the slightly crazy world of Sturmey Archer single toggle dog-locking 5s hubs.

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Brucey
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the slightly crazy world of Sturmey Archer single toggle dog-locking 5s hubs.

Postby Brucey » 24 Feb 2019, 11:22am

This post describes some operational features of the following models of hub; Sprinter 5s (1993-1998), Sprinter elite 5s (1993-1998), SRF5(W)/X-RD5(W) (2009-2016), all of which have sun pinions that are locked via 'dog locking'. Mention is also made of 'ball locking' 5s hubs as well as the S3X three-speed fixed gear hub.


Dog-locking 5s hubs use a single-sided sliding key in the axle to lock one of two sun pinions. These hubs are commonly found in Bromptons and Pashleys, amongst others. From about 1998 to 2008 5s SA hubs used 'ball locking' for the sun pinions instead of dog locking. These models were outwardly near-identical to the earlier sprinter 5s models and were variously called sprinter, sprinter elite, and Summit whilst made in Nottingham. Versions built in Taiwan were named X-RD5 and SRF5; they were retrospectively dubbed SRF5(N) and X-RD5(N) in order to distinguish them from the later (W) models. You can tell a ball-locking hub from a dog locking one by the shape of the LH end of the axle; ball locking hubs have a chamfer on the axle end, but dog-locking hubs have a square-ended axle instead.

Background:

SA filed patents for a 5s hub about ninety years ago. However the closest they came to making one prior to ~1965 was to be found in various four-speed hubs, including FC, FM, FW and FG models. Some four speed hubs were produced prior to WWII but they only started to be produced in serious quantities in the late 1940s. Like a five speed, four-speed hubs had two sun pinions, one of which was only used in a single gear, first gear. This was achieved by using a complicated control rod with lots of springs in it, which had a high preload so that they would only deflect during a 2-1 shift. This shift was quite baulky, had a false neutral in the middle of it, and required a high force on the trigger. It didn't take folk too long to work out that by implementing a separate LH control for the sun pinions, and carrying out some simple modifications, you could arrange to have a five-speed hub with an extra high gear ratio.

DIY conversions of this sort were being made as early as 1950. Arguably this conversion made the hub more reliable; the complex and delicate 4s control rod was gone, replaced with a simpler, more robust AW style system on the RH side. In the case of a converted FW/FG hub, even with no LH control fitted, gears 2,3,4 would be accessed using the RH control, just as in the 'bulletproof' AW three speed. The quirky sun-swapping shifts (2-1, 4-5) were not required on a regular basis, and with a little practice could be 'fed in' without too much trouble. I have happily used a converted FW for many tens of thousands of miles.

In 1965 SA launched the S5 hub, which was little more than an FW with two separate controls, the LH one being a pushrod, operated via a bellcrank. Surprisingly this remained the most sophisticated hub gear in production, until about 1990. In the late 1970s this was revised to the S5-1 model, with a pull chain on the left side. Unfortunately the springs were not the correct rating and sun slippage was almost inevitable with this hub. There were also problems with the new aluminium hubshells. S5-1 models were upgraded to S5-2 specification (using different springs) and finally the axle was revised in 1988 to a design that (like converted FW and S5 hubs) made it virtually impossible to engage both suns at once; prior to this final revision to S5-1 and S5-2 models in some cases the engaged sun pinion was only pushed out of engagement by a spring, whilst the newly engaged sun could be positively moved into engagement via the shift mechanism. If the spring failed to do its job for whatever reason, both suns could be enaged at the same time, which is incredibly destructive; far higher torque values than normal are easily generated this way.

S5-2 hubs were basically OK, but presumably because of S5-1 problems they were viewed with some suspicion by cyclists and the cycle trade alike. Latterly these hubs were supplied with a large plastic shifter -seemingly inspired by Lego 'Duplo' blocks- which had two cables coming out of it, so that it would be simpler to operate the hub. The shifter basically worked, looked (and felt in use) quite horrible, but it was a good enough scheme to be used by Sachs too (I don't know who copied who).

