The mechanical heart of your bike
The groupset or ‘gruppo’ is the collective term for the components on your bike that take care of gear shifting and braking.
As a result, the groupset is a key part of the make-up of your machine, alongside the frame itself and the wheels. In this buyer's guide we'll take a closer look at the groupset components, run through which manufacturers supply the mechanical heart of your bike and consider what you get for your money.
The components of a groupset consist of a set of combined brake and gear levers, otherwise known as shifters. The chainset is made up of a crankset (to which the pedals, not considered part of a groupset, are attached) and the chainrings. The chainset spins on a set of bearings known as the bottom bracket.
The cassette is the cluster of sprockets housed on the back wheel and the number of sprockets determines the ‘speed’ of the groupset i.e. eight, nine, ten or 11-speed. Both the cassette and chainset are connected by the chain to drive the bike.
Front and rear derailleurs work in conjunction with the shifters to move the chain across the cogs and chainset as you pedal to select your chosen gear. The brakes, erm ... brake.
Shimano, SRAM and Campagnolo are the three big players that dominate the UK groupset market, though you'll sometimes find a smattering of parts from other manufacturers when buying an off-the-shelf bike. These include FSA (chainset and brakes) and Tektro (brakes).
Back to the big three, and market share swings heavily towards Shimano - the Japanese firm supplies 13 of the 17 WorldTour teams, and you'll find Shimano components on most off-the-shelf bikes - while SRAM and Campagnolo (Campag) sweat it out in Shimano’s wake.
All three manufactures offer a hierarchy of groupsets; this is based on manufacturing costs, material quality, performance, durability and weight. As you rise through the range, the use of more exotic materials means the weight (in most cases) will drop, and the performance (the precision and refinement of shifting, and braking performance, for example) will rise - as will the cost.
Although many components may look alike, there is little room for crossover between each manufacturer’s components. The only gap in this rule can be found in cross-pollination of some chainsets and cassettes.
You can’t mix-and-match the components of different speed groupsets either, i.e. you can’t put a ten-speed derailleur on an 11-speed bike and expect it to work properly.
With that in mind, let's take a closer look at each individual groupset component.
Shifters are there to change gear and apply the brakes. Although the shifters from the three major manufacturers work slightly differently (and we'll come on to the intricacies of each), braking remains the same as you only have to pull the brake levers back towards you.
Shimano introduced the STI (Shimano Total Integration) system in 1990, effectively integrating the shifting mechanism and brake lever into one unit. To change to an easier gear on the cassette, the rider is required to push the right-hand brake lever inwards, while to flick into a harder gear, there is a separate paddle behind the brake lever. The left-hand shifter operates the front derailleur; press the inner paddle to move the chain onto the inner chain ring.
Most road bikes are fitted with cable-operated caliper brakes with pads which squeeze up against the wheel rim to slow you down and stop. Direct mount calipers, which attach directly to the frame and fork by two bolts, rather than by a single, central bolt, are increasingly popular and offer improve braking performance, but only work with compatible frames.
Disc brakes are becoming more popular and are seen fitted to many endurance and sportive bikes; these can be either cable-operated or hydraulic depending on the price and specification of the bike. Hydraulic discs not only offer greater stopping power and modulation but the wheel rim itself may be lighter as there is less need to reinforce the rim against braking forces.
Road chainsets come in two main categories: double and triple, referring to the number of chainrings.
While doubles adorn race and sportive bikes, triples are normally (but not exclusively as they can be found on some road bikes) reserved for heavy audax or touring bikes, which require an especially low gear. However, the advent of the compact double chainset has seen the popularity of triple chainsets fall, with riders able to achieve a similarly low gear but without the added weight.
While road racers favour the classic double chainset, using chainrings with 53 and 39 teeth, compact chainsets use a combination of 50-34t. The larger the number, the bigger the gear, so a compact allows for a lower gear, ideal for climbing, and compacts are now fitted as standard to most sportive and endurance road bikes. A third option growing in popularity is a ratio of 52-36t, known as a mid or semi-compact and thus bridging the gap between a standard and compact. Shimano and Campagnolo's upper-level chainsets now have a universal BCD (Bolt Circle Diameter), which enables you to change the chainrings without replacing the whole chainset.
Crank lengths vary and, when buying a bike, are usually directly related to the size of the frame. For example, a 160mm crank will be fitted to a very small bike, while a 172.5mm crank will be found on 56cm frame. 175-180mm cranks will be fitted to larger frame sizes.
The cassette is the collection of sprockets (and so effectively the gears) fitted to the rear wheel and cassettes come in a vast array of sizes.
Unlike chainrings, when it comes to the cassette, the larger the number, the easier the gear. Professional riders and time trial specialists may prefer a close 11-23t or 11-25t ratio for super-smooth gear changing and only small gaps between each sprocket, while hill climbers may prefer a wider 12 to 27 or 28-tooth cassette.
