how many "mm" are in an inch???
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From: A-town, TX
how many "mm" are in an inch???
how many milimeters are in 1 inch? i want to get some hp evo's 9 inch rears and get them widdened to 11" so that would add 2 inches to the backspacing. if the wheels have a 38mm backspacing now what would they have after an aditional 2 inches? 
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Re: how many "mm" are in an inch???
25.4 mm/inch
And here is some info that will show you how to do the calculation
http://www.tirerack.com/wheels/tech/offset.jsp
And here is some info that will show you how to do the calculation
http://www.tirerack.com/wheels/tech/offset.jsp
Last edited by Brent94Z; May 13, 2005 at 08:00 PM.
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Re: how many "mm" are in an inch???
No.... both you and the original post are confusing "backspace" with "offset". 38mm and 53mm are typical values for "offset". That is the amount the hub mounting surface of the wheel is "offset" from the centerline of the wheel.
If you have a 53mm offset (roughly 2" offset), your backspace will be the wheel width + 1" (allowance for bead retention flanges), divided by 2, plus the offset.
A 10" wide wheel with a 53mm offset would have a 7.5" backspace.
((10 + 1) / 2) + (53 / 25.4) = (11 / 2) + 2.08" = 5.5" + 2.08" = 7.58" backspace
If you have a 53mm offset (roughly 2" offset), your backspace will be the wheel width + 1" (allowance for bead retention flanges), divided by 2, plus the offset.
A 10" wide wheel with a 53mm offset would have a 7.5" backspace.
((10 + 1) / 2) + (53 / 25.4) = (11 / 2) + 2.08" = 5.5" + 2.08" = 7.58" backspace
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Joined: Jan 2005
Posts: 162
From: Scottsdale, AZ
Re: how many "mm" are in an inch???
Originally Posted by Injuneer
No.... both you and the original post are confusing "backspace" with "offset". 38mm and 53mm are typical values for "offset". That is the amount the hub mounting surface of the wheel is "offset" from the centerline of the wheel.
If you have a 53mm offset (roughly 2" offset), your backspace will be the wheel width + 1" (allowance for bead retention flanges), divided by 2, plus the offset.
A 10" wide wheel with a 53mm offset would have a 7.5" backspace.
((10 + 1) / 2) + (53 / 25.4) = (11 / 2) + 2.08" = 5.5" + 2.08" = 7.58" backspace
If you have a 53mm offset (roughly 2" offset), your backspace will be the wheel width + 1" (allowance for bead retention flanges), divided by 2, plus the offset.
A 10" wide wheel with a 53mm offset would have a 7.5" backspace.
((10 + 1) / 2) + (53 / 25.4) = (11 / 2) + 2.08" = 5.5" + 2.08" = 7.58" backspace
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