Tire Size Question

WOT Bimmer · 04-28-2014, 07:31 PM

I have an XI, and I'm a little confused about the offset/1% difference discussion. I just need someone to confirm my suspicion here.

I found a set of new wheels/tires and the dimensions are 225/45/17 front, 255/45/17 rear. The calculator is telling me (if correct) that this is a 4% difference, in which case I should NOT put these on my XI. Is this correct?

Thank you!

Goldenc717 · 04-28-2014, 07:50 PM

Correct.

WOT Bimmer · 04-28-2014, 10:58 PM

What if I put spacers in the front? Would that make a difference?

I'm sorry I'm uneducated on this topic, but I'm trying to get my head wrapped around it. Thanks for your help!

WOT Bimmer · 04-28-2014, 11:08 PM

Whoops... Just realized I received the wrong tire specs. They are actually 225/45/17 front and 255/40/17 in back. It looks like he is .2% difference. Is that correct? What would happen if I put 20mm spacers on the rear? I don't think that would affect it because I am under the impression only diameter is the concern, not width. Correct?

Goldenc717 · 04-29-2014, 04:45 AM

Those specs will be fine. Offset doesn't matter.

WOT Bimmer · 04-29-2014, 06:24 AM

Quote:

Originally Posted by Goldenc717

Those specs will be fine. Offset doesn't matter.

Thank you!

petelazro · 04-29-2014, 08:43 AM

you should be fine. mine came with those tires stock from bmw.

b_minus335 · 04-30-2014, 11:49 AM

Correct, offset doesn't influence the rolling diameter of the wheel.

WOT Bimmer · 04-30-2014, 09:43 PM

Quote:

Originally Posted by b_minus328

Correct, offset doesn't influence the rolling diameter of the wheel.

So us with AWD need to be concerned about rolling diameter, not offset, right?

b_minus335 · 05-01-2014, 12:11 AM

Quote:

Originally Posted by WOT Bimmer

So us with AWD need to be concerned about rolling diameter, not offset, right?

Correct. Rolling diameter is the only thing thats important. Offset just changes how far the wheel/tires stick out among other things,but that doesnt interfere with the AWD system. Just focus on getting that rolling diameter under 1% which you will already have with that square set up

WOT Bimmer · 05-01-2014, 07:09 AM

Quote:

Originally Posted by b_minus328

Correct. Rolling diameter is the only thing thats important. Offset just changes how far the wheel/tires stick out among other things,but that doesnt interfere with the AWD system. Just focus on getting that rolling diameter under 1% which you will already have with that square set up

Awesome! That makes a lot of sense. Thank you!

ajsalida · 05-01-2014, 07:50 AM

Wait a minute, even if within 1% rolling diameter, wheel offset does matter depending on what kind of wheels they are. If they are OEM e9x you're likely fine but lot of wheels will not work due to clearance issues.

WOT Bimmer · 05-01-2014, 08:23 AM

Quote:

Originally Posted by ajsalida

Wait a minute, even if within 1% rolling diameter, wheel offset does matter depending on what kind of wheels they are. If they are OEM e9x you're likely fine but lot of wheels will not work due to clearance issues.

I am referring to OEM, but my main concern was the AWD system. I don't mind working with clearance issues as long as I am not tearing my AWD system up in the process.

vaughnairforce · 05-01-2014, 09:10 AM

I am running the following without issues for several months.

MRR GT7 18x8.5 +35 5x120 72.6 HS

MRR GT7 18x9.5 +40 5x120 72.6 HS

P235 40ZR18 Hankook VENTUS V12 EVO K110 95Y XL B

P265 35ZR18 Hankook VENTUS V12 EVO K110 97Y XL B

shadow191 · 05-01-2014, 09:26 AM

Your tire sizes should work and the systems are so sensitive that they really won't let you do much damage. It should go into limp mode if the tire sizes are way off because it thinks something is wrong.

Quote:

Originally Posted by WOT Bimmer

I am referring to OEM, but my main concern was the AWD system. I don't mind working with clearance issues as long as I am not tearing my AWD system up in the process.

KMEninety335 · 05-02-2014, 08:44 AM

Hey I'm really really sorry to try to jack the thread but I thought it'd be better than posting new since there are a thousand tire size questions. I'm looking at getting staggered on my xi as well. I'm looking at Apex EC-7 18x9 ET31 with 245/40/18 and 18x10 ET43 with 275/35/18. Will this work well with my car? I believe I saw it is .5%. Currently I am stock suspension but I heard I still might need slight rolling in the back. I know when I lower it later I definitely will. Thank you!

