Sturmey Archer Duomatic
 

Anyone use one of these? I purchased one and am waiting for the rim to arrive so I can build it up for my Hercules.

This is the S2C model with coaster.

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Torker has one of these hubs on their KB2 model--you may want to search to see what people say about that bike.

Marin uses the non-coaster equipped hubs on two of their bikes.

Yep. Someone locally decided they didn't like the way it shifted and sold the wheel from a Marin to me on CL. It's on my cruiser-ized Raleigh Marathon.

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Still trying to decide if *I* like the way it shifts. The issue I have is that it does not downshift on its own when the bike comes to a full stop. This, to me, is a design flaw.

I have close to 1000 miles on mine. I was running SS for quite a while, which was fine, but the gearing was a compromise so I thought that this 2 speed hub would be just the ticket. So now I have pretty much another compromise. A gear a bit lower and one a bit higher. After playing with the different chainwheel/sprocket combos it is actually set up quite nicely. So here are my impressions:

The Good:

No cables! This hub is simple and clean.
It works as advertised - rugged and reliable
The 138% low to high is about right.
It looks good.

The not so good:

It is hard to know what gear you are in. I found this troublesome at first but after riding it a while I have become adept at getting it right most of the time. The hub pawls make a different clicking sound in each gear and this is the biggest clue,

Shifting reliably takes some practice. The hub will always shift if you backpedal within a certain range; however at first I had some difficulty calibrating my motion to this range. Again, practice is the key to success. I now make reliable shifts most of the time pretty much without thinking about it.

If you stop in high gear without realizing it, you're just going to have to gut it out when you start. I find that, while you can try a quick downshift, you can be pretty much up to speed in the same amount of time. When I ran SS, I used to coast to a stop, and then spin the crank backwards to orient the pedal for take off. If you do this with this hub, you may find yourself in the wrong gear (high). What I have trained myself to do now is to make sure that I am in low before the stop, and then coast with the pedal in the correct orientation.

There are occasional phantom downshifts when you coast over biggish things like speed bumps. The trick is to keep pedaling- apparently letting up makes it think you have backpedaled. These are not a big deal but if you are going rather quickly, getting back into high is a bit exciting.

It weighs more than the SS setup.

Overall, I am very happy with the hub and would recommend it instead of a SS setup in pretty much all cases. I'd say though, that if you don't mind the cabling and the tiny little bit of extra complexity, you may be happier with a 3 speed hub.

Good luck - and just be patient and give it some time when you start using it. You'll like it more and more each day.

-G

It's old technology. I had one on my secondhand school bike, and it survived its six years of 2 x 17 kilometer a day without giving any trouble. [>100 mile a week, 40 weeks a year, times 6, equals 24,000 miles].

It may take some time, indeed, to know how to shift down instinctively.

I mainly used it in the biggest gear though, the lower one was there to get me going after a stop at a traffic light, and as a home comer on the really windy days.

Although I don't have as many miles as gmt13 does, I can second pretty much everything he says. That's pretty much what it's like living with a SA S2 or S2C.

That's why I built up a SRAM Automatix instead of the kick-shift. I like the automatic shifting vs having to kick back to shift.

Looks interesting. I'd like to know more about your experience with it.

-G

I had an older bike that had a rear derailleur, plus an automatically shifted two-speed internal hub. I no longer have the bike, but I have to say that I really, really liked the automatic shifting. That hub had an adjuster that let you change the RPMs of the shift over a range (could only be set when the bike wasn't moving). It was clean and crisp shifting, and I really liked that it downshifted to Low when the wheel stopped spinning. THAT is what I would like... it sounds like that's what the Automatix is.

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