Bigger tire for rear 189 rim? (18x8.5 rim)

06E90Rostik · 02-05-2012, 01:13 AM

I am in the process of replacing tires on my e90. Fronts were much worse (plus one had a bulge) so I replaced both fronts with OE sizes, went with Michelin PS2s. Great tires BTW. Now I want to change the rears as well, but thinking about deviating from OE sizing. I want more sidewall, for cushier ride and more pothole protection. So, will 255/40 18 be ok? Or even /45? The OE is 255/35 18.

cxc511 · 02-05-2012, 09:16 AM

Could you fit a 255/40/18 on the rear? Probably, but that is an inch taller than the proper fitment. 255/45/18 would most certainly rub at 2 inches taller. BTW, despite the lower aspect ratio, the stock 255/35/18 provides the same amount of sidewall as the front 225/40/18. The profile of the tire is measured as % of width - so 40% of 225 is nearly the same as 35% of 255.

My girlfriend drives an IS250 and Lexus equips the car with 225/40/18 front and 255/40/18 rear. The wider sidewall on the rear tires is definitely visible and I don't like it. Going one step further, 255/45/18 would give your car a ridiculous "hot rod" look beyond the fitment issue.

Hope that helps.

remmib · 02-05-2012, 09:54 AM

255/40/18 should work, but 255/45/18 is too big.

06E90Rostik · 02-06-2012, 12:35 PM

Thanks for the input. So definitely no to /45. Now, regarding /40. Oddly enough the /40 costs about $10-15 cheaper per tire than its cousin /35 (OE size). It is not just coincidence, I checked 4 independent sources. All have /40 as a cheaper tire. It uses slightly more rubber, no? So it should cost more. But maybe it's not as popular so, they discount it?

AU335i · 02-06-2012, 12:49 PM

will 265/35/18 fit a rear e92 on OEM 189's?

06E90Rostik · 02-06-2012, 01:00 PM

Quote:

Originally Posted by AU335i

will 265/35/18 fit a rear e92 on OEM 189's?

From the research i have done, 265s are too wide on 8.5" rim, you would get very uneven wear pattern, and too much deflection on sidewalls. In other words, premature death without much benefit.

spool twice · 02-06-2012, 02:20 PM

if the difference in overall diameter is too great between front/rear tires, the cruise control will not hold a speed. It may attempt to, but will eventually stop holding a speed. Something about the ABS sensors sensing too different of wheel speed.

I know from personal experience

02-05-2012, 01:13 AM	#1
06E90Rostik 2006 join date crew 182 Rep 1,482 Posts Drives: 2006 325i, 2011 335i Join Date: Feb 2006 Location: CA, Sacramento iTrader: (10) Garage List 2011 335i [10.00] 2006 325i [0.00]	Bigger tire for rear 189 rim? (18x8.5 rim) I am in the process of replacing tires on my e90. Fronts were much worse (plus one had a bulge) so I replaced both fronts with OE sizes, went with Michelin PS2s. Great tires BTW. Now I want to change the rears as well, but thinking about deviating from OE sizing. I want more sidewall, for cushier ride and more pothole protection. So, will 255/40 18 be ok? Or even /45? The OE is 255/35 18.
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02-05-2012, 09:16 AM	#2
cxc511 Private First Class 14 Rep 109 Posts Drives: 2007 E92 328 6MT Join Date: Jul 2010 Location: Erie, PA iTrader: (0)	Could you fit a 255/40/18 on the rear? Probably, but that is an inch taller than the proper fitment. 255/45/18 would most certainly rub at 2 inches taller. BTW, despite the lower aspect ratio, the stock 255/35/18 provides the same amount of sidewall as the front 225/40/18. The profile of the tire is measured as % of width - so 40% of 225 is nearly the same as 35% of 255. My girlfriend drives an IS250 and Lexus equips the car with 225/40/18 front and 255/40/18 rear. The wider sidewall on the rear tires is definitely visible and I don't like it. Going one step further, 255/45/18 would give your car a ridiculous "hot rod" look beyond the fitment issue. Hope that helps.
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02-05-2012, 09:54 AM	#3
remmib General 1568 Rep 29,202 Posts Drives: 2013 F10 520d M-Sport Join Date: Feb 2006 Location: Norway iTrader: (0)	255/40/18 should work, but 255/45/18 is too big. __________________ F10 520d M-Sport Alpine White \| HRE P43SC 20x9+20x11 \| Michelin PSS 255/35+295/30 \| KW V3 Coilover \| M5 Front Sway Bar + M550d Rear Sway Bar \| 3DDesign Front Lip \| BMW M Performance CF Spoiler \| BMW M Performance Diffuser \| BMW M Performance Black Grills \| BMW M Performance Pedals \|
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02-06-2012, 12:35 PM	#4
06E90Rostik 2006 join date crew 182 Rep 1,482 Posts Drives: 2006 325i, 2011 335i Join Date: Feb 2006 Location: CA, Sacramento iTrader: (10) Garage List 2011 335i [10.00] 2006 325i [0.00]	Thanks for the input. So definitely no to /45. Now, regarding /40. Oddly enough the /40 costs about $10-15 cheaper per tire than its cousin /35 (OE size). It is not just coincidence, I checked 4 independent sources. All have /40 as a cheaper tire. It uses slightly more rubber, no? So it should cost more. But maybe it's not as popular so, they discount it?
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02-06-2012, 12:49 PM	#5
AU335i Captain 78 Rep 887 Posts Drives: 2008 335i E92 Join Date: Dec 2010 Location: Auburn, AL iTrader: (3)	will 265/35/18 fit a rear e92 on OEM 189's?
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02-06-2012, 02:20 PM	#7
spool twice Rainbow Racer 1008 Rep 2,539 Posts Drives: BMW M4cs Join Date: Sep 2010 Location: Tampa Bay, FL Area iTrader: (7) Garage List 2019 M4cs [0.00]	if the difference in overall diameter is too great between front/rear tires, the cruise control will not hold a speed. It may attempt to, but will eventually stop holding a speed. Something about the ABS sensors sensing too different of wheel speed. I know from personal experience __________________ -Loe P.- Prior Car:'14 Audi S5 3.0t DSG [ APR ECU/TCU \| Pullies + basic bolt-on mods \| 10.861@127.90mph ] Current Car: F82 M4cs \| TT-RS \| On Order: i4 M50
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