Road Bike Groupsets: What to Know

August 22, 2016
Road Bike Groupsets: What to Know

A groupset comprises of brakes and the drivetrain which is thought of as the bike's engine room. The drivetrain consists of the cranks, chain rings (front cogs), chain, cassette (rear cogs), derailleurs and shifters. It's a closed circuit which propels the bike. As you spend more money, the efficiency, durability and shifting performance increases while the weight decreases.

As you work up the groupset hierarchy, the materials change. Entry level groupsets are made up of mostly low-grade alloys which move to the higher-grade alloys, and then the highest-grade alloys, carbon fiber and titanium for the top-of-the-line options.

In this article we explained what you need to know when it comes to groupsets, including the difference between mechanical and electronic, the features of every groupset from each manufacturer and other differences you might come across when trying to decide on the best groupset for you.

The difference between mechanical and electronic groupsets

Each groupset provider offers multiple mechanical and electronic options with different names and operating procedures. In the electronic shifting variants, Campagnolo has 'EPS' which stands for 'Electronic Power Shift', Shimano has 'Di2' which stands for 'Digital Integrated Intelligence', and SRAM have 'eTap', which stands for 'electronic tap'. Campagnolo and Shimano both use wires that actuate the front and rear derailleur via the trigger at the shifters. SRAM eTap is the first wireless groupset using a proprietary protocol called Airea working in a similar way to ANT+ or Bluetooth to communicate between the shifters and derailleurs.

Mechanical shifting works via cables that are attached to the shifters, and run via the frame (internally or externally) to the front and rear derailleurs. Moving the shift lever pulls or releases the cables which then activates the derailleurs to either shift up or down. The benefits of mechanical shifting include; weight reduction with no battery or junction boxes required, less expensive and provides a more 'natural' feel. The downsides of mechanical shifting include; shifting not as flawless as it relies on the cables to be in perfect working order, frames with long sections and acute angles can make installing cables difficult, frames with acute angles can also decrease braking performance because cables aren't optimally orientated and needs regular adjustment.

As mentioned, electronic shifting works via wires attached to the shifters and derailleurs that transfer a signal, or via wireless technology similar to boothtooth or ANT+ devices. The benefits of electronic shifting include; precise shifting, does not go out of set adjustment, easier shifting at the lever, two shift points via the use of satellite shifters, frame shape not an issue, programmable shifting and downloadable information on shifting habits and efficiency. The downside of electronic shifting includes; the system breaking down if batteries are not charged, increased price and generally heavier than mechanical versions.

Shimano

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The clear market leader, Shimano has the largest range of road specific groupsets and is a favorite with professional teams too. Shimano pioneered the STI (Shimano Total Integration) lever which is the most commonly used lever today. The ingenious system allows the user to change gears up or down and brake with one hand. The right-hand lever controls the rear derailleur and front brake (brake orientation can change based on country), while the left-hand lever controls the front derailleur and rear brake. The STI lever allows for multiple shifts and means never having to move your hand position to slow down or change gears. To operate, the brake lever swings inwards to pull the derailleur in one direction, with a smaller shift lever sitting behind the brake lever which releases the cable for the derailleur to go the opposite direction.

Most of Shimano's groupsets are designed to work together (as long as they share the same number of gears), making it possible to mix componentry, although for optimal performance it's best to keep uniformity.

Below is a brief description Shimano's groupsets.

  • Claris: Claris is Shimano's entry level groupset best suited to recreational or fitness bikes. It has an 8-speed cassette and comes in either a double or triple crankset providing a multitude of gearing options. The triple is available as a 50 / 39 / 30 tooth crankset, while the double is available in a traditional 50/34 tooth compact set-up or a smaller 46 / 34 option. Claris uses simple and intuitive dual control levers with gear indicators so you'll always know what gear you're in without having to check the cassette at back. Claris also has an option for flat bar road bikes, a purpose built shift lever known as 'RAPIDFIRE Plus'.

