Sturmey Archer 5 speed adjustment?

[nye terry]

Hi,
I have been working on a Mission trike for a disabled friend. Mission have been great in supplying parts quickly and efficiently, however it is fitted with a Sturmey Archer 5 speed hub. It is an alloy shell, but because it's on a trike it is a remote unit, driving through a link chain to the axle. Misson aren't sure what model the hub is as the trike is not that new, the only writing I can make out on the shell is 'Sturmey Archer', anything else is rubbed off. It has a twist grip shifter and the indicator rod has a blue band around it. I have tried various adjusting methods according to advice I've been given but seem to get no discernable diffence in gear ratios, (but no slipping) It has a window type wheel nut on there on the rod side.
So far I have tried:
Adjusting cable tension so it is taught when in first gear on the shifter, that resutling in full movment on the shifter but no changes in gears.
Adjusting it so the blue line is level with the end of the axle in 2nd, and in 3rd, the tension was too much and I couldn't get the shifter to move through all gears.
I suspect there maybe an internal problem, howver I would have thought it would have just spun in some gears if that was the case?
Also unless I am sure of the diffinative method of adjustment I can't then decide if there is something wrong inside. Or is it the wrong indicator? again if I don't know what hub it is how can I tell?

Any ideas anyone?

Thanks in advance. Terry

[WOOLIFERKINS]

http://www.sturmey-archer.com/userfiles ... 5-Tech.pdf

Any help?

[Brucey]

you may have the wrong indicator rod fitted. The band colour indicates the length of axle to which it fits. If you have the wrong length rod it doesn't stop you from adjusting the gear correctly and using the hub OK, but it will make it confusing because the index mark will be in the wrong place.

There are a few things to understand about SA single-cable 5s hubs;

1) not all the shifts will go when the hub is stationary.

2) for each shift to go in, pedalling forwards about two turns (without significant pressure) is the only sure-fire technique. Backpedalling, freewheeling etc don't work.

3) If the wrong shifting technique is used when riding the bike, the hub can be damaged.

There are at least two different flavours of shifter and hub. Some hubs look identical externally and are only marked differently on the outside, using marks that rub off.

The plastic shifters (e.g. 'Nimbus' model; I think 'Orion' is similar but am not 100% sure) pull about 23.5mm of cable (total) and are designed to work with the 'sprinter' hub models with ball-locking sun pinions. These hubs have control rods which move ~22mm (total).

The nice later model alloy thumbshifters and other levers are designed to work with the (W) suffix models and these pull about 20mm of cable (total). The control rods in the (W) hubs move ~20-21mm (total).

I think that a later shifter will work an earlier hub OK if it is in perfect order, but once the hub is a little worn, this combination may result in bad shifts. I am trying to establish exactly what is and isn't possible at present.

In any event, in first gear the adjustment should be within 1mm of the hard stop where you can't pull the control rod any further out of the hub.

If your hub just doesn't ever change gear regardless of where the control rod is in a ~20-22mm stroke, there is an internal fault of some kind, and repair is necessary. Remember that the gear range isn't that wide on older hubs; bottom gear is x0.667 and top is x1.5; put marks (e.g. tipp-ex) on the input and output and see how they move when pedalling forwards.

My understanding is that all single-cable 5s SA hubs are NIG type, i.e. there are no false neutrals in the range.

cheers

[nye terry]

Thank you Brucey and Wooliferkins, I will carefully go through the suggestions and check it all out.
3 speeds were so much easier

[Brucey]

shifts 2-4 in a 5s are just like shifts 1-3 in a 3s hub, actually.

So it isn't all bad.

cheers

[nye terry]

So am I right in saying if you can't back pedal or freewheel to change, and you you should pedal forward, are you not able to change gear when stationary then?
Slightily confused

[Brucey]

it is a fair question. In some cases a stationary downshift gear change will only be completed once the hub is turned forwards.

On a modern 5s hub the 4-3 downshift and the 3-2 downshift are basically 'safe' when stationary. The 4-3 shift will go instantly (provided there is no load on the pedals) but the 3-2 shift may sometimes be delayed. Unlike many earlier SA hubs the clutch has a shift spring on it; this means you can move the shifter but the clutch may not move, even on a downshift. With practice you will normally feel the difference between the clutch moving (shift is almost complete) and the shift spring loading up, because the latter needs slightly more force to move the shifter. On a well-used and well-lubricated hub with no forward drive load on it, the 3-2 shift goes in nine times out of ten when stationary. The tenth time the shift only completes when you start to pedal forwards and the result is an unpleasant noise, if you are pedalling firmly as you might when starting off. I have yet to verify exactly what causes the noise and if there is any significant risk of damage arising.

By contrast with an older (non NIG) 5s hub there is no shift spring on the 4-3 or 3-2 downshift and if you move the lever, the gear is in. (the same applies to 3-2 and 2-1 downshifts on older AW hubs, too.) However with any upshift on any hub it is obvious that the shift can be delayed after you move the shifter because the mechanism is spring loaded.

With any SA 5s hub, the 5-4, 4-5, 1-2 and 2-1 shifts will not be complete when stationary more than (maybe) one time in twenty. In the other 19 from 20 instances these shifts won't be complete until you have pedalled forwards a couple of pedal revolutions at road speed, preferably without any significant load on the pedals.

So when using a 5s hub in town, using gear 2 to start off in and then shifting to gear 3 (which is safe under modest load on all SA 5s hubs) is probably the best way.

cheers

[nye terry]

Cheers again Brucey,
my friend would benefit from hub he can change at times he gets stuck, such as driveways or crossing roads. (up and over the crown of the road) so having discussed this with a collegue with some very useful engineering tools and the trike user it is felt he would be better using a 3 speed hub,so he can shift into an easier gear when he gets stuck. Because his travelling speed is low it isn't a complete range of gears he needs, indeed when on his Try 1 Pashley 7 speed then 2 or three gear changes is all he uses.
Thank you.
Best wishes
Terry

[Brucey]

in fairness the 3-2 shift on a 5s hub isn't much different to the 2-1 shift on a 3s hub, so if gear 2 is low enough -and it is almost as low as gear 1 on a 3s if direct drive (gear 2 on the 3s and gear 3 on the 5s) is set the same- then maybe the 5s hub would be OK.

Remember that on a 5s hub, the range from 2-5 is still wider than the range from 1-3 on a three speed.

So in fact you would lose little with the 5s hub but gain a wider gear range, albeit that you can't make all the shifts all the time. As long as you know about that, it shouldn't be a problem.

cheers