Welcome to our 100th edition of Ask a Mechanic! For the event Daniel has put together a special tutorial on wheel truing. If you have a question for Daniel, please post it on our Facebook Wall or e-mail him directly at firstname.lastname@example.org.
Question: I’ve watched quite a few videos about wheel truing, but whenever I start with a true wheel that just needs spoke tensioning I just wind up with an out of round wheel. I start at the valve stem and make 1/4 turn until I complete the circle 2 or 3 times, by that time the wheel has a hop. What is going on here? From: Scott
This question came in response to our wheel Ask a Mechanic wheel truing video on Velonews.com. Go to the Art’s Cyclery Learning Center or the Velonews.com Bikes and Tech page to watch the full series.
Answer: The problem you are experiencing is rooted in the way the entire wheel performs as a system. Every spoke you tighten will add tension to every other spoke on the wheel. So, by the time you make your way around the wheel that quarter turn you are making on spoke 32 (if you had a 32 spoke wheel) is equivalent to 3/8ths of a turn or more on spoke 1.
When I am tensioning a wheel I can feel the tension increase through the resistance on the spoke wrench as I make my way around the wheel. So I gradually back off a little on how much I rotate each nipple on the final 1/3 of each lap around the wheel. But this is something that takes a while to figure out how to do well. A good solution is to fix the uneven tension problems after each lap around the wheel. Doing 2 or 3 laps without making corrections each time compounds the problem you are experiencing, so you definitely want to avoid doing that.
A good truing stand can help you to identify these problems as they crop up to fix them more accurately.
Daniel Slusser is a professional bicycle mechanic with over ten years of experience. He holds a bachelor’s degree in business administration from HSU and a master’s degree in history from Cal Poly. When he is not riding, wrenching, or writing he enjoys spending time with his wife and two children.