  • Sora: Sora is similar to Claris but adds an extra gear with a 9-speed cassette and is also available in a double or triple crankset. Sora has a different aesthetic to Claris and features a four-arm crank instead of five. Sora also offers 'RAPIDFIRE Plus' shift levers for use on flat bar road bikes.

  • Tiagra: Tiagra appears on many entry level bikes priced just over the AU$1,000 mark and gets another gear with a 10-speed cassette. While still seen on recreational bikes, Tiagra is common on entry level road bikes or off-road adventure bikes thanks to its combination of durability and performance. The crankset is also available in a double and triple, with up to a 34T sprocket available on the rear cassette providing a huge range of gears. In order to accommodate the larger sprocket, Tiagra's rear derailleur comes in a long and short cage option. The options for cranksets increases by one, with a 'mid-compact' 52/36 gear option available which has proven popular in upper-tier groupsets.

  • 105: 105 is considered Shimano's first step into the performance orientated groupset market and is the most popular groupset on road bikes. Aimed at the entry to intermediate level road rider, 105 is durable, reliable and features much of the technology found on the more expensive Ultegra and Dura-Ace. 105 has 11 cogs on the cassette, the same as Ultegra and Dura-Ace, so at this point you can change and swap componentry with a minimal decrease in performance. Interestingly, there are three different crankset options for 105; a four arm double crankset, a five arm double crankset and a five arm triple crankset. 105 is the first groupset to provide a traditional 53/39 crankset, while still offering a mid-compact (52/36T) and traditional compact (50/34T) set-up. A 32T sprocket is the largest 105 can accommodate, and like Tiagra, the rear derailleur comes in a long and short cage option.

  • Ultegra: Ultegra is for intermediate to high-level road riders with almost identical features to Dura-Ace, albeit with a weight penalty. Many professional teams will use Ultegra cassettes and chains mixed with Dura-Ace components to save money in the off season. Ultegra is only available in a double crankset with various combinations; 53/39, 50/34, 52/36 and 46/36. One of the big advantages of Ultegra is the longer derailleur cage which allows for a 32T sprocket to be used, unlike Dura-Ace which can only accommodate a 28T at a maximum. (The new 9100 and 9150 Dura-Ace release can accommodate a 30T sprocket).

  • Ultegra Di2: Ultegra also comes in an electronic version known as 'Di2'. Unlike the mechanical version which requires cables to change gears, Di2 uses motor-driven mechanics at the front and rear derailleur to provide a crisp perfect shift, every time. The Di2 version is slightly heavier than mechanical (about 80g) but can be activated at two different locations thanks to satellite shifters, which are commonly found on the inside of the drops for sprinting, or top of the handlebars for climbing.

  • Dura-Ace: Dura-Ace is the gold standard of groupsets from the Japanese company. The groupset uses a mixture of carbon fibre, titanium and high-grade alloys to create precise shifting and unmatched reliability. 17 teams at the 2015 Tour de France used Shimano Dura-Ace as their groupset of choice, highlighting its status in the professional ranks. Dura-Ace shift levers have a shorter lever stroke and more ergonomic design to improve rider feel and comfort. A longer derailleur cage is used to accommodate a 30T sprocket on the new Dura-Ace, where previously a 28T sprocket was the largest available. The derailleur cage borrows technology from the MTB world, sitting lower and more central to improve aerodynamics and reduce damage in the event of a fall.

  • Dura-Ace Di2: The latest edition of Dura-Ace Di2 gets a significant upgrade from the current wired-only (and Windows PC-only) setup with wireless communication, for both ANT ‘Private’ (works with ANT+) and Bluetooth connectivity. The upgrade, in association with Shimano’s soon-to-be-released ‘E-Tube Project’ app, will allow for complete customisation of shift settings, shift button purpose, shift speed, and wireless firmware updates. 'Syncro' shifting is another new feature that provides an almost automatic response in front shifting based on your choice of rear gear.

