Cranks skip when braking and starting

Hiya. I've got a question, I'm hoping it's an easy fix.

Today when I was going to do some skidding or whatever you want to call my feeble attempts at it, my cranks sort of pulled back a couple of inches. Sort of like there was a freewheel on it. If I peddle forward after that it happens that way. But if I brake(with front brake) it doesn't happen when I start again. It's not the wheel that spins I've checked this.

Anyone know what this is because?

check your sprocket and lockring dude - sounds like they need tightening

sounds like your rear cog is not on tight enough, and the lockring too.

edit.grrrrrrrrrr!!! tooo late

Firstly, skidding is not something you should be trying to AVOID doing, definetly not something to be proud of.

Next, I dont really know what your on about as you write with less logic than me.

Skipping can be caused by a number of things, worn out chainring/chain/sprocket, bad chainline etc.

If your using old perished tyres with low pressure, they can actually spin on the rim, your tube wont last long in this case so it will be come clear if this is the case.

forgot about the cog & lockring deal, mines on super tight never had a problem.

To get it tight, stick a lock through your chainring and rotate the wheel backwards with your hands. Then get the lockring tight, by using a good quality lockring tool (you may have to go to the shop)

the explanation was pretty clear to me, slipping when back pressure = cog undoing, slipping when opposite rotation starts = cog doing up again. Jonny and Murt hit the nail on the head. Rotafix/chainwhip the cog on good and tight, but grease the threads first. Then put the lockring on good and tight and greased with a lockring tool/C-spanner

Thanks all of you. I was afraid I'd be something like that. More tools, yay!
Tools are almost as expensive as parts.

Yes, skeletonboy, I know I have my own sense of logic when it comes to explain in writing.

stick a lock through your chainring and rotate the wheel backwards with your hands.

This is not a good way to rotafix, you can bend chainrings, or worse. Best to pop the chain off the front and wrap it round the BB shell, no chance of damaging anything then.

tools are always a good purchase, my stock have come about from numerous occasions of "bollocks, well that's fucked, how do I fix that" - cue trip down to lbs or search on ebay.

forgot about the cog & lockring deal, mines on super tight never had a problem.

To get it tight, **stick a lock through your chainring and rotate the wheel backwards **with your hands. Then get the lockring tight, by using a good quality lockring tool (you may have to go to the shop)

Our survey says.. No

Bad idea matey

This is not a good way to rotafix, you can bend chainrings, or worse. Best to pop the chain off the front and wrap it round the BB shell, no chance of damaging anything then.

after spending the whole of yesterday beating the fuck out of an an old mavic ma2 rim to get it back into shape. I have come to the conclusion that all bike parts are not as fragile as they look. And so forth, I shall never handle bicycle componentry "tenderly" ever again.

oh yeh...
http://204.73.203.34/fisso/eng/schpignonestep1.htm

after spending the whole of yesterday beating the fuck out of an an old mavic ma2 rim to get it back into shape. I have come to the conclusion that all bike parts are not as fragile as they look. And so forth, I shall never handle bicycle componentry "tenderly" ever again.

Your call I guess, rotafix properly or spend a whole day 'bashing' things back to nearly as good as they where before you started.

I went up to cycle surgery in kings cross since I work on caledonian road with it and they fixed it in a couple minutes for me, for free. So now all is well. Thanks alot.