Hi Mailman / All:
I have an uncle who has owned a bicycle shop for many years (like around 50 years, since he was a teenager) and he taught me how to true wheels when I was a kid heading off to Europe with my 10 speed in the 1970's I trued my bike wheels every night after dinner because of bashing over the cobblestone streets in Germany and France. He does wheels for bicycles, motorcycles, horse racing sulkies, wheelchairs, even a couple of vintage aircraft - anything with spoked wheels - and the basic skills are the same for each.
In all sincerity, wheel truing simply isn't a big deal. There are a few tricks, but if you understand how spoked wheels work and go about the task methodically, it isn't rocket science and you can do it if you try.
Sit on the ground behind the rear wheel of your motorcycle and stare at how the wheel is constructed. You will note that some of the spokes go from the rim to the right side of the hub (let's call those the RH spokes) and others go to the left hand side (LH spokes). If you tighten the RH spokes and loosen the LH spokes at a given point on the circumference of the wheel - the rim around that point will shift a tiny bit to the right and vice-versa. For out-of-round adjustments (i.e. "hop") - you tighten
both the LH
and the RH spokes at the high spot
by the same amount and if the wheel is really egg-shaped, possibly loosen both LH & RH spokes at a point
90 degrees away around the rim of the wheel.
You can assess the tension in the spokes by "plucking" them like a guitar string, or even striking them lightly with a small piece of wood. The tighter the spoke - the higher the pitch of the "note" will be when you strike it. NOTE - this works well with thinner and longer bicycle spokes than with short and large diameter motorcycle spokes. The whole idea is to wind up with approximately the same amount of tension in every spoke around the circumference of the rim.
So, those are the basic principles and here are the finer points:
- You must create a fixed reference point near the edge of the wheel rim - like a piece of wire attached to the fork or rear swing-arm. The end of the wire must juuussssttttt about touch the rim as you turn the wheel so that you can detect any high spots or left-right shifts. An actual wheel truing stand off the bike is better - but if you pay attention, you can do the job with the wheel on the bike.
- Make only very small adjustments and then observe the effect: turn the spoke nipples no more than 1/4 to 3/4 of a turn at a time and observe, or you will likely just make the problem worse.
- If you are making an adjustment at a given point on the wheel rim, don't try to do it with adjustments to just one or two spokes right AT that point: adjust one or two spokes on each side of the point you're trying to adjust and make a slightly smaller adjustments as you move away from that "centre" point - so that you distribute any extra spoke tension adjustments across several spokes. Again, the idea is to have about the same tension in every spoke.
- Get the wheel round first (remove any "hop") and THEN deal with any left-right shifts.
A potential pitfall is a spoke that has a seized nipple (sounds painful doesn't it??) - but as long as they can all be turned, you should be fine with old spokes.
My uncle taught me on a scrap wheel. I just went to a junk yard and found an old bicycle wheel, set it up in an old set of forks mounted in a vise and within an hour or so, I had it running true as a wheel on a race bike. Just go slowly, make small changes and observe the effect and be patient.
Cheers,
Pete