Pinging sound on new radial front wheel

Question

I just installed a new Shimano WH-RS100 radially spoked rim-brake front wheel. It was purchased new, and the shop checked it for trueness. I think they made one or two small adjustments.

After putting it on my bike, with a freshly pumped tire, I applied the front brake and leaned on the handlebars to check that the tire was pumped sufficiently, and I was surprised to hear a single ping from the wheel. I assume this was a spoke doing something, although what exactly I'm not sure.

I then rotated wheel about 1/4 turn, and did the same thing, just bouncing my weight down onto the handlebars a couple times. Repeated this around the whole wheel a couple times. I think I got two more pings out of it like that.

After that I went for a short ride, and did more bouncing weight on the front wheel. Again, I think I got one more ping out of the front. Then I did a couple of drops off curbs, with no more pings resulting.

What if anything should I do now?

Do those pings tell me the wheel has an issue? Or is that just fresh wheel spokes settling in? Or is it from the adjustment at the bike shop settling in?

Do I need to do anything beyond just checking that the wheel is still true?

Note: the matching rear wheel, which has a cross-spoke pattern, did not do this when I installed it, although I don't think the local shop made any tweaks on that one.

I searched for related questions, and found this, which seems to suggest pinging sounds mean the wheel need re-truing.

Answer 1

I think you have found the answer to your question, about the cause and meaning of the pinging.

I would suggest however that to assert the wheel invariable needs re-truing (at that answer does) is perhaps a bit of a reach. It's definitely possible the wheel needs to be re-trued, but in practice the difference in length/tension of the affected spokes might not always be enough to really affect the truing. (Obviously it will depend by how much the spoke unwinds.)

Personally, I would do a quick manual check for trueness (e.g. a chalk test) before deciding if I need to take the bike in. Even if the shop won't charge, there's the time factor involved in taking the bike in and waiting for the work; my local shop is currently quoting service dates in May even for simple repairs.

Answer 2

I get that noise briefly when I true a wheel, then ride on it without "stress relieving" the spokes.

Stress-relieving can be as simple as squeezing each pair of crossing spokes so the sliding part finds a better resting point. You can also push and pull on the rim and axle (most satisfying when its on the ground) This should be done as part of truing so that the end product is not going to change/move.

The only thing that confuses me is that the spokes in a radial wheel don't touch each other, so stress relieving shouldn't do a lot. The only part that could turn would be the spoke nipple in the rim as it slightly un-winds d the bottom of the roll, due to the pressure dropping and the built-up "twist" in a spoke forcing the nipple to rotate against the rim.

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The wheel only needs a re-true if its out of true. Do a quick spin check, perhaps use your finger as a sensor, and if its got a wobble then tweak the worst spoke. It shouldn't take a lot of work at this point to get the rim flat and planar.

Answer 3

That's a sign of a poorly built wheel. Either the wheel was built by an incompetent human, or it's a machine-built wheel and the engineer who created the machine was cutting corners to save money or incompetent.

Poorly built wheels ping because the spoke nipples have been tightened without releasing the wind-up. The spoke twists and friction helds it in the twisted state. Then when a load is applied to the wheel, if a spoke is momentarily unloaded, the twist will release and a ping can be heard.

Experienced wheelbuilders correct for this by over-doing the nipple adjustment and then backing up. With experience, the wheelbuidler can learn how much exactly the nipple needs to be over-done and backed up. Then the wind-up remains so small that if it's released, the ping is so silent it can't be heard. Perhaps it could be heard in a laboratory setting but not on the road with other noise sources.

A machine can do other tricks, such as pressing the rim with a hydraulic press to momentarily release tension of one spoke to release windup. A human wheelbuilder isn't strong enough to do that so that's why the over-do-and-back-up trick is needed. However, doing such tricks obviously makes the wheelbuilding machine more costly.

With lubricated spoke threads, the windup becomes less, so that's why it's heavily advisable to oil or grease all spoke threads before building a wheel, and to apply light easily penetrating oil to the thread-to-nipple interface if adjusting a previously built wheel.

If the ping is audible, most likely it somewhat affects the wheel trueness. For disc brake wheels, the effect on trueness may not cause any harm. So it may be possible to continue riding the wheel, but if the human or machine that built the wheel was so incompetent that spokes are pinging, it's very likely that the spokes have both uneven and low tension. So checking for tension equality and tension magnitude with a tensiometer and by plucking the spokes is advisable. Such an unevenly tensioned low-tension wheel is prone to lose all spoke tension and become too wobbly to ride, if the bicyclist is heavyweight or the wheel is used as a disc brake front wheel. A proper count of spokes (36) may somewhat decrease the risk of wheel losing all spoke tension, but for a heavyweight rider self-building a wheel without tensiometer the risk is still present in 36-spoke rear and disc-brake-front wheels (been there, done that, bought a tensiometer).