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.