What’s a groupset? part 1: The collective anatomy of a bicycle

For the uninitiated, hearing the words “frameset,” “groupset” and “wheelset” being thrown about in cycling circles can be intimidating. What are these things anyway? These labels refer to the three major collections of bicycle parts, each one commonly sold as a unit.

These days, the core of a bicycle is made up of the frame; a corresponding fork and its headset bearings; and a compatible seatpost. All these parts are collectively called the frameset.

Giant’s TCX SLR frameset from 2014. Note the 15mm through-axle fork.

Apart from providing steering, and perhaps suspension for a mountain bike, a frameset doesn’t do anything on its own. It is the foundation to which additional mechanical parts are installed to perform power transmission and braking. The most obvious of these is the wheelset, which consists of hubs laced with spokes to rims, then tensioned. For bikes that have disc brakes, the hubs have a facility to mount a brake disc or rotor.

Shimano’s WH-RX31 road bike wheelset for disc brakes; the rotors are sold separately.

After adding in personal-fit items such as a compatible stem, saddle and handlebars, that leaves the actual guts of the bike. This is the modern groupset (or “gruppo” for short), and it consists of the shifters, brake levers, chain, cassette sprockets, crank arms, chainrings, bottom bracket parts, derailleurs, and brake hardware. Some of them include pedals, too.

Shimano’s full 105 groupset, in its 10-speed 5700-series incarnation. As this is a road bike groupset, the brake levers and shifters are integrated into one unit.

In years gone by, groupsets encompassed even more parts; it was not unusual to see wheelsets, headset bearings and seatposts marketed under one groupset banner.

Shimano’s Dura-Ace 7400-series “25th Anniversary” groupset, on display at Shimano Cycling World in Singapore. Note the headset and seatpost at the far right, as well as the Seiko wristwatch.

Parts manufacturers such as Shimano, SRAM and Campagnolo promise that all the parts of a certain groupset are made to work best together. This is most obvious in how certain groupsets make up 9-speed drivetrains, for example, while others are 10- or 11-speed – 11-speed shifters and chains aren’t meant to be used with 9-speed cassettes. This “best compatibility” principle for groupsets also shows in more subtle things such as brake caliper actuation and cable pull.

There also exists a hierarchy of groupsets for a certain manufacturer’s wares. Shimano, for example, has the following hierarchy from top to bottom tier:

  • Dura-Ace & Dura-Ace Di2
  • Ultegra & Ultegra Di2
  • 105
  • Tiagra
  • Sora
  • Claris

The top tier groupset, Dura-Ace, is what Shimano equips its sponsored professional cycling teams with. These are cost-no-object, no-expense-spared parts made of exotic materials such as titanium and carbon fiber, while employing hollow construction techniques made to shave the last gram of weight.

Every tier down from Dura-Ace foregoes more of the cutting-edge tech, swapping in progressively more affordable materials such as aluminum and steel, and introducing less hollow parts, as amateur and recreational riders don’t require light weight as much. For the even lower tiers, the number of rear cogs goes down as well. With time, though, all that cutting-edge technology employed in the top tier eventually trickles down to the lower tiers.

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