Squealing/whistling noise that gets higher-pitched the faster I'm moving My bike has started making a high-pitched whistling noise when I get moving and I'm not sure what's causing it, though I have a suspicion.


It starts happening after a few seconds of pedalling
It gets higher-pitched the faster the bike's going
It's dependent on the speed of the bike, not how hard I'm pedalling


I tried pushing the bike along a short distance and couldn't hear it but I might just not have been going fast enough. 

So, that suspicion about the cause. When I got it out of the bike shed at work last night, the seat and handlebars were covered in some kind of dust. A colleague realised that it was probably from the work in the car park that day - someone was cutting into the road surface and apparently kicking up a big cloud of tarmac/concrete dust that could've easily gone through the widely-spaced slats of the bike shed.

Could that dust (presumably gumming up some lubricated part) be the cause of this noise? If so, where should I focus my cleaning?

If not, any ideas what it could be instead?
If the noise is related to road speed rather than pedaling force or cadence, it's coming from the wheels. 

I doubt that dust is the problem, bearings have dust seals and dust settling downward on the bike isn't going to get into any bearings.

Hold the bike off the ground, spin the wheels and see if you can recreate the sound. Check brake pad clearance. Disc brake pads rubbing on the disc can make a high pitched sound. You can also check the wheel bearings for play by pushing and pulling laterally on the rims.