When I measure the distance, I'm having a hard time getting consistent measurements.

I have two boards (generic white shelves) from home depot. They're up against the tire (I have some negative camber so I need to lean them up against the face of the wheel).

It'll start and get something like 69 12/16R and 69 4/16F, that seems ****ed up, so I re-measure and get 69 8/16R and 69 7/16F. That's a little more reasonable, but leaves me doubting the measurements.

I do have a person on the other end keeping pressure (as best as they can) on the board making sure its centered. I do try and have the tape as straight as possible.

Do I just keep measuring till I get something logical? I understand they're boards and I'm doing it in my driveway but there has to be some consistency for it. I feel like I'm doing it wrong.

 

You need to make sure the board is in the same spot front to rear on both wheels and each time you measure. Paint marker, tape, whatever. Make it easily repeatable.

Also make sure you measure to and from the same spots on the boards each time. same deal, make marks on the boards or use tape or something.