Whining Wheel

*sigh* So, I bought this great bike (y'all were very helpful on that thread!) and it's getting on my nerves. Something - I think it's the front wheel, but it's hard to tell, because I'm on top of it! - whines, and I think it's heat-related.

It's a mid-pitched whine, sort of like what I hear out of my water pipes when I'm running hot water through them on a cold day. When I'm pedaling, it whines on the downstroke of each foot. When I stop pedaling, it whines continuously.

When I first start riding, there's no noise. It takes, usually, a quarter mile or so to start making noise, and the longer I ride, the louder it gets. If I stop for a minute and start up again, the whine vanishes for a little while - a block or so - and then comes back.

When it's raining, it doesn't whine. When it's not raining, I can make it go away for a while by riding through a puddle.

So, I'm thinking it's either A) something that's getting hot, or B) something that's getting dry. I'm leaning towards A because, on a dry day, when the bike's been stored inside, it doesn't whine when I'm starting out. I think the water just cools down whatever is being noisy.

I haven't been able to duplicate the noise by just spinning the wheels, so it's really hard to tell exactly where it's coming from. I've checked the brake alignment - as far as I can tell, there's nothing rubbing. I've tightened up the quick release on the wheel as much as I can, and there's no looseness in the wheel.

I took it back to the shop where I bought it, described the problem, and left it in their care for a week (I can only get there on weekends). They seemed unsure what would be causing it, but promised to find out. The guy who worked on it wasn't in when I picked it up, but they assured me that whatever was wrong, he would have fixed it. I'll probably take it back next weekend and make someone from the shop take it out for a longer ride so they can hear it, but until then...

Does anyone have an idea what could be causing this? What should I check to help troubleshoot it?

You might be able to troubleshoot noises starting here:
http://sheldonbrown.com/creaks.html

Have you checked that the hub cones are tight? Do this by grabbing the rim and trying to move it side to side relative to the frame. Try this from several places on the rim. If you haven't done so recently, remove the wheels from the frame and feel the bearings for smoothness by turning the axle between your thumb and forefinger. Feel the spoke tension in your wheels. Grab two adjacent spokes that cross each other and squeeze them together. You should be able to move the crossing point by a couple millimeters, but not much more. Feel every pair of spokes. Sometimes there is one or more much looser than the others, usually due to a flat spot in the rim.

If you don't find anything wrong here, I'd be suspicious that the dust cap which surrounds the hub cones has too tight a clearance, so that when it gets hot the dust cap is rubbing the cones. And being wet lubricates it enough to suppress the sound. Interesting problem. I hope you find your solution.

Thanks, Deb - good call!

I put a drop of oil right at the edge of the dust cap and slowly turned the wheel to let it work its way around. That's all it took - blissful silence!

I need to write this down for future reference :)

Glad you found the problem. If you get tired of having to oil your dustcaps frequently, you could pull them out and file out the inner diameter just a bit. The tolerance shouldn't be that tight.

I definitely will fix it properly! I had to oil it again this morning about halfway to work. That'll get old in a hurry.

This will keep me going until the weekend, though, when I have time to figure out how it comes apart. (I'm not much of a mechanic!) I may just haul it down to the shop and make them do it!

Thanks again for the advice. :)

Deb, you continue to amaze me. Your thorough knowledge of bikes is incredible.

What did this forum do for technical advice before she came along??