Campagnolo

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Campagnolo is the longest standing groupset manufacturer and has been innovating cycling for over 80 years. Many riders have a romantic notion of the Italian company thanks to its longevity and reputation for high-end products. The vast majority of work still takes place at Campagnolo's headquarters in Vicenza, Italy.

Campagnolo has five groupsets but enters the road market at a higher price point than SRAM and Shimano. It's rare to see a Campagnolo groupset on a budget road bike, but very common on high-end Italian road bikes and expensive bespoke creations.

Campagnolo levers feature curved hoods to improve ergonomics and unique shifting, a single lever behind the brake lever is used to go to an easier gear, while a small thumb lever on the inside of the hood is used to go into a harder gear. This design makes it virtually impossible to mistake an upshift for a downshift and vice versa. It's also said to allow easier access to shifting while in the handlebar drops and covering the brakes.

Below is a brief description of Campagnolo's groupsets.

  • Veloce: Veloce is the entry level groupset for Campagnolo but is similar to Shimano Tiagra or 105 and SRAM Rival. Veloce means 'fast' in Italian which indicates it leapfrogs the recreational or fitness bike and jumps straight into performance road bikes. Even at this entry level, the Veloce levers feature 'POWER-SHIFT' which allows you to upshift three sprockets at a time. Veloce is a 10-speed groupset option that comes in a short or medium cage derailleur to cater for 29T large sprocket. The crankset comes in either a compact 50/34 or traditional 53/39 set-up with limited crankset lengths of 170, 172.5 and 175 mm.

  • Athena: Athena is Campagnolo's first 11-speed groupset but will be replaced with the new 'Potenza' groupset at the end of 2016.

  • Potenza: Potenza is an Italian noun for power, intensity and strength and is the new mid-range groupset that will replace Athena and compete again Shimano Ultegra and SRAM Force. Potenza features a four-arm crank and re-designed front and rear derailleur to improve shifting. While the Potenza features resemble Chorus, Record and Super Record, a mix of alloys is used throughout the groupset to cut down costs. The introduction of an 11-32 cassette is a welcome addition and requires a change in rear derailleur geometry to accommodate the larger range. The new design allows owners to fit compact (50/34T), semi-compact (52/36T), and standard (53/39T) chainrings to the same crankset.

  • Chorus: Campagnolo describe Chorus as 'the perfect solution for sophisticated cyclists searching for Super Record performance at a more competitive price'. That price is still likely to be on bikes in excess of $5,000 with high-grade carbon fibre featuring throughout the groupset. Chrous has the regular chain ring options; 53/39, 52/36, 50/34, but still only the three crank lengths; 170, 172.5, 175 mm.

  • Chorus EPS: Chorus is the first groupset in Campagnolo's range to have the option of electronic shifting known as 'EPS' (Electronic Power Shift). The shifting allows you to run up and down the cassette. EPS allows the rider to make adjustments on the fly, the "mode" buttons allowing riders to check battery charge, make fine adjustments to the rear or front derailleur, and set the zero position of the rear and front derailleur.

  • Record: Record is a professional quality groupset despite having one groupset sitting above it, it's comparable to Shimano Dura-Ace. Record combines carbon fibre and high-quality alloys to create a groupset that is lightweight, provides impeccable shifting and looks stunning. Record hubs feature 'USB' (Ultra Smooth Bearings) ceramic bearings to 'further enhance the wheels' smoothness and reduce weight.'

  • Record EPS: The electronic version of the already elite Record groupset. At this level it is possible to 'manage your bike fleet and personalise the way your Record EPS groupset works according to your needs' via the 'MyCampy App'. You can even add the information gathered from your shifting habits to your usual riding metrics like power, speed, heart rate and distance.

