Urban Velo

Sturmey Archer S2 Duomatic Kick Back Hub

Kickback hubs aren’t familiar to most riders these days, having gone all but extinct decades ago even if once relatively popular on cruising and folding bikes. Before this past year I’d only had the chance to ride one such hub and at that only once, nearly a decade ago in a motel parking lot during Interbike. Just last year Sturmey Archer resurrected the kickback concept—I had the chance to ride the coaster brake equipped S2C hub on the Torker KB2 we reviewed back in December 2010, and recently have been putting in time on the rim brake use Sturmey Archer S2 hub.

For the uninitiated, a kickback hub is an internally geared hub that shifts by backpedaling while coasting, no external shifters or cables required. Each time you backpedal, the hub shifts. The S2 has two gears that you can switch between, a direct drive low gear and a 38% higher second gear. The hub body accepts standard 3-tab Sturmey Archer or Shimano cogs common coaster brake and internally geared hubs.

My particular S2 hub is laced to a 700c rim and finds itself on a Pake track bike with front and rear handbrakes and a CETMA front cargo rack. I have it setup with a 48 x 20 gear ratio, which gives a 64.2 in low gear and a 88.6 in high gear, straddling my usual low 70 in gear that I prefer on most single and fixed gear street bikes. A good compromise between a low, but not too low, climbing gear and a high gear suited to flat and downhill sections without having to spin like mad.

Riding and shifting is easy enough, though I’ll admit that even after a couple of months of riding this hub I’ve not mastered shifting in certain situations. At normal riding speed I find the shifting easy enough, and while coasting you can audibly tell which gear you are in as the direct drive low gear is nearly silent while the high gear has a whirring click to it. Starting off from a stop has proven more difficult however, whether at a redlight or just pull off the sidewalk. When stopped you can still shift the bike by pedaling backwards, but without the sound of the freewheel to guide you it’s impossible to tell what gear you are currently in. I personally find it hard to accurately shift the bike when accelerating from a stop as well, but I think it’s more poor technique and lack of patience on my part than anything to do with the shifting mechanics. The S2 definitely shifts best with some patience and a solid back pedal motion. The only strange behavior I’ve encountered is the hub ghost shifting when I cross railroad tracks—it is the only place it happens, and it happens consistently but not really each and every time no matter how careful I am to make sure I’m not inadvertently back pedaling.

For the right person and the right application, the S2 hub is a worthy addition to the stable, a hub with most of the advantages of a single speed drivetrain but with two gears and no external shifting bits to speak of. I plan on keeping this hub on a bike long term, it is a great piece of componentry for my more utilitarian riding around town. The hub is heavy, weighing in at 980 g without a cog on my scale, but internally geared hubs aren’t known for being lightweight. The S2 hub is available for a bargain price of $90 in either 110 mm or 120 mm spacing, in black, silver, red, gold, purple, and turquoise.

23 Comments

  1. BobAugust 11, 2011 at 10:20 am

    Can you backpedal “past” the shift point with this hub? for example, if you were stopped at a light and wanted to bring a pedal to the top of its stroke, could you juat rotate it backwards like with a freewheel or would you be stuck like with a coaster brake?
    I havent been able to find an answer to this anywhere. inquiring minds wanr to know.

  2. bradAugust 11, 2011 at 11:56 amAuthor

    Yes. You can backpedal past the shift with this hub to reset your pedals. As you backpedal past the shift however, it continues to shift each time you make a given amount of the crank revolution.

    In other words, you can freely backpedal on it, but as you do so the hub shifts back and forth between the gears, 1->2->1->2 and so on.

  3. BikeBikeAugust 12, 2011 at 8:30 am

    I have been riding one on a Brodie Remus for about a year now and I can echo all of Brad’s points, except I have never had the strange ghost shifting over train track he speaks of. One thing I have noticed is that if you do not kickback hard/far enough sometimes the hub “hiccups” until you perform a better shift.

    Otherwise it does exactly what is claims and is kinda quirky – both of which I like. We have also built a handful for customers and they are all happy with teir purchases.

    Have a great weekend!

  4. TerryAugust 12, 2011 at 4:30 pm

    I have one of these. Once I got used to the shift point, it works fine every time (well, almost every time). I have the non-coaster brake model.

    The only thing I wish was that it had a standard and low gear instead of a standard and high gear. It would be easier to find chain wheels to get your gearing the way you want it that way.

