Sturmy Archer AW 3-speed english hub.
Can this be made into a shiftable fixed hub for a unicycle?
If so describe how, because i can get a rediculously good deal on one locally.
I know nothing about them but im saying no. How would it even work. Theres no where to atach cranks or anything. It could work for the wheel of a giraffe but thats about it.
I understand that all the pre-schlumpf hubs were adapted from bike hubs, but it took hundreds of hours of precision machining to sort them for unis. If it were easily doable then schlumpf wouldn’t bother making unicycle specific ones.
EDIT: And infact they weren’t on the fly shiftable.
Someone had a giraffe at the 1995 (IIRC) BJC with a SA 3-speed hub. Unfortunately I didn’t get to ride it and, although I believe it was fixed, I’m not certain.
The same machine was also featured in (again IIRC) The Catch around the same time (could have been Kaskade). All my old juggling magazines are in the loft, but I’ll try to pop up there and take a look at the weekend. I doubt I’ll find anything particularly helpful, although I /will/ be able to find the names of the guys who built it.
I’m pretty sure I’ve seen, somewhere, instructions for converting a 3-speed hub gear into a 2-speed fixed. I’m afraid I can’t remember where, though.
It might be possible to convert it to a 2-speed fixed hub then use it in a giraffe.
http://www.users.globalnet.co.uk/~hadland/fairbrothersa.htm
According to this article, the high-gear is 1 to 1 and there is a good amount of backlash.
Still, it would be an interesting project.
Possible if you use a setup like purple faze.
I’m not sure whether this is a special version of the sturmey archer hub, but at least in England, you can often pick up Sturmey Archer 3 speed hubs for about 20 pounds, with a free bike attached. Or maybe for not much at all if you go to the dump / look in skips.
Joe
Save your money. If it was even remotely easy to do, they’d already be on the market. Take a girl out for ice cream instead.
Ditto. Many before have contemplated this with the S-A, and while some have done the fixie conversion, that hub has too much lash to be suitable. And there’s the issue of attaching cranks to the axle in conflict with the shifting cable, which was solved so eloquently by Mr. Schlumpf’s design.
A unique little bike shop in Seattle called The Bikesmith did two speed conversions of a Sturmey-Archer hub into a two speed fixed gear hub. Sadly that shop is out of business now. But he may still possibly make the hubs on the side. I just don’t know how to get in touch with him now. I’m also not sure of what model of S-A hub he did the conversion with.
The two speed fixed gear system worked well for bikes. It is, however, not strong enough to work on a unicycle. A unicycle has too much torque. The gears inside the hub are not strong enough to handle the torque that unicyclists put on their hubs. It’s not even suitable for a giraffe.
What compounds the problem is that unicyclists gear the unicycle too low. Hubs like that need to have bike style gearing ranges. If you gear them too low you can put too much torque on the hub and break the gears. So hubs like that come with specs that tell you the minimum size front chainring and maximum size rear cog that you can use so that you don’t overpower the hub and break it. Unicycles, unfortunately, are way out of spec for that.
Putting such a two speed fixed gear hub on a bike would be cool. I just got a single speed road bike and if I get to liking the fixed gear option I just might consider getting one of those two speed shiftable fixed gear hubs.
It was a 3 speed fixed hub. A sturmey archer ‘ASC’. They are very collectable in two wheeled cycling so if you see one, buy it. That giraffe had about 1/4 of a pedal revolution of play when you changed gear which was a little sketchy.
interesting thread. I had this conversation with my dad in the pub a couple of weeks back. he was convinced it could be done. Looks like it is, but maybe not worth it…
Thanks Nick. I couldn’t get to the mags in the loft, I believe they’re behind a hefty pile of baby clothes and toys that I’m trying to get DW to dispose of and that I CBA to move.
Three speed
First thing to check out. Can you peddle the hub backwards with it engaged?? If you can’t then it has a free wheel and you’ll have to get rid of that. Next is there a reaction arm? Do you have to hold the threaded “axle” inmobile for the gears to work?? I’m betting you will have to hold the axle still So… Your cranks would have to go on the sproket or the “shaft” the sproket turns and your frame needs to be attached firmly to the threaded axle. I don’t think you can do that because the cranks will be attached to the sproket and will run into the frame legs. Kind of confusing… take a look though and I think you will see the threaded axle needs to hold firmly to the bicycle frame. You’ll see how it works if you look at it and fiddle with it a bit.