get the car in the next 2 days.

Think you're making the right call, replace the busted winter and get a real set of summer, perfect time for it.

245-40-18 will work just fine for a square setup on OE wheels. I ran my 245-40-18 PS4S on my OEM 397's before getting new wheels, they look pretty good with a 245 on them. You won't have to worry about clearance issues. With the 40 section tire the overall height is 1.2% less than 225/45 so you'll have that much less height and that much more wheel gap, which shouldn't really be percetible. Do you have adaptive suspension? M Sport package on xDrive still comes with the xDrive suspension, the only upgrade option being adaptive.

You will notice a big increase in grip, much sharper turn in, and increase in comfort if coming from RFTs. I'm no fan of staggered setups, adding in understeer is literally the last thing the F3X chassis needs, especially on the stock suspensions.

[benoitch2]

Originally Posted by alohasurftoad

http://f30.bimmerpost.com/forums/sho...mmmm+new+tires

Thanks. Exactly what I was looking for. Sidewalls look better with 245 than the stock 225. Dont see the width on these pictures, but on the Flickr link further on that thread we can see it a bit.

it confirms my choice. Thanks again !

[benoitch2]

Originally Posted by MacklinUSOB

Think you're making the right call, replace the busted winter and get a real set of summer, perfect time for it.

245-40-18 will work just fine for a square setup on OE wheels. I ran my 245-40-18 PS4S on my OEM 397's before getting new wheels, they look pretty good with a 245 on them. You won't have to worry about clearance issues. With the 40 section tire the overall height is 1.2% less than 225/45 so you'll have that much less height and that much more wheel gap, which shouldn't really be percetible. Do you have adaptive suspension? M Sport package on xDrive still comes with the xDrive suspension, the only upgrade option being adaptive.

You will notice a big increase in grip, much sharper turn in, and increase in comfort if coming from RFTs. I'm no fan of staggered setups, adding in understeer is literally the last thing the F3X chassis needs, especially on the stock suspensions.

Very nice and detailed. Pretty much what I anticipated but was looking for confirmation. It does confirm my choice. I dont think it has adaptive (did not see it in the VIN decode) and like you said from what I understood the xDrive does not include it with the M package.

I plan on asking for the Firestone Firehawk tires (hopefully they will accept to select them -- otherwise I might simply ask them for a credit and buy them myself).

Thanks for your feedback ! CANT WAIT TO HAVE ITS STEERING IN MY HANDS !!!

[Schwabing2020]

New to the forum , cannot post only reply so apologies for using your post, but it is close to my question. I have 2016 340iX supplied with OEM 225 45 R18 91V run flats all around. I bought non runflats in the Conti Extreme DWS-06 but I see the tire shop put these on with lower sidewall in 225 40 ZR18 92Y. What are the concerns and performance issues with this setup? I thought I saw that there may be spedo inconsistencies and also handling/DTC issues? Any technical comments are very much appreciated, thank you.

[alohasurftoad]

Originally Posted by Schwabing2020

New to the forum , cannot post only reply so apologies for using your post, but it is close to my question. I have 2016 340iX supplied with OEM 225 45 R18 91V run flats all around. I bought non runflats in the Conti Extreme DWS-06 but I see the tire shop put these on with lower sidewall in 225 40 ZR18 92Y. What are the concerns and performance issues with this setup? I thought I saw that there may be spedo inconsistencies and also handling/DTC issues? Any technical comments are very much appreciated, thank you.

the factory speedo reads about 4.5% high. if your speedo shows 70mph, true speed is 67. 225/40/18 = 25.1", 225/45/18 = 26", about 3.5%. with 225/40/18 your speedo will now be reading about 8% high. 70 speedo = 65 true. your mileage will be accruing 3.5% greater than actual. for every 10000 true miles your odometer will add +350. on a positive note, the gearing at the pavement with the lower diameter should improve acceleration. with square setup, you're transfer case should not be affected, even if it is a profile size lower.

[Schwabing2020]

Originally Posted by alohasurftoad

the factory speedo reads about 4.5% high. if your speedo shows 70mph, true speed is 67. 225/40/18 = 25.1", 225/45/18 = 26", about 3.5%. with 225/40/18 your speedo will now be reading about 8% high. 70 speedo = 65 true. your mileage will be accruing 3.5% greater than actual. for every 10000 true miles your odometer will add +350. on a positive note, the gearing at the pavement with the lower diameter should improve acceleration. with square setup, you're transfer case should not be affected, even if it is a profile size lower.

Mahalo!

[thisismikeyb]

I ran Bridgestone RE050's at 245/40r18 without an issue with 8.5et35, which is pretty much the same clearances as the stock 8et34. Currently running 245/45r18 MP4S with no issues, however I doubt Bridgestone's in that size would have been problem free.

[RubenD]

Hello guys
I need help with my car��
I have to replace my tires Bmw 4 series gran coupe 2014 2l tdi automatic
At the moment I have 225/45/18 front and rear
I would like to go wider 245 front and rear for more grip
Do u think 245/40/18 will be ok for front and rear?

[alohasurftoad]

https://f30.bimmerpost.com/forums/sh...d.php?t=831520