  • Super Record: As previously mentioned, Campagnolo have been innovating for over 80 years, trying to push the limits of performance and with their elite performance groupset, they think they've found it. The Record groupset was already so good Campagnolo could only come up with one name for a groupset even better, 'Super Record'. Campagnolo describe this as, 'the maximum evolutional and technological expression of a mechanical drivetrain for bikes'. The differences between Record and Super Record are minor, mostly based around the inclusion of titanium and ceramic bearings which further decrease weight and improve efficiency. Super Record is for elite cyclists or ones without budget restraints. Super Record EPS even more so.

  • Super Record EPS: If Super Record is for 'elite cyclists or ones without budget restraints', Super Record EPS is even more so. The absolute top of the tree when it comes to groupsets, Super Record spares no expense or design innovation to create the ultimate groupset.

SRAM

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SRAM has four road specific groupsets available and is considered the lightest groupset at any price point.

As well as being lightweight, SRAM is well known for its 'YAW' angle technology. In this, SRAM's front derailleur cage has the ability to rotate as the gears change to maintain a 'consistent angular relationship with the chain'. This optimises chain alignment and is said to improve shifting performance while reducing chain rub.

Shifting with SRAM is controlled by 'Double Tap' technology, utilizing only one lever to change up and down which is separate from the brake lever. Double Tap features throughout SRAM's road range and incorporates 'ZeroLoss' resulting in 'instant and precise' gear changes. It's a bit odd to explain, but a single shift of the lever actuates the derailleur in one direction, continue to push the lever and the derailleur is actuated in an opposite direction.

Below is a brief description SRAM's groupsets.

  • Apex: Apex is the entry level groupset from SRAM featuring a 10-speed rear cassette, two chainrings up front and a five-arm alloy crankset. The front chainrings are a traditional compact set-up featuring a 50 tooth large chainring and 34 tooth small chainring, perfectly suited for touring or recreational riding. Apex comes with an 11-32 cassette, perfect for beginners who are after easy pedaling gear ratios. The large cassette range offers more coverage than a standard triple crankset, eliminating the need for a triple crankset at all according to SRAM (who were first to bring the idea to road bikes). To accommodate the wider gear range the rear derailleur has a longer cage and slight variation in geometry.

  • Apex x1: As the name suggests, Apex x1 features only one front chain ring, creating a single derailleur drivetrain. The technology is simple, easy to use and removes potential mechanical issues by having less moving parts. The 1x is available for drop or flat bar road bikes, and features an enormous 11-42T cassette. There are four options for the chain rings; 38, 40, 42 and 44T, all of which feature 'X-SYNC' tooth profiles that are 'tall and square' to 'engage the chain earlier than traditional triangle shaped teeth'. Crank arms are only available in 170, 172.5, and 175mm. The 1x setup is ideal for commuters or those into adventure and/or off-road riding like cyclocross.

  • Rival: Rival is SRAM's answer to Shimano's 105 groupset aimed at the entry level rider with a lot of technology trickling down from the Force and Red groupsets. A step up to Rival gives you an extra gear on the rear cassette (11), providing 22 gears in total and a huge range with up to an 11-36T cassette available. Rival weighs less than Apex, has hydraulic disc options and a greater range of crankset lengths; 165, 167.5, 170, 172.5 and 175 mm. The chainrings are available in 52/36, 50/34, or 46/36, the traditional 53/39 set up saved for Force and Red. Rival still features aluminium crank arms and machined alloy ring and spiders.

  • Rival x1: Rival x1 is similar to Apex but extends its chain ring options (38, 40, 42, 44, 46, 48, 50T), sheds a little weight, and has an even larger rear cassette available (10-42T).

  • Force: Force is similar to Rival in a lot of ways but at this price point carbon replaces aluminium, making an appearance in the rear derailleur and crank arms. The crank arm utilizes unidirectional carbon which is matched to a forged alloy spider, creating a lighter and stiffer crankset available in 165, 170, 172.5, 175 and 177.5mm. A traditional 53/39 set up is available along with 52/36, 50/34 and 46/36 options. Force is for intermediate to elite level racers looking for a lightweight, high performing groupset. Force too is hydraulic disc compatible and available in a 1x version. The rear cassette option extends to an 11-32 option but requires a longer cage version of the rear derailleur.

