rocket22

iTrader: (2)

Can somebody convert my backspace measurement to offset,my math isn't working to good.

My backspace is 71/4

Thanks
Rocket

Oh yeah,I'm planning on 18x10's

SJM Manufacturing Inc

iTrader: (5)

you need to mention the current wheel width of that 7.25" backspace.

Xsta Z 28

iTrader: (2)

Approximately 44 mm . . . back space and offset are related, but not directly linked.

To accurately calculate the offset from the BS one needs to know how thick the bead is. By rull of thumb I use 1/2" as the bead thickness.

rocket22

iTrader: (2)

there 18x10

Troy@DTD

Xsta is correct. Approximate offset is 44mm on a 10 inch wheel with a 7.25 inch backspace.

rocket22

iTrader: (2)

So then would a 38mm offset be a 7inch backspace,on a 10 inch wheel.And would this work on a 94 z,and be in the wheel still,

NOBR8KSS

iTrader: (12)

The 38mm offset will place the rim closer to the fender...it should fit fine, but you may need to roll the fender lip. And yes, it would be close to a 7" backspace.

Fulton 1

iTrader: (9)

Easy way to calculate offset from BS is:

1) Add 1" to advertised width of wheel to account for flanges

2) Divide that width by 2 to obtain centerline of wheel ("zero offset")

3) Subtract this quotient from the backspacing number you have to calculate the offet from centerline. (note that positive offset means the wheel center section is offset outboard and negative offset means the center section is offset inboard)

4) Convert the resultant from inches to millimeters if necessary (usually BS numbers are quoted in inches and offsets are quoted in mm - not really sure why that is).

EXAMPLE:

You want to calculate the offset on a 17x11 wheel with an 8.0" backspacing:

1) 11"+1" = 12" overall width

2) 12"/2 = 6"

3) 8"-6" = +2" (note that its positive in this case)

4) 1" = 25.4mm, so 2" = 50.8mm

ANSWER ==> +50.8mm offset, which can be rounded to +51mm

So, +51mm is equivalent to 8.0" backspacing on the 17x11" wheel.