Hub gear

Changing the gear ratio was traditionally accomplished by a shift lever connected to the hub with a Bowden cable, and twist-grip style shifters have become common.

Hub gear systems generally have a long and largely maintenance-free life though some are not suitable for high-stress use in competitions or hilly, off-road conditions.

Many commuter or urban cycles such as European city bikes are now commonly fitted with 7-speed gear-hubs and 8-speed systems are becoming increasingly available.

[5][6] The first patent for a compact epicyclic hub gear was granted in 1895 to the American machinist Seward Thomas Johnson of Noblesville, Indiana, U.S.A.[7] This was a 2-speed but was not commercially successful.

[10] In 1903, Frank Bowden, head of the Raleigh Bicycle Company, formed The Three-Speed Gear Syndicate, having obtained the rights to both the Reilly/Archer and Sturmey 3-speeds.

Since the 1970s, they have become much less common in English-speaking countries, but in many parts of northern Europe, where bicycles are regularly used as daily transport rather than merely for sport or leisure, hub gears are still widely used.

In 2007, NuVinci started manufacturing continuously variable transmission ("stepless") ∞-speed hubs for commuter bicycles, with an increasing range of about 380%[16] (2016).

While anti-rotation washers between the dropout and axle nut have often proved adequate, wider-ranging modern systems use a reaction arm affixed to the chain stay.

An exception is the older style of Sturmey-Archer 5-speed, which used a second shift cable to change between close and wide-range sun gears, effectively giving two 3-speed hubs in one unit.

Traditional hub gears are indexed at the shifter, making operation dependent on correct cable tension (and lubrication thereof).

Most Sturmey-Archer and Fichtel & Sachs "Torpedo" systems default to top gear at slack-cable, which could make the bicycle usable for long-distance travel in flat terrain, even if a fault developed in the change mechanism.

A freewheeling hub with a sprocket suitable for narrow chain can be combined with a double or triple crankset and front derailleur, in order to provide a wider range and closer gear ratio spacing.

When both front and rear derailleurs are used with a geared hub, the result is a very wide-ranging drivetrain, at the expense of increased weight and complexity.

A particular use of the dualdrive systems is on recumbent bicycles where starting off from a standstill, or after braking hard, is very difficult if a high gear is engaged.