# Thread: should I go long cage crank?

1. ## should I go long cage crank?

Hello guys,

I got 1x10 drivetrain. front 32 t, rear 36t-11t.

if I use the "formula" - I get:

T = (32-0)+ (36-11) = 57.

I know that:

Shimano
Long = 45T
Medium = 33T
Short = 28T
SRAM
Long = 45T
Medium = 37T
Short = 30T

does it mean I need to go long cage? currently I think I got a small or medium cage (can you tell what length exactly it is?) and run o.k. I think. should I change it anyway?

there is the picture my derailleur:

https://s1.postimg.org/ynrfsulcf/20151017_180616.jpg

thanks

2. You did the calculation incorrectly. Because you have only one ring in the front you do not need to include it in your calculation. Your calculation should simply be 36-11 which is 25.

3. Edit: or what ljsmith said^^

Your formula is wrong, you don't need to consider the front chainring because you only have one, with 2 or 3 chainrings you add the difference between them. In your case the total spread is 25t so a short or medium cage derailleur will work fine.

4. thanks very much

5. Math is fun!

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