In 1991 the final twin-toggle SA 5s hub was produced; the 'five star' hub. This instantly developed an appalling reputation; the worst of this was caused by a faulty batch of sun pinions, which when they broke, had the unfortunate habit of causing parts of the internal mechanism to exit abruptly via the hubshell, where no hole should be. [If you imagine the 'chestburster scene' in the film 'Alien', played out with hub gears, this isn't far from the truth...]. Very occasionally you still see failures of this kind, where hubs slipped through the recall net. This hub had some other unfortunate design features, including cantilevered planet pinions. However few of these hubs did enough miles for these features to manifest faults as a consequence. The reliability problems did nothing except cement the bad reputation of SA 5s hubs in many people's eyes.

However it is worth noting that the 5-star hub did (for good or ill) introduce some new parts to SA designs; first use of a 'skinny' control rod in modern hubs (on the left side), and first widespread use of a new driver and sliding clutch type that forms the basis of the NIG three speed designs. In fact the 5-star hub had NIG operation in 2-3-4 shifts, but still had a false neutral in 2-1 and 5-4 shifts; a single key was used to lock the sun pinions and this was slightly narrower than the gap between the sun pinions, so that it ought to be impossible to engage both at once.

Single toggle 5s designs.

Faced with problems such as those found with the 5-star, in times past SA would have either carried on obstinately making an old design, perhaps gradually improving it, or would have given up on the whole idea. I expected them to do one or the other thing with the 5-star hub, but I was slightly baffled by the whole business tbh; I'd already done several tens of thousands on miles on a converted FW and I was struggling to see what real benefits there might be in any of the designs which had been intended to better this approach.

So imagine the surprise which greeted the 1993 'sprinter' 5s hub; a single cable design, but one which somehow managed to lock either sun pinion as required and therefore boasted five gears. The duplo twin-cable shifter was gone, replaced with a slightly less naff looking but equally plasticy affair. The sun pinions were locked with a sliding key and the simplicity of the S5/converted FW design (which has just two springs to control both clutches) was replaced with a cunning arrangement which required no less than five (!!) springs to make it work. Since I was happily using my converted FW hub I didn't take the plunge myself, but if that had broken, I might have.

Outwardly the 'sprinter' didn't look any more complicated than a 3s gear, and was almost as simple to use. However sceptical, hard-bitten folk with long memories drew sharp intakes of breath when they saw the internals and struggled to see how the thing worked at all, leave alone how it might be reliable in the process.

Dog locking sprinter coaster.jpg
dog locking sprinter 5s, coaster version


IRRC Chris Juden tested an early example of this hub and found that he couldn't reliably engage all five gears unless the hub was adjusted to a non-standard internal clearance (RH cone adjustment) setting.

The sprinter 5s had full NIG operation, which meant that there was no false neutral in the hub. However with a bi-directionally loaded sun pinion (ie the same gear train is used to increase as well as reduce) that uses simple locking, NIG operation requires that both sun pinions can be locked at the same time. Hopefully this is momentary, and the shift is soon completed, but such shifts are not especially smooth. I have never ridden one of these hubs which had a 'smooth' 2-1 shift, and this is the reason why.

In about 1997/1998 SA revised the design to allow 'ball locking' of sun pinions. This is a clever system (with smoother shifting) but ball-locking hubs turned out not to be especially reliable; it is beyond the scope of this article to delve too deeply into 'why?'. However it is often assumed that the ball-locking arrangement simply isn't strong enough. I think this is half-right; it certainly isn't strong enough to survive fault conditions which includes having two sun pinions locked at once! Unfortunately bad shifting technique and/or bad adjustment of the hub allows this condition to arise and the result is that the ball-locking mechanism fails. It fails at loads which are many times the normal service loads, but it isn't clear when the parts are examined that both suns were locked at the same time, or that one sun was partially locked; also, dog-locking hubs usually make horrible noises when things are going wrong and ball-locking hubs tend not to (not in the same way). [FWIW I have used a ball-locking 5s hub in a utility bike for about 10000 miles and it saw enough torque to challenge the NTW arrangements but the ball-locking mechanism was fine.]

