The Simplicity of a 3 Speed.

Hi.

I haven’t posted here until now. Lets hope I’m not way off track, and that I am not covering old ground.

This is a quick one for those of you that have hit a brick wall trying to understand how a 3 speed hub actually works.

There are quite a few bits inside an internally geared hub. They can seem a bit daunting. This site gives some insight into what you can expect to find. But what about the fundamentals?

A 3 speed hub basically only contains ONE gear.

This is one reason why they are so reliable, and such a masterpiece of engineering.

One gear is cleverly controlled so that it is possible to switch input and output.

In addition to this, a “locked” or 1:1 (input = output) standard freewheel option is included.

With the one gear, plus the direct drive, 3 gears are available…

For arguments sake lets say that the one gear gives a 3 to 4 ratio, (hubs differ).

By swapping input and output on the one gear it is possible to achieve either a 3:4 ratio or a 4:3 ratio. When 1:1 is added you have 3 gears.

4:3, 1:1, 3:4. It’s that simple.

The internal workings of the hub are designed to control input and output around one gear, and to eliminate that gear to give you a 1:1 ratio.

So if you have been looking at the guts of your hub wondering where the 3 gears are, you are on the right track. They aren’t in there.

Ben Skinner, Hjulcompaniet.


  1. Eri Hyva

    I love 3-speed, too. I have many Sachs Torpedo 3-speed bikes. They are all 46/18 gearing.
    Sheldon said
    http://www.sheldonbrown.com/sturmey-archer.html
    that one could use even 46/22 gearing. Is there going to be any problem with 46/22, do you guys have experience?

  2. leonwoodbine

    2009-2010 Sturmey Archer looks amazing! What a change. They appear to making 3-speed FIXED hubs, which take a Shimano style spline cog – in coloured hub shells. More than one fixed rider I know has asked me about that exactly. And the 8 speed hubs now have the cable mechanism inside the frame, rotary style instead of the classic bellcrank on the end of the axle. Great to see.
    Thanks for the link Fabien!

  3. Dawid

    Hi,
    first of all – this is an amazing site, I read most of the info you’ve got on the older Sachs hubs with fascination! Duomatic ftw😉

    I’m writing cos I’m currently renovating an ’88 Batavus Winner with a Sachs Torpedo Dreigang hub. While dismantling all the accessories, I cut the shift cable for my hub… which turned out to be a silly thing to do!

    No matter what cap I put on the new cable, it snaps right off when I start shifting. Not sure if any of you know a way around? Where to find / how to DIY and adjust shift cables for these hubs?

    Thanks in advance for all ideas!




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