Original sentence: Groupsets commonly include: crankset comprising cranks and chainrings; chain; rear gear cogs or cassette; gear shift levers; brakes; brake levers; cables; front and rear gear mechanisms or derailleurs.Shimano products include drivetrain, brake, wheel and pedal components for leisure, road and mountain bikes.The Italian firm Campagnolo is a competitor as the other major manufacturer of road groupsets.These components are generally organised and sold as groupsets intended to be supplied as a near complete collection of a bicycle's mechanical parts
Edited sentence: For example, maintining some Shimano parts require propietary Shimano tools.From an engineering perspective, Shimano creates optimized systems at the grouppo level.Often these innovations result in propietary technologies.Shimano is innovative.Shimano products include drivetrain, brake, wheel,headset, seatpost, and pedal components for leisure, road and mountain bikes.Shimano seems unwilling to delay the introduction of an innovation to build consensus for an industry standard and instead introduced the innovation as part of yearly incremental improvements.Since innovations are introduced ever year as part of a gruppo, this cycle is endless.The Italian firm Campagnolo is the primary competitor as the other major manufacturer of road grouppo.The parts of the system are optimized for use in the system and are often difficult to maintain, repair, or replace with other components.There is no major comtetitor in mountain bike gruppos.These components are generally organised and sold as gruppos intended to be supplied as a near complete collection of a bicycle's mechanical parts.This almsot guarentees that at the time of release no part from another manufacturer can be substituted for a Shimano part in the gruppo