So by 2009 SA had decided that they needed a wider range to their 5s hub (quite why I don't know; IGHs are mainly sold in flattish countries) and decided to have another go at dog locking of the sun pinions. The result was the (W) series of 5s hubs. The spacing of the middle gears is about the same as in an AW hub, so one advantage (slightly closer gear ratios) in the older 5s hub was lost. The (W) hubs use an axle that looks a lot like the first sprinter 5s axle, but with a beefed-up key. At about the same time the S3X (fixed gear 3s) hub was produced. [This is not a coincidence; the S3X internals are very similar to the (W) 5s internals, using gear ratios which correspond to gears 1,2,3 in the 5s hub. Sensibly this allows two low gears for climbing as well as an efficient direct gear for riding on flat roads.]

To get the wider gear range in the (W) hub required different planet pinions and SA took the opportunity to revise the planet cage design to a riveted 'Atlas' assembly which cannot be disassembled. The (W) hubs have markedly inferior quality bearings on the planet pinions. These may limit the service life of the Atlas assembly to about 20000 miles; the weaker planet pinion bearings (on the RH side) see high load in gears 1,2,4,5. Even with better lubricant inside the hub, wear is inevitable. Having said this, I have yet to see one badly worn out in this way; normally the hub has broken for another reason first. The (W) internal is a different length from the earlier hubs and it isn't possible to swap (W) internals for other single-toggle 5s ones.

Anyway the operation of the sliding key (dogs) in these hubs is more than a bit weird. The same (secondary) sun pinion is locked using the same part of the key, in gears 2,3,4. This is despite the fact that the key must move almost 8 mm in these shifts and there ought to be so much relative movement of the sun vs the key to make engagement impossible. The clever way this is addressed is to allow the sun pinions to move slightly. In gears 4 & 5 they are in a leftwards position but as soon as the main sliding clutch moves away from the planet cage (4-3 shift) the sun pinions can slide rightwards by about 2mm to a new position that is used in gears 3,2,1. This movement is enough to allow the secondary sun pinion to remain locked by the same dog in gears 2 and 4.

The key looks like this;

Image
HSA663 for (W) hubs NB the part is mounted in the hub with the key spring leftwards.

And is loaded thusly

Image01368.jpg
suns try to turn 'fowards' in high gears, 'backwards' in low gears

the visible spring is the shift control spring; the key spring is hidden inside the left side of the axle

the key is shown in the default (~ gear 5) position; arrows show the key loading -including the direction- in the various gears.

You can see that the RH key dog is only used in gear 5. The rest of the gears use the LH key dog, but it isn't always loaded in the same direction.

The chart below shows how the key is positioned relative to the sun pinions in the various gears. The lines are (scale size) 1mm apart.

Image01362.jpg
dogs ahoy!


There are eight rows;
1) gear 5 key alignment
2) sun pinion position for gears 4 and 5 (blue blocks)
3) gear 4 key alignment
4) gear 3 key alignment
5) sun pinion position for gears 3,2,1 (blue blocks)
6) gear 2 key alignment (RH part of the key not shown)
7) as row 5
8 ) gear 1 key alignment (RH part of the key not shown)

You can see several things;

a) all shifts require that the sliding keys are able to slide in the axle
b) shifts which require a change of sun locking (2-1, 5-4) potentially lock both suns momentarily during the shift
c) If the cable setting is the slightest bit too slack in gear 4, the gear 5 (RH) dog is going to interfere with the primary (RH) sun pinion
d) if the cable setting is the slightest bit too tight in gear 2, the gear 4-2-1 (LH) dog is going to both lose engagement with the secondary sun pinion (the engagement is at best ~2.5mm) as well as interfere with the primary sun pinion.

