Gear explanation

gunny_bedford

Hi,

Could somebody give me a bit of a clue re sizes of cassettes and chaninsets and the the gear/tooth ratios ?? it looks to me to be fairly complicated, so a nice "idiots" summary would be fine ie the more teeth the faster you go or what ever, also what is the difference between compact and normal chainsets?

thanks

Neil

k-dog

Basically the more teeth on the front ring and the less teeth on the back cog the faster you will go - if you can turn it.

And the opposite is true - if you're in the small ring on the front and the big cog at the back then you will go slower - but it's easier - so you would use that for steep hills.

Normal front chainsets have rings with 53 and 39 teeth. Baci cassettes are something like 11 - 25 (but can be 11/23, 12/25,12/27... and all sorts of other combinations).

A compact chainset has rings with 50 and 34 teeth usually. This loses you a little at the top end (the big gears for going fast or downhill) but gains you a little for climbing (because the 34 is smaller than the 39 ring of the "regular" chainset - so is easier).

It's not really that complicated in practice. When you are riding on the flat I would usually be in the big ring and somewhere in the middle of the rear cassette. You want to be able to turn the pedals at a decent pace - too hard and your muscles will get tired, too easy and your legs will spin like crazy - so somewhere inbetween is best.

If you're going downhill you could be in a smaller cog at the back and still pedalling at a simiilar pace.

If you're climibing you probably want to be in your smaller front ring - so either the 39 or 34 and nearer the top of the rear cassette - depending on how steep the hill is.

I suppose the basic idea is to keep your legs turning at a reasonably constant pace by using the gears - although your speed will obviously vary according to whether you are going up or down.

gunny_bedford

thanks that makes sense, so a 12/27 rear cassette is "easier" to peddle than a 11/25 therefore better suited to climbing etc ?? is that correct?

JGS

Gunny Bedford wrote:

thanks that makes sense, so a 12/27 rear cassette is "easier" to peddle than a 11/25 therefore better suited to climbing etc ?? is that correct?

Yes, but on the less hilly stuff you will notice a bigger jump in intensity per gear on a 12-27. I think a 12-27 is a good one for a beginner though as it gives you all the low down grunt for getting up hills. In reality even on a compact with a 50-12 gearing you can still do a good 35mph+ with a decent cadence, which as a beginner will feel pretty fast indeed.