All three component manufacturers now offer even wider cassette, up to 32-teeth with Shimano and SRAM, and 30-teeth with Campagnolo, but be careful before you upgrade as these cassettes will often require a 'long-cage rear' to work. Check with your local bike shop first.
The type of chain fitted to your bike is totally dependent on the number of gears on your bike. A ten-speed groupset must run a ten-speed chain, and so on.
Wheels have not got wider to accommodate wider cassettes, so the sprockets themselves have got narrower and so have the chains. An eight-speed chain is much wider than a ten or 11-speed chain.
Sadly most of us neglect our chains and they often wear out significantly quicker than other groupset components, so check the length of your chain regularly and change it when required to reduce wear and tear on more expensive components and to prolong the life of your cassette and chainset.
Often known as mechs, the derailleurs are responsible for moving the chain from one sprocket to another, or one chainring to the other. The front mech takes car of the chainrings and the rear mech looks after the cassette.
Cable-operated mechs are the most common type (the shifter 'pulls' the cable to move the derailleurs) but electronic shifting such as Shimano’s Di2 and Campagnolo’s EPS systems do away with cables and use wires and battery-operated motors to refine the shifting. Electronic groupsets come with a weight penalty over cable-operated systems but offer super-smooth shifting, especially under load. While initial setup can be tricky, long-term maintenance should be trouble-free thanks to the superb reliability of electronic systems, particularly as the front mech will self-align to avoid chain rub. SRAM currently only offer cable-operated groupsets but are expected to launch a wireless electronic setup in 2015.
Front mechs are fitted to a bike in either band-on, which is a clamp system that fits around the frame near the bottom of the seattube, or braze-on. The braze-on system employs a small bracket that’s either brazed, bolted or riveted to the frame depending on the frame shape and material from which it’s made. Whether you need a band-on or braze-on front mech will depend on your frame.
Now you know what each component is responsible for, it's time to consider the intricacies and hierarchies of Shimano, SRAM and Campagnolo's systems.
Each groupset manufacturer employs a variation on the style of gear shifting.
Shimano STI (Shimano Total Integration) system, first introduced in 1990, allows the brake lever to be swung inwards to change up into an easier pedalling gear on the right-hand shifter. A smaller lever sits just behind the brake lever and when pushed in allows the chain to move down onto a harder pedalling gear.
Meanwhile, on the left-hand shifter, swinging the lever inwards moves the chain onto the larger chainring. An identical small lever behind the shift/brake lever brings the chain back down onto the smaller chainring when clicked.
All three major manufacturers offer competing groupsets, at a variety of prices, but the Japanese giant, Shimano, offers the widest choice.
The entry-level Claris system is an eight-speed system which is usually found on bikes ranging from £500 to £750, though, as is the case with all groupsets, what you get for your money when buying a complete machine varies from one manufacturer to the other.
Next up the ladder is the Sora groupset, which is nine-speed system seen adorning bikes at around £700 to £1,000.
Tiagra is now Shimano's sole ten-speed gruppo and is regularly fitted to bikes priced in the £900 to £1,500 range - with a new iteration, Tiagra 4700, due out later this year.
Shimano’s 105 groupset is a well-respected system and is regarded as the Japanese company’s first level performance groupset. The latest version has jumped ten to 11-speed and strikes a popular balance of price, durability and performance. Expect to see this fitted on bikes ranging from £1,200 to £2,000. Shimano 105 will boast hydraulic disc braking from late 2015.
One step away from the top sits the much-loved 11-speed Ultegra system. In performance levels, Ultegra is on par with Shimano’s top-flight Dura-Ace groupset with only a 258g weight penalty and slightly less refinement keeping them apart. Ultegra also boast a fully hydraulic disc brake option. Expect to find Ultegra on bikes at £2,000-plus.
At the pinnacle of Shimano’s groupset order sits Dura-Ace, used pro riders and weight/performance obsessed riders everywhere (unless you prefer SRAM or Campag, that is). High grade alloys, titanium and carbon fibre all help to keep this groupset fitted to top-flight bikes only. One added benefit here is that you can start replacing worn out 11-speed components on lower level systems (105 or Ultegra) with pro-level bling as you go along, if you're so inclined
Dura-Ace and Ultegra groupsets are both available in Shimano’s electronically-operated Di2 system. Di2 dispenses with traditional cables and incorporates motor-driven derailleurs to change gear. The weight penalty of the Di2 system may be minor but the cost penalty is significant.
Next up, SRAM...
US-based SRAM have four groupsets for dedicated road use, but unlike Shimano and Campagnolo do not currently offer an electronic gear system.
SRAM’s gear changing system is known as DoubleTap and moving the gears both up and down the range is actuated by the smaller lever that sits behind the brake lever: one long sweep to change into an easier gear, and a short stroke to click down into a smaller, harder pedaling gear.
Apex is a 10-speed groupset that features SRAM’s proprietary WiFli system. WiFli offers an extremely wide spread of gears on the rear cassette (between 11 to 32 teeth) and negates the requirement for triple-ringed chainsets. Apex is normally found on bikes in the £750 to £1,200 price bracket.
