BurbMan wrote:
The driveway isn't level per se, but it's flat, meaning that if he got the same F/R frame to ground measurement on the left side it should be the same on the right too if the TT frame is flat.
Have you ever set forms for a concrete driveway? Sight down an old 2x6 that has been used multiple times and it's not unusual to see a 1/2inch of bowing/twisting.
Unless it's something like a machine shop where the floor had to be precision leveled for a special piece of machinery, I wouldn't trust a concrete floor to be that precise.
To really get it accurate, you would need to do something like:
- Place thin shims where the tires will sit and using a laser level, make sure they are perfectly level under all 4 tires. Probably need them level to less than 1/16th inch if you want to check for better than 1/2 inch accuracy.
- Verify the tires are identical and aired up to the same level. Low air pressure could throw off the measurement.
- Use a laser level to set a baseline and measure from the frame to the baseline on all 4 corners.
And even then, little things could throw off. Is there camber to the main beams?