Wheels - 3; Truing

Now that I had the frame in a state where I could fit the wheels, I could true up the rims - i.e. get them to turn in proper circles and with no side to side buckles.

The method I used was a bit unorthodox, but worked fine. First I mounted the front wheel in the forks:

Then I clamped a piece of scrap wood across the fork legs and marked this up with the lines that each side of the rim needed to follow when it was true horizontally. I also set the vertical position of the wood at the point where any vertical run-out was maximum.

I chose to tackle the vertical run-out first; not sure why but it just seemed instinctively right to get that done first! The method I used was to identify where the maximum run-out was and then slacken spokes opposite to that and tighten corresponding spokes 180 deg around from there. i.e. in the diagram below, if the rim was high in quadrant A compared to quadrant B, I tightened spokes in A and loosened in B. The adjustments were no more than 1/4 turn at a time and you kind of develop a "feel" for what to do. As the rim came into true, I adjusted the piece of timber down and eventually it was pretty much there but not quite, as the horizontal "buckles" also impacted on the rim height.

So, moving on to the horizontal adjustments, opposing pairs of adjacent spokes were tightened/loosened, again using no more than 1/4 turn at a time. I had to move backwards and forwards between vertical and horizontal truing a couple of times to get it there. At the end I was within about 1mm, which looked OK to me.

As a final check, I made sure that the spokes were all roughly similar tension by "pinging" them with a screwdriver - very technical!

I followed the same process on the rear wheel, but clamped the wood across the shock absorbers.

Finally, I checked that none of the spokes were protruding above the nipples (which could cause a puncture). I found one very slight protrusion and filed it down.

One thing worth mentioning was that I found both rims had a built in "fault" where they had been welded together. The width of the rim at this point was about 1-2mm less than the rest of it and actually there was also a vertical dip as well. Nothing I did to the spoke tension could take that out. I'm assuming it will be OK in practice.