Close ratio hub gears
tgotb
Posts: 4,714
I'm toying with putting together a cheap Winter hack, but I don't want to ride fixed/ss. In fact, I'd really like similar gearing to the ones I use to commute on my decent bike, which means 5-6 gears reasonably well spaced between 50" and 75".
Does anyone know whether this is possible with hub gears? Every other hub-geared bike I've ever ridden has a huge cadence jump, which I really hate...
Does anyone know whether this is possible with hub gears? Every other hub-geared bike I've ever ridden has a huge cadence jump, which I really hate...
Pannier, 120rpm.
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What does 'reasonably well spaced' mean to you? For regular hubs, the minimum is about 14% change per step. For a road bike, you can have steps of 6%.
The ultimate is CVT of course, which doesn't have steps, but has a continuous change. NuVinci is the only CVT available for bikes. A bit expensive, though.0 -
What I really want (though it sounds like it can't be done with an off-the-shelf hub gear) is something similar to my road bike, which is somewhere between 5-7%.Aapje wrote:What does 'reasonably well spaced' mean to you? For regular hubs, the minimum is about 14% change per step. For a road bike, you can have steps of 6%.
My Brompton achieves reasonable spacing with a combination of hub gear and 2-speed derailleur, but that defeats the object for this build (which is to try to avoid a derailleur altogether)...Pannier, 120rpm.0 -
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TGOTB wrote:I'm toying with putting together a cheap Winter hack, but I don't want to ride fixed/ss. In fact, I'd really like similar gearing to the ones I use to commute on my decent bike, which means 5-6 gears reasonably well spaced between 50" and 75".
Does anyone know whether this is possible with hub gears? Every other hub-geared bike I've ever ridden has a huge cadence jump, which I really hate...
I don't think there's anything currently on the market. Even the (fixed) Sturmey S3X, which is a "reinvention" of the old close-ratio ASC has a wide range.
Sturmey used to make some close-ratio hub gears- two, three & four speed ones were available at different times. You could probably find one used if you looked hard enough but it's probably not the sort of option you want for a winter hack.
My inclination would be to go for a simple derailleur system (close ratio seven or eight speed, friction shift, single chainring) or live with the cadence jump and get a three-speed hub. Neither is really what you want....sorry.
Cheers,
W.0 -
WGWarburton wrote:TGOTB wrote:I'm toying with putting together a cheap Winter hack, but I don't want to ride fixed/ss. In fact, I'd really like similar gearing to the ones I use to commute on my decent bike, which means 5-6 gears reasonably well spaced between 50" and 75".
Does anyone know whether this is possible with hub gears? Every other hub-geared bike I've ever ridden has a huge cadence jump, which I really hate...
I don't think there's anything currently on the market. Even the (fixed) Sturmey S3X, which is a "reinvention" of the old close-ratio ASC has a wide range.
Sturmey used to make some close-ratio hub gears- two, three & four speed ones were available at different times. You could probably find one used if you looked hard enough but it's probably not the sort of option you want for a winter hack.
My inclination would be to go for a simple derailleur system (close ratio seven or eight speed, friction shift, single chainring) or live with the cadence jump and get a three-speed hub. Neither is really what you want....sorry.
Cheers,
W.
Following up my own posting- sad or what?
OK: try these guys: http://oldbiketrader.co.uk
They do lots of SA stuff, and are listing an "AM" model reconditioned 3-speed at the moment.
That (I believe) is a medium ratio 3-speed- roughly 15% above & 15% below the middle gear, instead of the 33% up & down that normal SA 3-speeds have. Set up a 65" middle gear and you ought to get a 56" low and a 74" high... which isn't far off what you were asking for!
I bet if you tried it you'd find three gears were enough.
Cheers,
W.0 -
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