36mph chain jump

[Fixedwheelnut]

 
 This morning as usual going to work spinning down the hill I felt an un nerving rattle then felt the chain jump and within seconds was locked up skidding away.

 Luckily I managed to stay upright and stay to the left, then spent a few minutes unravelling the chain from behind the sprocket with a spanner.

Probably all my fault for allowing the chain to get slack in the first place, I is a lucky bunny 

[nuttycyclist]

I had some of those rattles this evening coming home too    I'd slackened the chain on purpose.

Do I need to learn something else about Fixie riding?

[Fixedwheelnut]

 Yes, if you leave it loose going fast downhill learn to do very looooooooooooooooooooooooooooooooooooooooooong skid stops 

[rogerzilla]

You're lucky it didn't come off the chainring and get caught round the crank.  That's what destroys frames - the rear triangle folds up.

[andygates]

Holy crap!   

Just thinking about that gives me the Fear!

[Deano]

That's terrifying.  I need to delete this thread from my mind.

[Ian H]

I think I've had the chain unship three times in total. Every one has been harmlessly off the sprocket outwards on to the spindle.

Luck?

[MrGrumpy]

mine came of 3 days ago, first time no skidding just slammed on brakes and pulled in. Was going down hill at time so it was a "bricking" it moment.

[Charlotte]

*runs into bike room to wind up chain tugs*

[nuttycyclist]

* Looks at bike *

* Considers creating chain tugs via a cunning fettling scheme *

[rogerzilla]

*laffs at tugs*

[Frenchie]

Holy cow! Well done FWN.

*laffs at tugs*

+1

[Si]

Sometimes it's good to have forward facing dropouts and QRs.  Chain unships and jams, wheel wants to carry on and so pulls itself forward out of dropout, chain frees, wheel wobbles round a bit in the mudgurd until the whole thing is brought to a controlled halt.  Look down, big sigh of relief.

Of course the question is...would the chain have unshiped in the first place if it'd had trackends and tugs...

[Adam]

Perhaps someone clever could design something with some spring tension in it, to take up the slack up on the chain? 

[Tim Hall]

Perhaps someone clever could design something with some spring tension in it, to take up the slack up on the chain? 

Taking you idea a step forward, perhaps it could use the small amount of sideways movement available to shift the chain laterally. You could have a bunch of different coloured sprockets, moving the chain onto the one that suited your mood.

I briefly considered different sized sprockets, allowing differing gear ratios to be chosen instead, but, in the words of Father Dougal "That'd be mad Ted". 

[Adam]

Perhaps someone clever could design something with some spring tension in it, to take up the slack up on the chain? 

Taking you idea a step forward, perhaps it could use the small amount of sideways movement available to shift the chain laterally. You could have a bunch of different coloured sprockets, moving the chain onto the one that suited your mood.

I briefly considered different sized sprockets, allowing differing gear ratios to be chosen instead, but, in the words of Father Dougal "That'd be mad Ted". 

Tim - you're a genius.  You could be onto a winner there!

[hazeii]

Perhaps someone clever could design something with some spring tension in it, to take up the slack up on the chain? 

Taking you idea a step forward, perhaps it could use the small amount of sideways movement available to shift the chain laterally. You could have a bunch of different coloured sprockets, moving the chain onto the one that suited your mood.

I briefly considered different sized sprockets, allowing differing gear ratios to be chosen instead, but, in the words of Father Dougal "That'd be mad Ted". 

Tim - you're a genius.  You could be onto a winner there!

Nah...it'd never catch on.