The amazing unimportance of chainline and chain lubrication

There are a lot of myths circulating in various forums about the importance of chainline. Chainline refers to how straight the chain runs between front and rear sprockets. In single speed set-ups and where an internal hub gear is used, it’s often possible to get a near perfect chainline. Sheldon Brown explains chainline in three articles, the lead one of which is here. With derailleur gears, the general guidance is to set up a straight chainline based on the position of the middle sprocket on both back and front, where there are 3 on the front, or in the middle on the back and between the 2 front chainrings in the case of a double, or aligned with a single front chainring. The problems with running the chain at an angle include lower efficiency, greater chain wear and noise. But just how big an issue is it?

Chainline
This 2001 paper shows just how little difference chainline and lubrication make to pedalling efficiency

This paper, written in 1999 by members of the American Society of Mechanical Engineers (ASME) throws up some interesting conclusions. The reason that a ‘poor’ chainline is cited as reducing pedalling efficiency is that there is increased friction causing energy to be wasted as heat. The paper doesn’t argue with this point but the conclusion is that these losses are negligible compared with non-thermal losses. The paper describes how an experiment was set up to measure efficiency relating to 3 characteristics of a chain drive: the ratio of sprockets and their relative alignment (chainline), variations in input power and rotation rate (cadence) and lubrication, or lack of it. The detailed results make very interesting reading. The authors concluded that chainline offset and lubrication have a negligible affect on efficiency, at least under laboratory conditions and no significant efficiency differences could be detected between a lubricated and dry chain. (I wonder if a dry chain might actually last longer because grit and grime would not adhere to it and cause greater wear?) The major factors affecting efficiency are spocket size, larger sprockets providing better power transfer, and chain tension. Most importantly, there is a reciprocal linear relationship between chain tension and efficiency, the higher the tension the higher the efficiency. The latter makes a huge difference. With a chain tension of 305N the experiment revealed a drive efficiency of 98.6%. When the tension was reduced to 76.2N, efficiency fell by nearly 18% to 80.9%. Don’t worry about getting your chainline accurate to within mm, don’t worry about lubrication, but do keep the chain well tensioned. I don’t know how the  figures above relate exactly to chain slack but 305N is pretty taught!

The problem with fixies – they’re much too complicated

Advocates of fixies and other single-speed bicycles point to their glorious simplicity. No shifters, no derailleurs, no mysterious inner workings in hub gears. Sometimes, they don’t even fit brakes. But even the most stripped down fixie can’t match the sleek lines and minimal number of components of this wonderful machine, which was recently auctioned on eBay.

Velocipede
This Scottish-made velocipede would make an excellent winter trainer – there’s very little to go wrong

I can’t remember the name of the Scottish manufacturer but I believe the velocipede, draisine, or bone-shaker (a multiplicity of terms were used to describe these early bicycles) dates from around 1860. That’s well before the emergence of the car, and before speed limits of 4 miles per hour were imposed to protect pedestrians from the dangers of motorised transportation. Admire the sheer simplicity: 16 spokes per wheel, but no spoke nipples, hub bearings, inner tubes (with valves), tyres, or any of the other unnecessary extras found on the modern bicycle. By comparison, even the simplest fixie is a monumental piece of engineering complexity. Incidentally, the velocipede fetched £5400, a lot of money for a winter trainer, you might think. I wonder where you’d put the DI2 electronic shifters?

A new twist on drinking and driving….boozing and biking

In a very imaginative brand extension, New York’s Cooper Spirits International LLC, which owns the St Germain French drinks brand, is selling a single-speed bicycle complete with bottle holder on the crossbar and a free bottle of the firm’s sweet spirit drink. The $1000 steel-framed bike, which is described as a ‘limited edition’ (although no numbers are quoted by the company) uses a coaster brake and combines combines clean, classic looks with some nice bits from Brooks, North Road and Michelin.

St Germain bicycle
The St Germain single speed bike comes complete with a bottle of booze to keep your spirits up

Choose a medium (20 inch) or large (23 inch) frame in any colour you like, so long as it’s navy blue.