Tire size help

lrcigar · 09-29-2010, 07:17 AM

i'm considering getting a new set of Apex-arc-8 wheels. the people at Appex recommended 225/40/18 or 235/40/18. can someone explain the difference between to two sizes.

Thanks

Z4Murder · 09-29-2010, 01:24 PM

Quote:

Originally Posted by lrcigar

i'm considering getting a new set of Apex-arc-8 wheels. the people at Appex recommended 225/40/18 or 235/40/18. can someone explain the difference between to two sizes.

Thanks

those are tire sizes. the only difference being the 235/40/18 is slightly wider, 10 millimeters wider to be exact. which also changes the aspect ratio of the sidewall to the tire width. the 235 tire will also be slightly taller

lrcigar · 09-29-2010, 01:46 PM

Thank you,
I'm going with a squared set of the acr-8's 18X8.5 with the 235/40/18 tires.

3002 tii · 09-29-2010, 02:05 PM

225 is width
40 is sidewall
18 is diameter

the difference in 225/235 will be width and height.

width:
225mm vs 235mm

height:
225 x .40 = 90mm
235 x .40 = 94mm

diameter is same for both at 18"

you're basically looking at 4mm difference in height. i'd go with 225 only b/c assuming you're going with 255/35 rear, they're essentially the same height (90mm and 89.25mm). plus 225/40 is a more common size so it'll be easier to get rubbers.

lrcigar · 09-29-2010, 02:21 PM

Quote:

Originally Posted by Dubbedown

225 is width
40 is sidewall
18 is diameter

the difference in 225/235 will be width and height.

width:
225mm vs 235mm

height:
225 x .40 = 90mm
235 x .40 = 94mm

diameter is same for both at 18"

you're basically looking at 4mm difference in height. i'd go with 225 only b/c assuming you're going with 255/35 rear, they're essentially the same height (90mm and 89.25mm). plus 225/40 is a more common size so it'll be easier to get rubbers.

I was thinking of going 235/40 all around because it was a squared set. what would be the atvantage of going 255/35 in the rear?

lrcigar · 09-29-2010, 04:04 PM

Quote:

Originally Posted by Z4Murder

those are tire sizes. the only difference being the 235/40/18 is slightly wider, 10 millimeters wider to be exact. which also changes the aspect ratio of the sidewall to the tire width. the 235 tire will also be slightly taller

Thanks

Thisisdudewhoru · 09-29-2010, 10:53 PM

Since this is a tire help thread and he's been helped...

Will
245/40/18F and 275/35/18R work on stock wheels, stock suspension, no spacers and NOT rub?

Also, how big spacers will I need to make my wheels pretty much flush? and does our stock suspension have enough travel to hit the tire when I make them flush?

09-29-2010, 07:17 AM	#1
lrcigar Enlisted Member 4 Rep 45 Posts Drives: 2003 2.5 Roadster Join Date: Feb 2009 Location: NYC and PA. iTrader: (0)	Tire size help i'm considering getting a new set of Apex-arc-8 wheels. the people at Appex recommended 225/40/18 or 235/40/18. can someone explain the difference between to two sizes. Thanks
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09-29-2010, 01:46 PM	#3
lrcigar Enlisted Member 4 Rep 45 Posts Drives: 2003 2.5 Roadster Join Date: Feb 2009 Location: NYC and PA. iTrader: (0)	Thank you, I'm going with a squared set of the acr-8's 18X8.5 with the 235/40/18 tires.
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09-29-2010, 02:05 PM	#4
3002 tii Lieutenant General 2286 Rep 12,565 Posts Drives: Z4 M, X5, GX460 Join Date: Apr 2008 Location: CT iTrader: (99) Garage List F15 X5 xDrive35i [8.75] E86 Z4 M [10.00] F10 550i (Retired) [9.17] F25 X3 xDrive35i (R ... [9.43] E82 135is (Retired) [9.50] E85 Z4 M (Retired) [9.41] E90 328i xDrive (Re ... [9.25] E86 Z4 3.0si (Retired) [9.24]	225 is width 40 is sidewall 18 is diameter the difference in 225/235 will be width and height. width: 225mm vs 235mm height: 225 x .40 = 90mm 235 x .40 = 94mm diameter is same for both at 18" you're basically looking at 4mm difference in height. i'd go with 225 only b/c assuming you're going with 255/35 rear, they're essentially the same height (90mm and 89.25mm). plus 225/40 is a more common size so it'll be easier to get rubbers. __________________ Follow for latest mods
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09-29-2010, 10:53 PM	#7
Thisisdudewhoru Captain 82 Rep 698 Posts Drives: 16 BSM 340i Join Date: Mar 2010 Location: 423 iTrader: (1)	Since this is a tire help thread and he's been helped... Will 245/40/18F and 275/35/18R work on stock wheels, stock suspension, no spacers and NOT rub? Also, how big spacers will I need to make my wheels pretty much flush? and does our stock suspension have enough travel to hit the tire when I make them flush? __________________ '16 BSM 340i M Sport + Track Pack.:.M Perf Exhaust.:.Polished BBS RS-GT.:.JB4.:.BMS Intake.:.H&R Sport.:.
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