Rear wheel offset/backspace Q?

[Jayru 17]

I know this comes up a lot, but what is a safe offset or backspace you can run with an 8-9 inch wide wheel in the rear?

 

Now that my rear suspension is rebuilt the car is sitting much lower than it was before. The moronic PO had an offset/backspace on the wheel that makes the rear of the wheel sit flush with the brake drum. The front of the wheel doesn't protrude past the quarter lip, but the large tires are hitting the lip under suspension travel now. I've rolled the fenders and it's still doing it!

 

I wanted to save up and buy a really nice/light set of 4 wheels/tires for auto crossing, but i don't think i can wait because when it hits it's actually cutting the tire now. I'm hoping to get a cheap rear set or cragar knock offs ( i have pacers on the car now) to alleviate the problem till i can afford all new wheels/tires. I need a rear rim that sits in more (seems to be plenty of room in the inner wheel well from where the rim sits now).

 

I am always really bad at figuring backspace out. Everywhere i turn online gives a different formula and it makes my head spin!

 

Any help is greatly appreciated!

[Jayru 17]

I know this comes up a lot, but what is a safe offset or backspace you can run with an 8-9 inch wide wheel in the rear?

 

Now that my rear suspension is rebuilt the car is sitting much lower than it was before. The moronic PO had an offset/backspace on the wheel that makes the rear of the wheel sit flush with the brake drum. The front of the wheel doesn't protrude past the quarter lip, but the large tires are hitting the lip under suspension travel now. I've rolled the fenders and it's still doing it!

 

I wanted to save up and buy a really nice/light set of 4 wheels/tires for auto crossing, but i don't think i can wait because when it hits it's actually cutting the tire now. I'm hoping to get a cheap rear set or cragar knock offs ( i have pacers on the car now) to alleviate the problem till i can afford all new wheels/tires. I need a rear rim that sits in more (seems to be plenty of room in the inner wheel well from where the rim sits now).

 

I am always really bad at figuring backspace out. Everywhere i turn online gives a different formula and it makes my head spin!

 

Any help is greatly appreciated!

[LoneWolf2U 136]

Your back space is depending on your set up, So not all will be the same unless stock.

With the stock Magnums 4 3/4 bs run on mine and the inner tire rubs on corners with my oversize rear sway bar, So I run a 4 1/2 with my Cragers.

 

Simplest way to measure what yours will allow.

Place straight edge across wheel hub, Measure from straight edge to any point that the tire/rim may strike going toward the frame.

Measure from the straigt edge to the outer wheel well lip and add that to your back space amount. The total is the width of rim/tire you can stuff under it.

 

:huh:

Edited July 3, 2010 by Mach1Rider

[RPM 1,190]

If the wheels on it now are the size you want, it easy. With weight on the wheels, measure inward to check how far in you can go, then see how much clearance you need at the wheel opening. If the inner is flush with the backing plate, you have a ton of room inward.