Bicycle Mechanics - Increasing wheel tension
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10-19-10, 12:01 PM
I've just about finished building my first wheel!!It didn't go well.I made a ton of mistakes to the extent I started to doubt my basic mental competence.However,after many starts and restarts my wheel is starting to look pretty decent.The wheel is pretty true and round and evenly tensioned(I check with a tensionmeter)There does remain however more tensioning to do.When one wants to increase tension on the whole wheel that is true do I give twice the amount of turn on the drivetrain side than the non drive side?Or equal amount of turns all around and then retrue?My rim is a Mavic open sport and I think 110 kgf of pressure would be enough(about 24 on the scale)Is that right??Any help would be appreciated!!
10-19-10, 12:34 PM
When you're that close you want to work around the wheel a 1/4 turn or one nipple flat at a time. Do both sides the same and then go back and tweak the drive side as needed to re-center the dishing. Certainly at this point the amount more that the drive side needs will be just a slight fraction of one turn. And certainly no more than an 1/8 turn more than the non drive side.
If you want to work up a full turn then do it in four passes of 1/4 turn each so the wheel isn't pulled so far out of true per pass.
A deflection value of 24 would be correct if you are using a Park TM1 tool and if the spokes are 2 mm straight, and not double butted. The non-drive side spokes will be much lower if you have a multi-speed cassette or freewheel.
10-19-10, 04:47 PM
Don't worry about the tension on the left side it will be what ever the dish allows. Bring the drive side up to tension and use the non-drive side spokes to true the wheel laterally and center the rim.
When I overhaul a wheel I check the trueness and use the left side to retrue the wheel.
110kg is the max that Mavic reccomends for their rims.
10-19-10, 05:07 PM
There does remain however more tensioning to do.When one wants to increase tension on the whole wheel that is true do I give twice the amount of turn on the drivetrain side than the non drive side?Or equal amount of turns all around and then retrue?My rim is a Mavic open sport and I think 110 kgf of pressure would be enough(about 24 on the scale)Is that right??Any help would be appreciated!!Good job on your 1st wheel! The ratio of right-to-left side turns will vary depending upon how much dish you have in the wheel. A 126mm wheel with 8-spd cluster will require close to the 2:1 ratio you mentioned. However, a 135mm wheel with hi-lo hub-flanges and offset-holes in the rim may need close to a 1:1 ratio to increase tension evenly. So.. it depends.
For simplicity's sake, I recommend you break up the final tension-increase into separate steps. First increase tension by turning both sides the same amount so that they're both at around 75kgf. Then check the dish and the rim may be off to the left a tiny bit. Then increase tension on the right side some more to correct the dish and verify tension. You may need to go back and forth a couple times with decreasing turns of the spoke-wrench (1/16th turns sometimes for the final pass). You may end up with 80/110kgf tension, which is decent. In some cases of severe dishing, you may end up at 60/110kgf. In which case, double-butted thinner spokes on the left side would help keep the spokes tensioned in the load zone.
10-20-10, 10:02 AM
UPDATE!!Finished the wheel!Brought the tension up slowly and the wheel is pretty much equally tensioned,Mostly 24's and a couyple of 23"s and 25's.The true is perfect,the wheel looks great and I am very pleased.As I said I made lot's of mistakes.Improper lacing and I had to start from scratch.Short spokes on the wrong side, again had to do it all over.Probably the most potentially drastic mistake was I put the spacers on the wrong side of the hub so my computations for spoke length was off.I measured the hubs and ordered the spokes with the spacers on the opposite side of the hub!!Somehow the spoke length was allright (the ends protruded from the nipples a little but the rim is double walled so they go no where near the tubes.)I took the bike for a little spin and it feels great.Hopefully the front wheel go's smoother.Thanks for everyones input!
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