The first time I tried to true my own rear bicycle rim was an unmitigated disaster. It was the first time I’d attempted a truing, so I had no idea what to expect.
It’s not an article on truing, so I’ll skip the description of my ineptitude. Suffice to say that it was hilarious…. If you weren’t me.
The important point was that it was taking forever. Convinced of my incompetence I was sure that persistence was the key to a trued wheel. So I kept tightening. But the damn thing would not go true. Whenever I rode it and used the brake, I could feel the pulsation.
It turns out that there was actually a deformity in the rim which caused the rim wall to buckle. That meant no matter how much I trued, I could not get the rim equidistant from the guides on both sides all the way around. The buckle would always show and it would always pulsate when braking.
Before I figured this out though, I had tightened the spokes near the deformity so much that I created a flat spot on the rim. Now, when the wheel rotated there was a slight bump as the flat spot rotated under me.
After I fixed the buckle (using a hammer and a 2×4) I had to fix the flat spot. Here’s how I fixed it without spending money on fancy setups and tools.
First thing you need is a board that is longer than the radius of your tire. It should also be thicker than the length of the bolt that protrudes from the rim on the freewheel side. We’re going to use the board to mount the wheel.
Get a nail. A nice long one. It has to be longer than the freewheel preferably by about an inch. The nail is going to be the guide. We’re going use this to measure (eye-up) the roundness of the wheel as we rotate the rim.
Drill a hole in the board that’s approximately the same diameter as the bolt from the freewheel. You’re going to push the bolt into the drilled hole. A snug fit is nice. I’m lazy, and I have a knotty old deck, so it was really convenient for me.
Put the wheel in the hole and mark a spot for the nail. It should be as closely lined up with the rim edge as possible.
*******Don’t nail the nail into the board with the rim in the way*******
Remove the wheel, then nail in the nail. Put the wheel back into the drilled hole and lightly tap the nail from the side until it’s very close to the rim.
Now spin the rim on the freewheel. If you have a flat spot it should be obvious because the rim comes away from the nail. If you have a high spot, the wheel won’t rotate past, or it will push the nail out and it won’t contact any part of the rim but the high spot.
To raise a flat spot, you have to loosen the spokes, to flatten a high spot, you have to tighten them. Now, here’s the tricky part. Which direction is loosening when you’re using a spoke wrench on the spokes? I always remember that the spoke is just like a screw, except instead of driving a screw using the head, you’re pulling it using the body. Therefore – lefty-tighty, righty-loosey.
Keep in mind that the spokes don’t work in isolation. If you have a deformity, you’ll probably want to make the adjustment on at least 3 spokes surrounding it. Maybe more. You might also need to true the wheel again after if you tightened too much on one side.
Something else to remember when working with spokes on the back wheel – the angle of the spoke on the freewheel side is different than the non-freewheel side. This means that tightening the spoke one rotation on the non-freewheel side will have a greater impact on the wheel true-ness than the same rotation on the freewheel side. Now, print out this paragraph, go out and look at your bike and convince yourself that’s true. Just make sure you are tightening about twice as much on the freewheel side vs. the non-freewheel side.
You can make some adjustments this way. But if the wheel is really out of round, watch out, you could screw up the rim by nuts-ing with it yourself if you don’t know what you’re doing. My philosophy is that I don’t attempt to fix something myself unless I can afford to replace it. Sage advice.