Wheel mock up
 

I need to mock up my wheels to get a measurement for my rearend to be cut down. The problem is......the rearend is already at the machine shop and I'm not 100% positive of where the wheel should sit in the wheel well!! I have my subframe that I could reassemble to measure the wheelbase, but, if someone knows of other measurements that i could use that would save me some time......that would help.

What is the car and what is your rim width and backspace and is it mini tubed?

I'm sorry, I guess I left out the most important parts!! Its a 68 camaro, dse mini-tubs with 18 x 12 Budnik's. The wheels are 5.5" backspaced.

It should be around 6 inches total but you will have to mesure pretty close and take into acount for rotor/drum thickness. The easy way to do it will be put the tires under the car centered in the wheel wells and make sure there square with the car and measure it might help to bolt your axels to your wheels to help center and get a better mesurement. It might not be a bad idea to go 1/4 more then you think you need cuz you can always run a spacer.

Okay, this is what I came up with, 55 7/8" between mounting surfaces of the rims with 1" clearance all the way around. The rotors are 3/8" thick each. I'm thinkin I should drop that 55 7/8" to 55 3/4", subtract the 3/4" for rotor thickness and my overall axle to axle length should be 55"???? Does this sound right?? Again my wheels are 18x12 w/ 5.5" backspace on a 68 camaro?? Thanks for all your help.

Rotor thickness of .75? edit drrrrr both sides

UMMM,that would be .75 total slick.....3/8" + 3/8" = 6/8" = 3/4".