  5. KevinAugust 16, 2011 at 3:35 pm

    I have had a B2C (coaster brake version) of this hub laced up under my steam roller since January. The hub has developed some play and a bit of stickiness to the shifting. I like to think of that as character. Overall I really like this hub. It is more for riding by yourself, or in a relaxed pace around town in a group. Since mine is a coaster brake hub every time I have to slow down I change gears. This can be problematic when following a group of SS/Fixed bikes since they can easily come out of a corner.

  6. AlexFebruary 28, 2012 at 9:56 am

    I got one as standard equipment on a Marin Hamilton. Worked out well because I have long since wanted a 29er steel rigid mountain bike, and the Hamilton, while designed for street use is a mountain frame, a 29er, and 4130. The S2 hub got my interest for a mountain biking application to have a way to get singlespeed simplicity with a high gear for longer downhills. The hub works great under singletrack conditions, no ghost shifting and once you get used to it the hub is a great asset. I wouldn’t want to submerge the hub underwater because it doesn’t seem to be sealed up for this use, but overall I am very happy with it.

  7. Phil BMarch 31, 2012 at 4:39 pm

    I’ve got a B2C that’s developed the strange habit of shifting while coasting. It’s always been a little noisy – particularly when I was new to it.

    Does anyone know about adjusting these hubs? Or where I should inquire?

    Phil B
    Sonoma County

  8. Erik GMay 9, 2012 at 3:13 pm

    Brad,

    Not sure you are correct about the way the hub performs when you backpedal…I am pretty it only shifts once every time you start backpedalling. You would have to pedal forward to engage whatever gear, then backpedal again to shift again. I have not tinkered with this hub so I cannot say for certain, but I have read other forums that describe the way it shifts when backpedalling freely.

  9. Perseu MandilloJune 6, 2012 at 6:01 am

    Hi just got a bike which came with the non-coaster S2 version. I am really happy with it. The only thing is that i would like to increase my high gear. Does anyone know how that could be done. Changing the chain set? I am pretty new to modification issues so any help would be great to steer me in the right direction.

  10. gentjimJune 22, 2012 at 3:23 am

    This sounds really interesting. Would this work with a track bike rear triangle – i.e. with the narrower spacing at the dropouts?

    I’m trying to find a way to convert super-trendy fixie (an old condor pista I’ve had for about a decade) to a more useful/comfortable utility bike with 2-3 gears and coaster brake.

    (I’m now far too old and boring to be trendy any more, and riding with my toddlers / groceries has become more important these days!)

  11. ecycledJune 26, 2012 at 3:28 pm

    gentjim said: “This sounds really interesting. Would this work with a track bike rear triangle – i.e. with the narrower spacing at the dropouts?”

    Yes. It should unless you have a very unique situation. I’ve just put together an older model (2001) Gunnar Street Dog which used 120mm track spacing/horizontal dropouts. Using the 148mm axle S2 Duomatic gave me the perfect urban commuter. CHeck it out here…

    http://www.flickr.com/photos/ecycled/7449984816/in/photostream

  12. Street BullyJune 27, 2012 at 9:35 pm

    I just picked up my new 2012 Schwinn Super D and it has one of these 2 speed kick back hubs with a coaster brake. I HATE IT!!!!! Love the bike but this hub has got to go and go fast. How can I change it over to a 3 speed Nexus? Can someone please help me?

  13. Phil BJune 28, 2012 at 12:53 am

    As I posted earlier, it’s a great concept, but I had trouble from the start.

    I’ve tried three hub cores and a whole replacement hub since March. Sturmey (Sunrace) has made no bones about the replacements, nor has QBP balked at re-lacing a new hub into my wheel. My LBS was also very supportive.

    Mine was a S2C and I strongly suspect the S2 without the coaster brake would be less problematic; although the last new hub seemed fine in most other aspects for a short while, it skipped continually in low from the start (!), which was the last straw. I’ve had my money refunded.

    What’s next? Probably a SRAM Automatix with a coaster brake. It would be good to adjust the speed for the automatic shift, but I have a feeling it may require a tear down so probably voids the warranty. I think they come from the factory set for shifting at 11.5 mph, and I would prefer a 8.5 setting. Chances are, I speculate, that the coaster brake would be less in conflict with the shifting, since it’s not dependent with operator input.

    Anyone have any info on these?

