Please help - unidentified noise from rear wheel

Jamey

I noticed a noise coming from the general area of the rear wheel this morning and I suspect it may be something to do with the spokes but being a mechanical dunce I'd really appreciate some help/opinions.

The noise sounds halfway between a rattle and the sound you get when you grind a pepper mill and it only happens when I'm actually on the bike. If I turn it upside down and just spin the wheels (or pedal) then everything sounds fine again and there's no noise.

Here's a summary of when the noise does and does not occur:

Riding (seated)
Pedalling = noise occurs
Coasting = noise occurs

Riding (standing)
Pedalling = noise occurs (but slightly quieter)
Coasting = noise occurs (but slightly quieter)

Bike upside down for inspection
Spinning wheel freely = no noise at all
Pedalling forwards = no noise at all
Pedalling backwards = no noise at all

I assume the reason the noise is quieter when I'm standing up on the pedals is because the weight is spread more evenly between the two wheels so the back wheel isn't under as much pressure.

So does this sound like a spoke thing? If so, what do I need to ask the shop to do? Will simply asking them to true the wheels sort it out?

term1te

From the description of the sound and when it occurs, it sounds to me as though you may have an issue with the bearings. It may be worth removing the wheel and taking a look at the ball bearings. I've had a wheel with a damaged surface on the cup section of the bearing, similar sound of pepper mill. I gave it a good clean, repacked it with grease and tightened them up properly, which helped for a while.

Often just taking the wheel off and checking everything is adjusted properly is enough. When you put the wheel back the noise may be gone, or you'll have a completely new noise to wonder about.

Jamey

Regreasing bearings (or even just taking a look at them) on the rear wheel means removing the cassette and I don't have the tools, confidence or knowledge to do that myself so maybe I'll just take it to a bike shop and say "It's making a funny noise, can you fix it?" and play dumb.

Jamey

Well I've booked it into the shop tomorrow for them to investigate.

The question now is whether to go for a service or just get them to look at the noise from the rear wheel. If it turns out that the service will only be another tenner (or so) and the labour will include the work done to fix the noise, I might as well do that.

But how do I tell?

Monty Dog

Sounds to me too like worn wheel bearing - rock the wheel from side to side to see if there is discernable play in the hub - the hub cones might need adjusting. Your LBS would be able to diagnose problem and the work depending on the type of problem and the type of hub. A basic service would include adjustments of the wheel bearings, but unlikely to include a strip-down, regrease or replacement of any damaged or worn parts.

Monty Dog

Sounds to me too like worn wheel bearing - rock the wheel from side to side to see if there is discernable play in the hub - the hub cones might need adjusting. Your LBS would be able to diagnose problem and the work depending on the type of problem and the type of hub. A basic service would include adjustments of the wheel bearings, but unlikely to include a strip-down, regrease or replacement of any damaged or worn parts.

biondino

"maybe I'll just take it to a bike shop and say "It's making a funny noise, can you fix it?" and play dumb."

I've been thinking of doing this for exactly the same reason and exactly the same problem, but in truth the bike needs a full strip-down and service anyway so I presume they'd sort this problem as part of it?

Jamey

Just to update you all (and give the thread some closure) it turned out the problem was the spokes. Some were loose.

I guess instinct counts for something after all, even with mechanical noobs