Originally Posted by
cyccommute
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.
One of the earlier comments by 'Tourist in MSN' linked to a thing called "Mountain Tamer Triple adapter - LOWER GEARS for bikes of all kinds", which when you follow that link, it's a device to allow as small as a 17t chain ring to be installed. This device also allows 18, 19, 20, and higher, but it seems silly to buy such an adaptor when cranks with 20 and 22t are already available. If someone were to put this thing on, I'd guess the whole point would be to go from a 20 or 22t ring to a 17t. This would increase chain tension quite a bit, and while repairing a chain is much easier than repairing a hub, buying a decent hub means such a repair is probably never needed.
It's not possible to buy stronger 10 speed chain, while putting a bit of money into a good hub with steel parts instead of alloy, and a reliable pawl mechanism can pretty much reduce the chances of hub failure down to a level not worth worrying about. I'd rather break a chain than a hub too, but I'd rather break neither more. A decent steel (at least steel cassette body and innards) and a 20t ring up front with a 40t in back will give as low of inches as can be really used (~13") without putting more stress on either the chain or the hub than can be reliably tolerated.