FanPost

Techs-Mechs: the case of the slipping chain

I cannot be the only person who finds the maintenance of bicycles to be a mystery. Some people are able to speak gaily of popping open the inner crank to massage the bottom bracket. Me, I can change a tyre (though, as theBongolian will tell you, that statement is only true on a good day, and with a certain degree of humour being deployed). Therefore, when i get asked questions about bikes, I can answer the theory, but am deeply aware that the ice below my feet not so much thin as transparent. However, I feel I know you all well enough (don't take it personally) that I can ask for advice if I lay out my case. So could I ask you all to put your best Cummerbatch on, and see if you can help me crack - on behalf of, what else, an indirect relative, the mysterious case of the slipping chain?

So - the facts of the case, since I know none of you will be prepared to theorise without data.

* The relative in question is six foot five in height, and in the immortal words of Le Carre, built by the same firm who did Stonehenge. He also is an ex boatie, with thighs roughly the circumference of Brighton. Not a natural cycling shape, shortainly, but given that he is rapidly approaching what is politely put as late middle age - he certainly puts out the watts

*The bike is a Cannondale, so should be up to the task

*The chain only slips on climbs, which suggests that some combination of power and weight is at fault here

* The symptom is that the chain is apparently slipping between cogs (I am not sure if it is slipping between teeth on the same cog, or slipping between gears - I think the former)

* We are talking rear deraileur here

* The chain is new, but the cassette isnt and possibly has some distance on it (though no visible damage)

*Pretty much every amateur bike mechanic in Catalunya has looked at this

Now, I have a theory, but since what I know about bikes can be written on the back of a fag packet, and what you ladies and gentlemen know could easily fill the first six volumes of the Encyclopaedia Britannica, I thought I would, in the tradition of weekly guest stars the universe over, get down on bended knee and listen to suggestions.

All thoughts welcomed. If I get murdered in the second act, my training partner did it.