Originally Posted by
dutret
No it doesn't or at least it shouldn't(sheldon made a fair number of claims that are quite questionable). What breaks mtb chains is being cross geared with a triple and a 24.
In the 36x18 the 36 allows the rider to put more force on the chain.
As the size of the rear cog goes up however the rider does so less and less frequently. A 36 only allows for 33% more force than a 48. That it is not enough to break chains. The low gearing further limits this especially off road.
Oh yeah, I agree that a 36x18 would probably not generate enough force to break a chain. My point was that as the gearing goes down, the amount of torque on the drive train goes up, which makes it more likely to break a chain.
Although you're right, cross chaining probably has a lot to do with it.