Bicycle Mechanics - spoke tension
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So, tonight I'm retensioning the spokes on my first wheel build and was hoping for some tips. Should I tension all the spokes first and then true? or should I true and then tension? Also how does one figure out the tension that the spokes should be?
12-21-05, 04:47 PM
Measure the tension frequently as you are truing. The target spoke tension for most common wheels (32hole/3x and similiar) is between 90-120 kgf. Balanced spoke tension is very important. You should be trying to get each spoke to the same tension. I have found that if you monitor spoke tension as you increase it, you will usually find a point where all the spokes start to equal out. This usually happens at some point after you reach 90kgf.
12-21-05, 04:47 PM
a great resource is:
sheldon brown's wheelbuilding page (http://sheldonbrown.com/wheelbuild.html)
compare the tension with the tension of a wheel that you know is good. squeeze two parallel spokes (of the same side) to check tension. alternatively you could use a tensionometer, but i dont use one. the way i do it is go all the way around the wheel tightening each spoke the same amount, until they feel like they're about the right tension. then true it. once its tight and true, remember to stress relieve the spokes then true them, and repeat one or two times. stress relieving is getting them used to bending in the way they're bent. squeeze them in groups, then retrue. once it stays true after squeezing, then yr done.
12-21-05, 04:59 PM
Spoke tension is most dependant on the weakest part of the wheel, the rim. If possible, contact your rim manufacturer for the recommended tension. I know Sun and Velocity will respond usually within 48 hours
12-21-05, 06:38 PM
When building the wheel, work on out of round first. On the rear, once you start getting some tension in the wheel start working on dish and lateral trueness. If you true from only one side of the wheel, the right side indicator for example, and flip the wheel frequently, the dish will take care of itself.
For final tensioning, you can do it by feel, like coyotecrust said. Take a wheel that you know is properly tensioned and feel the tension in the spokes of that wheel and you will have a good guide for the tension of your new wheel.
The last thing I do is stress the wheel. I put the wheel on the floor, balance my self on the edge of a table and put one foot on the rim. With the other foot, I gently push on the other side of the rim until it just starts to flex. Go easy. You will hear lots of pings and pops. Go around the wheel, flip it over and do it on the other side. Put it back in the truing stand and re-tru. Repeat the process until you can stress it and the wheel does not go out of true.
I've used this method and had wheels that have lasted for 15+ years of consistent riding with maybe one or two truings.
12-21-05, 07:16 PM
Front wheel or rear wheel?
Front: add tension of all spokes...divide by number of spokes...all spokes must be within 20% of average tension. (My wheels average less than 10%).
Rear: use same formula as above, but do so for each side separately (drive side vs. non-drive side). Drive side should be substantially tighter than non-drive side. (In my experience about a 30% difference in tension).
Mavic has a tech link on their web site that specifies tensions for their rims. I would imagine that most rim manufacturers would as well.
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