Rear alligning

[tom j]

I have adjustable uppers and lowers and getting ready to install brackets to lowers to change instant center. I have not yet plotted the car I will before I remove anything to get a baseline. I know that you use the lowers to square the rear end and uppers for pinion angle. At what points do you measure for squaring the rear end to the front. Hub center to axle center? Ball joint center to axle? Also should this maybe be done in an X LF to RR and RF to LR?

 

[jdpolzin]

Tom, your going to be farely limited on your adjustability of your lowers. Start off with one side and adjust the lowers to where it wants it to sit. Then measure the total length and make the other side the same. Install the other side. If you want to check the in an x pattern or front to rear, go head. Once thats set, install one upper and use it to adjust your pinion angle. Then adjust the other side the same lengt and install.

BUT.....I have heard of people making the passneger side a half turn shorter. I'm going to be looking into that a little more myself once i get my new rear end built. I'll keep you more updated as I find more info as well.

 

[DR BOOST]

the only right way to do it is on an alignment rack. square it to the front wheels, adjust pinion angle , and square it again.

eveything is done with the uppers. the lowers are used to center the wheel in the opening

 

[tom j]

The rear end is not sitting center in the opening now,but I have not measured it to the fronts. What does an alignment rack due that some measuring cant?

 

[DR BOOST]

the problem with measuring is that i couldnt get a clear shot with a measuring tape. either the trans or the exhaust gets in the way.

give it a whirl and let me know how it turns out.

 

[tom j]

Were you trying to triangulate(cross measure it to the front) I was thinking of this and thought of dropping some plumb bobs. Still what are the best measure points

 

[DR BOOST]

maybe plumb bobs from the ball joints in front and the control arm bolts in the rear

 

[tom j]

This brings me to another question is there any other way to fugure out CG without scaling the car.

 

[disco stu]

Plumbob through centerline of wheel, mark floor for measuring. That's how you do it when you front or rear clip a car, same for determining wheelbase here.