In fairness some of the above are mitigated by the fact that the key assembly is in two halves so that that the 4-2-1 part can deflect leftwards against (a very strong) spring and also the sun pinions can deflect in some cases too (which sometimes is good, sometimes bad). But there is basically no leeway in the hub; one full turn on the barrel adjuster is often enough to throw the adjustment out; this is the kind of thing that you expect with an Alfine 11 perhaps but not with something ostensibly less complicated. The most commonly found SL-S50 thumbshifter has almost enough (sticky) backlash that the hub won't work even when the shifter is new; it soon develops far more backlash than that. It is easy to shift 3-2 and to end up in a d) type problem, only gear 2 is lost because the sun pinion deflects leftwards. This makes a terrible racket and will soon damage the hub.

It is possible to rebuild the SL-S50 shifter so the backlash at least isn't sticky, but the backlash itself is problematic; you soon get into a situation where the shifter won't latch in first gear unless the cable is pulled really tightly; this is exactly the sort of thing that causes the cable to go out of adjustment.

I note with interest that the key used in an S3X hub is different; it has a smaller dog for the low gears, which presumably leads to fewer problems in the 3-2 and 2-1 shifts.

Image
HSA737 for S3X hub

I may yet try an S3X key in a (W) hub; even if there is then a false neutral this may be preferable to the usual mechanical commotion.

Other things that go wrong with (W) hubs are that the high gear drive pawls are only partly engaged in case d) which can lead to them getting broken when the gear slips, the actuator plate can fail (the same things happen with NIG three-speeds too BTW) and the screw that holds the key assembly together occasionally backs out, which is pretty disastrous.

So I have a (W) on my carrier bike and it works OK for the most part. But for the life of me I can't get it to shift smoothly and quickly 2-1, I don't think it is a terribly efficient hub, I don't expect it to last forever, and even the normally slick 4-3-2 shifts are not quite as smooth as they could be. I'd go as far as to say I have made the hub work only with some difficulty (eg re-engineering the shifter); lots of other people have, under similar conditions, either given up with the thing or have broken the hub so badly that it can't sensibly be fixed.

Spare parts for all single-toggle 5s hubs are now not widely available; they are no longer being made (unless you count the S3X) and whilst you can still buy complete internals I suspect that they will go NLA as stocks run low. Most in the cycle trade assume (not without good reason) that repairs may not be worthwhile because another breakage is never far away. I take the view that these hubs can be made to work OK provided they are controlled using carefully chosen shifters and are kept meticulously adjusted. But this is not for everyone; as a general rule it is a good idea to ask the question "if the hub goes out of adjustment, is it likely to break before anything is done about it?". With some hubs/users the sad conclusion is that the hub will nearly always get broken before it is attended to.

So what are the IGH alternatives? Not SRAM any more, which (at reasonable cost/availability) leaves you with a choice of another SA hub or a shimano one. Fortunately it seems that it is possible to engineer a set of SA 3s internals which will fit inside SA single-toggle 5s hubshells (and also SA 7s hubshells). In most cases this uses a non-standard combination of parts which are not usually found together. This isn't as good as having a fully functional 5s hub but it is cheaper than a new hub/wheel and the resultant internal is both less likely to give trouble as well as easier to sort out should it ever do so.
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Greystoke
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Re: the slightly crazy world of Sturmey Archer single toggle dog-locking 5s hubs.

Postby Greystoke » 25 Feb 2019, 6:50am

Thanks Brucey, my bus journey after my cycle commute flew by :D
So really the best 5 speed hub is the twin toggle early version?
I see them on ebay now & again, are spares available for these still?

Great stuff

Brucey
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Re: the slightly crazy world of Sturmey Archer single toggle dog-locking 5s hubs.