04-28-2014, 07:31 PM	#1
WOT Bimmer Major 1227 Rep 1,126 Posts Drives: 2018 BMW M2 Join Date: Jan 2013 Location: Columbus Ohio iTrader: (3)	Tire Size Question I have an XI, and I'm a little confused about the offset/1% difference discussion. I just need someone to confirm my suspicion here. I found a set of new wheels/tires and the dimensions are 225/45/17 front, 255/45/17 rear. The calculator is telling me (if correct) that this is a 4% difference, in which case I should NOT put these on my XI. Is this correct? Thank you!
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04-28-2014, 07:50 PM	#2
Goldenc717 Private First Class 7 Rep 109 Posts Drives: 2007 E90 335xi Join Date: Feb 2013 Location: Lebanon, PA iTrader: (2) Garage List 2007 BMW E90 335xi [0.00]	Correct.
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04-28-2014, 10:58 PM	#3
WOT Bimmer Major 1227 Rep 1,126 Posts Drives: 2018 BMW M2 Join Date: Jan 2013 Location: Columbus Ohio iTrader: (3)	What if I put spacers in the front? Would that make a difference? I'm sorry I'm uneducated on this topic, but I'm trying to get my head wrapped around it. Thanks for your help!
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04-28-2014, 11:08 PM	#4
WOT Bimmer Major 1227 Rep 1,126 Posts Drives: 2018 BMW M2 Join Date: Jan 2013 Location: Columbus Ohio iTrader: (3)	Whoops... Just realized I received the wrong tire specs. They are actually 225/45/17 front and 255/40/17 in back. It looks like he is .2% difference. Is that correct? What would happen if I put 20mm spacers on the rear? I don't think that would affect it because I am under the impression only diameter is the concern, not width. Correct?
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04-29-2014, 04:45 AM	#5
Goldenc717 Private First Class 7 Rep 109 Posts Drives: 2007 E90 335xi Join Date: Feb 2013 Location: Lebanon, PA iTrader: (2) Garage List 2007 BMW E90 335xi [0.00]	Those specs will be fine. Offset doesn't matter.
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04-29-2014, 08:43 AM	#7
petelazro Second Lieutenant 14 Rep 208 Posts Drives: 2008 328xi Join Date: Apr 2013 Location: Toronto iTrader: (0)	you should be fine. mine came with those tires stock from bmw. __________________ 2008 E90 328 X-drive -KW V1- Auto-Sport-Blacklines-LED interior lighting Summer: Style 195 F-225/40/18 R-255/35/18 on Bridgestone RE760 Sport Winter: Style 161 - Sottozero RFT 225/45/17 square
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04-30-2014, 11:49 AM	#8
b_minus335 Private First Class 3 Rep 167 Posts Drives: E92 335i X Drive Join Date: Jan 2014 Location: Mile High, Colorado iTrader: (0)	Correct, offset doesn't influence the rolling diameter of the wheel. __________________ Alpine White\|Coral\|e92 ZSP\|ZCW\|ZPP\|X-Drive
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05-01-2014, 07:50 AM	#12
ajsalida Colonel 226 Rep 2,387 Posts Drives: 95 M3, 02 R1150GSA, 09 335xi Join Date: Aug 2010 Location: SW USA iTrader: (2)	Wait a minute, even if within 1% rolling diameter, wheel offset does matter depending on what kind of wheels they are. If they are OEM e9x you're likely fine but lot of wheels will not work due to clearance issues.
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05-01-2014, 09:10 AM	#14
vaughnairforce New Member 0 Rep 24 Posts Drives: 335ix Join Date: Apr 2012 Location: Washington iTrader: (1)	2008 335xi - Staggered I am running the following without issues for several months. MRR GT7 18x8.5 +35 5x120 72.6 HS MRR GT7 18x9.5 +40 5x120 72.6 HS P235 40ZR18 Hankook VENTUS V12 EVO K110 95Y XL B P265 35ZR18 Hankook VENTUS V12 EVO K110 97Y XL B Attached Images
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05-02-2014, 08:44 AM	#16
KMEninety335 First Lieutenant 13 Rep 342 Posts Drives: E90 Monaco Blue 335i xdrive Join Date: May 2013 Location: Central NJ iTrader: (0) Garage List 2010 BMW 335i xdriv ... [10.00]	Hey I'm really really sorry to try to jack the thread but I thought it'd be better than posting new since there are a thousand tire size questions. I'm looking at getting staggered on my xi as well. I'm looking at Apex EC-7 18x9 ET31 with 245/40/18 and 18x10 ET43 with 275/35/18. Will this work well with my car? I believe I saw it is .5%. Currently I am stock suspension but I heard I still might need slight rolling in the back. I know when I lower it later I definitely will. Thank you! __________________ 2010 E90 335i xdrive \| Monaco Blue with Black Interior \| All Packages except Sport :/ \| Apex EC-7 \| Active Autowerke Strut Bar \| Roc Euro DCI \| Roc Euro Hyperboost DVs \| aFe Scoops \| BMW Performance Exhaust \| BMWCCA member
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