question on swapping tire size 225/45/18 to 245/40/18

Whatsnext · 02-08-2017, 05:04 PM

I have an F30 3351 sport with the sport rims. I need tires and debating on if it would look good to go from the standard size on the car of 224/45/18 to a 245/40/18. It looks like the tires are about the same price either direction I go.

YeaG30 · 02-08-2017, 07:26 PM

I went with 245/40/18 on my sport line and have zero regrets. There have been no issues with the size and they look better/wider. Also if you go to tirerack.com and look at the Michelin A/S 3+, there is a review video comparison and the car they use is a 3 series sport line with 245/40/18. So that further validated my decision. Hope this helps.

Whatsnext · 02-08-2017, 07:51 PM

I found a post with the same tire specs and think that is the route I will go. Did you go that same size all around or stagger the setup? I thought of going the same size so I can at least rotate.

YeaG30 · 02-09-2017, 06:35 AM

I have square wheels (OEM 397s) so I kept them square and also to allow for rotations. I don't think its recommended to stagger tire sizes on square wheels. Going with a larger tire is a very nice upgrade for grip providing a much larger contact patch.

NiskyOB · 02-09-2017, 09:15 PM

Are you putting the wider 245s on the same 18" wheels that originally came with 225s? With all the comments about how go flat Michelins or Contis transform the ride I'm considering putting these tires on my new 440i this spring --- maybe staggered with 245s on the rear, but I thought the wheels wouldn't accept the wider tires. If so are there any negatives to putting wider tires on this size wheel?

Whatsnext · 02-10-2017, 06:39 PM

OEM rims and a 245 fits fine on an 8".

chuckles01 · 02-10-2017, 07:04 PM

I have been considering the same swap in tire size, though I do want to stick with run-flats knowing my luck. My question is... because of the shorter sidewall, do you find that the ride over potholes and bumps is noticeably harsher with the 245/40/18 than the oem size of 225/45?

Quote:

Originally Posted by YeaF30

I went with 245/40/18 on my sport line and have zero regrets. There have been no issues with the size and they look better/wider. Also if you go to tirerack.com and look at the Michelin A/S 3+, there is a review video comparison and the car they use is a 3 series sport line with 245/40/18. So that further validated my decision. Hope this helps.

.BMW. · 02-11-2017, 12:58 AM

Quote:

Originally Posted by chuckles01

My question is... because of the shorter sidewall, do you find that the ride over potholes and bumps is noticeably harsher with the 245/40/18 than the oem size of 225/45?

The sidewall is only 3mm shorter for 245/40 compered to 225/45, that is about 1/8".

But you also have the option to fit 245/45-18 which has 9mm (3/8") taller sidewalls than 225/45.

chuckles01 · 02-11-2017, 06:04 PM

Quote:

Originally Posted by .BMW.

Quote:

Originally Posted by chuckles01

My question is... because of the shorter sidewall, do you find that the ride over potholes and bumps is noticeably harsher with the 245/40/18 than the oem size of 225/45?

The sidewall is only 3mm shorter for 245/40 compered to 225/45, that is about 1/8".

But you also have the option to fit 245/45-18 which has 9mm (3/8") taller sidewalls than 225/45.

Ah got it, thanks for the info! That little of a difference shouldn't impact ride quality much then.

chicagoshark · 02-11-2017, 07:36 PM

Quote:

Originally Posted by chuckles01

Quote:

Originally Posted by .BMW.

Quote:

Originally Posted by chuckles01

My question is... because of the shorter sidewall, do you find that the ride over potholes and bumps is noticeably harsher with the 245/40/18 than the oem size of 225/45?

The sidewall is only 3mm shorter for 245/40 compered to 225/45, that is about 1/8".

But you also have the option to fit 245/45-18 which has 9mm (3/8") taller sidewalls than 225/45.

Ah got it, thanks for the info! That little of a difference shouldn't impact ride quality much then.

I run 245/40/18 currently for winter. It works fine. A touch smaller then OEM. Speedo is off a few MPH. But no problems, will work fine

I will run 255/40/18 which is same size as OEM

millertime22 · 02-28-2017, 12:43 PM

Happen to know if the 245/45 is an option for the sport line? Shouldn't cause any rubbing is what I'm trying to confirm.

Reason being I prefer the look of filling the wheel well vs. low profile look...subjective trade offs. It seems that the 245/40 is more similar size to stock than the 245/45 would be from a gearing standpoint.

I am also stuck between A/S 3+ and the Pilot Sport 4 (coming off of PSS and want a change). The PS4 seem to be hard to come by as all the info now is for the new PS4S (for larger than 18 rims FYI) I really don't care for the A/S 3+ tread pattern especially after being spoiled with
the sexy smooth PSS

lorenzoX · 06-13-2019, 02:16 PM

Hello guys, I have a question.
Yesterday while driving I felt something weird so I decided to stop... I had a flat tire in the back. Fortunately a mechanic was really near so I could get new tires for the rear. The problem is that he didn't have the size I needed 255 35 18, he only had 245 45 18 and he said that by putting the both of them in the back I was going to be fine.. Is that so? I agreed for this combination because I was in a rush and I had to get back on the road as soon as possible. My front tires are 225 40 18... as suggested by BMW. Thanks in advance to anyone will take the time to answer.

