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Servicing The Sturmey-Archer
ASC Three-Speed Fixed-Gear Hub
Spoke Divider
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Sturmey-Archer ASC Page

Reportedly, SunRace/Sturmey-Archer is considering doing a new production run of the ASC 3-speed fixed-gear hub, or an updated version of it. Given SunRace's track record with Sturmey-Archer, I would expect a new version to be more reliable than the original.

They're not certain about how much demand there might be for it though. If this is something that would be of possible interest to you, let them know by sending an email to them using the link below:

ASC Hub cutaway

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ASC Hub exploded

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CODE No.DESCRIPTION
K831 Axle, 5 1/2" long
K805A Low Gear Dog
K806Dog Sleeve
K402Low Gear Key
K809ASecondary Sun Pinion
K811Locating Plate
K 412Locking Washer
K812Locknut
K8l5ASecondary Planet Cage
K816ASecondary Planet Pinion
K8lOBLow Gear Spring
K808Primary Sun Pinion
K715Planet Cage
K16Planet Pinion
N24Pinion Pin
K716Indicator
X8Collar for Compensator Spring
K8l3BCompensator Spring
K527Clutch Sleeve
K5O5ASliding Clutch
K526AAxle Key
K807ZACoupling complete
K807ZCoupling complete, quick-release type. Not illustrated
K74OAZQuick Release Connection. Not illustrated
K528AThrust Ring
K411Thrust Washer
K530BClutch Spring
CODE No.DESCRIPTION
K529 Spring Cap
K511BGear Ring
K228R H. Ball Ring
K23OZBall Cage with 3/16" ball-hearings
K462Driver
K67ZBall Cage with S I" halls
LB405Outer Dust Cap
K506ZAxle Cone with Dust Cap
K516R.H. Cone Locksng Washer
K718ZShall, 40 holes, with Ball Cup
K7l8AZShell, 36 holes, with Ball Cup
K227Connection Locknut
X42AAxle Spacing Washer
K47ACone Locknut
K521Axle Locking Washer
N190L.H. Axle Nut
N200R.H. Axle Nut
K229Sprocket, Dust Cap
K464Sprocket, 14 reeth
K465Sprocket, 15 teeth
K466Sprocket, 16 teeth
K467Sprocket, 17 teeth
K468Sprocket, IS teeth
K469Sprocket, 19 teeth
K470Sprocket, 20 teeth
X49Sprocket Spacing Washer
K463Circlip

TO RE-ASSEMBLE THE ASC HUB

Proceed as follows:

Prepare the following preliminary sub-assemblies:
    1. Fit the ball cage into the left-hand ball cup, with the ring of the ball-retainer facing outwards and the recess in the dust cap also facing outwards. If a new ball-retainer is being fitted, the dust cap also should be new.
    2. Fit the ball cage into the driver, with the ring of the ball- retainer facing outwards and the recess in the dust cap also facing outwards. If a new ball-retainer is being fitted the dust cap also should be new. If the sprocket has been removed see No. 27 below.
    3. Smear grease in the channels of the dust cap of the left-hand ball cup and the driver and in The recess of the right-hand ball ring. Do not use grease anywhere else.
  2. Hold the axle in a vice, with the smaller slot uppermost, and fit the low-gear clutch sleeve with its flange on top.
  3. Slip the small low-gear key through the holes of the low-gear clutch sleeve, making sure that the hole through the key is in line with The bore of The axle. Hold The key temporarily in position by dropping the indicator rod down the axle through the key.
  4. Holding the indicator rod in position with one finger, remove the axle from the vice and hold it the other way up. Fit the low-gear clutch on to the axle, with the four dogs pointing downwards.
  5. Fit the large low-gear spring and the primary sun pinion, with its four large legs pointing downwards and so engaging the low-gear clutch. (The low-gear spring, The compensating spring, and the clutch spring must be of the same series. If one has to be replaced The other two must be.)
  6. Slip the indicator rod out of the axle (the low-gear clutch key will now stay in position) and put the axle back in the vice.
  7. Fit the primary planet cage complete.
  8. Drop The compensating spring down the axle, collar first.
  9. Fit the clutch sleeve (flange first) and the sliding clutch with the recess over The flange of The sleeve.
  10. Lift the clutch sleeve and the clutch up to the top of the long axle slot and insert axle key Through The clutch sleeve, making sure That the two flats on The key are facing upwards.
  11. Fit The indicator coupling by passing the rod, down the axle through the axle key and onto the compensator spring. Note that the indicator coupling must always be fitted before the indicator rod.
  12. Remove the axle from the vice and push the indicator rod into the left-hand end of the axle. Press the assembled mechanism down on a flat surface to force the indicator rod into the axle, at the same time pressing down on the sliding clutch. Then rotate the indicator chain to screw it to the indicator rod. When the chain is felt to be fully screwed home insert a small screwdriver into the slot of the indicator rod and exert a slight extra pressure on the chain, to make sure that the indicator and the rod are both fully screwed together, taking care not to twist off the small threaded end.
  13. Fix the axle in thc vice again and make sure that the clutch slides quite freely on the axle when the indicator chain is moved up and down.
  14. Fit the thrust collar, making sure that both slots fit over the flats of the axle key. Add the thrust washer.
  15. Fit the gear ring, the ball ring (with ball cage), the driver, the axle spring and the clutch spring cap in that order.
  16. Fit the right-hand cone and screw it up finger tight. Then slacken it back half a turn and lock it in that position with the special washer and locknut. On no account must the cone be unscrewed more than half a turn, as that would throw the gear mechanism out of adjustment.
  17. Remove the assembled mechanism from the vice and replace it the other way up.
  18. Fit the secondary planet cage, with the pins upwards and the slots engaging the limbs of the low-gear dog.
  19. Fit the secondary planet pinion.
  20. Fit the secondary sun pinion, with the recess downwards, so that the sun pinion engages with the square flats on the axle.
  21. Fit the locating plate and tab washer and tighten the locknut. Turn over the edge of the washer on two opposite sides of the locknut.
  22. Remove the assembled mechanism from the vice, hold it vertically with the planet cage uppermost and pour about two teaspoonfuls of a good quality thin oil into the cage.
  23. Insert the assembled mechanism into the hub shell and screw up the right-hand ball ring finger-tight only.
  24. Make sure that the marks put on the ball ring and the hub flange before dismantling will register properly, and then screw up tightly.
  25. Fit the left-hand cone, washer and locknut in the arrangement noted when dismantling, and adjust the hub as described in The Fitting and Adjustment of Sturmey-Archer Hubs.
  26. Fit any special washers noted when dismantling the hub.
  27. If the sprocket has been removed from the driver, fit the outer dust cap over the driver before replacing the sprocket, and see that the dust cap is properly centered on the flange of the driver. Replace the sprocket and the spacing washers in the arrangement noted when dismantling, and add the circlip.
  28. Replace the wheel in the cycle frame and adjust the gear as described in `The Fitting and Adjustment of Sturmey-Archer Hubs.'

Spoke Divider

Thanks to Harvey Sachs for sending me this information.

Spoke Divider

Click here for the main

Sturmey-Archer ASC Page

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