Next up, SRAM’s Rival system sits in competition with Shimano 105. And just like 105, Rival upgrades to 11-speed for 2015. There’s also a fully hydraulic brake option at an extra cost. Expect this evergreen, performance-driven groupset to adorn bikes around £1,000 to £1,500.
Next in line is SRAM’s Force groupset where lightweight alloys and carbon fibre provide a very competitive 11-speed system that’s normally found on bikes in the £1,500 to £2,500 price category. Force is popular with racers who want a lightweight, performance-focused groupset which won't break the bank. Expect to pay a little more if you choose the hydraulic disc brake option.
SRAM’s Red gruppo is their pro-level system and is regarded to be the lightest groupset on the market. Ceramic bearings, titanium, carbon fibre and high-grade alloys all add up to a tour winning combination. The Red groupset is also available with WiFli gearing and hydraulic disc brakes.
How about Campagnolo?
This iconic Italian brand started it all with Tullio Campagnolo in the 1920s, and they’ve been developing and refining their products ever since.
To some riders, Campagnolo is the one true brand that they aspire to use and Campag has a strong, loyal following for its beautifully crafted components. Although their groupsets generally come in at a higher level than Shimano or SRAM, they have a broad enough range to entice most pockets.
Changing gear on Campag is via their ErgoPower system, operated by swinging the paddle (inside the brake lever) inwards to change up the cassette (into a lower gear) or onto the big ring, while to come down the rear block or to shift onto the inner ring you click the small thumb tab on the hood.
As you may have noticed by now, Shimano, SRAM and Campagnolo groupsets all have their own personalities when it comes to shifting, and it's horses for courses as far as what works for you in terms of the feel of the shifting mechanism and lever ergonomics.
Campagnolo's Veloce 10-speed groupset comes in somewhere between Shimano Tiagra and 105, or SRAM Rival, and is constructed using lightweight alloy. Often found on Italian bike brands at around £1,000 to £1,500
Until recently the Centaur gruppo was the next in line (though it has been phased out), so it may still feature on some bikes. Centaur offered 10-speed shifting and some carbon components, and can be found on bikes around £1,500-plus.
Campag’s Athena groupset is the company’s first 11-speed system and comes up against SRAM Force and Shimano Ultegra. Elements of Campagnolo’s top-flight groupsets can be found here as well as a greater use of carbon composite materials. Athena can be found on bikes around £2,250 and upwards.
Muscling in just below the two top-flight groupsets of Shimano and SRAM sits Campag Chorus. Here you’ll find refined lightweight alloys, a smattering of titanium, and more than a handful of carbon fibre. Chorus can be found on bikes above the £2,500 range.
Keep rising up the Campag ladder and you'll find Record, which is constructed using top-grade alloys, carbon fibre and titanium. Found mostly on dream bikes coming in at £3,000 or over.
It doesn’t quite finish here as Campagnolo also offer Super-Record which is lighter again than Record thanks to its construction using only the strongest and lightest materials available.
Still not quite there, Campagnolo also produce Chorus, Record and Super Record using their proprietary EPS electronic shifting system. If you have to ask how much it is, you can’t afford it.
|Super Record EPS||£3,749.99|
So that's all you need to know about Shimano, SRAM and Campagnolo. Finally, let's consider what you get for your money.
So, what do you get for your money? Weight, performance and durability
Less is more, and a top-flight groupset, such as Shimano Dura-Ace, Campag Record/Super Record and SRAM Red will be significantly lighter than an entry-level gruppo.
Needless to say, performance also rises as you climb the ladder, with crisper, more refined shifting, increased braking power and feel, and more stiffness as far as the chainset is concerned, converting more of your power into speed. Often there's very little to call between the top two tiers (be it Shimano Ultegra and Dura-Ace, SRAM Force and Red, or Campagnolo Record and Super Record), with weight the most significant factor in driving up the cost.
Durability is another consideration, and while it's easy to assume that a more expensive groupset should outlast a more affordable option (and that is usually the case), the very best groupsets, are crafted with performance and weight at the top of the agenda. Top-flight groupsets are designed for racing rather than everyday use, and therefore may not be the best option for long-term durability, especially if you train using this kit through the long winter months.
For most of us, somewhere in the middle sits the groupset that strikes a balance between weight, performance and durability. These are the 105s, Ultegras, Rivals, Force, Chorus and Athenas of the groupset world.
You really can have you cake and eat it now because the technologies developed by manufacturers alongside pro teams and riders has drip-fed down to the lower castes. For example, Dura-Ace was Shimano's first groupset to go to 11-speed, but Ultegra and, now for 2015, 105 have followed suit, sharing many of the top-tier gruppo's flagship features, including a stiffer, four-arm chainset.
And with only relatively minor weight penalties to contend with, those mid-priced groupsets can offer almost just as much riding joy as the mouth-watering pro versions.