Moulton APB Bicycle

Moultons need no introduction. I have sought one ever since I learned about these amazing bicycles and their designer, Dr Alex Moulton. I finally snagged a Moulton APB (built by Pashley) from a fellow enthusiast here in Melbourne. This was how I bought it.

I replaced most of the componentry with my own choice bits but retained all the original bits in case I ever want to sell it. The bike is a workhorse and I wanted it to fit me perfectly and be a joy to ride.

It got a carbon handlebar with light but inexpensive Avid FR5 brake levers and XT shifters. For touring comfort I use ergo grips and barends. A quill adapter plus ahead stem replaced the original steel quill stem.

I splashed out a bit and got a Brooks B17 Special in green. A carbon Easton post with shim replaced the original heavy steel post.

The steel chainrings were replaced with aluminium ones; the big ring is a Vuelta 60T and the small has 42T. This was the biggest difference the front derailer would allow. With a 11-34T rear cluster, this gives me 440% of gearing range, ample for any sort of touring. I use slightly fatter tyres for touring, giving me a gearing range of 24"-105". To improve shifting to the big ring, I used a screw in the big ring sticking 1-2mm out as a chain pickup pin. This made quite a difference but also snags the chain if I cross-chain with the chain on the small ring.

The bike inherited the light wheelset from my Swift (which got a new 451mm wheelset). For touring I used a stronger wheelset with more spokes. The rear cluster is 11-28T for closer spaced gearing but smaller range of 27"-99", still larger range than typical road gearing.

The front suspension has a bush sliding inside the steerer tube. The original bush could not take lubrication as these tend to swell and may become stuck. That bush did not have a nice smooth movement. A new bobbin-shaped bush did not last long due to the pitted and rough interior surface of the steerer tube, and also did not improve the movement much.

To solve the issue, I made a new sleeve to fit over the worn bush. The worn bush was turned down to 16mm to match a 16mm boring tool. With the boring tool, I hollowed out a Delrin rod so it fits tightly over the turned-down bush. A groove at each end of the bearing surface takes O-rings. Together with molybdenum disulfide gel grease, the new bush slides extremely smoothly with almost no stiction. The O-rings should keep dirt and moisture out, and lubrication in.

To polish the inside of the steerer tube, I took a 18mm dowel, sawed a longitudinal groover in it to accept the end of a small sheet of sandpaper which wraps anti-clockwise around the dowel. A screw provides for clamping in the chuck of a drill. This setup was highly successful in removing most of the surface roughness and polishing the tube.

I used the bike to tour New Zealand.