Gears and gear adjustment

Moulton APBs have been fitted with a wide variety of gearing systems. The first APBs were fitted with a budget Shimano 12-speed derailleur system. The Sturmey-Archer 5 Star 5-speed hub gear became an option fairly soon, followed by a 14-speed Shimano derailleur system on the APB14. The traditional Sturmey-Archer 3-speed gear became an option at about the same time. The Land Rover APB introduced the hybrid Sachs 21-speed derailleur and hub gear system. Last year the Sturmey-Archer 7-speed hub gear became available on the APB S7.

Model Gear System
APB 12-speed Shimano derailleur
APB3 S-A AW 3-speed hub
APB5 S-A 5 Star 5-speed hub. Later models have Sprinter 5-speed hub.
APB14 and APB14 Shimano Plus 14-speed Shimano derailleur. Some have Sachs front derailleur.
APB16 Sun Tour Sun Tour 16-speed derailleur
APB14 Sachs Sachs 14-speed derailleur
Land Rover APB Sachs 3×7 hub wotj Sachs Centera rear derailleur
APB T21 Sachs 3×7 hub with Shimano RSX STI shifters and RX100 rear derailleur
APB S7 S-A 7-speed hub

All rear derailleurs are adjusted in broadly speaking the same manner, including the Sachs used in the 3×7 system. Derailleur gears need regular lubrication, particularly if ridden in wet conditions. The chain should be lubricated with purpose designed chain lubricant. Replace any frayed cables as this will hinder the gear’s correct operation. Inner and outer gear cables also wear and should be replaced yearly if your Moulton is used regularly. [Damage to the outer cable, sometimes almost invisible, can interfere very badly with the operation of indexed gears, as I found on my original APB – AssEd].

Adjusting derailleur gears

On the rear of the rear derailleur there are two adjusting screws that limit the travel of the gear and hence the chain. The upper one controls how far the chain moves outwards onto the small sprockets and the lower one (which is more critical) how far the chain moves inwards. These should only be adjusted if the chain comes off the sprockets. There is also a further adjustment screw – the B adjustment screw. This adjusts how close the derailleur runs the chain to the sprockets. It is generally a good idea to get the upper pulley wheel running as close as possible to the sprockets for good gear changing. Correct chain length can be important. The chain should be approximately two links longer than the shortest chain which could be used when it is on the largest rear sprocket and largest chainwheel. With the 12, 14 and 16 speed derailleur systems never use the extreme chain positions (large chainwheel to large rear sprocket or small chainwheel to small rear sprocket) whilst riding the bike.

Adjusting rear index gear operation

Most troubles with the indexed derailleur gears are due to incorrect cable tension.

Adjusting cable tension

  1. Select top gear (smallest sprocket) and back off all the adjustment on the cable adjuster by turning it clockwise on the back of the derailleur. Loosen the cable clamp bolt, pull the cable through and re-tighten the clamp bolt.
  2. Lift the rear wheel off the ground, turn the pedals forward and select the next gear. If the chain does not move cleanly to the next sprocket turn the adjuster anti-clockwise half a turn and repeat the test. Repeat this procedure until the chain will move cleanly from the top gear sprocket to the next largest sprocket.
  3. Once the downward shifts are correct, check that the downward shift from the the third smallest to second smallest sprocket is still OK. If not, back off (turning clockwise) the cable adjuster half a turn – see the photograph on the right. Repeat if necessary until both upward and downward shifts are correct. If you cannot get the indexed shifts to work correctly, consult your nearest Pashley dealer.

Adjusting the front derailleur

On the top of the front derailleur there are two adjusting screws that limit the movement of the front derailleur and hence the chain. Do not adjust these unless your chain comes off one or other of the front chainwheels.

Adjusting the hub gear control wires on a Sachs 3×7 system

Select top gear (number 3) on the control, rotate the pedals back half a turn. Unclip the cable at the hub end (see the photograph on the right.) Pull the cable tight and remove any slack from the hub’s toggle chain and clip together. Check that there is no slack in the cable. A sure sign that the Sachs hub gear is not correctly adjusted is if there are clicking noises from the hub whilst the pedals are being turned.

Derailleur fault finding

Fault Solution
Chain comes off or won’t go onto large chainring Adjust high gear adjuster (outer screw) on front derailleur 1/8 turn at a time until gear change is fine.
Chain comes off or won’t go onto small chinring Adjust low gear adjuster (inner screw) on front derailleur 1/8 turn at a time until gear change is fine.
Chain comes off or won’t go onto small rear sprocket Adjust high gear adjuster (upper screw) 1/8 turn at a time until it no longer happens.
Chain tension needs adjusting.
Cable needs lubrication/replacement.
Chain comes off large rear sprocket or chain/rear derailleur catch spokes Screw in low gear adjuster on rear derailleur (lower screw) 1/8 turn at a time until it no longer happens.
Derailleur hanger bent.
Rear derailleur not changing gear when selected or changes two gears at a time, or indexing imprecise Cable tension needs aadjusting.
Cable needs lubrication/replacement.
Chain needs cleaning and lubricating.

Hub gears

Adjusting the Sturmey-Archer 3-speed hub gear

  1. Select second gear on the handlebar trigger control. Turn the pedals backward a full turn. Unscrew the locknut on the connector.
  2. Look through the axle nut window. Screw the connector in or out until the shoulder of the rod seen through the window is flush with the axle end. Back pedal, recheck the adjustment.
  3. If the cable canÕt be tightened enough, slacken off the connector. Loosen the cable clamp nut, pull the cable through the clamp. Tighten the cable clamp and adjust the cable as in step 2.

Adjusting the Sturmey-Archer Sprinter 5-speed hub gear

Most APBs are not fitted with the roller wheel shown in the picture as there is in sufficient clearance at the dropout. Sturmey-Archer gave permission to Pashley Cycles for the 5-speed Sprinter hub to be used without the pulley but with the normal flanged hub nut as used on 3-speed hubs.

  • Select fifth gear initially, rotate the pedals and then select second gear on the control and rotate the pedals a whole turn backwards.
  • Turn the knurled cable adjuster until the centre of the red raised boss on the indicator rod is level with the axle end. Tighten the locknut against the adjusting nut.
  • Select fifth gear and rotate the pedals before selecting second gear again. Check that the adjustment is correct and tighten the locknut against the adjuster.

Adjusting the Sturmey-Archer 7-speed hub gear

  1. Select 5th gear on the handlebar twist grip control. Turn the pedals back a full turn.
  2. Check that the white mark is perfectly centred in the window. If not turn the adjustment screw until the white mark is perfectly centred.
  3. Rotate the pedals at least one full turn and recheck that the white mark is fully centred, if not readjust. Tighten the locknut on the cable adjustment screw.

For the illustrations which go with this article, please see the printed copy in issues 52 and 53 of The Moultoneer.


REMEMBER THE WARNING

Modification, repair and renovation work should only be carried out by qualified people. If you do not have the experience and/or expertise to judge whether any procedures described in Masterclasses are correct, DO NOT ATTEMPT TO DO THE JOB. The information given in Masterclass articles is intended to act as a reminder to capable people who are carrying out repair work. The authors, the Moulton Bicycle Club and its Officers accept no responsibility for work carried out by owners or their agents, whether that work is done in accordance with any information contained in these articles or not.