Postby Brucey » 25 Feb 2019, 8:30am

well there are many different SA 5s hubs including

- converted 'F' series hubs (of which FW and FG models are the strongest, and give the same gear ratios ( and 225% range) as all the following hubs in the list until 2009. NB: FM and FC hubs can also be converted to 5s but these hubs have their own problems anyway)
- S5
- S5-1
- S5-2
- S5-2 post 1988
- 5-star (twin toggle, NIG on the RH side, ~1991-1993)
- Sprinter 5 (NIG dog locking, single toggle ~1993 to ~1998)
- Sprinter 5 (NIG ball locking, single toggle, ~1997 to ~2009)
- (W) hubs (NIG dog locking, single toggle, 2009-2016, 256% range)
- C50 hubs (RX*-**5 models, NIG rotary shifting, pawl locking, 2016- current, 243% range)

Of these converted FW/FG and S5 hubs use a LH pushrod. S5-1 hubs need the internals upgrading to at least S5-2 specification and the S5-1 aluminium shell isn't strong enough (in a curious echo of problems which afflicted FM and FC hubs thirty years earlier....). S5-2 hubs work reasonably well and the post 1988 specification is an improvement. Any of these hubs can (points above addressed and when controlled with two separate triggers) be a reliable unit, and shifting in 2,3,4 is almost identical to the workings of a pre-NIG AW hub. Arguably having a LH pushrod is better than having a pull-chain, because the gears default to the most-used 2,3,4 gears if the LH control is disconnected. If you have a LH pull chain the LH control system needs to be working and the control pulled, else you end up gears 1,3,5 only. An advantage of these hubs is that if you have a problem with the 5s internal, a standard 3s AW internal can be substituted temporarily (or permanently). (However you can't always fit a 5s internal in a 3s AW hubshell; most 3s hubshells from ~1970 to ~2005 have a centre protrusion which fouls this type of 5s internal).

I wouldn't recommend a 5-star hub because every single one I have seen has been broken, and even now, a NOS hub could still be one that ought to have been recalled. Maybe there are some happy folk using them out there somewhere but I have yet to meet any.

Of the remainder it is too early to say if the C50 series is really robust or not (it ought to be, it is heavy enough...); the same thumbshifter internals are used as per the (W) hubs but the hub may tolerate the sticky backlash better than a (W) hub. I have owned and used both types of sprinter 5 and several (W) hubs; of these my favourite is the ball-locking sprinter 5. This can be made to work without the daft sun-shuffle in the dog locking hubs, and since shifting between 2,3,4 only moves a sliding rod in the middle of the hub a little bit (without swapping sun locking) in addition to the usual 3s style shift on the RHS, the hub is basically reliable provided the 2-1 and 5-4 shifts are executed properly. I wouldn't recommend a dog-locking 5s hub unless you are absolutely confident that you will keep it adjusted/lubricated properly and overcome the deficiencies in the shifters.

Note that only a few of the above hubs are intrinsically proof against engaging both suns at the same time; if there is a fault that permits this (which in some cases can be an adjustment fault) then the hub will definitely break, and it won't be clear exactly why this has happened.

Shimano avoid this problem by using a more complex arrangement, and only loading each sun pinion in one direction via a one-way pawl drive; if there are two suns engaged at the same time, one pawl will be overrun and there is no conflict. However there are as many planet gears in one Nexus 7s hub as there are in two SA 5s hubs, and the efficiency does suffer for it.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

Sid Aluminium
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Re: the slightly crazy world of Sturmey Archer single toggle dog-locking 5s hubs.

Postby Sid Aluminium » 26 Feb 2019, 8:00pm

Fascinating, you know, if you go in for that sort of thing.

For visual learners, Dan Burkhart has a video on the ball locking 5-speeds:

https://youtu.be/R_Z0H2U6ejs

and a new video overview & teardown of the C50:

https://youtu.be/Ew9v8soSC5c

Brucey
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Re: the slightly crazy world of Sturmey Archer single toggle dog-locking 5s hubs.

Postby Brucey » 26 Feb 2019, 10:46pm

ball-locking hubs are a fair bit simpler in operation; you can see what is going on quite easily, on a bare axle assembly. If you understand how a 3s hub works it is only a small leap to understanding how a ball-locking 5s hub works. The only thing that is not widely understood about ball locking hubs is why they break; IMHO this is almost invariably because the sun-locking mechanism can lock (or partially lock) two suns at once.

