Why is it that when you go into a higher gear on a bike, it is harder to pedal?

Question

The lower the gear, the easier it is to pedal. I noticed that the larger the back gear is and the smaller the front gear is, the easier it is. Conversely, the larger the front gear and the smaller the back gear is, the harder it is to pedal. I noticed this effect on car transmissions as well. Also, I have another question. I don't know if the same effect applies here. You know those small, thin, metallic screwdrivers with a black tip about 1/4 inch of the entire length of the screwdriver? Why is harder to twist these than it is to twist the other ones with the large grip (those that can change bits). I think the same effect applies to both of the questions. Please respond with an explanation, sources would be great, websites would be even better. Thanks in advance.

Answer 1

look up gear ratios. the higher the ratio, the farther you will go with the same number of pedal strokes, but it may be harder to push. Ideally you want to be pedalling at an optimum rate, like 60-90 pedals per minute, and change the gear so you're not pushing too hard or light.

as for the screwdriver, the bigger grip is easier to turn because it has a larger radius and you can apply more torque without it slipping in your hand

Answer 2

You can't get something for nothing. In a higher gear your bike will move faster, in order to go faster you must work harder.

Answer 3

It's all about lever arms, essentially.  When you have a big gear on a bicycle (large chainring in front, small cog in back), that is equivalent to having a small lever arm trying to lift something a long distance.  Think of a see-saw, the situation would be you would have the board so that very little length would be on your side of the see-saw fulcrum, and a lot of length on the other.  If you were able to push the board down, the other person would go a long way, but it takes a lot of force to push the board down.  

In contrast, a small gear is equivalent to a big lever arm.  Going back to the see-saw, most of the board would be on your side, very little on the other.  It's easy to raise and lower the other person, but they don't go up and down very much given the distance you raise or lower your end.  

More commonly, in terms of gears, the above description gets explained in terms of torque.  So googling "gears torque" will get you "classical" explanations.  But the see-saw analogy isn't all that bad.

Answer 4

a large gear in front and small gear in back is made for climbing hills. since the gear you  are pushing is bigger, when it goes once around the smaller gear in the back is pushed around two or more times. that moves the tire faster and propels the bike further and sends you up the hill.

the smaller gear in the front with the big gear in the back is for going down hills. when the small gear in the front rotates once the big gear in the back rotates 1/2 way around. this makes the tire spin letting the hill do most of the work.

the same size gear in front and in the back is made for level ground. when the front gear moves once around the back gear moves the same amount. this gives you moderate speed and is slow enough to stop fast.