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Hello
My buddy who is doing a resto-mod on his 68 C3 coupe having mild flares installed on all 4 corner's (wheel wells) He is having 18X12 Custum wheels built but needs to measure off set to clear e-brake
How does one measure the offset needed?
i THINK you mean 'backspace', not offset. if so, measure from the face of the axle hub (the surface the wheel bolts to) to the closest part on the trailing arm (or other close parts) at about a distance of 8 inches from the center of the hub (use a straight-edge to lay against the face of the hub, then move outward from the center and measure the closest points in the 8 to 10 radius inch range from the straight-dge to the closest point)
bear in mind that this measurement is the backspacing that the RIM will hit the closest point; if the tire sidewall extends beyond the width of the rim, then the tire will hit something before the rim will, soooo, you have to decide on a tire size, then determine the section width (widest part of the tire) and use that in combination with the wheel width to figure out the maximum wheel backspacing (with a tire mounted) that will give sufficient clearance...
Hello
My buddy who is doing a resto-mod on his 68 C3 coupe having mild flares installed on all 4 corner's (wheel wells) He is having 18X12 Custum wheels built but needs to measure off set to clear e-brake
How does one measure the offset needed?
May be a silly question
Happy Easter
Bill
This drawing may help. The 102 dim is backspace. The one above is offset
Last edited by Nev Williams; Mar 21, 2008 at 06:39 PM.
There are actually TWO different types of measurements that characterize a wheel....offset and back space.
Backspace - the distance from the mounting face of the wheel to the BACK of the wheel lip
Offset - the distance that the mounting face is from the "center" of the wheel.
It is much easier to measure backspace since all you do is lay a straight edge across the back of the wheel and measure down to the mounting face. BUT, in order to figure out where the tire will be, you need to know where the center of the tire is relative to the mounting face, hence the need to know where the offset is. Once you know that you have a pretty good idea where the edge of the tire will fall.
After you do all the calculating, I would leave an extra 1/4" of clearance for the tire "just in case" on both sides. Crap happens
How do I mesure off-set