When one sun is locked the other sun (which is in constant mesh) rotates at about x1/5 the speed or something. If the second sun tries to lock it tries to stop everything from turning, but it sees about x5 the input torque. No hub is going to withstand this even if you only use a normal amount of pedalling force. Unfortunately to provide a NIG characteristic, both suns try to lock at the same time, mid shift; if you don't back off during some shifts it is possible for the secondary sun to stay locked until the primary sun is engaged; if the secondary sun doesn't pop out of engagement (there is only a feeble spring pushing the control rod rightwards) then both suns will be locked . They also try to lock at the same time if the shift control is badly adjusted. I don't think that this is quite as sensitive as the adjustment in a dog-locking hub, but it is sensitive enough that ball-locking hubs which are averagely treated almost invariably manifest wear in the sun pinions; this wear is created by the locking balls being partially thrust against the sun, i.e. it is caused by bad adjustment, not 'overload' per se. I think this wear can occur without making a lot of noise, in normal operation. In hubs which have not been run whilst badly shifted/maladjusted, no such wear occurs.


Ironically I created the above post about dog locking hubs specifically for 'those who learn visually'; AFAICT no-one has previously published any information about exactly how the parts in the dog-locking sun locking mechanism move during the shifts. Unlike a ball-locking hub you can't see what is happening (because the sun pinions are moving around as well as the dogs) and it takes a lot of careful measurement to be able to produced the 'dogs ahoy' diagram.

cheers
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Patrickpioneer
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Re: the slightly crazy world of Sturmey Archer single toggle dog-locking 5s hubs.

Postby Patrickpioneer » 27 Feb 2019, 5:47am

I live in fear of my 1998 sprinter going bang, Must get a spare one one day.
All interesting stuff Bruce, thanks
Pat

Brucey
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Re: the slightly crazy world of Sturmey Archer single toggle dog-locking 5s hubs.

Postby Brucey » 27 Feb 2019, 7:01am

1998 could be a dog-locking or ball-locking internal (is the LH end of the axle chamfered?) . Mind you if it hasn't broken yet it probably won't, not without provocation. There are (mostly small) parts which wear inside the hub and these may eventually need renewal. From my direct experience (even with improved lubrication etc ) a 5s sprinter hub ought to last between 20000 and 50000 miles before there are small parts which are going to wear out or break. [By contrast a converted FW ought to go at least double this distance without anything important wearing out; mine was stopped by axle breakage but only when it had done over 70000 miles.]

The good news is that even though spare parts for 'sprinter' 5s hubs will doubtless become more difficult to find as time goes on, and no standard 3s internal fits inside a 'sprinter' hubshell, my measurements indicate that it is possible to build a 3s internal (using a mixture of mostly standard SA parts that are not normally found together) which will fit inside a 'sprinter' 5s hubshell. This is potentially a get-out-of-jail-free card and makes a difference to the long-term viability of any bike which is fitted with such a hub. At the least having a 3s internal on hand means that it can be substituted whilst repairs are carried out to the original.

cheers
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Patrickpioneer
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Re: the slightly crazy world of Sturmey Archer single toggle dog-locking 5s hubs.

Postby Patrickpioneer » 27 Feb 2019, 3:26pm

Brucey wrote:1998 could be a dog-locking or ball-locking internal (is the LH end of the axle chamfered?) .


Hello, just been and had a look, its what i would call square cut, no chamfer at all. I have read on the 'A to B' web site that the newer 5 speed hubs (W) or at least one of them will fit in the older shell but at over a hundred quid a pop that's too much to have as a spare, I like the idea of the emergency 3 speed hub. I have found in the past that when I have spares nothing ever goes wrong but no spares and it will go bang! I will sort something out one day, the bike, my Brompton has a great deal of sentimental value to me as it was bought (used) for me by the person I care for as a gift to me for all I have done and still do.

see you around, take care
Pat

Brucey
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Re: the slightly crazy world of Sturmey Archer single toggle dog-locking 5s hubs.

