which cassette ?

[Adam4868]

I'm going to buy a new cassette for a new set of wheels,my question is what is the difference in the ones available (I.e say a 12/25) ? Its a nine speed triple thanks

 

[cyberknight]

The numbers mean the highest and lowest number of teeth on the individual gears .
E,g 12 / 25 means the smallest has 12 and the biggest has 25 teeth
If you went for something like a 12-23 the gears would have less jumps in the number of teeth between each gear but harder on the hills compared to a 12-30 which would have bigger gaps between gears but easier gears for going up hill as the last number would have 30 teeth compared to a 23 tooth .
Best bet is to count the highest and lowest teeth on what you have and decide if you want the same or something faster if you do not use the easiest gears or a wider range if you struggle on hills.

 

[Adam4868]

Thanks have a 12/25 on a triple at moment but very rarely need the lowest, but something a bit more at top end maybe.

 

[sreten]

Hi, Then you probably want an 11/23, /sreten.

 

[raleighnut]

Thanks have a 12/25 on a triple at moment but very rarely need the lowest, but something a bit more at top end maybe.

11-23 sounds about right to me also as it would "corncob" the first 6 then have a 2 tooth jump on the climbing gears. Probably be a bit lighter too.