wheel offset
08-09-2007, 10:07 PM
#1
wheel offset
ok say for two given tires I want to put on 275/55/20's Both wheels are 18mm offset but one is 8.5" wide and one is 9" wide. Now check my thinking here. The wider wheel will stick out .25" further (9-8.5/2), but since the tires are the same size.. the actual tire won't stick out any further. I mean to say that the side walls will be more vertical on the 9" wide rim and turn inward more on the 8.5" rim. But the should of the tread will be in the same spot. is this right?
08-09-2007, 10:51 PM
#2
if you're rims stick out 1/4 of an inch more so will your tires. If the 9" wide rims had an offset with the same ratio as the 8.5's then they wouldn't sick out any further.
What I mean is that if the 8.5's have a 5.5" backspacing, the 9" rims would need 6" of backspacing to stick out the same
What I mean is that if the 8.5's have a 5.5" backspacing, the 9" rims would need 6" of backspacing to stick out the same
08-10-2007, 06:55 AM
#3
I know that with the same backspacing the 9" wide rim will stick out further than the 8.5" rim. But since both will get the same tire, will the tire stick out any further? I would think that the tire will be just as wide at the shoulder, but its sidewalls won't have to come inward as far to meet the rim. This drawing is what I'm talking about with the Red being the 8.5" rim and blue being the 9" rim
08-10-2007, 08:39 AM
#4
I see what you're saying, but no it will still push the tire out the same. The best example is that: bagged guys may be able to run a 20x8.5" rim with 5.5" of backspacing on a 255/35/20 but they can't run a 20x9.5 with 5.5" of backspacing on the same tires. With the same 5.5" of backspacing the center of the rim/tire is pushed out further
08-10-2007, 09:21 AM
#5
gotcha.. but I think the isuse here is back spacing and offset aren't the same. Offset is the distance from the center of the wheel to where it bolts onto the axle. Backspacing is the distance from the back of the rim to the bolting surface.
So when you get a wider rim, but keep the same backspacing the extra width pushes the rim/tire centerline out more. But if you get a wider rim with the same offset it doesn't push the centerline of the rim out any further. Since the tires are wider than the rims their location depends on the centerline of the rim not the outside edge
So when you get a wider rim, but keep the same backspacing the extra width pushes the rim/tire centerline out more. But if you get a wider rim with the same offset it doesn't push the centerline of the rim out any further. Since the tires are wider than the rims their location depends on the centerline of the rim not the outside edge
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