What Gear Ratios Do I Need On My Bike?

Jimmy B is worried that his question is silly, well its not, the question is about what gear ratios he should get for his bike, he is changing his chain set and cassette so this is a good time to get the gearing he needs for his area, if your about to do the same this could be very helpful for you

Question: I need a new crank set and cassette for my bike, I’m on Shimano Ultegra at the moment and am quite happy with it so I’m going to replace with the same, but, and here is the question, what cassette and chain wheel ratios should I get? Here where I live there are only small hills but we do get wind from the coast, so what should I get? Thanks for your help. Jimmy B.

Hi Jimmy,
I don’t have your problem where I live, its hilly so I go for a good selection of low gears. You don’t have this problem, so I would for a 53 x 42 tooth set up, unless you plan on going on a trip to the alps or Pyrenees then I would fit a 53 x 39, just incase, but if you don’t intend to do many “BIG” climbs then 53 x 42 should do you fine.

For the cassette I would think a 12 tooth for the smallest is great and then if you keep all the other sprockets with one tooth more till you get to the 21, this is called a straight through cassette, if you are a bit worried that maybe you might suffer on some of the longer climbs then go for the 23 tooth on the inside or go back to the idea of a 39 tooth chain wheel.

I hope this helps, Jimmy, if you lived in a mountainous region I would suggest getting one of those compact chain wheel sets, but with the roads you have I wouldn’t bother.