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Rebuilding the Sturmey-Archer FW
Wide-Ratio Four Speed Bicycle Hub
This information is from the 1956 service manual. More information
with links to an exploded drawing and a parts list can be found in another file.
- Remove the indicator from the hub and remove the internal from the hub shell as described in the general instructions.
- Place the left-hand end of the axle in a vise and remove the right hand locknut, washers if any, the cone lock washer and the right hand cone, making a note of their arrangement so that they can be replaced in their original positions.
- Lift off, in the following order, the clutch spring and cap, the driver, the right-hand ball ring and the gear ring.
- Remove the thrust washer and ring. Push out the axle key and remove the clutch sleeve and sliding clutch.
- Push out the pinion pins and remove the pinions and planet cage.
- The low gear pawl pins are riveted in position. If they have to be removed, file the riveted part flat and knock out the pins with a small punch. The pawls and springs can then be removed.
- Remove axle from vice. The internal compensating spring, complete with collar, can now be taken out of the right-hand end of the axle.
- Place the right-hand end of the axle in a vise, straighten the edges of the tab washer, and remove the nut and tab washer holding the internally toothed dog ring. Remove the dog ring.
- Push the two sun pinions along the axle so that the larger one engages with the axle dogs and move the sleeve under the smaller one in the opposite direction in order to expose the second axle key. Push out this axle key.
- Slide the two sun pinions, sleeve and spring off the axle.
- If necessary, because of a worn bearing surface or ratchets, the left-hand ball cup may be removed. It has a left-hand thread and is removed by gripping the outside flat surfaces in a vise and spinning the wheel in a clockwise direction.
- The channel-section dust caps in the driver and the left-hand ball cup are pressed into position and can be prised out with a wide screwdriver. It is recommended that a new dust cap be fitted if a new ball retainer and balls have to be fitted.
- If the left-hand ball cup has been removed from the hub shell, replace it by screwing anti clockwise because it has a left-hand thread.
- Prepare the following preliminary sub-assemblies:
- 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.
- 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. 19 below.
- Fit the balls (only 24) and the inner dust cap to the right-hand ball ring, making sure that the balls can revolve freely with the dust cap in place.
- Fit the pawls, pins and springs into the gear ring as described in the general instructions to 'The Re-assembling of Sturmey Archer Hubs.'
- Fit the pawls, pins and springs into the planet cage and rivet the pins on the left-hand (ball cup) side as described in the general instructions to 'The Re-assembling of Sturmey-Archer ' Hubs.'
- Smear grease in the channels of the dust caps 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.
- Working from the left-hand (short slot) side of the axle, slide the low gear spring, the primary sun pinion, and the secondary sun pinion and sleeve on to the axle in that order, and push them along until the dogs engage. (The low-gear spring, the compensating spring, and the clutch spring of a four-speed hub must be of the same series. If one has been replaced, the other two must be.)
- Holding the pinions in position, withdraw the secondary sun pinion sleeve until the low-gear keyhole is exposed, and insert the low- gear key making sure that the hole through the key is in line with the bore of the axle. Release the pinions, so that they can spring back and secure the key. Use the indicator rod to check that the hole in the low-gear key is still in line with the axle bore.
- Fit the dog ring so that it engages on the axle square, and secure it with the washer and nut, spanner-tight. Then turn down the edge of the lock washer over two opposite sides of the locknut, to secure it. (Earlier models of this hub may not be fitted with tab lock washers.) Drop the indicator rod down the axle to check that the end of the indicator rod comes level with the end of the axle.
- Remove the indicator, then hold the axle vertically in a vise by the flats on the left-hand end, and put the planet cage in place.
- Add the double planet pinions and pins so that they engage with the two sun pinions. The marked teeth must in each case point radially outwards, as shown in the drawing, or the hub will not be correctly timed. (Notice also that three teeth on the small end of each planet pinion are visible over the end of the planet cage.) To check the timing, engage the gear ring with the pinions and rotate several times. It should rotate quite freely. Remove gear ring after testing.
- Drop the compensator spring down the axle, collar first.
- Fit the clutch sleeve (flange first), the sliding clutch with the recess over the flange of the sleeve, the key and the thrust ring and thrust washer. The notches on the thrust ring must engage with the flats on the key.
- Remove the axle from the vise and insert the indicator chain and coupling into the right-hand end, threading it through the main key and the compensator spring collar.
- Insert the indicator rod, and press the left-hand end of the axle and indicator rod against a solid surface while holding the assembled mechanism vertically and pressing downwards on the sliding clutch, so that the indicator coupling can be screwed 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 (rotatory) pressure on the chain, to make sure that the indicator rod is tight, taking care not to twist off the small threaded end. Make sure that the sliding clutch is free to move along the axle when.the indicator chain is moved up and down.
- Fit the gear ring, the right-hand ball ring, the driver, the clutch spring, and the clutch-spring cap, in that order.
- Fit the right-hand cone and screw it up finger-tight. Then Loosen it back half a turn and lock it in that position with the special locking 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.
- Hold the assembled mechanism with the planet cage uppermost and pour about two teaspoonfuls of a good quality thin oil into the cage.
- Insert the assembled mechanism into the hub shell and screw up the right-hand ball ring finger-tight only.
- Make sure that the marks put on the ball ring and the hub flange before dismantling will register properly, and then screw up tightly.
- Fit the left-hand cone, washer and locknut in the arrangement noted when dismantling, and adjust the hub bearing as described in 'The Installation and Adjustment of Sturmey-Archer Hubs.'
- Fit any special washers noted when dismantling the hub. 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. Fit the sprocket and spacing washers in the arrangement noted when dismantling and add the circlip.
- Replace the wheel in the cycle frame and adjust the gear as described in 'The Installation and Adjustment of Sturmey-Archer Hubs.'
Back to Sturmey-Archer Service Page
Thanks to Jane Thomas, who originated these pages,
later revised © 2007 by Sheldon Brown
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Last Updated: by Harriet Fell