I am a cyclist and am starting to think about gear ratios. I have counted teeth on my bike gears (touring) and calculated ratios and the results do not make sense to me. I am left with the beliefe that ratio is not all at work here. It seems that it also has to do with the diameter of the gear in a kind of lever kind of way. In other words the bigger gear on the front the tougher it is, the smaller on the back the tougher it is. Can someone please explane this to me in a way that makes sense to a non physicist?