Gearing ratios are really interesting, it can be the maker or decider of your riding endurance. I think it is more of a personal bike ratio v.s. human capabilities thing, meaning it really comes down to the individual on how they ride that bike with that “Front Crank to Rear Cassette gearing” .v.s. the rolling distances of your chosen wheel size (26″, 27.5″, 29″).. v.s. your fitness level v.s. how much “grit” you have got in you, to keep you ‘bloody’ going.
To save me getting too scientific and repeating what has been outlined many times online by others more qualified by me, if you google Bike Gearing you will find some detailed explanations with fancy charts showing you mathematically why paying attention to your gearing set up can work in your favour. (or destroy your soul)
The MTB Cross-country website people created a Bicycle Calculator that is really fun to play with if you are that crazy obsessed as I am
http://gears.mtbcrosscountry.com
Using their online gear calculator, if you understand what your set up is, you can make some configuration changes to work out if it is worth changing up your Ratios to a new Groupset or mix and matching up the existing Cogs and Cranks.
For me, because I used to pedal a Eagle GX 12 Speed Groupset (32 Crank, 10 -50 rear) I wanted to understand is it worth changing to it and ditching the stock 10speed set up (36/22 Crank, 11-36 rear).
The Sram X0 Mountain Groupset is actually not to bad to work with.
Firstly, she can take a hammering and Secondarily, man she shifts well.
Here is what the X0 on my Fat Boy Expert looks like:
This chart is telling you some really cool things
1. In basic math.
In whatever gear you are in,
One full turn of your Crank (Pedals) in the selected gearing will = X amount of turns of your Rear Wheel.
So for example
In my lowest gear and in my lowest crank wheel 22
or, In my highest gear, one full turn of my front crank (in the top crank 36 tooth) = over 3 full turns of my rear wheel. (3.27)
2. In your highest or lowest gear, what your Cadence would be to achieve a KM/hr speed.
I’m currently not measuring cadence when I’m riding, but knowing what the theoretical top speed output of your gearing is always good to know. (So you can beat it)
So the pending questing I had (and is the reason for doing this), is what is the justification for changing to a 1×12 speed system. (32t Crank & 10 -50 Rear Cassette)
Here is how the Eagle GX stacks up, running on 26″ wheels
For gaining an overall advantage by changing to a 1×12 system from a 2×10,
The 2×10 lowest climbing gear is almost the same as the Eagle 12 Speed lowest gear (0.03 difference), and its highest gear is better than the 12 Speed (by 0.07 difference)
There would be smoother gear shifting increases/decreases
However, there would be another reason to still change to the 1×12 and that would be for weight reduction.
The actual reduction is 460g
Achieved by:
Removing the XO Crank, Cassette, Front and Rear Derailleur
Then adding the GX 10-50 Cassette, Rear Derailleur, 32t Crank and updating the Grip Shifter to a 12 Speed.
Plus the 1×12 would look cool.