    Happy shifting,
    Phil B

  14. Scott BAugust 3, 2012 at 3:43 pm

    I agree…great concept but terrible product. My S2C was a mess from the beginning. Sturmey Archer/Sunrace replaced the hub without question but stuck me (and/or my bike shop) with the bill to re-lace the wheel. When pushed on the lack of logic in making a customer pay twice due to their faulty product the rep told me I was entitled to my own opinion but that they have been around for a long time so he wasn’t too worried about the policy/lack of service hurting sales. Unbelievable.

    I haven’t tried an alternative hub yet but have to think SRAM would at least have better customer service.

  15. DanAugust 27, 2012 at 8:22 pm

    I bought two of theses hubs online from a reputable ebay seller. I laced one up with a 26″ rim for a cruiser/street bike and kept the other in reserve. No matter what I do with the hub adjustments, I cannot get rid of this gawd-awful chunking when braking at certain speeds. It’s as if the hub keeps shifting back and forth when I apply the brakes of a given torque. Kinesthetically it is very unnerving and wholly unacceptable. WTF?

    Anyone?

  16. Jørge USeptember 2, 2012 at 1:27 pm

    Same with mine, when applying the brakes I would constantly hear a grinding noice, Ive adjusted the positioning of the coaster brake arm with the chainstay brake arm braze-on with flat washers for perfect alignment and symmetry and added Chain Tugs as I’ve seen pics of other Duomatics with them to no avail, and worst of all, the whole thing froze up on me when i accelerated at a traffic light. Supposedly Sturmey Archer offers a 2-year warranty from the date of purchase, so i will contact seller about problem!

    I have a question; does anybody know if the innards of the S2 Duomatic with out brake would work in the B2C Duomatic steel hubshell??

  17. Jørge USeptember 4, 2012 at 6:51 pm

    ↑ The above comment is about the Duomatic Kick Shift 2 speed hub with coaster brake.

  18. TomSeptember 13, 2012 at 11:30 am

    Above: you guys are basically describing a normal kick back. Give it some time to wear in and expect it to be a little raw. If it’s “unacceptable” then kick backs are not for you…

  19. BiggusNovember 8, 2012 at 1:59 am

    Hey gang!

    Got that coaster brake version for less tan a week. Im already reflex shifting and cant really describe how I shift the thing after a bit less than 200km. The clicketting high gear is almost silent and I only ear it while walking beside the bike. Laced on a 700c, mounted on a 1945 Huffman cruiser and a front drum brake on Abraham linkage fork, defo not a racer but a delight to ride and awesome look.

  20. JMacNovember 27, 2012 at 5:56 pm

    Ive had my black S2 free wheel hub for about 4 months now. Its nice to have the versatile gearing of two speeds, but finding the right 138% gear-inch (GI) gearing was a bit of a bugger. After some different chainring and cog combos i settled with a 64.3 GI 138% and a 47 GI one 2 one low gear. This gives me a nice cruising gear but getting used to the tall low gear is making me change my climbing technique. taking me some time to used too mainly b/c it falls right between what technique youd use on a SS and a geared bike. I sometimes wonder if

    The hub is laced 3x to a 32H Mavic Open Pro mounted to an on one ill pompino SS CX frame with canti mounts and 120mm spacing/track ends. Bikes really turned out fun.

  21. NEPMTBAMay 31, 2013 at 1:31 am

    Run’in this non coaster brake hub on a Redline MonoCog 29er SSer now a Two Speeder!

    After a bit of riding adjustment to get used to kicking back to shift. Love it!

    On trails I just look a head for a hill kick’er back and crank it up! I ride single speed most of the time and 2×8 on another rig, of course this is closer to an SSer than a geared bike, so it really extends the fun of an SSer, but this is perfect for where I ride, techy, rocky, singletrack!

    I have a regular coaster braked SSer also, but next on the list is a 2speed CB SA

  22. Harold SolomonNovember 4, 2013 at 5:01 pm

    I was lucky enough to find an original NIB Sachs Duomatic Torpedo 2-speed kickback. I built it into a DT Swiss 700c wheel and had a few really great rides on it. I need some space for more projects. So it (and a Zeus and next a 1940′s Raliegh) has to go.

  23. mike tJuly 20, 2014 at 1:14 pm

    Spot dualie new in 2014 failed hub after 40miles
    just kinda kicked the bucket mid stride…could tell after that it dragged like heck. Shifted on its own/not at all have a new rear wheel replacement after being without a bike for 2 months.
    So this is a broke bike more than a new shiny one.
    Not very enthused about the replacement (msrp 1300 fyi)
    Would like to sell it.
    let me konw if you are interested !! 0 miles on the new hub!

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