Sturmey Archer S2C Duomatic Kick Shift Hub Specs and Info
Marco first let us know about Sturmey’s new 2 speed kickback hub here. Let’s look into the S2C further, which has been available since later this summer.
There are actually two variations of Sturmey’s new kick shift hubs, the S2 and the S2C. The S2 is a dual shifter without the break and the S2C includes a coaster brake mechanism. The S2 is not currently available but the S2C is.
The S2:
And the S2C:
Here are the basic specs from the Sturmey Archer site:
Specs for 162mm Axle
• Hub Shell Material – 6061 Aluminum
• Axle Diameter – 13/32” Slotted
• Axle Length – 162mm
• Over Locknut Dimension – 116mm
• Right Axle Protrusion Length – 23mm
• Left Axle Protrusion Length – 23mm
• Spoke Holes – 36
• Pitch Circle Diameter – 67mm
• Flange Width – 53mm
• Spoke Compatibility – 13g or 14g
• Sprocket Teeth – 13T through 22T
• Chain Line: 1/8” Flat 43mm
• Chain Line: 1/8” Dished 41.2mm, 44.8mm
• Chain Line: 3/32” Flat 42.6mm, 43.4mm
• Chain Line: 3/32” Dished 41.1mm, 44.9mm
• Weight – 1400g
Gear Ratio
• Overall Range – 138%
• Gear 1 – 100% Direct Drive
• Gear 2 – 138% (+)38% (Gear 1 + 38%)
Gear Changing With the S2 and S2C
Gear switching on the S2 and S2C is accomplished by back pedaling slightly. On the coaster brake version, the S2C, a more deliberate and powerful back pedaling will result in the coaster brake being engaged.
S2 and S2C Installation
Download S2C Manual and Instructions PDF
Below is a video of the S2C Setup in Moulton Bike. It shows the kick back action and coaster braking.
More to come!
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Pingback on May 12th, 2011 at 11:12 am
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Recent Comments
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November 29, 2010 at 9:57 am
Thank you for enlightening me on this revamp of a great old idea !! the 2 speed kickback hub. John
December 9, 2010 at 11:33 am
I’ve been using a Duomatic for around 4 years now – first a 28 hole one I got off eBay, then a 36 hole I got from Marco. I love them.
I would be very interested in a comparison between the Torpedo Duomatic and the new SC2. Can anyone provide one?
SO far, the only thing I don’t like about the SC2 is the brake arm. I much prefer the silver of the Torpedo.
December 12, 2010 at 4:05 pm
The SC has been produced before 1966-1970; then it had a steel case and the second gear was direct drive 71-100%; no coasterbrake. See my post at Velobase.
http://velobase.com/ViewComponent.aspx?ID=CB0007D0-DDFC-4E9A-82FB-ADF402961F7B&Enum=121&AbsPos=34
December 30, 2010 at 3:33 pm
Yes, the earlier version called the S2 geared down and is not to be confused with the current version, which gears up. Both are now covered on Sheldon Brown’s gear calculator, http://sheldonbrown.com/gears/index.html. But has anyone taken the new version apart and counted gear teeth to have a gear ratio more accurate than the one to two decimal places given by Sturmey-Archer?
November 28, 2011 at 2:07 pm
The tooth count and other details about the internal workings of this hub can be found here:
http://www.squidoo.com/sturmey-archer-s2c
January 14, 2011 at 5:56 am
Just wondering, for the S2C, backpedalling hard results in a braking effect since it has a coaster brake. What about for the S2? After the kickback gear shift happens, does it continue backpedalling?
January 27, 2012 at 9:55 am
Yes, it continues to freewheel. You hardly notice any difference between it and a plain single speed freewheel until you begin pedaling forward again.
July 8, 2011 at 8:23 pm
Another video of the hub in action:
October 8, 2012 at 7:06 am
Great site!
You also might want to take a look at Dualspeed at WordPress.com: dualspeed.wordpress.com
Enjoy, Ingo.