Groupsets are the collections of parts that makes up a bike's gearing and braking. This comprises the shifters, crankset, front and rear derailleurs, chain, rear cassette and brakes.
Components of a groupset
There are four types of front crankset found on road bikes.
The first is a standard double, as used by pro riders. It consists of two front rings one large 53-tooth outer ring and a smaller 39-tooth inner ring.
The second and most common type of crankset is a compact. This uses a smaller inner ring (34-tooth) to allow for a lighter bottom gear to make climbing steeper slopes easier. You can read more about compact gearing here.
There's also a halfway house between standard and compact gearing, in the form of Pro-Compact (aka Semi-Compact) crankset, which use a ring combination of 52 and 36.
The last type – and one that has fallen a little out of favour since the introduction of the compact crankset – is the road triple. This usually combines a 50-tooth outer ring, a 39-tooth middle ring, and an inner ring that has just 30 teeth. Road triples offer the widest and lightest bottom gear but nowadays they are only really found on lower-priced entry-level road bikes, although they are still favoured by touring cyclists riding bikes laden with the extra weight of luggage.
The crankset spins on bottom bracket bearings that are housed or threaded into the bicycle frame. Bottom brackets are available in a staggering array of configurations; you might find our complete guide to bottom brackets useful.
Cassettes come in a huge range of sizes. Professional riders and time triallists favour a rear cassette with as few jumps between gears as possible, because it makes it easier to maintain a consistent pedalling cadence as you accelerate or climb. These close ratios are most commonly 11-25, although they do go as low as 11-23, where there will be a maximum of two teeth between jumps.
Most people favour a cassette with a slightly wider spread of gears to make climbing easier. The most commonly found setup on standard bikes is a 11 or 12 to 27 or 28.
Recently, all of the gear component companies have released even wider cassettes, designed for serious mountain climbs. SRAM has its WiFli cassettes, which go as large as 11-32, Shimano offers a 32 in its 10-speed systems and a 30 in 11-speed, while Campagnolo offers up to 30-teeth. To put this in context, mountain bikes commonly use 34 or 36t as the largest cog.
The groupset brand and number of gears dictate the chain. The more expensive chains often have smoother, more durable and corrosion resistant coatings than their cheaper counterparts.
Additionally, some more expensive chains have the pins and plates drilled to remove weight. A chain is a wear item though, and is cheap to replace, so the one included with a bike isn’t worth stressing about.
Derailleurs are the components that move the chain between rings at the front and across the gears of the rear cassette. Each different brand offers its own design, but the principle is generally the same, with a cable connected to the shifters doing the pulling.
Both Shimano and Campagnolo offer electronically-actuated derailleurs.
Road bike gears are changed using gear levers that are integrated with the brakes. Each company offers its own design, and while all shift gears, they each have a particular way of doing it.
By far the most common is Shimano's STI (Shimano Total Integration). The STI design uses two levers – one sits just behind the brake lever and the brake lever itself, which doubles as a gear shift lever.
Swing the right-hand brake lever inwards on Shimano and the rear mech shifts the chain upwards on the cassette (to a lighter gear). When the inner lever is pushed inwards the chain is shipped down the cassette (to a harder gear). STI is designed to allow multiple upshifts at one time, so the further you push the brake lever, the more gears you'll shift (up to a maximum of three).
The left-hand shifter operates the front derailleur, the brake lever swings inwards to move the chain onto the larger chainring, the small lever moves it to the smaller ring. Cheaper Shimano shifters, such as Sora or Claris, offer a slightly different setup, with the small lever moved to the top of the hood and operated by the thumb.
SRAM's system is called Double-Tap. Double-Tap has one lever on each side (just behind the brake lever). Push the right-hand lever in until its first click, and the chain will drop into a smaller gear on the cassette, but keep pushing the lever until it hits a second click (or double tap) and it'll rise up the cassette to a lighter gear. The left-hand lever's first click shifts the chain to the smaller front ring, and the second click moves it up onto the bigger chainring.
Campagnolo's Ergopower uses a combination of a lever sitting behind the brake lever and a small button shaped lever on the inside of the hood (the rubber coated housing is referred to as the hood). The right-hand lever swings inwards to make the chain rise up the gears, while pushing the button shifts the chain into harder gears. Pushing the lever further or the button through more clicks allows Campagnolo users to shift multiple gears at a time. The left-hand lever lifts the chain onto the bigger chainring while the button trigger drops it onto the smaller chainring.