  • Force x1: Force x1 had been predominantly used for Cyclocross at an elite level as Red is currently only available in a double crankset option. The performance and reliability of 1x makes it perfectly suited to the demands of cyclocross, but it has started to be seen more on crit specific or triathlon bikes that don't require an extensive gear range, or never get into the small chain ring. The chain ring choice is impressive; 38, 40, 42, 44, 46, 48, 50, 52 and 54 enabling you to customise your drivetrain to any style of riding.

  • Red: Red is at the top of SRAM's tree in terms of performance, featuring on professional teams and International level triathletes. SRAM describe Red as the 'pinnacle of road racing technology' and it's the lightest groupset on the market. Carbon fibre features more heavily on Red, and the introduction of ceramic bearings further improves performance. The shifters feature 'ErgoFit' technology which SRAM say 'improves grip and finger wrap with reduced diameter, providing better control and a better transition to the bar'. The crankset features a 'completely hollow construction all the way to the spider' to further improve stiffness and weight over Force. The mechanical Red 22 can cater for a large cassette sprocket up to 32T, whereas eTap can only cater for a 28T sprocket as a maximum.

  • Red eTap: SRAM eTap is the first wireless groupset using a proprietary protocol called Airea to communicate between the shifters and derailleurs, via tiny removable and interchangeable batteries located on each derailleur. The technology mirrors Formula 1 race cars by having left and right side shifting paddles. The right shift paddle produces an up-shift, the left shift paddle produced a down-shift, and hitting both paddles together shifts the front derailleur up and down. The total weight for the groupset is a still slightly heavier than mechanical Red, despite there being no cables required. Remote satellite shifters in the form of 'blips' can be placed anywhere on the handlebars to suit the rider's preference and potentially improve aerodynamics. The 'Ergoblade' levers also come equipped with larger paddles to ensure the rider has complete control and doesn't miss a shift. Despite the tiny size of the batteries they have a 1,000km range and can be re-charged in 45 minutes according to SRAM. eTap can only currently fit a 28T sprocket but look out for a wider cassette range, hydraulic option and 1x alternative in the future.

Gearing options

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Gear ratios on road bikes vary depending on the purpose of the bike. Gear ratio is a combination of the number of chain rings on the front of the bike, the number of teeth on those chain rings, the number of cogs on the rear cassette and the number of teeth on those cogs.

Traditionally there will either be two or three chain rings on the front, although in recent times some road bikes have followed the mountain bike trend of having a single chain ring. Having a single chain ring minimises potential mechanic issues and simplifies the shifting to the rear cassette. The majority of road bikes will have either two or three front chain rings, although three front chain rings (known as a 'triple') are commonly reserved for recreational, entry level or touring bikes.

Bikes with two front chain rings are normally split into a 'regular', 'compact' or 'pro-compact' (also called a 'mid-compact' or 'semi-compact' set up). A regular set-up sees the large chain ring with 53-teeth and the small chain ring with 39-teeth and is most commonly used by professional riders. A compact set-up sees the large chain ring with 50-teeth and the small chain ring with 34-teeth which provides easier pedaling ratios when compared to a regular set-up. A relatively new option, mid-compact set-up, is in between the two, the large chain ring with 52-teeth and the small chain ring with 36-teeth. A common crankset option for commuting, fitness or cyclocross bike has a 46 tooth large chain ring, paired with a 36 tooth small chain ring.

A 'triple' will normally have a 50-tooth large chain ring, a 39-tooth medium chain ring and a 30 tooth small chain ring.

