Australian Cycling Forums - Bicycles Network Australia

My chain came off suddenly leaving some nasty scratches on my near new gray Shimano Ultegra 6770 crankset.

Its purely cosmetic I know but I'm wondering if anyone has touched up such scratches successfully. I contacted Shimano and they said they dont make touch up paint. They suggested using coloured nailpolish. I could probably get some paint matched at a car repair shop too, but as I only need about 5ml of paint that is probably not a viable option.

And if anyone has matched paint already to the gray Shimano Ultegra 6770 crankset, can you share what colour and brand of nailpolish/paint you used for the colour match?

Model paint maybe?
Tamiya Paint Enamel Gloss

Can't help with the scratches except to say they probably wont be the last on the bike.
To stop the chain jumping off again make sure the front derailleur limit screw is adjusted so that the chain is just off touching, or very lightly touching the outer side of the cage when in the hardest gear.

Nail polish.

Also check your chain to see if it has stretched or is worn. If so it needs to be replaced.

Thanks! Perhaps the X -10 Gun metal is the closest match? Is it a good match?

http://www.modelkitsonline.com.au/pages ... p?Key=2394" onclick="window.open(this.href);return false;

Humbrol enamel sticks to bicycles pretty well and stays on it under outdoor conditions - can be had in 14ml tins from hobby shops. Should be able to find a close enough gray.

I'll be amused if you do touch it up that way though, as that is how their business started in the 1920s (more things change, the more they stay the same).

I would ride my bike to a model shop and then ask them what colour.

I first noticed the bike slipping out of gear when riding uphill, I should have stopped then and checked the chain but I thought maybe the gears just needed adjusting. Then all of a sudden the chain came off. Of course I stopped then to put it back on and noticed that one of the links on the outside of the chain had failed at the pin. (Not the usual adjustable link). The chain was still a loop, held by the inside link of the chain in the same spot where the outside link failed.

So one of the outside chainlinks failed, causing the chain to stretch slightly causing the gear slippage. Then the loose link got caught somewhere in the derailieur causing the chain to come off, leaving nasty scratches on the outside of the chainring. What i dont understand is how the scratches got on the outside of the chainring because the chain, after it came off was wedged tightly between the frame and the inner chain ring on the front and not on the outside to do damage to the chainring. It was wedged in there so tightly I could hardly get it out.

I've since had a new link put in and also had the chain checked for stretch and it was fine, as it should be, as the bike has done less than 2000km. So perhaps a faulty link?

I was not very happy and these are the first marks ever on this bike!

Arlberg wrote:I first noticed the bike slipping out of gear when riding uphill, I should have stopped then and checked the chain but I thought maybe the gears just needed adjusting. Then all of a sudden the chain came off. Of course I stopped then to put it back on and noticed that one of the links on the outside of the chain had failed at the pin. (Not the usual adjustable link). The chain was still a loop, held by the inside link of the chain in the same spot where the outside link failed.

So one of the outside chainlinks failed, causing the chain to stretch slightly causing the gear slippage. Then the loose link got caught somewhere in the derailieur causing the chain to come off, leaving nasty scratches on the outside of the chainring. What i dont understand is how the scratches got on the outside of the chainring because the chain, after it came off was wedged tightly between the frame and the inner chain ring on the front and not on the outside to do damage to the chainring. It was wedged in there so tightly I could hardly get it out.

I've since had a new link put in and also had the chain checked for stretch and it was fine, as it should be, as the bike has done less than 2000km. So perhaps a faulty link?

I was not very happy and these are the first marks ever on this bike!

Sounds to me like you missed the opportunity to replace the broken part (the chain) and are now chasing paint.

I realise it's good advice too late, but your chain is a sacrificial component, and you should ideally get it checked and replaced if your LBS mechanic deems it necessary at major service intervals. You can even replace it yourself with little trouble - just buy the chain and a chain breaker on PBK or similar.