Cranks and Chainsets
Cranks / Chainsets
Previously part of a groupset, there are now more and more manufacturers offering a chainset solution outside the confines of a groupset. The most common is FSA, although there are many other manufacturers who make them. The rationale behind non-groupset chainsets is that many other manufacturers are able to offer a more customised option than the larger groupset manufacturers. For example, it is sometimes not possible to get a compact option with all gropupsets.
A chainset traditionally consists of the cranks and bottom bracket, but this is not always the case so it is worthwhile checking.
There are 2 types of bottom bracket and 2 different types of thread to be aware of. Most frames will have a standard 'English' thread although many high-end Italian frames will have an Italian thread. It is worth making yourself aware of the type you need prior to ordering. Bottom brackets have recently started evolving. For a great deal of time they have been a primitive axle and bearing system with the cranks bolted on. They have now evolved, in the majority of cases to sealed outboard bearings that have a 2-piece crankset bolted through it. These are in the main, stiffer and lighter than the older 3-piece system.
These are fast becoming more widespread. The idea was originally introduced in the late 80's by Suntour of Japan. The theory being that by reducing the size of the front chainrings and fitting a more compact rear cassette, it is possible to get a wider spread of usable gears than the more traditional road chainset combination. Popularity is growing as people discover the increased comfort and convenience. A sensible spread of gears is more beneficial to them than having the same options as a highly trained pro-tour rider. Although small, there is also a slight weight saving gain to be had. Unless you are seriously racing a compact would be the way forward.