A bike’s groupset is essentially the collection of moving parts on your bike that drive or stop the wheels.
From the chainset to the gear levers, the brakes to the bottom bracket, the groupset or ‘gruppo’ is what translates pedal power into forward motion.
A bike’s full groupset normally consists of the following:
These are your interface with the gears. Available as thumb switches or (less commonly) grip shifters, these select the gear that best suits the terrain.
The chainset (crankset in the US) is the large, toothed set of rings that are spun by the pedals. A triple chainset uses three rings (abbreviated to 3X, or “three by”), a double uses two (2X), and a single – of course – is just the one ring (1X). Triple chainsets have become less common, especially on mountain bikes and high-end road groupsets.
The rear cassette is the collection of sprockets on the back wheel. Each sprocket contains a different number of teeth, requiring a different degree of torque to spin the rear wheel. Teeth numbers range anywhere from nine to 50, and a cassette is usually described by stating its smallest and largest sprocket – 10-50, for example. The number of sprockets and the type of chainset is often used as shorthand for the bike’s gearing. For example, in a 2X10 bike, the pedals are attached to a double chainring with 10 sprockets in the cassette at the back.
The front derailleur (or front mech) sits above the main chainring. It’s a mechanical arm, controlled by the shifters, that moves the chain from one chainring to the other.
The rear derailleur (rear mech) is attached to the rear of the bike’s frame. Again it moves the chain across the rear sprocket when activated by the shifters.
A bike’s brakes form an important part of a groupset, improving in quality as you move through the hierarchies. Brakes come as traditional calipers (mostly road) or the increasingly popular disc-brake format (mostly MTB).
The bottom bracket is the axle through which the pedals are connected, and around which they rotate. The bottom bracket is an unexpectedly complex part of the groupset and its intricacies are best explored in a separate article.
Chains come in different lengths to suit different gearing options on bikes. For example, an 11-speed gear set-up has larger sprockets and requires more links. Sprocket widths are also important, with more compact cassettes requiring more slender chains. Higher quality chains are lighter, last longer, and less likely to snap.
The cables connect your shifters and brake levers to the relevant mechanical components.
Basically, these are all the parts on your bike that are not your frame, wheels, or finishing kit.
These components have shared a long journey of constant development and refinement for both road and mountain bikes. Over the years, three leading manufacturers have emerged, each pushing the groupset to unprecedented levels of precision and performance.
That fierce competition has led to the creation of stunning cycling technology, with today’s top-of-the-range groupsets realising an incredible engineering leap-forward for the bicycle.
And the process of refinement continues to this day, with regular componentry updates creating lighter, faster, and more durable drivetrains than ever before.
The level of constant research and development of bicycle groupsets obviously comes at a cost.
Precision machinery, endless testing, super-light materials, and expert engineering at the top end of the groupset market can be expensive, but there is good news for those at the entry level.
To ensure cycling remains affordable, each of the main manufactures uses a groupset ‘hierarchy’ system, with suites of components assembled at differing levels of quality and price.
And while the elite components offer the latest weight-saving and speed-shifting advances of the day, lower groupsets continue to be updated with many of the breakthroughs made at the higher tiers, creating a ‘trickle down technology’ effect.
This means even entry-level gruppos are packed with features and top tech contributed from the advancements in the drivetrain engineering.
When trying to choose components or a full groupset, the hierarchy system makes it easy to know instantly which components are the most advanced, use the best materials at the highest quality, and represent the best value for you.
While the big three continue to duke it out with new innovations and refinements, you may be wondering what separates each of the brands.
When it comes to finding the right set-up, your decision on whether to choose SRAM over Campagnolo, or Shimano over SRAM will simply come down to personal choice.
In terms of quality and performance, each of the three are closely comparable, so your choice will be based on price, operation dynamics, available features, and ‘feel’.
Here’s a quick summary of some of the elements that separate each of these companies.
The Italian company has created an attractive, aspirational brand image based on its long and respected heritage. ‘Campy’s’ components are known for their satisfying mechanical ‘clunks’, sensational precision, and an artistic, almost artisanal approach to product finish, design, and activation. Campagnolo’s focus is also solely on road components, which some feel adds to the quality of their mechanisms.
Shimano is the industry’s biggest player, and is almost standard issue in some quarters. That means its components tend to be more widely compatible with different systems and bikes. It’s shifting feel tends to be slicker than its two rivals, while the brand is typified by quality and performance from its rock bottom gruppos right up to its highly-regarded top-line electronic Dura-Ace Di2 systems.
The youngest of the three, SRAM’s unique selling point is its dedication to constant innovation. The US brand was behind the ground-breaking 12-speed Eagle mountain bike groupset that dispensed with most double and effectively all triple chainrings on the trail, quickly ushering in a new standard. SRAM groupsets are also sought-after for their industry-leading weight-saving properties for both road and MTB.
Groupsets are divided into road and MTB. There’s no subdivision for commuter bikes, which tend to use entry level road gruppos. The components for the trail and the road have increasingly diverged in function, appearance, and configuration over the years.
The modern MTB groupset is probably the most removed from traditional cycling componentry.
Dominating the mountain bike groupset market are Shimano and SRAM, due to Campagnolo’s decision to focus exclusively on the road market since the 1980s.
