I am unsure how to calculate the total capacity for a 1x drivetrain, I have 46t up front and 11-32 10 speed cassette.

How can I determine which derailleur will work with this setup? E-mtb build.

I was looking at the Shimano Saint and Deore XT, Saint has total capacity of 25t and Deore Xt has 47t.

Also should I go long or medium or short cage? Deore XT is long cage and Saint is short cage but has a 'wide option' to run an 11-32 cassette for freeride use, I would be using it on quite a high powered emtb so maybe this isnt ideal?

1 Answer 1


You only need 21t total capacity (32-11).

If you are looking at currently produced mountain rear derailleurs, the conversation here isn't about total capacity, because they all have more than that. If 11-32 is really what you want to be running, what's in question is choosing from the relatively few Shimano mountain 10 RDs that both are desirable for narrow range 1x (has a clutch and a short cage) and where 32 isn't less than the minimum for their low cog clearance. You would go to the spec tables to find options. Saint RD-M820-SS is the best out there that meets this criteria.

For the cage length, shorter is always better if you don't need what a long cage gives you, which is more total capacity. Your total capacity needs are about as low as it gets with 11-32 on 1x, so short cage is ideal.

If you tried to cheat the minimum low cog, you would likely find that even with the b-screw all the way out, the guide pulley is further away from the cogs than ideal, and shifting will suffer.

  • Very helpful thank you, in your opinion am I right to go for a 10 speed 11-32 for quite a high powered e-bike?
    – Confused
    Feb 20, 2023 at 20:36
  • @Confused I would only consider going with such a narrow range if your terrain is very flat. If this is a mid drive I think the most prudent choice is use an off the shelf Linkglide group. Feb 21, 2023 at 0:49
  • 1
    I've placed an order for the complete Linkglide drivetrain now, thank you so much for bringing it to my attention as it sounds ideal.
    – Confused
    Feb 22, 2023 at 6:35
  • Just regarding tyres, would you know if I could get away with 2.0" tyres on a 30mm rim or should I go around 2.2" - 2.7"?
    – Confused
    Feb 22, 2023 at 6:38
  • 1
    You've been so helpful, my Shimano 11 speed Linkglide drivetrain arrived yesterday and its beautiful, exactly what I was looking and I've ordered my 2.0 tyres too. Thank you very much
    – Confused
    Feb 26, 2023 at 0:15

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