Q. I recently saw some advice that suggested rotating the 10-speed chains on aluminium alloy cassettes every 250-500 miles is this perhaps a bit over cautious?
This would be every one to two weeks for many of us. At £20 or so for a chain, this seems excessive for running a bike, and is comparable to my diesel bills for my car. Can we clear this up or possibly have some manufacturer's comment on this?
Shane Travis, email
A. Shane, the idea isn't to replace them every time, but to buy two chains and simply remove one and fit the other every 500 miles. I do this myself and it results in the chainrings lasting a lot longer than they would if you were running just one chain all the time.
Chainring and sprocket wear occurs because the chain wears, that's a simple fact. The chain wears as the outside facing of the pins and the inside facing of the rollers wear, and this essentially makes the chain longer (add up all the little bits of wear per roller, and your chain can be 3mm longer inside of a couple of weeks). So when you load up the chain through pedalling, this isn't spread across several teeth of the chainrings and sprockets as with a new chain, rather, it means excessive loading on fewer teeth, which causes wear.
If you rotate your chains, though, you are spreading the wear that occurs on the chainrings and sprockets, allowing them less time running with a worn chain. Running two chains and rotating them also reduces the accelerated wear which happens when a chain reaches a very worn state.
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