Quote Originally Posted by marfa View Post
Hey chaps

I've just counted the number the teeth I have 11-23.

What does that mean then?
The other way I have used to explain to friends what Grog has said so well is..

If you have 52 teeth on your big front ring, then every time you turn your pedals around one full revolution, you move forward by 52 teeth. This is because for every tooth you move your chainring around, you move your rear wheel around a tooth too. So you will move your rear wheel around by 52 teeth too.

So, if you are using your 11 tooth gear on the rear then you will turn your back wheel around 52/11 times (ie. 4.7times) each time you rotate your pedals once. That's hard work!

But if you are using your 25 tooth gear on the rear, then you will turn your back wheel around 52/25 times (ie. 2.1times) each time you rotate your pedals once, which is a lot easier.

Similarly, if you are using your small ring on the front, it may have 39 teeth (or 42 or some other number depending on what type of gearing you have). In this case you will go forward say 39 teeth each time you turn the pedals.

So when you use the 11 on the rear, you are turning your rear wheel 39/11 times (ie. 3.5times) each time you turn the pedals, which is easier than if you were turning it 4.7times on the big ring. Or if you are on the 25 at the rear it will be 39/25 times (ie. 1.6times) each time you turn the pedals. And that's got to be a lot easier!

Who loves their MTB that has a 22 on the front and a 34 on the back? That is 22/34 times, in other words, two thirds of a turn of the rear wheel for each pedal rotation! We LOVE the granny!