Thirty Years with a Sturmey Gear.

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Brucey
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Joined: 4 Jan 2012, 6:25pm

Thirty Years with a Sturmey Gear.

Postby Brucey » 15 Aug 2012, 5:40pm

Thirty Years with a Sturmey Gear; or 'how many gears do I need anyway?'

In my youth I owned several (mostly terrible) bikes which had a Sturmey Archer three speed gear in them. Albeit heavy, the gear was largely trouble free and resisted the ingress of dirt and water far better than anything else on said bikes.

Later I got a 'proper racing bike' but this wasn't suitable for everyday riding and keeping it in fresh freewheels and chains was getting pricey; more so when I started doing lots of miles for training.

Around this time I realised that maybe the three speed might be a good idea again, for certain types of training, anyway. Better than a fixed gear, especially in the hills. The three speed worked out OK but I quickly noticed that more gears might be a good idea... why not a four speed then? A little dabbling inside an FG hub showed me that the shifting mechanism for the sun pinions and the control rod (already then NLA as a spare part) were potential weak spots. I thought about a five speed hub, but -although they were then the most sophisticated hub gear available- these were both very expensive and had a poor reputation for reliability.

One day I bumped into a chap who had successfully converted a four speed to a five speed; I had previously realised that this must be possible, but had not appreciated that there were good solutions to the main problems.

1) the sun pinion; the FG/FW 'high gear' sun pinion has chamfers on one side of the dogs so that it disengages (or slips) when turned in the correct direction for the 'missing' (on a four speed) high 5th gear. The solution was to modify the original sun pinion or to purchase the equivalent five speed part which has square dogs. I used part number HSA345 but there is another SA part which will do the same job in most hubs.

2) the control rods and toggle keys. On the right side, an AW toggle key and control/rod can be used and this controls gears 2,3,4 in much the same way as an AW hub. On the left side a new toggle key can be made (e.g. from a modified pawl pivot pin) and this is controlled using a second (left side) lever/cable and a pushrod. Pushing the rod in on the left side shifts 2-1 or 4-5. Original SA five speed hubs (Circa 1965) worked like this with a second gear lever and a bellcrank on the left. [Some later SA five speed hubs for a while had different springs inside on the sun pinions and this was meant to allow a conventional pull chain for the left side gear control. Due to poorly chosen springs, these hubs were an unmitigated disaster, and may not be reliable even when fitted with a revised kit of parts. Many long-term users of such hubs have converted to a left-side pushrod in search of proper reliability.] Sneakily, if the LH control chain is routed behind (say) a dropout cutout, onto the end of a specially made 'L' shaped pushrod, no bellcrank or revised sun pinion springing is necessary; a 'pull' on the chain creates a 'push' on the pushrod.

I robbed a Moulton Mk1 of its FW hub internals, and used the longer axle from an FG hub plus the modified parts as above to create a set of innards which would fit in an AW shell and thence into a 120-126mm OLN frameset. I rebuilt the wheel with double spoke washers and DT DB stainless spokes, and proceeded to abuse the heck out of it for several decades. In the meantime I've owned and used MTBs, touring bikes, racing bikes etc etc; all this time the hub gear bike has done the brunt of the dirty donkey work on a diet of minimal maintenance.

It is now over thirty years later; how did it work out?

-No spoke breakages
-Hub has variously been run with; two SA triggers, Campagnolo friction DT levers, and latterly with modified under-stem-mounted thumbshifters, friction on the left, indexed on the right. All schemes worked reasonably well, obviously indexing is more convenient.
-Hub has not broken in use, ever (*).
[edit; (*) that was true in 2012 but as of july 2017, it isn't true any more. The axle, which was old before I used it for ~35 years (and now well over 50000 miles plus whatever it had in its previous life), finally broke. The bike was soon repaired using a stash of parts that I had squirreled away. Despite everything, the other parts of the gear were still in GWO.]
-Only 'in use' incidents are due to indexing going out of adjustment, or massive water ingress into hub (rumbly bearings).
- replacement internal parts used to date are; 1 packet of ball bearings (for the clutch driver ball ring), two pawl hairsprings. In both cases corrosion had necessitated precautionary replacement.
-Due to ill health on my part and another problem with the bike I effectively left it parked outside in a damp hedge for 18 months at one point; this is when the worst of the water got inside it.
-Total mileage is conservatively estimated to be 30-40000 miles, in all weathers, quite a lot of bridleway work as well. Mostly the chain just gets fresh oil, no real cleaning.
-It has gone through about ten chains, half a dozen sprockets, about a dozen sets of tyres. The frame that the hub spent most time in has had to have three or four paint jobs in the meantime.
-The chains last about half as long again as I would happily run a derailleur chain/block. I reckon I would have replaced the chain and freewheel about fifteen or twenty times in that use, even if I'd have done more maintenance.
-I have found that with a few tools (two spanners, a hammer (or rock) and a punch) the whole gear can be stripped down inside 15 minutes if necessary.
-I'm still using it; I've done about 500-600 miles in the last month and a half alone. I generally go out with a saddlebag containing a few odds and ends, and might ride for four or five hours, taking in bridleways and so forth as the mood takes me.

