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Help converting 110mm O.L.D. singlespeed to Sturmey Archer 5sp
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01-05-2011 12:35pm#1
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I don't have a hub gear, but I have vague recollections of fixing my dads Sturmey Archer. If I recall, the cable was sheathed to the cable stop on the chainstay where it was secured by the fulcrum cable clip.
The cable was clamped to the frame at various spots by spring clips, it would run over the top of the BB.
St John Street Cycles are a great source of the necessary bits http://www.sjscycles.co.uk/sturmey-archer-internal-hub-gear-spares-dept426/0 -
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For shifting, I have a choice of grip shifters or thumb shifters. I want the shift action to be as light as possible. Any opinions/experiences?
There are strengths and weaknesses for both, but on balance I'd go for thumb shifters.
I had first grip shift, then thumb shift, on my Nexus 8, and I have grip shift on my current Nexus 3-speed. For the 3-speed grip shift is fine as the gears are pretty widely spaced on the shifter, but the 8 speed had a slight tendency not to engage precisely if the shifting wasn't firm, as the gaps on the shifter were smaller (I hope that makes sense- think of three big slices of cake vs 8 smaller slices of cake
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One advantage of thumb shifters is that you're less likely to end up 'between' gears, i.e. a single firm click bumps you up or down one gear (assuming they're indexed correctly). But that's also a drawback - probably the only one - of thumb shifters- every gear change required a solid click, whereas with grip shifters you can jump multiple gears at a time if required. This can be handy after, say, an emergency stop, if you want to go from 8th to 3rd.
Another advantage of thumb shifters is that your hand can stay solidly on the bars while you change gear, but grip shift requires a slight loosening of your grip on the bars. The difference is marginal, but if you spend any length of time on the bike it might start to count. ("My doctor says I have the wrists of an 80 year old" &c.)
I've never noticed any tightness with grip shifters like Beasty describes.
Having said all that, I've never used modern SA hub gears, only Shimano.0 -
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Interesting, thanks folks.
The only recent experiences I have of flat bar shifting is Dublin Bikes (3sp, gripshift, easy action if a bit sloppy, Sturmey Archer?) and a SRAM 3.0 7sp gripshift with derailleur, which is accurate but quite tight (maybe a cable kink issue).
I suspect that gripshift works better with hub gears, but I think I'll try thumb shifters for a change - the bit about keeping a firm grip seems appealing for the intended use.
I don't think Shimano or SRAM is an option for the hub due to the narrow dropout width; I don't want to spread the frame as it's very small and I might convert it back to singlespeed for sale at a later stage.
PM sent to Holyboy regarding wheel build
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My Brompton has a very old-fashioned thumb shifter. Can't find a specific image, so this'll have to do.
I like it. I've never tried grip shifters with hub gears, but I didn't really like them with derailleurs.
The only downside is the old-fashioned thumb-shifter gets in the way when you want to turn the bike upside down for maintenance.
I'm pretty sure you aren't interested in this type of thumb shifter (in fact, it may not even be one, strictly speaking), but sure I've posted now.0 -
It's done!
Thanks all for the help, particularly Holyboy @ Bee Cycles for the fantastic little wheel build.
In the end I went with a Dahon rim and stainless steel plain guage spokes. I calculated the spoke length using 14mm nipples but ordered 12mm ones, so Holyboy had to find some of those.
The 1mm mismatch in OLD wasn't a problem for getting the wheel into the dropouts, but due to the thickness of the dropouts the axle wasn't long enough to take both "lock washers" so I left one out. I have no idea if this is important.
The hardest part of the install was getting the tyre on the rim, probably due to its narrowness. I've never had to use a metal spatula as a tyre lever before. :eek:
I'm not quite sure how well the shifting works, as the wheel has so little inertia it's difficult to feel the changes on the stand and I'm too big to ride the bike. :pac:
The geared hub has added less than 450g to the weight of the rear wheel, so it doesn't feel particularly unbalanced.
Until someone can disprove the assertion, I'm claiming this as the smallest geared bike in the world. Still, this has probably superceded my travel bike as most dubiously-justifiable-and-arguably-pointless project ever.
To the trails!
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Too late to be relevant to the discussion at this stage, but another selling point for thumb shifters for me is that you can change gear in a variety of hand positions. I have them on my MTB as I fitted them at a time when grip shifts were relatively new and not entirely reliable when faced with mud/grit. I'm sure the reliability of grip shifts has improved in the intervening years but I'm still a fan of thumb shifters. Mine are positioned so that I can change up or down with a twist of my wrist much like grip shifts (relying on first knuckle to change up, which is easy, base of thumb to change down, which is admittedly more tricky), and I can also change up/down with my thumb when my hands are on the bar ends. Mind you, it's all just a matter of what you are used to, to a certain extent.Lumen wrote:I'm too big to ride the bike.
"There is no tiny bike, there is only fear!" as Jens probably said at some stage or other...
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<sharp intake of breath>
- Rim: £46 shipped
- Spokes: £9 (+shipping, but I was ordering a bunch of stuff from SJS anyway)
- Hub: £126 shipped from oldbiketrader
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£181 (€204)
+ Wheel build: €30
= €234, ish.
Yes, it's complete madness - it's basically doubled the cost of an already expensive bike, by kids bike standards. Still, it's cheaper than any of mine.
I could have saved some money by using the existing rim, and the result would have been better (the Dahon rim is really too narrow for this application) but that would have meant more delay sourcing a 20h hub, and it was hard enough getting the hub with 28h in the right OLD as it was, although oldbiketrader reckons he has an inside line to Sturmey Archer so it might have been possible. As it is I have a spare SS wheel and unless I find someone else similarly unhinged I'm expecting to sell the original bike on and use the hub for something else (or sell it).
Installation was super-easy, the hub kit came with good instructions. Apparently the wheel build was hard. It would have been easier with 1x lacing, but I couldn't easily source the shorter spokes.
We went for a spin in the Park today and Little Miss Lumen (four next month) was faster than she's been on her CNOC 14.
Hub gears make loads of sense on small kids bikes. Apart from the cost. There are no derailleur clearance issues and the ability to change to any gear at a standstill is a bonus.
As for your requirement, my shortish almost-6 year old just fits a Beinn 20 and he loves it. I'd question the value in doing the same job for a 5 year old unless you have a smaller child lined up to inherit it.
Thanks Lumen, madness it may be but still great fun and an interesting project, if hard to justify in my case as you say. I've just received a Beinn 20 Large for my 6 year old and passed the Cnoc 16 down to 5 year old, but I tend to agree that its more sensible to buy him a Benin also when needed next year. My wife is not convinced our 5 year old with Evel Knievel tendencies needs to go any faster anyhow! Its a pity Islabikes don't do a hub geared 20" bike as I can see the gears on the Beinn having a hard life, its difficult to convince a 6 year old to treat them nicely.
BTW, I think you'll find you will fit on the Cnoc 16, I'm 6'1" and 88kg and I manage to ride one, not the most graceful sight I'll admit but possible none the less
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