Rear Wheel
 

Dumb girl-newbie question-Why won't the rear wheel engage? The gears on bf's bike seem to work fine, but I can't get the rear wheel to engage, and can't figure it out. Any ideas? I'm newer to cycling myself, and am new to the art of maintenence...Thanks!

Help us by describing what "engage" means to you.

Okay, so the back wheel spins loosely, when you pedal forward, the rear wheel does nothing. You can't go forward.

Doesn't sound too good so far. What kind of bike do you have?

Is the chain running over a cog in the freewheel/cassette? Is it making a nice backwards 'S' through the derailleur?

The pawls in the freehub (or freewheel) are probably stuck. The grease is most likely old and gummed up. Try dripping oil into it while spinning it to see if it loosens things up.

I agree with Supcom. Has your bike been sitting for some time? Is it older? If so, a little bit of penetrating oil or even WD-40 sprayed around the rear gears may help. Turn the bike on it's side so gears are facing up. Turn the gears by hand and drip the lube, where the moving gears and non moving lockring meet. There should be a gap there.

Could be your chain is routed wrong. It should look like this, Link.