What is it like to use then?

Well most of the time it is like a closer ratio three speed gear with 1 and 5 for emergencies. 4-3, 3-2 shifts are simple; as soon as the lever is moved, the gear is definitely in. Shift 2-3 can be performed under a fair load; too much load and it won't go, but damage is very unlikely. Shift 3-4 requires no-pressure, some pedal movement (in either direction) to be sure that the gear is in. Shifts 2-1 and 4-5 require the left lever to be pulled whilst pedalling forwards ; you feel the gear go in, the lever moves to the end of its travel, and then you can apply as much pedal pressure as you like. Shifts 1-2 and 5-4 are a bit like 3-4; you have to move the pedals and wait for the hub to do its stuff. All this sounds more complicated when written down than it is in practice. Similar techniques in fact apply to all known SA five speed hubs (albeit with slight revision to allow for single lever operation). Even though later versions use different internals, the required shifting technique is similar. It should be clear from my experience that if the correct technique is used, this version of the SA-5 is actually very durable and reliable. [As soon as I realised that the later versions need a similar shifting technique, I stopped making foul crunching sounds when riding my Pashley town bike, too.].

The gear is mostly very quiet; the overrun low gear pawls make a tick-tick-tick sound in the high gears but are much quieter in gear #3 for some reason; barely audible at present. In the low gears you can just about hear some gear noise, but not much. It is on average much quieter than any derailleur geared bike I have used.

What about efficiency?
In the HPVA archives there is a test of various transmission efficiencies. Deraillaur gears, hub gears (including a Rohloff) were tested. Just for fun, they also tested some old three-speed gears. The old three-speed gears showed about the best average transmission efficiency as well as about the highest single gear efficiency. From this I take it that the reputedly 'inefficient' hub gears have perhaps been unfairly slighted. On the five speed, in gear three the hub is subject to little or no losses of any kind as it is direct drive (say 98% then). In flat and rolling terrain most riding is in gear three with my set-up and most of the rest is in gears 2 and 4. If we assume that kind of duty cycle and (say) five percent additional losses in 2,4 and ten percent losses in 1,5 then the average efficiency is still 96 or 97 point-something percent. I reckon this knocks spots off anything else for my use and probably for many other people's use too.

If the gearing is set for loaded riding than again gear three might be most used and a similar average efficency obtained. Only riding loaded in extremely hilly terrain would nudge the average well below 95%.

If my estimates of efficiency are hopelessly wrong and it is actually (say) twice as inefficient in the other gears, then again the average efficiency won't drop below 90% for most usage patterns and even in extreme conditions is unlikely to drop below about 85%.

what about gear range and gaps?

With five gears there will likely be big gaps and/or a compromised total range. Arguably the five speed has elements of both. I run 46x18 on 700c tyres. If you wanted to compare the gears you get with a derailleur set-up then (give or take the odd 0.2 of a tooth) it would be like having a 12,14,16,18, 21, 23, 27 T block, which sounds quite sensible until you realise that some cheeky get has pinched the 16 and 21T sprockets. This is surely a mad set-up...? Well yes it is a culture shock and it requires that you are able to pedal at a slightly wider range of speeds or accept that you are not going to be going optimally fast all the time. The low gear isn't really low enough with a 'gear three normal' set-up like mine, so honking or walking are on the cards for some riders on very steep gradients. For moderately loaded riding a 40 x 22 gear is perhaps a better choice; this gives ~62" in 4th for tapping along and a ~32" bottom gear.

