Which is to say, how long a distance would you expect one to last?
The reason I ask is that on several occasions lately my commuter UO8 has thrown the chain from the chainrings, sometimes inside on a downshift, sometimes outside on an upshift. The chain is an SRAM PC870 with about 700 miles and a reasonable number of shifts (I guess). The crank is a VeloOrange compact double. When I first installed this chain back in April it shifted impressively promptly with no trouble whatsoever. I suppose it is possible that the RD (a Suntour Vx w/GT-cage) is keeping it under less tension. But I'm thinking that the chain is now worn and more laterally flexible.
Yea or nay? Comments?