Have questions or want to discuss cycling? Join Now or Sign In to participate in the BikeRide community.

New: Take part in the April Giveaway for an Electric Bicycle Roadster V2 from Ride1UP

Crank turning, but wheels aren't
I just got a cheap mountain bike (off craigslist) for riding from A to B, but ate it real bad when I got home.

Not sure what happened, but now the crank will turn separately from the chain holder (sorry don't really know bike part names yet) (The pedals will spin, but nothing else will move.) if there is weight on the back tire. If there is no weight then the crank will spin the tire (Like having it upside down on the seat and spinning it.)

Any help would be appreciated!
If it looks like the chain has not fallen off either of the gear clusters and is running smoothly, I think it means that the read gear cluster is broken (specifically there is a ratchet inside that is broken.) It would be pretty weird for this to break from a crash, so maybe something else is going on, but I suppose it's possible.

When it's upside down, can you shift the gears ok and all else seems fine?
Ref: http://bikeloft.com/merchant/257/images/site/bike01.jpg
so the cranks are turning but the chain rings are not?

Or when you turn the cranks, the chain moves, but the rear cogs (freewheel) does not transmit the power to the rear wheel - more likely.

I suspect that you need to replace the freewheel - always replace the chain at the same time as you replace the freewheel or cassette.
I guess it's kind of hard to explain. I was riding really fast and I I think the crank gave out. Pretty much the pedals will turn the wheel, chain, chain holder all like normal when there's no weight but I can hold the back wheel and the only thing that will turn is the pedals ans crank the chain holder doesn't move. Doesn't make sense. Would replacing the crank + pedals possibly fix this?
I think we need to get some terminology down to help you.
Pedals - the things your feet go on
cranks - the two arms the pedals attach to
chainrings (front chainrings) - the toothed wheel attached to the cranks/pedals
rear cogs (freewheel/cassette) - the gear cluster at the back wheel

When you pedal, which parts move and which don't?
This might help.


Thanks guys
The chain rings have come loose. I do not know if they can be reattached again, it looks like a one piece crank set
I guess either the pin is worn / broken or the crank has become loose. I'd (personally) replace the crank set and bottom bracket with something more modern, but first check if something is loose that should be fixed.
Without seeing the driveside arm closer - I'm with Joe that the pin that is welded to the arm and fits into a hole on the rings has broken off. Quite a common problem.

Wheelies don't pop themselves. (from a QBP fortune cookie)

Possibly Related Threads...
Last Post
01-25-2015, 01:50 PM
Last Post: Bryanc
10-23-2011, 10:48 PM
Last Post: biciloco
07-06-2010, 01:23 PM
Last Post: Billy
02-15-2010, 04:44 AM
Last Post: cyclerUK

Forum Jump:

10 Latest Posts
Are electric bikes the future?
Today 06:58 AM
Gear shift is stuck!
Yesterday 05:57 PM
Help with filling up hydraulic brake lev...
Yesterday 09:25 AM
Freehub body change compatibility
Yesterday 09:22 AM
cable loose from gear handle shifter
04-10-2021 12:40 PM
What’s the name and code for this bottom...
04-10-2021 11:01 AM
What’s the name of this bottom bracket ?
04-10-2021 10:58 AM
Grip shift gear on kids bike difficult t...
04-10-2021 10:16 AM
introduce yourself and your ride :)
04-10-2021 05:57 AM
Horrendous noises when pedalling
04-10-2021 03:14 AM

Top 5 Posters This Month
no avatar 1. Jesper
11 posts
no avatar 2. Kgirl
6 posts
no avatar 3. Criminal
5 posts
no avatar 4. Mark Zucker
5 posts
no avatar 5. Papa Dom
4 posts