What effect do the gear gaps have then?

Well it depends on the rider. Everyone has a range of cadence and effort that they are happy with. If this isn't enough to straddle the gaps in the gear range then there is a problem; most likely you will have to use a lower gear than you might otherwise for a while. Thus 20% gearing gaps are dealt with OK if cadence and effort can vary +/- 10%. But if the gear gap is 25% then maybe the speed will be up to 5% less than optimum, for about 20% of the time. Supposing you are a fussy pedaller and are only happy +/- 7.5% on cadence/effort, this leaves up to a 10% speed reduction which will come into play about 40% of the time. In the latter case the net effect is that your average speed may be reduced by 2% and in the former case it will be reduced by just 0.5%. This is a much smaller effect than I expected. In fact it is probably not as bad as that even, because if you ride at a lower effort in a lower gear for a while, you are having a bit of a rest, and may be able to work a bit harder than normal later on.

I think that the ability to pedal smoothly over a wider range of speeds is worth cultivating; it is in good part why riding a fixed gear is such good training, and I think it may make you a better cyclist when all is said and done.

What of the future?

I am experimenting with a contact seal near the clutch driver ball ring to help stop the water from getting in. I am also experimenting with the use of a thixotropic semi-fluid grease instead of gear oil. The seal should help the grease stay inside the hub as well as keep the water out, and this may allow a higher fill of grease (I'm aiming for about 1/3 full) and longer intervals between lubricant replenishment.

A recent stripdown (one of only three or four in as many decades) showed that there isn't much wear on any of the gear parts but there is some pitting from (self-inflicted) corrosion. I lightly reground the corroded clutch driver ball race and later fitted new balls in the ball ring. The new balls made a bigger reduction to the rumbling than the regrind. I may yet replace the threaded ball-ring race as this is somewhat pitted from corrosion and I don't fancy regrinding it.

Overall

I have been very happy with my SA5 speed gear; although I am sure that many others will say that they couldn't ever do this, I found that -for the use I have put it to- I can live with its shortcomings and I certainly have come to appreciate its strengths.

The potential drawbacks of such a hub gear (gear range, gear spacing, efficiency etc) in reality mostly have much smaller consequences than you might think likely. The benefits are that you get to spend much more time riding your bike and much less time faffing about cleaning or replacing transmission parts. The chains I use presently cost £2.40 each and I expect to get 3000-5000 miles out of them. The gear itself should last decades with just a little care.

I went on a (for me) fairly typical ride a couple of days ago; 15 or more miles on bridleways variously bumpy, rutted and muddy, followed by about 25 miles on tarmac to get home again, the last 20 of which were knocked off at evens or better courtesy of a tailwind. I can't think of another bike/gearing setup (except perhaps another hub gear) that would do that job as well with so little collateral damage/maintenance required.

I hope this write-up is of interest to others, I can post pictures if anyone is interested.

{edit- pictures of the tatty bike added}
DSCF2341v3.jpg
'bout 130 miles in the last four days, maybe 40 of which on bridleways and byways...

DSCF2340v3.jpg
frame is a Claud Butler (circa 1968), 531 main tubes and forks, pencil stays. Braze-ons (inc. canti bosses) are mostly Brucey-add ons. Bike weighs about 28lbs or so without the saddlebag.

DSCF2342v3.jpg
partial black paint is recent and is to test for a reaction with the (many) underlying layers prior to the (long overdue) next respray. I am thinking of Black with white panels. Not that there is much danger of it I suppose but I am wary of it looking too nice in case someone (mad) takes a fancy to it.


cheers
Last edited by Brucey on 7 Jul 2017, 8:48pm, edited 2 times in total.
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breakwellmz
Posts: 1982
Joined: 8 May 2012, 9:33pm

Re: Thirty Years with a Sturmey Gear.

Postby breakwellmz » 15 Aug 2012, 11:54pm

Hi.

Excellent,really enjoyed that.

Cheers

Russcoles
Posts: 342
Joined: 6 Nov 2010, 8:09pm
Location: Bristol, UK

Re: Thirty Years with a Sturmey Gear.

Postby Russcoles » 16 Aug 2012, 2:25am

I use a modern 5 speed on my favourite bike. It did okay on a ride from John O Groats to Bristol covering 900 miles. I took a spare rear sprocket with me, it doesn't take very long to change the ratios when you are moving between hilly and flat areas.

