DIY Alignment

famous bob said
I wondering about 4 exact spacers to put the pipes up against the rear wheels , seems it would be solid and closer/easier to measure the front wheels . Would still have to be spot on perfect on the end pipe lengths tho .
Like it better than strings !

that would work, but if you are going to pilot off the rear wheels you should still first verify that the rear end is square. A small deflection at the rear will be quite large over the 10 feet or so to the front.