Originally Posted by
dwinks
There's a few companies making 40t and 42t replacement cogs for 10 speed cassettes. Here's one of them:
OneUp Components US - 40/42T Sprocket + 16T
This is a much better option than putting a 20t or lower chain ring on, as the smaller rings up front increase chain tension, while larger ones in the rear give the same benefit of lower gear inches, but without the increased chain tension. Larger rear cogs do, however, put more stress on the cassette body and hub, so you'll definitely want a nice beefy rear hub, but a beefy rear hub is easier to manage than constantly snapping chains with a 17t chain ring.
I'm confused. No one is talking about a 17 tooth chainring. Do you mean a 17 inch gear, perhaps? Either way, I have never snapped a chain of any kind and I ride gears that are lower than 17" all the time in high torque situation (steep off road riding in rocky terrain). I also ride 20 tooth inner rings and haven't had any problem with them. I haven't had any troubles with a freehub breaking either although, given the choice, I'd rather break a chain than a hub. A chain I can fix on the side of the road but a hub is a whole different animal.