Ayesha
Posts: 4192
Joined: 30 Jan 2010, 9:54am

Re: Thirty Years with a Sturmey Gear.

Postby Ayesha » 16 Aug 2012, 7:37am

I have a SA AW3 on a 1974 BSA Twenty. No trouble whatsoever.
I've Audaxed it but I wouldn't timetrial it.

20" wheel. 46 ring and 20 sprocket. 36, 48 and 64" gears.

resus1uk
Posts: 243
Joined: 12 Mar 2007, 9:28am

Re: Thirty Years with a Sturmey Gear.

Postby resus1uk » 16 Aug 2012, 8:16am

My old (1980) pashley picador trike corroded to bits. I saved the AW3 hub which had a double sprocket as part of the rear drive chain system. Just a good clean-up, standard sprocket fitted & it goes on into a wheel for another project. Hub gears may be heavy but have their uses for utility riding.

GavinC
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Joined: 9 Mar 2009, 10:38pm

Re: Thirty Years with a Sturmey Gear.

Postby GavinC » 16 Aug 2012, 8:36am

Excellent write up Brucey.

I've had a two cable S5 on my F-frame Moulton for a year without a hiccup. Hopefully there are another 29 troublefree years to come :) Before that, the Moulton was fitted with an FW 4 speed. I've also got an 4 speed FG on another bike.

I really like the spacing between the ratios on the Sturmey FW/FG and old five speeds. Although the gaps are fairly wide, I always seem to be able to find a gear near enough to what I need, unlike the AW on which the gaps between gears are just that bit to widely spaced fro me to ride comfortably.

I've set my S5 up so the ratios are 34", 40", 50", 64", 75". The top two gears are great for bowling along, with three lower gears for any more challenging terrain; for downhills I just freewheel 8)

Gavin

cycle tramp
Posts: 487
Joined: 5 Aug 2009, 7:22pm

Re: Thirty Years with a Sturmey Gear.

Postby cycle tramp » 16 Aug 2012, 9:36am

blimey... i have to admit to being just slightly jealous, of your bike, your mechanical skills and your mileage...
And more proof, if one were to need it, that simply having lots of gears does not increase your annual mileage :)

(sometimes i like to write the words 'labyrinth seals' on post cards and send them to other hub gear manufacturers).
http://www.sandsmachine.com/a_syc_r1.htm

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simonineaston
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Joined: 9 May 2007, 1:06pm
Location: Bristol - work in... Yate!

Re: Thirty Years with a Sturmey Gear.

Postby simonineaston » 16 Aug 2012, 9:46am

Great Fun - Thanks for taking the trouble to write this :-) Wot a Great Advert for "tin-cans".
ttfn, Simon in Easton
(currently enjoying a Moulton TSR & a nano Brompton...)

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hubgearfreak
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Re: Thirty Years with a Sturmey Gear.

Postby hubgearfreak » 16 Aug 2012, 4:15pm

Brucey wrote:Everyone has a range of cadence and effort that they are happy with.


i wonder if there's a difference between what a particular rider would have been happy with had he not been seduced by marketing.

also, i'd like to add that aesthetics matter, as well as not having vulnerable parts hanging down in the weeds/anti-motorbike barriers.

thanks for the eloquent report. :D

ambodach
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Re: Thirty Years with a Sturmey Gear.

Postby ambodach » 16 Aug 2012, 7:55pm

It will be interesting to find how you get on with the grease for lubrication. My problem is that my 3 speed SA on the Kingpin leaks oil when at rest. Mebbe I use too much oil which I will admit is a failing of mine but grease would seem to be an answer.

Brucey
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Joined: 4 Jan 2012, 6:25pm

Re: Thirty Years with a Sturmey Gear.

Postby Brucey » 16 Aug 2012, 8:34pm

cycle tramp wrote:blimey... i have to admit to being just slightly jealous, of your bike, your mechanical skills and your mileage...
And more proof, if one were to need it, that simply having lots of gears does not increase your annual mileage :)


don't be jealous of the bike; it looks like a tatty heap, 'cause it is, mostly. It is due a respray (yet again). On paper it could be nice again; it has a handbuilt frame and mostly parts that were quite nice when they were new... but that is a long time ago. I've settled for it just working mostly...