Until recently, brakes were simple items – cable-operated rim brakes were your only option. Now there’s the choice of cable-operated rim and disc brakes, or hydraulic (fluid based, like a car or motorbike) operated rim or disc brakes. Brake choice will be dictated by bike choice, and cable-operated rim brakes are still the most common at all price points.
SRAM has all four options available, while Shimano offers all but hydraulic rim brakes. Campagnolo currently only offers cable-operated rim brakes.
Price vs benefits
Like most components, groupsets vary in price a great deal. So what benefits do the more expensive groupsets bring?
Keith Bontrager famously once said of bicycle parts: "Strong. Light. Cheap. Pick two." A lighter bike will always accelerate, climb and brake better than a heavier one, but without giving up strength, something has to give. Whether you're looking at groupsets, wheels or even complete bikes, reduced weight is often the major contributor to increased cost.
With all the road groupsets, the more you spend, the lighter they get. Often the performance of the groupset plateaus at the second tier, with weight being reduced for the extra expense. For example, the difference between Shimano's top two tiers, Ultegra and Dura-Ace, is 258g, while the difference between SRAM's top-range RED and second-tier Force is closer to 400g.
These weight differences are the result of more expensive materials and refined, or more time-consuming, manufacturing processes. In addition to further machining, hole-drilling and high precision, more expensive components often use materials such as carbon fibre, titanium, lightweight aluminium and ceramic bearings to achieve the pinnacle in low weight.
If you're spending more money on a groupset, you'd expect it to outlast a cheaper option. Durability does improve with price, but our experience is that durability also plateaus at the second-tier options, and in some ways, actually starts to decline at the very most expensive option.
The more expensive technical components are built with greater precision, refinement and materials that lend themselves to greater longevity. This is apparent in derailleurs and shifters where the cheaper options will develop play and slop overtime, while the better parts often remain like new.
Wear items, such as cassettes and chainrings, however, are often the reverse of this. Cheaper options are made of heavier, but more durable steels, while the more expensive versions are made with lighter, but softer aluminium and titanium metals.
In addition to the benefits of reduced weight, more expensive groupsets find other ways of increasing performance. Most noticeably, higher priced options provide a smoother, more precise and quicker shift between gears. This includes reduced effort at the lever, something that becomes apparent once you've been on the bike for a few hours. It's an area where electronic gears set the benchmark; ultimate precision and speed at the simple push of a button.
Another performance example is increased crankset stiffness to provide crisper shifting and more efficient power transfer from the pedals to the rear wheel. This is achieved with more complex designs and materials that increase strength and stiffness, but don't add weight.
Braking raises an entire new list of benefits as prices goes up. Simply put, the more expensive brakes are stronger, offer better feel and control and stop you with less hand force required.
Besides offering extra gears, it's common for the more expensive groupsets to offer additional features, however subtle they may be. An example of this is the screw-adjustable brake lever position on Shimano's Ultegra and Dura-Ace shifters for improved ergonomics, something that's otherwise done with stick-in rubber pad spacers on cheaper models.
Another example of this is with Shimano and Campagnolo now offering its higher-end cranksets in a universal size that's cross-compatible with compact, semi-compact or standard sized chainrings. This means that if you ever wish to change your chainring sizes, you can do so without needing an entire new crankset.
The major brands and their groupset hierarchies
On the road there are three major brands making these parts, the first, biggest and most widely used is Shimano. Next is the newest manufacturer on the market, SRAM, and finally, the oldest, Campagnolo.
Japan's Shimano offers the widest range of groupsets for road cycling.
The range starts with the budget priced Claris, which is usually found on bikes at around £500 to £750. Claris is an 8-Speed system (eight gears at the rear) combined with either a double or triple crankset.
Next is Sora, which can be found on bikes from around £700 to £1,000 and is a 9-speed system. Both of these groups are available in either standard double cranksets or a wide range triple.
Next up is Shimano Tiagra, a 10 speed group that is found on bikes between £900 to £1500, it shares some of the designs and technology of the higher priced 105 system.
Shimano 105 is the workhorse groupset from the Japanese firm
Next in line is Shimano 105, widely considered to be the Japanese company's first serious performance groupset. It's 10-speed (though set to change to 11-speed for 2015) and is found on bikes from around £1.200 to £2.000.
Shimano Ultegra sits one below the professional-level Dura-Ace. This 11-speed group has the same design features as the range topping Dura-Ace and offers all the performance most riders will ever need, but is 258g heavier than Dura-Ace. It can be found on bikes at £2,000 and above.
Dura-Ace is the pinnacle of Shimano's range. It offers 11-speed gearing and combines top-end design with lightweight materials such as high-grade alloys, carbon fibre, and titanium.
