Chainless Bicycles

(Originally published in the June 17 to 23, 2012 issue of the Baguio Chronicle ---

a weekly newspaper based in Baguio City, Philippines ---

by Sly L. Quintos, Associate Editor.)

A CHAINLESS or shaft-driven bicycle is a bicycle that uses a drive shaft instead of a chain to transmit power from the pedals to the wheel. 

Shaft-driven bicycles were introduced over a century ago but were mostly supplanted by chain-driven bicycles due to the gear ranges possible with sprockets and derailleurs. But due to advancements in internal gear technology, a small number of modern shaft-driven bicycles have been introduced.

Chainless bicycles use a drive shaft instead of a chain to smoothly and efficiently transfer power from the pedals to the rear wheel. The common chainless bicycle in the market today uses the Shimano 8-speed or 7-speed internal hubs where all the gearing is neatly tucked away inside the rear wheel, practically no visible moving parts. 

Accordingly, chainless bikes allow you to ride in any weather without worrying about salt or sand build-up on the chain components since all the moving parts are enclosed and protected, drastically reducing repair and maintenance time and cost. 

One manufacturer claims that their shaft drives and gearing are designed to last 3 to 4 times as long as chains and derailleur components. It claims further that their chainless bikes offer a versatile range of gearing for climbing tough hills “as gracefully as they accelerate to comfortably fast speed . . . plus, shifting gears is fast, smooth and easy and help you use your gearing more frequently, which will help reduce fatigue and increase your energy during your ride by helping you maintain a more consistent pedaling speed”.

Shaft-driven bikes have a large bevel gear where a conventional bike would have its chain ring. This meshes with another bevel gear mounted on the drive shaft. The use of bevel gears allows the axis of the drive torque from the pedals to be turned through 90 degrees. The drive shaft then has another bevel gear near the rear wheel hub which meshes with a bevel gear on the hub where the rear sprocket would be on a conventional bike, and canceling out the first drive torque change of axis.

The first shaft drives for bicycles appear to have been invented independently in 1890 in the United States and England. 

In 1890, A. Fearnhead of North London developed a prototype shaft was enclosed within a tube running along the top of the chainstay; later models were enclosed within the actual chainstay. He was granted a patent a year later. Almost at the same on December 10, 1890 in the United States, Walter Stillman filed for a patent for a shaft-driven bicycle which was granted on July 21, 1891.

The shaft drive was not well accepted in England, so in 1894 Fearnhead took it to the USA where Colonel Pope of the Columbia firm bought the exclusive American rights. 

Belatedly, the English makers took it up, with Humber in particular plunging heavily on the deal. Curiously enough, the greatest of all the Victorian cycle engineers, Professor Archibald Sharp, was against shaft drive.

In his classic 1896 book "Bicycles and Tricycles", Sharp contended that “the Fearnhead Gear . . . if bevel-wheels could be accurately and cheaply cut by machinery, it is possible that gears of this description might supplant, to a great extent, the chain-drive gear; but the fact that the teeth of the bevel-wheels cannot be accurately milled is a serious obstacle to their practical success”.

In the USA, they had been made by the League Cycle Company as early as 1893. Soon after, the French company Metropole marketed their Acatane. By 1897, Columbia began aggressively to market the chainless bicycle it had acquired from the League Cycle Company. 

Chainless bicycles were moderately popular in 1898 and 1899, although sales were still much smaller than regular bicycles, primarily due to the high cost. The bikes were also somewhat less efficient than regular bicycles: there was roughly an 8 percent loss in the gearing, in part due to limited manufacturing technology at the time. The rear wheel was also more difficult to remove to change flats. Many of these deficiencies have been overcome in the past century.

In 1902, The Hill-Climber Bicycle Mfg. Company sold a three-speed shaft-driven bicycle in which the shifting was implemented with three sets of bevel gears. While a small number of chainless bicycles were available, for the most part, shaft-driven bicycles disappeared from view for most of the 20th century. There is, however, still a niche market for chainless bikes, especially for commuters, and there are a number of manufacturers who offer them either as part of a larger range or as a primary specialization. 

Product reviews are near unanimous that shaft drives operate at a very consistent rate of efficiency and performance, without adjustments or maintenance, though lower than that of a properly adjusted and lubricated chain. Shaft drives are typically more complex to disassemble when repairing flat rear tires and the manufacturing cost is typically higher.

A fundamental issue with bicycle shaft-drive systems is the requirement to transmit the torque of the rider through bevel gears with much smaller radii than typical bicycle sprockets. This requires both high quality gears and heavier frame construction. 

Since shaft-drives require gear hubs for shifting, they gain the benefit that gears can be shifted while the bicycle is at a complete stop or moving in reverse, but internal hub geared bikes typically have a more restricted gear range than comparable derailleur-equipped bikes.

Most of the advantages claimed for a shaft drive can be realized by using a fully enclosed chain case. Some of the other issues addressed by the shaft drive, such as protection for clothing and from ingress of dirt, can be met through the use of chain guards. The reduced need for adjustment in shaft-drive bikes also applies to a similar extent to chain or belt-driven hub-geared bikes. Not all hub gear systems are shaft compatible.*