Postby Brucey » 27 Feb 2019, 4:08pm

square cut LH axle end on a 5s at that date means you have a dog locking hub. The substitute internal that will fit as a replacement directly is the ball-locking 5s (~1997-2009). The later (W) internal is longer and won't fit in the original hubshell.

cheers
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Re: the slightly crazy world of Sturmey Archer single toggle dog-locking 5s hubs.

Postby zenitb » 9 Mar 2019, 2:03pm

V.useful article Brucey .. a good candidate for "too good to loose". I have a Sturmey Archer 5 speed hub which I got built into an alloy wheel for my GFs roadster bike back in the early 90s .. to replace the 3 speed steel rim wheel. I always wondered which SA 5 speed it was but it came with the monstrous plastic "lego brick" shifter you mention in your article so I am guessing its the S5-2, which seems to get a decent write-up from you.

(EDIT .. the "Lego Brick" shifter got its lever sheared off by my brother in law so I simply replaced it with two 3 speed shifters - which worked much better . the Lego Brick had to be critically adjusted to work properly .. this led to its demise)

The bike is long gone but I have just donated the hubs/wheels to someone rebuilding a Pashley Tourmaster tandem - I have pointed him at your article - and quoted your text. Hopefully the hub will survive light tandem use :-)

Incidentally the gear originally came with a steel hubshell but my local bikeshop (Fields in Fleet, Hampshire - RIP) offered me an alloy hubshell so I had the hub built into a wheel using that. So far the alloy hubshell has lasted well.. and it certainly looks nice :-)

Brucey
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Re: the slightly crazy world of Sturmey Archer single toggle dog-locking 5s hubs.

Postby Brucey » 9 Mar 2019, 3:59pm

the 'lego brick' shifters (with two cables coming out of them) were used with S5-2 and 5-star hubs, both of which were twin-toggle hubs.

This is the (slightly) more elegant version:

Image

see the picture below for the full Duplo-fest;

Image
chamber of plastic horrors; the two shifters centre bottom (with the red centres) are for single-toggle 5s hubs; the others are for twin-toggle hubs

Operating any twin toggle 5s hub with two 3s triggers is very much the best way IMHO. I think there isn't a really good off-the shelf shifter option for any of the single toggle 5s hubs.

cheers
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Rob_J
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Re: the slightly crazy world of Sturmey Archer single toggle dog-locking 5s hubs.

Postby Rob_J » 22 Mar 2019, 3:13pm

Thank you for the excellent posts, Brucey. I have been using an SRF5(W) for a couple of years when it suddenly lost gears 4 and 5. This happens after braking heavily at a T-junction to allow a motorist to clear the junction. The motorist politely stopped and beckoned me on, resulting in me applying a lot of force (in a high gear?) to get going again.

Yesterday I disassembled the hub - the first time that I had disassembled any Sturmey Archer hub. I carefully inspected the pawls as best I could without removing the grease (not having any suitable replacement grease to hand) but couldn't see any damage. However, I noticed that if I rotated the ball ring by hand (with the internals removed from the shell) the pawls inside would slip, rather than engaging on the ball ring. I suppose that this is an indication that they are damaged.

I have the HSJ959 SLS50 (T-type) shifter, which I have had great difficulty keeping properly adjusted. As you suggest, this has probably been the root cause of the failure of the hub gear. If I can get the gears fixed (perhaps by replacing those pawls) I will try the trigger shifter (HSJ958 DLS52), in case that works better. However, having read your description of the dog-locking arrangement, I am tempted to ditch this hub completely. I may try one of the new rotaty-shifting hubs (e.g. RX-RF5), but I'm not looking forward to either the financial outlay or trying to pick the bike up with the extra weight!

Rob

Brucey
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Re: the slightly crazy world of Sturmey Archer single toggle dog-locking 5s hubs.

