Sturmey Archer indicator rod (control toggle) lengths

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Brucey
Posts: 33525
Joined: 4 Jan 2012, 6:25pm

Sturmey Archer indicator rod (control toggle) lengths

Postby Brucey » 3 Feb 2019, 8:43pm

many sturmey archer hubs, (including Pre NIG AW, NIG AW, S5, S5-1, S5-2, 5-star, SW, converted AM, converted FW etc) use the same indicator rods. However they are available in different lengths to suit different axles and between all the different hubs and axle lengths that have been available, it is difficult to know what is the correct one. This illustration shows the variations possible in just the S5-2 model of hub.

Image
S5-2 indicator rod lengths

However in practice almost any length rod (that isn't too long) will work on the LHS of S5-2 hubs because the control is binary; almost tight cable or slack cable; there is no need for a shoulder or mark on the indicator rod.

Image
control rods for older (pre NIG) hubs. Note that many of the axles vary in the left side length only, so that there are many fewer different indicator rod lengths required than there are axle lengths

For all RH rods there is meant to be a specific length that will be correct in the direct drive ratio (second gear in a 3s hub) such that the shoulder on the rod is flush with the end of the axle. In some older 3s indicator rods there is a (largely superfluous) second mark about 4.25mm away from the main shoulder; this indicates the low gear position or can indicate second gear position in the case of a rod substitution.

The actual rod lengths from shoulder to shoulder (L) are;

Rod length (L).…solid axle length (non-NIG),toggle key depth (non NIG),solid axle length (NIG),toggle key depth (NIG),..... Part Number
Mk1 48.25mm (1.900")…42.5mm...………………………….56mm...………………………L-9mm………………………………L+ 7mm ......HSA125
MkII 54.8mm (2.155")…49mm...…………………………62.5mm...……………………………L-9mm……………………………L+7mm.....HSA126
MkIII 58-58.4mm...………….L-5.7mm...………………………L+7.7mm...…………………………49.1mm…………………………65mm......HSA315
MkIV ~62mm* .………….L-5.7mm...………………………L+7.7mm...……………………L-9mm………………………………L+ 7mm......HSA316
MkV ~66mm*.......................................................................................................................................................HSA420
MkVI 40mm*……………….HSA615
MkVII ~72mm*.....................................................................................................................................................HSA421
MkVIII ~75mm*...................................................................................................................................................HSA716
MkIX 69mm*................................................................................................................................................HSA715
* estimated values and/or not verified by personal measurement

In the table above the 'solid axle length' is the length from the RH end of the slot to the RH end of the axle. Use this measurement if you have a bare axle (NB not CS-series hubs).

'Toggle key depth' (KD) is the depth of the toggle key (eg as measured using a vernier caliper as a depth measurer) from the axle end when the hub is set in top (3rd) gear; use this measurement when you have an assembled hub and don't know what length control rod to use (again not CS series hubs).

So for non-NIG hubs the correct control length L is given by

L = KD - 7.7mm

and for standard NIG 3s hubs (not CS series, not S3X)

L= KD - 7mm

Specific rod applications in current hubs include;
MkIX 69mm (HSA715) used with SRK-3 hub
MkVIII 75mm (HSA716) used with CS-RF3 and CS-RK3 hubs
MkIV 62mm (HSA316) used with X-RD3 with 177mm axle
MkIII 58.4mm (HSA315) used with X-RD3 with 162.7mm axle, AW (NIG), SRF-3 with 163mm axle
MkII 54.8mm (HSA126) used with SRF-3 with 148mm axle. Also Brompton BWR and BSR with 148mm axle

I don't know what the 40mm long MkVI rod is meant to fit, but it occurs to me that if you fit one into a hub that normally uses a MkI rod, the shoulder will come about flush with the axle end when first gear is selected. Given that non-NIG hubs use shorter control rods than NIG hubs and the shortest non-NIG axles are barely long enough (for anything) on the RHS, it seems unlikely that there is an axle that gives a conventional setting (shoulder flush with axle end in second gear) when a MkVI rod is installed.

There is plenty more information (including lengths of 'skinny' i.e. single toggle 5s, and S3X rods) here https://www.sheldonbrown.com/indicators.html You can use a skinny rod in a 3s hub which normally uses a Mk1-MkVIII rod provided the length is compatible; the screw threads are the same.

some available control rods herehttps://www.sjscycles.co.uk/search/?term=sturmey+indicator

If you have no marks to go on, shift slowly from 1-2 and add 1-2mm more cable slack once second gear starts to catch. On an NIG 3s, once you are 1mm out of 3rd gear when shifting 3-2 then the adjustment for second gear is OK. On a non-NIG 3s, shifting 3-2, you need 3mm more cable pull from when second gear starts to 'catch'. If these tests indicate a range of satisfactory adjustments, aim for the middle of that range.