02-08-2017, 05:04 PM	#1
Whatsnext Private First Class 47 Rep 158 Posts Drives: 2012 335i/2016 Jaguar F Type R Join Date: Aug 2016 Location: AZ iTrader: (0)	question on swapping tire size 225/45/18 to 245/40/18 I have an F30 3351 sport with the sport rims. I need tires and debating on if it would look good to go from the standard size on the car of 224/45/18 to a 245/40/18. It looks like the tires are about the same price either direction I go.
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02-08-2017, 07:26 PM	#2
YeaG30 First Lieutenant 244 Rep 374 Posts Drives: 2017 540i Join Date: Jun 2012 Location: Charlotte, NC iTrader: (0) Garage List 2017 BMW 540i [0.00] 2006 BMW M3 Convert ... [0.00]	I went with 245/40/18 on my sport line and have zero regrets. There have been no issues with the size and they look better/wider. Also if you go to tirerack.com and look at the Michelin A/S 3+, there is a review video comparison and the car they use is a 3 series sport line with 245/40/18. So that further validated my decision. Hope this helps. __________________ 2017 540i :: 2006 M3 :: 2012 328i Sport Line (sold)
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02-08-2017, 07:51 PM	#3
Whatsnext Private First Class 47 Rep 158 Posts Drives: 2012 335i/2016 Jaguar F Type R Join Date: Aug 2016 Location: AZ iTrader: (0)	I found a post with the same tire specs and think that is the route I will go. Did you go that same size all around or stagger the setup? I thought of going the same size so I can at least rotate.
	Appreciate 0 Quote

02-09-2017, 06:35 AM	#4
YeaG30 First Lieutenant 244 Rep 374 Posts Drives: 2017 540i Join Date: Jun 2012 Location: Charlotte, NC iTrader: (0) Garage List 2017 BMW 540i [0.00] 2006 BMW M3 Convert ... [0.00]	I have square wheels (OEM 397s) so I kept them square and also to allow for rotations. I don't think its recommended to stagger tire sizes on square wheels. Going with a larger tire is a very nice upgrade for grip providing a much larger contact patch. __________________ 2017 540i :: 2006 M3 :: 2012 328i Sport Line (sold)
	Appreciate 0 Quote

02-09-2017, 09:15 PM	#5
NiskyOB New Member 2 Rep 6 Posts Drives: 2017 440i Gran Coupe Join Date: Dec 2016 Location: Upstate NY iTrader: (0)	Are you putting the wider 245s on the same 18" wheels that originally came with 225s? With all the comments about how go flat Michelins or Contis transform the ride I'm considering putting these tires on my new 440i this spring --- maybe staggered with 245s on the rear, but I thought the wheels wouldn't accept the wider tires. If so are there any negatives to putting wider tires on this size wheel?
	Appreciate 0 Quote

02-10-2017, 06:39 PM	#6
Whatsnext Private First Class 47 Rep 158 Posts Drives: 2012 335i/2016 Jaguar F Type R Join Date: Aug 2016 Location: AZ iTrader: (0)	OEM rims and a 245 fits fine on an 8".
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02-28-2017, 12:43 PM	#11
millertime22 New Member 7 Rep 11 Posts Drives: 2012 328i Join Date: Feb 2017 Location: Dallas iTrader: (0)	Happen to know if the 245/45 is an option for the sport line? Shouldn't cause any rubbing is what I'm trying to confirm. Reason being I prefer the look of filling the wheel well vs. low profile look...subjective trade offs. It seems that the 245/40 is more similar size to stock than the 245/45 would be from a gearing standpoint. I am also stuck between A/S 3+ and the Pilot Sport 4 (coming off of PSS and want a change). The PS4 seem to be hard to come by as all the info now is for the new PS4S (for larger than 18 rims FYI) I really don't care for the A/S 3+ tread pattern especially after being spoiled with the sexy smooth PSS
	Appreciate 0 Quote

06-13-2019, 02:16 PM	#12
lorenzoX Registered 0 Rep 3 Posts Drives: 2008 bmw 335i sport sedane Join Date: Jun 2019 Location: philadelphia iTrader: (0)	bmw 335i tires Hello guys, I have a question. Yesterday while driving I felt something weird so I decided to stop... I had a flat tire in the back. Fortunately a mechanic was really near so I could get new tires for the rear. The problem is that he didn't have the size I needed 255 35 18, he only had 245 45 18 and he said that by putting the both of them in the back I was going to be fine.. Is that so? I agreed for this combination because I was in a rush and I had to get back on the road as soon as possible. My front tires are 225 40 18... as suggested by BMW. Thanks in advance to anyone will take the time to answer.
	Appreciate 0 Quote