Dura-Ace Di2 is the top offering from Shimano
Shimano also offer both Ultegra and Dura-Ace in its latest electronically-operated Di2 design. This system does away with traditional cables in favour of a system that is actuated by motor driven mechs powered by a battery, which can either be frame mounted on hidden within the seatpost or seat tube, the advantage of the electronic system is consistent gear shifts and very low maintenance.
The downsides are mainly related to cost, but there’s also a minor weight penalty and remembering to occasionally recharge the battery is another.
The Di2 groupsets shares the same crankset, cassette, chain and brakes of the respective mechanical groupset (so Ultegra Di2 has the same as Ultegra).
Shimano's groupsets are designed to work with each other (providing they share the same number of gears), so you can easily upgrade 105 with a mix of Ultegra or with the pro-level Dura-Ace parts.
SRAM's road groupset range comprises four main groups – Apex, Rival, Force, and Red. SRAM groupsets are the lightest weight on the market at each price-point. Unlike Shimano and Campagnolo, SRAM currently does not offer an electronic shifting option.
The Apex group is a 10-speed group that features SRAM's WiFli system. WiFli offers a very wide gear range (between 11 and 32 teeth) for the rear cassette. That allows SRAM to offer the wide range of gears usually found by using a triple front chainring setup without the extra weight and complexity of a triple. Apex can be found on bikes from around £750 to £1,250.
Next in the line is Rival, which, like Apex, can use a wide range WiFli rear derailleur and cassette but is made from lighter materials than Apex. Rival is so-called because it was designed to be the main competition for Shimano's 105, by far the most popular drivetrain on road bikes. For 2015, Rival moves to 11-speed (as does Shimano 105). Rival can be found on bikes from £1,000 to £1,500.
SRAM's Force group uses lightweight materials such as high-grade alloys and carbon fibre to be a very competitive gear setup. Like Rival and Red, its an 11-speed groupset with only double chainring options (no triple). Force is usually found on bikes from £1,500 to £2,500.
SRAM Red 22
SRAM's Red group is a proven professional level groupset, and has been ridden to victory in the Tour de France on numerous occasions.
Red uses super light materials throughout, including high-grade alloys, plenty of carbon-fibre, titanium and even ceramic bearings. SRAM Red is also available in a WiFli option, allowing for an ultra-wide range of gears. Of all the top of the range groups, SRAM Red is the lightest on the market.
Italy's Campagnolo drivetrains start higher up the overall hierarchy than the competition, so you're unlikely to find the Italian brand on bikes that cost less than £800.
The entry-level group Veloce, sits around the same area as Shimano Tiagra or 105, or SRAM Rival. It's a 10-speed group and is all made from lightweight alloys.
Next in line is Centaur (discontinued for 2015), which is again a 10-speed group, although it's been discontinued for 2015. It’s fully compatible with the lower group but is the first in the Italians' lineup to offer high-grade carbon components. Centaur is usually found on bikes around £1,500 and above.
Athena is Campagnolo's first 11-speed groupset – it's a direct rival for both SRAM Force and Shimano Ultegra. It includes carbon composite components and the technical advances of Campagnolo's top-end groupsets. You'll usually find Athena on bikes at £2,250 and above.
Campagnolo Chorus is still a performance groupset and introduces carbon fibre
Sitting just below the range-topping Campagnolo Record family is Chorus. It sits between SRAM Force and SRAM Red, and between Shimano Ultegra and Dura-Ace. Chorus uses light alloys, carbon fibre and titanium in its construction. Chorus can usually be found on bikes above £2,500.
Campagnolo Record is the flagship groupset from the Italian brand. It uses the highest grades of carbon fibre in its construction combined with lightweight alloys and titanium. Record is usually found on the highest priced bikes – £3,000 or above.
Campagnolo also offers an even higher-level groupset in the form of Super-Record. While essentially the same as Record, it uses even higher grade materials to lighten and enhance each and every part. It is only usually found on the most expensive pro-level road machines.
On its own price tier, Campagnolo Super-Record EPS is the choice of many dream bikes
Campagnolo also offera an electronic range of groupsets (EPS), starting with Chorus EPS (it was Athena for 2014), which, like Shimano, is driven by electric motors and battery power – the batteries can either be externally mounted or hidden with the seat post or seat tube.
Record EPS uses lighter materials to reduce overall weight, and Super-Record EPS refines everything further. Super Record EPS is certainly the market’s money-no-object groupset. Just like Shimano, the EPS groupsets shares the same crankset, cassette, chain and brakes of the respective mechanical groupset (so Record EPS is the same as Record).