Double or Treble cog (2x9 or 3x9) questions.

[Dave7]

Having never ridden with just 2 cogs.....when buying my present road bike I got them to change it to a tripple (which they did at no extra cost). Looking to buy a new bike I am wondering whether to go for a double.
I ride mostly around the middle-maybe moving up or down 2 gears and when I come to a short/steep up-hill I simply change the front gear/cog.
I'm trying to get my head around it.....

• does having just the 2 cogs limit you and make it harder?
• Why do they have just 2 cogs.....is it purely weight ?

As you will note I am not very technical on terminology and can never remember if the bigger cog is changing up or down.....but hopefully you know what I mean.

 

[Scilly Suffolk]

If you don't already know, count the teeth on the sprockets (at the back) and chainrings (at the front) and enter them here.

As you already know what gears you normally use, you can then compare the gears on any new bike you are considering.

Having a double, rather than a triple chainset, is only limiting if you actually need to use all the gears on your triple.

Weight is one factor, another is that a double is less complicated and the chainline is less of a consideration.

High and low refer to the ratio between the front chainrings and the rear sprockets: there is the least difference between the smallest chainring and the largest sprocket, so this is the lowest gear; there is the greatest difference between the largest chainring and the smallest sprocket, so this is the highest gear.

 

[Dave7]

If you don't already know, count the teeth on the sprockets (at the back) and chainrings (at the front) and enter them here.

As you already know what gears you normally use, you can then compare the gears on any new bike you are considering.

.

I will do that tomorrow......thanks.
But further showing my ignorance-in what way will it "compare" the gears i.e. what will it be telling me?