Specification for New Conker Bike

Posted 29th August 2018


To provide year-round all weather comfortable commuting bike, with low maintenance, but good performance. To be traditional in appearance, but thoroughly modern in detail.

A good wheelset is the foundation for a good bike. I chose DT Swiss 700c 36 hole disc specific rims designed for heavy duty electric bikes, shod with 50mm Schwalbe Big Ben ‘urban MTB’ tyres for comfort. I built the wheels from scratch using DT Swiss double butted stainless steel spokes at Downland’s workshop. Gel filled tubes minimise risk of flats on the famously thorny Crab and Winkle cycle route.

Traditional lugged frame, with British made Reynolds 631 steel alloy double butted tubing. Frame was designed using BikeCAD by Bryan at Downland to suit my peculiar dimensions and requirements, one being that I tend to ride in site safety boots and need to avoid my size 12’s hitting the front mudguard. Geometry is a fairly relaxed 71 degrees for seat tube and 71.5 for head tube. The head tube is quite high for a comfortable handlebar height, the top tube is sloping down for a low standover height.
I built the frame at Dowland’s course under the amazingly patient guidance of Bryan Jackson. Tubes are cut, mitred, carefully fitted into the lugs, then brazed whilst held on a jig. Fittings were attached for mudguards, hydraulic hoses, cables, bottle mounts and mudguards. I added a special curved handle above the bottom bracket to aid carrying up the office stairs.
Forks are traditional tapered Reynolds tubes with a decorative fork crown.

Stainless steel mudguards from Gilles Berthoud, with alloy brackets. The biggest size available is only just able to cope with 50mm tyres.

Electrical installation
Shimano 1.5W Afline dyno hub provides free renewable energy for the front light, a Schmidt Edelux II LED unit with a very well defined beam cut-off, to avoid blinding other road users. Internal cable routing.

Mechanical Services
A Shimano Alfine 11 speed internal hub gear provides maintenance free transmission, operated by a thumb changer which can jump 2 gears at a time. I have been using hub gears for years for commuting, and have built wheels with 2 speed, 7 speed and 8 speeds hubs.
Chainset by Lasco, square taper single 1/8th 42 tooth chainring, however this needs to be swapped for a 39 tooth to obtain a better spread of gear ratios, with 22 tooth rear sprocket. Standard 68mm sealed bearing bottom bracket. An SJS Cycles chain tensioner keeps the chain taught, as I have used standard non-adjustable frame dropouts.

Plumbing installation
SRAM Level hydraulic disc brakes front and rear, 160mm Shimano ICE centrelock rotors. These perform far better than rim brakes especially in the winter.

Very difficult to find reliable decorators, as we all know. Colour Tech in Dartford provided the spray finish and hard lacquer top coat in RAL 1005 Honey yellow.

Fixtures and fittings
A used Brooks leather saddle provides rock hard support to the peach, on a second hand carbon fibre seat post. Temporary riser handlebars in place, with ‘wood’ handlebar grips. Platform pedals by Crank Brothers are most suited to riding in my safety boots, and replacement bearings are available, as I wear them out every year.
Hope headset in anodized aluminium.
Aluminium chain guard with custom bracket.