The frequency of dropped and jammed chains in this season’s pro races has become ridiculous (let alone frustrating for the riders). But why is it happening? In four decades of racing/driving it’s never happened to me – and I think there’s a clue in that timeline. I clearly wasn’t using any new fashionable bike technology—and still resist it (even the little accessory of a chain catcher). So
what exactly is the problem?
On stage 3 of today’s Tour de France, I heard Nico Roche (co-commentator on the NZ broadcast) interestingly refer to the ‘long chain’ phenomenon – which sounds plausible given close-up footage of chains bouncing wildly between the cassette and the chainrings. He further speculated that this may be a function of the now standard broadband cassettes (10/11 to 30/32) and chainrings (54/38). Obviously, in the extreme, using say a 10-sprocket with a 38-chainring will effectively lengthen the chain.
Maybe that’s the answer, but I suspect there’s more to it and would love to hear others’ opinions.
My own intuition also includes the still imperfect technology of electronic shifting (e.g. riders kicking the derailleur mechs to restart them), and the limitations of the single position of the rear dropouts, especially disc brake thru-axles (and are the latter also complicit in chain-drop I wonder?)
In the past, adjusting the chain mechanically was more satisfying and effective. First, with long-slot dropouts, the wheel could be locked in at the correct point of chain tension (using the trackies trick of, er, a finger). Second, the stop screws on both the front and rear derailleurs could be fine-tuned and threaded-sealed to prevent chain switching.
The old technology had elegant solutions for the skilled home mechanic, without the help and expense of your LBS.