Question on tire sizes.

Noc57 · 04-08-2010, 03:37 PM

I'm in the process of buying Vredsteins and many people here are running 235/35 19 front and 265/30 19 rear.

I just got off the phone from a guy at the tire shop and he says it's not recommended to switch tire sizes on BMW's (at least on the X5's.) over original spec.

Is this just a load of bull or is there some truth to this? Am I screwing anything up by altering my tire size over manufacturer spec?

Thanks guys.

Sifu-Lux · 04-09-2010, 10:26 AM

You can run different "inch up" sizes over stock, as long as the tyre OD is the same or within say 1% rolling circumference.

Normal steps on BMW are like so

Front: 225/45/17 -> 225/40/18 -> 235/35/19

Rear: 255/40/17 -> 255/35/18 -> 265/30/19

With the correct wheel offsets, these will be fine without issues.

I just bought a set of 220M reps 8" wide ET35 front, 9" wide ET34 rear, with
Continental CSPC3 235/35ZR19 front and 265/30ZR19 rear. Will fit them next week.

I'm upgrading from the factory OEM 194M style 17" wheels which look a bit small.

MassBimmer · 04-09-2010, 10:45 AM

The concern is making sure that the difference in rolling diameters of the front tires vs. the rear tires does not exceed 1% on AWD models. Having a difference from front to back of more than 1% makes the xDrive system believe wheels are slipping and constantly compensates for it. Not good for the long-term health of the transfer case

remmib · 04-09-2010, 10:53 AM

235/35/19 and 265/30/19 worked great on my e90.

gehmjc21 · 04-09-2010, 01:08 PM

same here, 235/35/19 - 265/30/19 on my E92 and I love the set up.

04-08-2010, 03:37 PM	#1
Noc57 Lieutenant Colonel 74 Rep 1,859 Posts Drives: e92 335 Join Date: Dec 2008 Location: Orlando, FL iTrader: (0)	Question on tire sizes. I'm in the process of buying Vredsteins and many people here are running 235/35 19 front and 265/30 19 rear. I just got off the phone from a guy at the tire shop and he says it's not recommended to switch tire sizes on BMW's (at least on the X5's.) over original spec. Is this just a load of bull or is there some truth to this? Am I screwing anything up by altering my tire size over manufacturer spec? Thanks guys. __________________
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04-09-2010, 10:26 AM	#2
Sifu-Lux New Member 2 Rep 26 Posts Drives: 2008 E90 335i Join Date: Nov 2007 Location: RSA iTrader: (0)	You can run different "inch up" sizes over stock, as long as the tyre OD is the same or within say 1% rolling circumference. Normal steps on BMW are like so Front: 225/45/17 -> 225/40/18 -> 235/35/19 Rear: 255/40/17 -> 255/35/18 -> 265/30/19 With the correct wheel offsets, these will be fine without issues. I just bought a set of 220M reps 8" wide ET35 front, 9" wide ET34 rear, with Continental CSPC3 235/35ZR19 front and 265/30ZR19 rear. Will fit them next week. I'm upgrading from the factory OEM 194M style 17" wheels which look a bit small. __________________ '08 BMW 335i Sedan Alpine White III Steptronic with paddles M-Sport package, Zenons, OEM Blacklines
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04-09-2010, 10:45 AM	#3
MassBimmer Major General 306 Rep 7,433 Posts Drives: 2023 i4 M50 Join Date: May 2009 Location: MA iTrader: (6) Garage List 2009 BMW [9.24]	The concern is making sure that the difference in rolling diameters of the front tires vs. the rear tires does not exceed 1% on AWD models. Having a difference from front to back of more than 1% makes the xDrive system believe wheels are slipping and constantly compensates for it. Not good for the long-term health of the transfer case
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04-09-2010, 10:53 AM	#4
remmib General 1569 Rep 29,202 Posts Drives: 2013 F10 520d M-Sport Join Date: Feb 2006 Location: Norway iTrader: (0)	235/35/19 and 265/30/19 worked great on my e90. __________________ 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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04-09-2010, 01:08 PM	#5
gehmjc21 Second Lieutenant 20 Rep 278 Posts Drives: 2012 650i X drive Join Date: Mar 2009 Location: Central NY iTrader: (0)	same here, 235/35/19 - 265/30/19 on my E92 and I love the set up. __________________ e92 retired B8 S4 retired F12 650xi retired F10 550xi retired F01 750xi
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