The Rohloff Speedhub is an epicyclic internal hub gear for bicycles, developed and patented by Rohloff AG. It has been manufactured and marketed by that company since 1998. The Speedhub 500/14 has 14 equally spaced, sequential, non-overlapping gear ratios operated by a single twistgrip. The overall gear range is 526%, meaning the highest gear is 5.26 times as high as the lowest gear. Individual gear shifts when shifting up give an increase of about 13.6% (equivalent to a decrease of about 12.0% when shifting down). The Speedhub is more expensive than competing bicycle gear systems (both hub gears and derailleur gears), and it is some 100 grams heavier than a comparable set of derailleur gears, but offers about the same gear range (and at its ratio of 5.26:1 more range than a typical road bike ratio of 4.28:1 with 50/34 chainrings and 11 to 32 tooth cassette) while requiring significantly less maintenance and having a longer service life. It is therefore mainly used in expensive touring bicycles and in mountain bikes, where its lack of (vulnerable) external components is useful. Versions There are different options available for the Speedhub to cater for different kinds of bicycle frames and applications that the bicycle it is to be fitted to might be used in. OEM (original equipment manufacturer),or OEM2 (for frames with the IS 2000 international standard disc brake mount). Either of the above comes with the following three options: DB (Disc Brake) EX (external gear mechanism) T (Tandem) option which could be any of the above but comes with longer cables. There also two types of axle available: the solid TS (Touring Axle), and the lighter, hollow CC (Cross Country) axle: the CC can be used with quick release levers. , the Speedhub is available in three colours: silver, red or black. Finally, the Speedhub is available with either 32 or 36 spoke holes. The above options are combined so a particular unit could be a Speedhub "CC DB OEM2 silver, 32 spoke holes" or a Speedhub "TS EX OEM black, 36 spoke holes" for example. Technical Operation The internal construction of the gear hub consists of three planetary gear series, connected one after the other, selectively engaged depending on the user’s gear choice, each containing a stepped planet. The first two gear series provide seven ratios, and the third a complete range reduction, doubling the number of speeds to fourteen.