The above comments apply to all toggle chain 3s hubs (bar CS-series ones and S3X) and apply to the RH adjustment of twin toggle 5s hubs. (NB the only NIG type 5s twin toggle is the 5-star hub.)

hth

cheers
Last edited by Brucey on 5 Feb 2019, 9:17pm, edited 11 times in total.
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fausto99
Posts: 377
Joined: 19 Sep 2011, 10:06am

Re: Sturmey Archer indicator rod (control toggle) lengths

Postby fausto99 » 3 Feb 2019, 10:18pm

Thanks for this. Very useful reference.
I've printed it to pdf and put it in my S-A folder. I always find searching the Cycling UK forum very hit-and-miss :oops:

Brucey
Posts: 33525
Joined: 4 Jan 2012, 6:25pm

Re: Sturmey Archer indicator rod (control toggle) lengths

Postby Brucey » 4 Feb 2019, 4:56pm

further to the above, I've been trying to get to the bottom of things concerning the skinny rods used in

-single-toggle 5s hubs and
-S3X hubs

The S3X is based on the 5s (W) architecture inside. The skinny control rods are required in these hubs because there is a spring that is set permanently inside the axle. Note that the spring is retained by a collar (Bissell or roll pin) that is a press-fit inside the axle. The spring length usually doesn't vary with axle length; thus if you don't need the index marks, you can use almost any skinny rod in any single-toggle 5s hub, provided it isn't so long that it is pulled sideways in the low gears. Typical single-toggle 5s hubs use about 20mm total cable pull.

When these skinny rods first appeared, they had a groove near the top which was filled with coloured paint. This groove acted as the index mark (aligned with the axle end in second gear) and the colour indicated the type of control rod. There were only a few lengths of control rod in use.

The adjustment scheme (which is similar for all single toggle 5s hubs including (W) hubs) is described here

http://www.sturmey-archerheritage.com/files/view-169.pdf

and requires that you set the index mark flush with the axle end in second gear.

Only one axle length and control rod was specified for the 'sprinter' 5s hub originally; HSA490, which is colour coded 'red'.

Image
HSA490 'red' control rod for dog-locking sprinter 5s, length 64mm

However as time went on further axle lengths and hub variants appeared and today we have (amongst others) the following PNs and lengths (measured from shoulder at threaded end to coloured mark)

HSA317 'blue' (pale blue) For internal HSX140 ball locking sprinter 5s length 59mm
HSA490 'red' For original (dog locking) sprinter 5s and pre-2000 single toggle Brompton 5s, length 64mm
HSA585 'yellow' For X-RD5(W) hubs with 175mm axle, length 68mm
HSA651 'green' E.g. for SRF5 with 148mm axle, length ??mm

These rods (in their original form) usually lost their paint after a few years but the groove was still clear for setting the hub up.

in addition control rods for S3X were introduced including some which were meant for use with a short RH nut; these control rods have the index marks as coloured splodges on the chain itself; this cuts down on hardware inventory (you can reassign a rod simply by putting a different splodge of paint on it) and allows the use of a short RH nut, because the part of the rod with the mark on it can go around the corner. The downside is that the index mark is not so clear when it is new, and the paint may flake off or be obscured in time.

Rods which are built this way include

HSA652 'orange' for S3X 120mm OLN
HSA653 'white' for S3X 130mm OLN
HSA717 'purple' eg for S-RK5(N)
HSA712 'navy blue'


for example

Image
HSA652 'orange' control rod. You can see the orange paint splodge between the first and second outer side plates in the chain

Image
HSA653 'white' control rod. The paint mark is (slightly) clearer in real life

Image
HSA717 'purple' control rod

if you have a 5s hub without a control rod, or the incorrect control rod, it is not so easy to measure the depth of the key because (unlike a hub that takes the fatter control rods) a standard Vernier caliper won't access down the small hole. However you can measure the key depth (KD) using a 13G spoke.

The correct 5s control rod length appears to be given by;

KD-14mm (for dog locking sprinters and (W) hubs) and
KD-15mm (for ball-locking sprinters)

KD values for ball locking hubs are also less than dog lockers by about 4mm; thus similar looking ball locking hubs require shorter control rods than dog-locking ones, by about 5mm. Ball-locking 5s internals may be identified by a chamfer on the left end of the axle.

cheers
Last edited by Brucey on 6 Feb 2019, 10:50pm, edited 3 times in total.
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Brucey
Posts: 33525
Joined: 4 Jan 2012, 6:25pm

Re: Sturmey Archer indicator rod (control toggle) lengths

Postby Brucey » 5 Feb 2019, 2:51am

here

https://hadland.files.wordpress.com/2012/07/3axles.pdf

there is a pdf with SA-supplied axle charts and also Jim Gill's comprehensive drawings of sturmey archer axles from ~1902 to ~1995. This includes the 'sprinter 5' and 'sprinter 7' models, in their original (dog locking) form.

Using this information an unknown axle can be identified and hopefully the control rod that goes with it.

cheers
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