I live in the mountains a few miles below Big Bear Ca. elevation is 5'5oo ft. and with in two miles it's at 7000 ft. I have two options, up hill or down hill. I've read not to use the throttle down hill and right now with my stock 44 tooth sprocket going up hill I still have to peddle most of the time and it seams to me this is quite a strain on the engine I know it is on me. My question's are can I safley break my engine in while it's working so hard going up hill? I going to order another sprocket but not sure what size to get 48 tooth 50 or maby 56, need help on this decision as the only experance I have is with the stock 44 tooth. I've been transporting my bike down the mountain to ride but I really want to be able to ride it up here.