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