Wheel Woes
 

The bike in question is my wife's Bianchi Volpe. It's about 3 years old, but with low mileage. I would guess about 1000 miles or less. It's been used primarily on short trips and rides, all on pavement, with the longest single ride being about 35 miles. It had one tune up at the bike shop after the initial break-in period.

So, yesterday we were riding merrily along when I noticed a wobble in the rear wheel of the Volpe. When we got home, I took a closer look and noticed the wheel was actually striking the brake pad in one spot on each revolution. I got out my spoke wrench and got ready to do some basic truing. That's when I noticed the wheel was in much worse shape than I thought. The spokes on one side were still tight, while most of the spokes on the other side were very loose. At least four of them were so loose, they rattled around when I shook them with my fingers.

I have never had a wheel go bad like this, much less after such gentle use and low miles. Was this the result of a bad wheel build, or could something else have caused it? I re-tightened all the loose spokes and have gotten it trued up again. Tightening all the loose spokes on one side has pulled the wheel very close to one of the brake pads, so now I have to re-adjust the pads too. But I was wondering if a wheel should just be re-built completely after it has gone so far out of whack?

Maybe your wife hit a very big pothole/rock/curb?

On the rear the nondrive side spokes are not as tight as the drive side, but they should not be loose. Sounds like you need to add tension into the drive side so that you can improve the tension on the NDS.

FWIW, dished wheels with a flatter spoke angle on one side as used on the rear of derailleur equipped bikes have significantly higher tension in the drive side with the cogs than the non drive-side opposite due to the angles - it takes much less tension on the shallower spokes for the horizontal component of that vector to match the steeper spokes on the drive side.

Non drive-side tension can be below 50% of drive side (I just built a wheel with 43%).

It's probably a bad build. The non-drive side nipples can unscrew on insufficiently tensioned rear wheels (machines often stop early because that lets the production line turn out more wheels in a day and people tensioning by feel can screw up) because they don't have enough tension for the friction with the rim sockets and spoke threads to keep them from turning as tension drops when they pass the ground.

You also get loose spokes when you bend a rim on an obstacle; although this isn't your problem if you can get the wheel true with uniform tension on each side (a damaged rim will need much less tension where it bends towards spokes and more opposite them).


You've messed up the dish (left/right centering) by not maintaining the drive-side to non-drive side tension ratio dictated by the spoke angles. About 2 turns on the drive side for every turn on the non-drive side is close when the wheel starts out correctly dished.

A dishing tool or flipping the wheel in the truing stand will let you see how far off it is.

Getting it right with appropriate tension will require less non-drive side tension and more drive side tension.

It'll probably be fine if you bring it to a uniformly high appropriate tension on the drive side (a measured 110kgf is usually good; with lighter box section rims having normal spoke counts you can also get there by alternately increasing tension and stress relieving until the wheel deforms in waves after stress relieving at which point you back it off half a turn and re-true) and stress relieve (you can squeeze near parallel spokes together hard with gloves helping, or twist the spokes around each other with something softer than them like a screw driver handle, left crank arm, or brass drift).

Tape flags on a representative spoke on each side will let you see what sort of windup you're getting so you can compensate as you tension the wheel.

Putting the axle end on the ground (a piece of wood will protect your floor) and pushing on opposite sides of the wheel can help undo what's already there (flip the wheel once you've gone all the way around).

Drew, thank you for that detailed response. Very helpful!