I pedal but the wheels don't turn

[skimmba]

Sometimes when pedaling hard, my pedals will turn, but the wheels will not. It feels as if something is loose, any idea what?
Thanks!

[cyclerUK]

The freewheel (or freehub) in the back wheel.<br />
It sounds like the "pawls" are sticking.<br />
You can flush out with say WD40 and then re-oil.
See:- http://www.sheldonbrown.com/freewheels.html
If this doesn't cure it then you may need to replace it.?

[TLSlusher]

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