The front chain ring set-up is the foundation for the gear ratios which the cassette on the back complements. The cassette is made up of a number of cogs or sprockets which can be changed to make the gear ratio easier or harder. Modern day cassettes feature 11 sprockets providing 22 gears when paired with two front chain rings but older and more entry level groupsets have either 8, 9 or 10 speed cassettes. Groupsets with a different number of cassette sprockets require a components throughout to work effectively, you can't simply swap an 8-speed chain with an 11-speed chain and expect it to work. Equally, even groupsets with the same amount of gears (105 and Ultegra for example) will not perform as well when the components are mixed, than if they are all the same.

fullpage shimano dura ace 9100 11 30t cassette

The sprockets and chain of 11-speed groupsets are thinner to accommodate the extra gears and provide smoother shifting. The required tolerance of 11-speed groupsets is much tighter than 8, 9 or 10-speed groupsets, meaning much careful tuning and fine adjustment.

The most common ratio on a cassette is an 11-25 or 11-28 whereby the smallest cog has 11-teeth and the largest cog has either 25 or 28-teeth. The cogs in between these two have a spread of teeth aimed to make shifting between gears smooth. The larger the difference between the smallest and largest cog on the cassette, the greater the chain has to move and the less consistent a rider's cadence becomes between gear changes.

Choosing a bike with smaller chain rings on the front and a larger ratio cassette on the back will provide a greater spread of gears and easier pedaling ratios. A bike with larger front chain rings and a smaller ratio cassette on the back will be more targeted for speed and provide less range of gears.

Crank length

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Crank length tends to varying according to the size of the bike and rider height. Typically groupsets will range between 165 mm and 180 mm but aftermarket creations can be made to any length. Most bikes will come with cranks between 170 mm and 175 mm. There is much debate about what constitutes the 'correct' crank length but comfort and efficiency should be the two main priorities when deciding. If you are getting issues with your knees, hips or lower back, look at your crank length is addition to the usual factors like seat height, frame size and flexibility. Adjusting crank length will also require an adjustment to your seat height and potentially other areas such as handlebar height and reach.

Longer cranks

Longer cranks create more torque due to the increased leverage, but require greater force to turn over. The longer the crank the harder it is to maintain pedal efficiency, as it is harder to maintain a consistent leverage throughout the pedal stroke when compared to a shorter crank. The longer crank will also require greater range of motion, producing a straighter leg at the bottom of a pedal stroke and a more acute angle at the top. Ground clearance will also be reduced which could be problematic on tight corners or if you plan to go off road. Another potential turning issue is the reduced clearance between your toe / shoe and the front wheel.

Shorter cranks

Shorter cranks require less effort to turn over, but have less leverage and produce less torque as a result. A sign your cranks are too short is if you have trouble producing power on flat roads but not riding up hills. Track riders will typically opt for shorter cranks to keep their cadence high and reduce the initial force required to turnover a gear, as they are on a fixed gear and can't change up or down as their pace increases or decreases. Shorter cranks require less flexibility as the range of motion is reduced, but this reduced range of motion can also be an opportunity to move the rider into a more aggressive position without compromising hip angle or reducing power.

Brakes

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Type and quality of brakes will differ from groupset to groupset. There are now four brake types available, none of which are necessarily dependent on the price. The four options are cable operated rim, cable operated disc brakes, hydraulic rim and hydraulic disc brakes.

Cable operated rim brakes feature on the most basic of bikes, right up to the most expensive bikes. Professional riders use cable operated rim brakes as currently disc brakes are banned, although this looks set to change in the near future. Cable operated disc brakes will typically feature on entry level bikes, while hydraulic disc brakes will typically feature on more expensive bikes. Road bikes are typically built to handle either rim brakes or disc brakes, and it’s often not possible to swap brake types on the same frame.

As with most other elements of the groupsets, as the price increases so does the quality of materials used, which provides lower weight, better modulation (brake control), durability and reliability.

We hope this guide has been helpful and provided some valuable information. You can browse BikeExchange for road bike groupsets and bike parts, or search for your local bike shop to get further assistance. Also check out our ultimate guide to buying a road bike for an even more detailed breakdown of what you should be looking for when buying a bike.


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