Postby Brucey » 22 Mar 2019, 3:38pm

Rob_J wrote:Thank you for the excellent posts, Brucey. I have been using an SRF5(W) for a couple of years when it suddenly lost gears 4 and 5.


If the high gear drive pawls are damaged, then gear 3 ought to be lost as well. Loss of gear 4/5 only is more suggestive that the sliding clutch isn't engaging correctly with the planet cage, or perhaps that the sun locking keys are not moving as they should.

Turning the ring gear backwards in gear 4/5 is not a good test; it simply causes the actuator plate to do its job; it is meant not to provide a solid drive backwards in those gears because if it did, something inside the hub would break.

FWIW since I posted the above I have briefly examined the trigger shifter that goes with the 5s (W) hub, and I think it probably doesn't have the enlarged quadrant in it that the 7s shifter has, so I provisionally give it a thumbs up.

If you don't really need five gears, it is possible to install a three speed internal (often it has to be built/checked for exact length) in most 5s hubshells.

cheers
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eclipse
Posts: 24
Joined: 1 Jan 2010, 2:08pm
Location: Darlington

Re: the slightly crazy world of Sturmey Archer single toggle dog-locking 5s hubs.

Postby eclipse » 24 Mar 2019, 7:45am

Interesting stuff....
One of my favourite bikes was a (very) old, black (naturally!) Raleigh gents roadster with sprung saddle , little home made aluminium box on the rack, and S.A. 4 speed gearing. I paid a fiver for it in the eighties, paid to the local council amenity dump , (where a lot of useful stuff could be had for pennies...... if only they were still like that now).. I used and abused that bike for years before giving it away, and despite my general thoughtless treatment, it never let me down once...needless to say, I wish I'd kept it, as for pure rugged functionality it was unbeatable.
...I digress..the 4sp gears worked great ☺

Brucey
Posts: 35954
Joined: 4 Jan 2012, 6:25pm

Re: the slightly crazy world of Sturmey Archer single toggle dog-locking 5s hubs.

Postby Brucey » 24 Mar 2019, 9:51am

an old 4s Raleigh roadster would have been fitted with a FW or FG hub. In these hubs gears 2,3,4 work just like 1,2,3 in a 3s hub, and are likely to be just as reliable.

The only shift where anything unusual happens in those hubs is 2-1, in which a different sun pinion is locked. That shift is not as slick or as reliable as the other shifts, but then it (and the 3-4 shift) isn't saddled with the somewhat questionable mantra that 'thou shalt not have a neutral', so it is infinitely better than similar shifts in more modern hubs.

Neutrals in hub gears are only a problem if

1) the hub is fitted with a back pedal brake, and it perhaps doesn't work when the gear is in neutral
2) the gear is in neutral when you want to pedal forwards.


IME no one brake is truly reliable enough to safely allow bicycles to have just the one brake. However this sentiment is not shared by inhabitants of all countries and some were daft enough to construct, sell, buy/use bikes with just one brake, a coaster brake, that wouldn't work at all should the gears be out of adjustment... :roll: For these people's stupidity, the rest of use are now saddled with gears that are NIG in operation, whether we like it or not.
Not getting forwards drive is not only embarrassing but potentially dangerous too. In the old AW hub, it was effectively NIG type between gears 1 and 2. This meant that even if the hub was badly out of adjustment, you would get some kind of forwards motion if first gear was selected. Cunningly (or perhaps accidentally) if the gear cable went slacker than normal, the gear would tend to slip in second gear (in a way that wouldn't be likely to break the hub) before you would get second gear instead of first when first was selected. This means that high gear drive pawls in old AW hubs are unlikely to be smashed up by partial engagement of gear 2 when gear 1 is selected. In other words the neutral between 2 and 3 is a 'safety valve' that alerts the user to a problem that ought to be fixed before the hub is likely to be damaged.

In any NIG hub there is no such 'safety valve' and if the hub gets out of adjustment, there are soon ominous crunching sounds to be heard. Some folk will ignore these sounds and carry on regardless; the result is invariably a broken hub....

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~