Question about sidewall size

BMW GENIUS · 08-28-2015, 03:08 PM

Would a 245/40/R18 tire on the OEM wheels make the car handle any differently than the OEM 245/35/R18? I really want to get a set of BFG G Force Rival Extreme Summer Performance tires that I can fit on the OEM wheels and I just wanted to see if there would be any difficulties or differences? Are there any?

DanG · 08-28-2015, 10:37 PM

I don't think you can get a 245/40/18 tire to fit on the front without rubbing.

BMW GENIUS · 08-29-2015, 12:04 AM

Quote:

Originally Posted by DanG

I don't think you can get a 245/40/18 tire to fit on the front without rubbing.

This would only be on the rears! Do you think it would fit?

DanG · 08-29-2015, 12:15 AM

Quote:

Originally Posted by BMW GENIUS

This would only be on the rears! Do you think it would fit?

Your speedometer will have a slight error but everything else should be ok. I don't think you will notice much difference in handling.

OpenAir · 08-29-2015, 09:39 AM

I'm working on a set of 8x8.5 ET35 5x120 w/235/40/18's. 245's didn't appear to fit the front without rubbing unless the fender was rolled.

DanG · 08-29-2015, 09:49 AM

Quote:

Originally Posted by OpenAir

I'm working on a set of 8x8.5 ET35 5x120 w/235/40/18's. 245's didn't appear to fit the front without rubbing unless the fender was rolled.

He was asking about the rears only.

OpenAir · 08-29-2015, 11:06 AM

Quote:

Originally Posted by DanG

He was asking about the rears only.

Color me yellow and call me a taxi! Missed that.

eclipes · 08-29-2015, 11:16 AM

40 sidewall will fit in the rear even if its lowered. But will rub over bumps ONLY if you have full load in the back. I thought it was too risky so i went with 265/35/18 instead

overcoil · 08-29-2015, 12:09 PM

Anyone think that slightly higher sidewall ratio would be detrimental to control under power? Particularly in those situation when the tail swaps back after overcorrecting oversteer?
I'm not sure it's worth deviating to a taller sidewall for the sake of a particular manufacturers tire particularly if your going to drive hard.

BMW GENIUS · 08-29-2015, 12:11 PM

Quote:

Originally Posted by eclipes

40 sidewall will fit in the rear even if its lowered. But will rub over bumps ONLY if you have full load in the back. I thought it was too risky so i went with 265/35/18 instead

You're running a 265?!

Transfer · 08-29-2015, 04:39 PM

BFG rivals? Why?

DanG · 08-29-2015, 05:09 PM

Quote:

Originally Posted by Transfer

BFG rivals? Why?

It is a strange tire request.

pikcachu · 08-29-2015, 09:31 PM

Quote:

Originally Posted by Transfer

BFG rivals? Why?

lol wondered the same thing but felt rude to ask

eclipes · 08-29-2015, 09:40 PM

yup, fits very nicely actually.

Quote:

Originally Posted by BMW GENIUS

You're running a 265?!

BMW GENIUS · 08-30-2015, 07:48 PM

Quote:

Originally Posted by Transfer

BFG rivals? Why?

Tire rack is having a clearance sale on them and I wanted a softer tire compound for when I want to track it again but still be DOT compliant.

pikcachu · 08-30-2015, 08:23 PM

Quote:

Originally Posted by BMW GENIUS

Quote:

Originally Posted by Transfer

BFG rivals? Why?

Tire rack is having a clearance sale on them and I wanted a softer tire compound for when I want to track it again but still be DOT compliant.

I would go direzza, rs3 or re-71r

Pparana · 09-08-2015, 09:24 PM

Will change the rake of the car, raising the back about 1/2". You should be trying to lower the car for track use.

08-28-2015, 03:08 PM	#1
BMW GENIUS First Lieutenant 153 Rep 397 Posts Drives: 2015 AW M235i 6MT Join Date: Oct 2014 Location: Manly, NSW, Australia iTrader: (0)	Question about sidewall size Would a 245/40/R18 tire on the OEM wheels make the car handle any differently than the OEM 245/35/R18? I really want to get a set of BFG G Force Rival Extreme Summer Performance tires that I can fit on the OEM wheels and I just wanted to see if there would be any difficulties or differences? Are there any?
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08-28-2015, 10:37 PM	#2
DanG Major General 10656 Rep 6,935 Posts Drives: 2018 M2 AW DCT Join Date: Aug 2012 Location: Seattle, WA iTrader: (1) Garage List 2018 BMW M2 [7.68]	I don't think you can get a 245/40/18 tire to fit on the front without rubbing.
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08-29-2015, 09:39 AM	#5
OpenAir Captain 432 Rep 887 Posts Drives: Enzo F23 228i Join Date: May 2015 Location: MD, USA iTrader: (1) Garage List 2015 BMW 228i [0.00]	I'm working on a set of 8x8.5 ET35 5x120 w/235/40/18's. 245's didn't appear to fit the front without rubbing unless the fender was rolled.
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08-29-2015, 11:16 AM	#8
eclipes Second Lieutenant 47 Rep 228 Posts Drives: 228i Msport Join Date: May 2015 Location: Toronto iTrader: (0)	40 sidewall will fit in the rear even if its lowered. But will rub over bumps ONLY if you have full load in the back. I thought it was too risky so i went with 265/35/18 instead
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08-29-2015, 12:09 PM	#9
overcoil Major General 3074 Rep 5,577 Posts Drives: M235i 6spd Join Date: Dec 2013 Location: Mid-Atlantic iTrader: (0)	Anyone think that slightly higher sidewall ratio would be detrimental to control under power? Particularly in those situation when the tail swaps back after overcorrecting oversteer? I'm not sure it's worth deviating to a taller sidewall for the sake of a particular manufacturers tire particularly if your going to drive hard.
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08-29-2015, 04:39 PM	#11
Transfer Major General 5254 Rep 5,874 Posts Drives: Bronco Wildtrak, Tesla MYP Join Date: Mar 2010 Location: Issaquah, WA iTrader: (1)	BFG rivals? Why?
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09-08-2015, 09:24 PM	#17
Pparana Captain 463 Rep 957 Posts Drives: 2015 m235i Join Date: Oct 2014 Location: Jacksonville Fl iTrader: (1)	Will change the rake of the car, raising the back about 1/2". You should be trying to lower the car for track use.
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