Both Shimano and SRAM groupsets are organised into tiered hierarchies, with Shimano boasting around eight complete sets (Deore to XTR), while SRAM has nine (X5 to XX1) – read our guides to SRAM and Shimano below for full details of the relative hierarchies.
MTB groupsets tend to lack the finesse of road components, and instead are designed to be tougher and more rugged to handle the rigours of the trail.
In 2012, SRAM introduced the 1X11 mountain bike shifting system with its XX1 groupset. The invention had a significant effect on the industry, with 1X systems becoming hugely popular, especially in Europe. Shimano soon introduced their own version, while the triple chainset has all but vanished from the mountainside.
Further innovations have been the launch of the 1×12 gearing of SRAMs X01 Eagle, and Shimano’s XTR Di2 electronic shifting system for mountain bikes (SRAM is expected to be releasing their own electronic MTB group soon).
Road groupsets have one purpose in mind – speed. Without the bumps, jumps and surprise tree stumps of the trail, road groupset designers have turned their attention to creating lean, clean, and obscenely fast shifting machines.
Gear ratios tend to be tighter, with pure speed and graduated climbing the focus.
Unlike MTB, 2X chainsets dominate the market. SRAM has several 1X systems (Force 1, Rival 1, and Apex 1) but cyclists are still warming to their benefits. The main exceptions to this are some Time Trial riders and cyclocross cyclists, many of whom have embraced the weight-saving advantages of the single ring.
But while roadies are yet to fully embrace the 1X, the emergence of the first 12-speed cassette from Campagnolo in the first third of 2018 is expected to inject yet more accelerated change into the industry.
Meanwhile, all three manufacturers have successfully introduced electronic shifting for their high-end groupsets; Shimano’s Di2, SRAM’s eTap, and Campagnolo’s EPS systems are now well established technologies.
So why would you buy a full groupset? Well, the reasons are many and varied…
Buying a full groupset is an option for road or mountain bike riders looking to equip a bare frame with their preferred components.
As riders improve and become more competitive, they may find they’ve outgrown their existing groupset and want to upgrade to a completely new suite of parts, saving them weight and improving the performance of the bike overall.
This can be just as true for the bike’s frame, with much-loved or classic frames – such as a classic steel-tubed steed with the geometry dialled just right – simply outliving their original drivetrains and crying out for an overhaul.
Or, as consumable parts breakdown (cassette, chain, chainrings, cables) or are damaged, it may make more economic sense to replace the entire set than individual parts.
Meanwhile, the constant progress and development in the industry means standard gearing set-ups change. Not long ago, 2×10 was the new standard on the trail. Now 1X set-ups are common-place. The road bike shift to 11-speed was once deemed cutting-edge, now Campaganolo’s 12-speed is expected to move the cycling world into another gear.
Electronic or even hydraulic shifting are among the other advancements pushing the groupset to new frontiers.
It’s understandable that competitive cyclists want to ensure their bike set-up is the best it can be, and taking full advantage of every technical improvement available.
Unless you’re replacing like-for-like, it’s worth bearing in mind that upgrading your groupset one component at a time can require some specialist knowledge.
Most components are designed to work best with those in the same brand and hierarchy. Cross-compatibility is not the norm, especially between the three different brands, although there are of course exceptions.
Entry-level bikes are sometimes sold with a mix of components, which are pre-checked by cycling engineers to ensure compatibility.
In general, however, the cable length and tensions used by Shimano shifters will only work with, for example, Shimano rear derailleurs – the same goes for Campagnolo and SRAM. A 10-speed chain, meanwhile, must be used with a 10-speed cassette and even using a chain from a different brand can cause difficulties if the width doesn’t suit the sprockets or derailleurs.
Some mechanically-minded cyclists have managed to hybridise their groupsets by applying their engineering know-how, but as the precision of engineering becomes increasingly precise, mixing and matching becomes increasingly rare.
This applies to combining MTB and road groupsets too, with both families of components deviating more as time goes on.
If you are determined to upgrade incrementally, The Hub’s advice is to stay within the brand and ensure your using the same gear configuration – for example, if you have a 10-speed cassette, then you can usually upgrade to a 10-speed derailleur from a different hierarchy as long as it’s the same brand.
Shimano components are known to be the best for incremental upgrading, but even their hierarchies are becoming more detached from each other as advancements are made.
However, the good news is that groupset parts that aren’t connected can easily be mismatched, especially on MTB, and you may find this on the stock components of some high-spec bikes. Want SRAM brakes with Shimano gears – knock yourself out! This isn’t so true for road bikes, however, which often have the shifters and brakes incorporated into one unit on the bars.
Before you buy, check with Chain Reaction Cycles Technical Support Team.
If you are at a complete loss as to which groupset to go for, there are ways of steam-lining your decision making.
Here’s some quick steps to help you narrow your search:
Establish your budget
This should help you eliminate, Guess Who-style, a large swathe of the groupsets to get your search narrowed down. If you plan on being competitive in the sport, then aim for the best groupset you can afford.
Make sure the groupset fits your bike
Is the hub in your fancy carbon wheels compatible with your new groupset? Will the huge new cassette fit into your frame? Use the dimensions of your existing groupset as a guide or check the specifications for the bike from the manufacturer’s website or catalogue.