Join Date: Apr 2009
Location: New Rochelle, NY
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Mentioned: 22 Post(s)
Tagged: 0 Thread(s)
Quoted: 887 Post(s)
Truing hops in radially spoked wheels is very easy, but the relative tension differences needed depend on the radial stiffness of the rim. The fact that the problem first manifested as some loose spokes at the low area indicates that the rim is bent inward there. As long as it's slight enough that it's still arched, tightening all the spokes elsewhere while leaving the low-zone spokes relatively slack will have the rim trying to shrink and bulge out there (like squeezing a balloon). This works best with radial spoking because there's nothing to resist the circumferential movement of the rim. When you've bulged the low area out to a high spot you then bring it back to line and align as usual, setting the overall tension within the target range, except for the affected area which will have lower tension.
This method works well with shallow rims that aren't too stiff radially, but stiffer rims need a bit of extra persuasion. My favorite method is to loosen the whole wheel slightly, and totally slacken or remove the spokes in the low zone. I then step on the low spot and pull the wheel up against my foot, pushing the area out to a slight bulge. Then retighten the low spot spokes until the now high spot comes into line, and align and retension as I would a nw wheel.
Don't forget that after all this work, there'll be stresses and twists in the spokes, so you have to resettle everything as if it were a new wheel.
BTW- if you can't save it and decide to rebuild, you don't need a super strong rim, just stop fooling around as aggressively.
An ounce of diagnosis is worth a pound of cure.
“Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin
“One accurate measurement is worth a thousand expert opinions”
- Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance