I am the destroyer of bikes...

[fossyant]

When did the chain come off - when shifting, or just fell off ?

You hear a crunch you stop - more mechanical sympathy needed.

 

[Matty]

Is it an Andy Schelck impression?

 

[magnatom]

When did the chain come off - when shifting, or just fell off ?

You hear a crunch you stop - more mechanical sympathy needed.

It doesn't actually come off. the bottom of the chain i.e. the part that is going away from the pedals when pedaling lifts up (with the bottom jocky), and this part of the chain gets stuck between the chainstay and the front derailleur. If I release the pressure on the pedals the chain falls back to the correct position and I can pedal again.

I thought it might be a sticky chain, and lubed it a bit, but that didn't solve it.

 

[HLaB]

Grrr!

I picked up the bike yesterday. It all looked good and a quick twiddle of the pedals etc, everything looked like it was working fine. So after checking the tyre pressures (why do bike shops always leave them well below the required pressure!?) I head off to work.

I was glad to have the Ribble back as it was a bit wet and manky this morning. I turn my first corner and there is a hill to climb. About 6%. Nothing much but as it is at the start I don't go too crazy, although I do the first half of it out of the saddle, just to stretch the legs.


CRRRUNCH. The pedals stop dead. I take the pressure off and the rotate again. Mmm. Perhaps just a glitch..........CRUNCH. Oh dear. It's happened again. I can't see what it is. Just near the top of the hill, CRRUNCH. I manage to keep the pressure on the pedals when I stop to see what is happening. The chain is caught between the chainstay and the front derailleur. ?????

So I get off the bike, lift the back wheel and spin the pedals a bit. Something, I can't see what is causing the lower jocky wheel to pull forward, forcing the chain up and getting it caught.

It was damn lucky I was going uphill when that first happened and not powering downhill at 30mph. I could have been off!

I'm not a happy chappy, having just spent £230.

I found the Kinesis limit screws are a bit sensitive the way Neil Bilsland had set them up it 99 times out of 100 it'd refuse to go into the small sprocket. I've loosened it a fraction and 99 times out of 100 its fine, but I was powering downhill at about 32mph on Tuesday night, when there was a strong gust of wind and I probably changed down too fast the chain jumped by the lower sprocket and caught between seatstay and cassette; no damage done but it feels horrible. Maybe I should tighten it 1/2 a fraction.

Fortunately when ever I've had something go wrong on the rear wheels of bikes, whilst its not nice, it has been controllable.

 

[HLaB]

Just a quick guess but when the lbs shop changed things, have perhaps used the wrong length of chain, different cassette size, the new rear hanger is a fraction different sized or the b screw in the new derailleur needs adjusting

 

[magnatom]

Just a quick guess but when the lbs shop changed things, have perhaps used the wrong length of chain, different cassette size, the new rear hanger is a fraction different sized or the b screw in the new derailleur needs adjusting

It's possible, but very poor if that is what has happened. That might explain it though. I assume if the chain is too short the tension on the chain might be high, resulting in the chain and rear derailleur being sucked forwards. Is that right?

Hmmm. Maybe a thread in know how is needed. I also need to look at the video from my camera. I might be able to see it....

 

[vorsprung]

In 2009 I had various things to put right on the single speed. It needed a new marathon plus for instance as I'd worn one out

At the end of 2009 it became clear that the single speed was in a state of terminal decline. The headset was notchy and impossible to replace as is was frozen. The rear freewheel needed replacing again. I was running out of old 8 speed parts to feed it.

So I bought an entirely new bike, cost approx 900 quid. It's a Cotic Roadrat with Alfine hub gears.

Since then I have bought a bit of oil from poundland, and just the other day another 1/8" chain

The commute is 30 mile round trip, according to my calculations the bike is getting to the point where it has paid for itself, maybe another couple of months

 

[HLaB]

It's possible, but very poor if that is what has happened. That might explain it though. I assume if the chain is too short the tension on the chain might be high, resulting in the chain and rear derailleur being sucked forwards. Is that right?

Hmmm. Maybe a thread in know how is needed. I also need to look at the video from my camera. I might be able to see it....

It is poor indeed, if the chain is the wrong length I would of thought it'd been an easy thing to spot for a lbs. Somebody in know how might have a better idea, I'm pretty useless in diagnosis often without actually seeing things.

 

[magnatom]

It is poor indeed, if the chain is the wrong length I would of thought it'd been an easy thing to spot for a lbs. Somebody in know how might have a better idea, I'm pretty useless in diagnosis often without actually seeing things.

Hmmm. I've certainly caught the crunches on video and you can just about make out what is happening. I might try and post that later. Not sure if it is the train length, but something is definitely happening.

 

[HLaB]

Just another random thought, how was the new chain joined by pin or by powerlink. Pin joints can sometimes result in stiff links if not done perfectly and the jockey wheels rising into the derailleur.

 

[goo_mason]

Sounds like a stiff link in the chain - each time it reaches the jockey wheel, it won't bend as it goes through, thus pulling the derailleur forward as it sticks. I once bought a Shimano chain with a pin-link after always using SRAM or KMC chains with Powerlinks and I had the same issue. I hadn't put the pin in right and it made the link extremely stiff, and it pulled the derailleur forward as it went through, and also got sticky on the front chainring when it reached that.

Lube won't work - you'll have do do a spot of manipulation on the dodgy link or remove it completely and replace it with a Powerlink.

 

[fossyant]

Not good - summat wrong with that chain if it's dragging. Check chain length - biggest chain ring, smallest rear sprocket - both jockeys should line up one on top of each other (viewed from the side for Shimano - assume Campag is similar) also check big to big - you should just about have enough slack in the mech without it pulling the cage too far.

There's no damage to the rear mech is there - jockeys not running freely/cage out of alignment ?

 

[BentMikey]

£230 for nine months riding and you're complaining about that? You should see my bill, it's waaaay worse than that.

p.s. no telling me about stingy scotsmen. You lot haven't got a hope against the thrifty Dutch.

 

[magnatom]

Sounds like a stiff link in the chain - each time it reaches the jockey wheel, it won't bend as it goes through, thus pulling the derailleur forward as it sticks. I once bought a Shimano chain with a pin-link after always using SRAM or KMC chains with Powerlinks and I had the same issue. I hadn't put the pin in right and it made the link extremely stiff, and it pulled the derailleur forward as it went through, and also got sticky on the front chainring when it reached that.

Lube won't work - you'll have do do a spot of manipulation on the dodgy link or remove it completely and replace it with a Powerlink.

Aye, I'll have a proper look at it tonight and see what's what. Still not amused that I get a bike back from a reputable LBS and it's dangerous!

 

[magnatom]

£230 for nine months riding and you're complaining about that? You should see my bill, it's waaaay worse than that.

p.s. no telling me about stingy scotsmen. You lot haven't got a hope against the thrifty Dutch.

Ha! If you knew how much I've just spent on the house (new heating, new windows, walls knocked down, new kitchen, new flooring still to sort) and you knew how much money we had left, you'd understand!