backspacing...

[Guest Anonymous]

okay, lets say i fabbed up the entire suspension...stuck some big azz brakes on my car. how do i determine what i need to make my backspacing? i know the Z is 10mm, but what can change that?

 

thanx,

eric

[Z-TARD]

We've been tossing around the idea of swapping the entire rear suspension carrier from a late 80's Toyota Supra into a Z. I havent taken a measurement on total width on one yet, but I'm betting its a little wider than a first gen Z. It also already has 5 lugs, rear disks, LSD, and CV shafts. it would just require some modification to the Z unibody to make mounting pads for it. As an added bonus, it has both upper and lower control arms in the rear, which lets you get away with running sub 10 second 1/4 miles without having to switch to solid rear axle as per NHRA (I think) rules.

 

 

Mike

[z-ya]

The backspacing on an early Z is not 10mm. The offset might be though.

 

Best way to measure backspacing of an existing wheel is to lay it face down on the pavement, place a straight edge across the rim (not tire), and measure the distance between the mounting pad and straight edge. That is you backspacing.

 

Now if you want to know what the maximum backspacing for a given suspension, do this:

 

Mount a wheel with tire on the car with a know backspacing. The tire should be the same diameter, and also have the same side bulge as what you plan on running. Then lower the car to the ground, or better yet, put it on a drive on lift. Measure from the rim or tire (whichever is closest) to the nearest supension component (probably the srping perch). Add that measurement to the wheel backspacing. Subtract an 1/8" or so, and that is the maximum backspace you can run.

 

Hope this helps.

 

Pete