Don't be too jealous of my mechanical skills either; -learned the hard way i.e. by breaking stuff, mostly. I built this hub/wheel when I was still a teenager, and I guess I just got lucky, or somehow managed to do it right anyway.

The mileage this bike has done is probably about a third or maybe half of all the miles I've done in that time. For quite a few years the SA5 was used for 'training' in the wintertime and this meant 100-200 miles a week for about half the year, plus commuting and other duties as needed. I've also used this bike for touring day rides and weekend rides with a saddlebag but not longer/heavier laden tours than that; I've got a 'proper touring bike' for that task.

In the USA and other places it is presently quite chic and trendy amongst certain cyclists to have a 50s/60s inspired French-style randonneur machine, complete with dinky front rack and weeny bar bag etc. (Presumably the bar bag is for random acts of mobile gastronomy...) Hence all the interest in nouvelle-retro stuff like Rene Herse cranks and so forth. This is all well and good but I think it is about time we better appreciated our homegrown stuff which originated in the same era; handbuilt frames, SA gears, Brooks saddles, Williams chainsets, GB stems and bars, Carradice saddlebags and so forth. Although a lot of modern equipment is splendid stuff, a good deal of the equipment that made sense to keen cyclists in our damp and bumpy isle fifty years ago still works pretty well today.

It was a slight surprise to me to realise that my hub geared bike, (by simple dint of having anything that didn't work right or broke removed and replaced with something that did, and would carry on working...) has ended up with mostly 'vintage' components on it, even though this was not a conscious effort on my part.

weird huh?

cheers
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mig
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Re: Thirty Years with a Sturmey Gear.

Postby mig » 16 Aug 2012, 8:53pm

very interesting and enjoyable.

there's something that i just like about using something lots over time on the one hand whilst maintaining and/or adapting it at the same time on the other. somehow far more satisfying than buying 'a new one.'

Brucey
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Joined: 4 Jan 2012, 6:25pm

Re: Thirty Years with a Sturmey Gear.

Postby Brucey » 16 Aug 2012, 8:55pm

ambodach wrote:It will be interesting to find how you get on with the grease for lubrication. My problem is that my 3 speed SA on the Kingpin leaks oil when at rest. Mebbe I use too much oil which I will admit is a failing of mine but grease would seem to be an answer.


A typical SA hub will hold about a teaspoon or two of oil without leaking if it is stored with the bike upright and it doesn't leak out of the ball ring threads. You can seal the ballring threads with PTFE tape during assembly. The end (hub) bearings are best greased I reckon.

The grease I am trialling is a semi-fluid thixotropic grease. It needs to be semi-fluid (rather than thicker grease) because otherwise the weaker pawl springs in older SA hubs won't push the grease out of the way and the gear might slip. The thixotropic nature means that the grease has the same kind of consistency as tomato ketchup; i.e. it won't necessarily move under its own weight, but once it starts to move (i.e. by shearing) it will carry on rather easily, i.e. it becomes inviscid. With the hub about 1/3 full there is very slight leakage if the bike is left on its side for a couple of hours. When I saw this I thought I had it licked, especially as the grease didn't at first come out of the hub in use, either. It turned out that the ball ring still had my assembly grease in it. Once that mixed with the rest of the grease the lubricant began to come out of the hub at the ball ring, particularly in the higher gears. It made quite a mess; there was about x10 the amount of lube in the hub as normal and about half of it came out....

Of course whenever the clutch driver is turning in the ball ring (all the time in use except when pedalling in the middle gear) the grease in the ball ring is being sheared and is therefore inviscid (runny) and will be prone to come out... hence my experiments with a contact seal at the clutch driver ball race. I've done over 500 miles with the prototype seal in so far and leakage is fairly well restrained to date. I will post further as things develop.

cheers
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breakwellmz
Posts: 1982
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Re: Thirty Years with a Sturmey Gear.

Postby breakwellmz » 16 Aug 2012, 10:24pm

Is there a photo of your bike on here somewhere Brucey?

Brucey
Posts: 32690
Joined: 4 Jan 2012, 6:25pm

Re: Thirty Years with a Sturmey Gear.

Postby Brucey » 16 Aug 2012, 10:26pm

breakwellmz wrote:Is there a photo of your bike on here somewhere Brucey?


not this one, not yet. I'll get on the case.

cheers
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