Whilst cleaning my bike and spinning the cranks backwards by hand, cleaning the chain in a rag I managed to make the chain jump of the chainwheel and jam against the chainstay just behin the chainset.
I've since noticed, whilst cleaning, a small gouge in the paintwork. Due to the awkward position I can't see whether there is any exposed aluminium. I've painted a small amount of clear car laquer on just out of habit (now look nice and messy) but was wondering whether I should be concerned. I've heard a lot about cracking around damaged areas on aluminium frames. I hope that it's just the paint that has be notched since the cranks weren't rotating under much force. How resiliant is 7005 T6 aluminium to this sort of damage? Am I being a little overly concerned?
Fortunately the chain coming off the rings is very rare but had I been peddling at the time I guess that the damage could have been substantial. I've noticed Shimano 'Shark Fin' chainstay protectors, is the 'fin' area designed to prevent the chain jamming?
"Paul" <[email hidden]> wrote in message "]news:[email hidden]...
Quoted message said:
Whilst cleaning my bike and spinning the cranks backwards by hand,
cleaning
Quoted message said:
the chain in a rag I managed to make the chain jump of the chainwheel and jam against the chainstay just behin the chainset.
I've had a 7005 aluminium frame for 3 years. It's fine, the chain stay (lost the protector) is very chipped but I've never given it a second thought, it is just the paint?
"Paul" <[email hidden]> wrote in message news:<[email hidden]>...
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Am I being a little overly concerned?
I think so. I've never heard of a single incident of this sort of damage leading to a failure (and chainsuck while riding along means there's a whole lot more force making a big gouge). I wonder if anyone will pop up saying it has happened to them? In any case, it is certainly rare and there can be very few bikes that don't have similar scratches, or worse.
Now I think about it, we made a couple of big gouges on our Cannondale tandem, about 25,000 miles ago.
In any case, it is certainly rare and there can be very few bikes that don't have similar scratches, or worse.
I'd think so too. When you think what well used MTBs go through on a typical trip, nobody would be using Al MTB frames if they were *that* fragile. Though the majority, including high end ones costing serious cash, seem to be made of it.
Pete. -- Peter Clinch University of Dundee Tel 44 1382 660111 ext. 33637 Medical Physics, Ninewells Hospital Fax 44 1382 640177 Dundee DD1 9SY Scotland UK net [email hidden] dundee.ac.uk~pjclinchOpen ↗
Thanks to you all for the thoughts, they're reassuring. Guess I'm a bit too paranoid after hearing about cracking aluminium.
Interstingly whilst I was out riding today I came across the same model bike as mine from some years ago which looked as though it had been used for some serious off-road and still appeared to be going strong.
Thanks for the reassurance James. You weren't in Cheddar (Somerset) today by any chance? I spotted a fantastic looking Cannondale off-road tandem (26" wheels, knobblies and suspension fork) on the roof rack of a parked car. It was an amazing looking piece of kit.
