SRAM Automatix 2-speed hub

6 Responses to SRAM Automatix 2-speed hub

1. Neal says:

   January 10, 2017 at 5:20 am

   Dear John,

   I’m thinking about purchasing this hub. But i want to use it on my single speed bike. It’s a retro Raleigh racebike. My current sprockets are 46/18 and that’s fine for normal riding but i live in Holland so the hills are most difficult.

   How can i calculate witch ratio i need tot have lighter with the hub and when it changes gear it will be something like 46/18.

   I have an SRAM automatix hub with a 19 and a 24 sprocket. So now i want to calculate which sprocket i need on the crank.

   Hopefully you can help me:)
   • John says:

     January 10, 2017 at 10:43 am

     Hills are difficult in Holland? Well, not much though I do understand that there are hills in the southeast of the country. Even without hills though, having a lower gear for acceleration is helpful.

     You say 46/18 but do you mean in the high gear or the low gear? And what is the wheel size?

     Once you assemble this information, you can answer the question using http://sheldonbrown.com/gear-calc.html. If the 1:1 gear is not the one you want to be like a 46/18, then adjust the size of the chainwheel until the other gear, with the sprocket you will use, gives you the development you get with 1:1 gear and 46/18. The chainwheel is going to be larger in proportion to the size of the sprocket, but also will be in inverse proportion to the hub ratio.

     (new chainwheel size) = 46 * (your sprocket) / (hub ratio * 18)
2. Jonathan Woolrich says:

   March 8, 2020 at 3:54 pm

   Do you have a diag for the version with no brake? Looks like there is nothing to stop the L/H bearing cap rotating!
   • John says:

     March 31, 2020 at 10:36 pm

     There’s a diagram on page 10 here now also on our page, and the user manual linked on our page shows a locknut. Sorry about the late response.
3. Ignacio says:

   April 11, 2020 at 7:11 am

   Do you know where I can buy the SRAM Automatix 2 speed
   • John says:

     April 14, 2020 at 8:00 pm

     I see a couple for Sale on eBay.

Comments are closed.