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What is a road bike? Every part explained in simple terms

A beginner-friendly guide to the components that make up a road bike

Joseph Delves
20 Jan 2022

A road bike is a bicycle designed primarily for riding quickly on paved surfaces. Road bikes have drop handlebars, fairly narrow slick tyres, and usually place the rider in a position where their bum is higher than their hands.

The average road bike comprises component parts that haven't changed all that much in over a century. However, if you haven't used that time to acquaint yourself with the correct terminology, we won't hold it against you.

Below we've broken down the typical road bike into its constituent parts. Once you've read this, you'll be able to walk into any bike shop and confidently identify each bit of the bike along with what it does.



Road bike frame and fork (or frameset)

The heart of the bike and the central elements to which everything else is bolted. More affordable road bike frames will be made of aluminium or if you spend a little more, carbon fibre. Older or more niche models can also be made of steel, while some boutique frames are made of titanium.

Even bikes with metal frames often have forks made partly or fully from carbon fibre.

Whatever it's composed of it will accomplish the same job, namely supporting the rider and allowing for the attachment of the other components.

Frames come in different sizes to match their rider. As these get larger or smaller, both the height and length of the frame change to fit the riders's legs and upper body.

Accommodating all the other parts of the bike, the frame and fork will determine the maximum size tyres the bike can accept, whether it uses conventional rim brakes or disc brakes and if it can take accessories such as mudguardspannier racks or bikepacking bags.

The dimensions and angles of the frame and fork – or geometry – also help determine the handling characteristics of the complete bicycle. Read our bike geometry explainer here. 

Road bike wheels and tyres

The part of the bike that allows the whole assemblage to roll along. Most road bike wheels are '700c', denoting a specific diameter. Smaller bikes or those for children may use different, more diminutive sizes.

Affordable and mid-range bike wheels have aluminium ('alloy') rims, while more expensive models get carbon rims.

Rims are laced to hubs using spokes commonly made from steel, but sometimes aluminium or even carbon. The rear hub on modern road bikes incorporates a freewheeling mechanisms knows as a freehub, onto which the cassette (see below) mounts.

Compared to those on other styles of bicycle, road bike tyres are narrow, without a pronounced tread pattern, i.e. near-slick.

Designed to roll efficiently on paved surfaces, tyres around 23mm in width used to be common; however, it's now normal to find tyres as wide as 30mm fitted in the interest of improved comfort and versatility.

Having a disproportionate effect on the handling and feel of the complete bike, road riders prize wheels and tyres that are as light as possible.

Road bike groupset

'Groupset' is fancy road bike-speak for the oily components that help drive your bicycle forward and also bring it to a halt. The groupset is generally considered to be made up of the following key components...

Road bike levers (incorporating shifters and brake levers)

SRAM Red eTap shifters

Modern road bikes use integrated shifters that combine the various levers that control brakes and derailleurs into a single unit.

Designed to work with drop handlebars, they provide multiple positions for your hands. The tops of the levers are called the 'hoods'. These provide an extra spot away from the bars from which to control the bicycle.

Road bike crankset (or chainset)

The cranks offer leverage and drive the bike forwards. The size of the chainrings attached then combines with the cassette to make efficient use of your pedalling efforts.

Traditionally, road bike cranksets have two chainrings with 53 and 39 teeth (or 'T'), respectively. However, to provide easier gears, it's now common to find a combination of 50 and 36. Formerly the norm, a combination of 53/39 chainrings is referred to as a 'standard double' crankset.

A 50/34 combination is 'compact', while in between the two, a 'pro-compact' chainset uses 52 and 36T chainrings and offers performance somewhere in the middle.

The newest SRAM 12-speed road groupsets offer crank ratios of 50/37, 48/35 and 46/33.

Some touring-style road bikes will also have a third chainring. Called a 'triple', this provides a vast range of gears and is helpful for very hilly terrain.

Also increasingly common are single chainring cranksets. Referred to as 1× or 'one-by', these use a single chainring, do away with the need for a front derailleur, and offer a simplified range of sequential gears.

Paired to a wide cassette, they give a similar spread of gears but with more significant jumps between each. They're particularly popular on mixed-terrain gravel bikes, although they do occasionally feature on road bikes too. Also largely the preserve of gravel bikes are 'super-compact' double cranksets with ratios such as 48/31, 46/33, 46/30 and 43/30.

The bearing assembly in the frame that the crankset rides on is called the bottom bracket.

Road bike cassette

The cassette is the cluster of cogs attached to the rear wheel. Driven by the chain, they convert your pedalling efforts into forward momentum.

The difference in size between the cog on the cassette and the chainring affects how easy it is to turn the pedals. Currently, the maximum number of sprockets on any cassette is 13. However, 11 and 12-speed cassettes are more common. Cheaper or older bikes might have drastically fewer.

Having lots of sprockets is good because it lets you pedal efficiently regardless of the terrain. However, just as crucial as having many individual gears is having a wide range of them. A cassette with a big difference between the largest and smallest sprocket is referred to as having a 'wide ratio'. This means it'll be well suited to both riding very fast and crawling along very slowly.

The cassette ratio is expressed as a range of tooth counts and modern road bikes typically come with 11-28, 11-30, 11-32 or 10-33 cassettes, although there are numerous other options.

Road bike chain

A road bike chain is an assemblage of links, rollers, and rivets that connects the cranks to the cassette. Transferring power between them, its width is matched to the number of sprockets. Keep it clean and make sure it's well lubricated.

Road bike derailleurs (or mechs)

Ritchey Break-Away Carbon rear derailleur

These mechanisms take care of changing gear. Controlled by the shifters, most are controlled by Bowden cables that directly transmit the force needed to move them in one direction, with a spring supplying movement in the opposite direction.

The rear derailleur pushes the chain across the cassette sprockets, while the front derailleur pushes the chain from one chainring to the other. 

Condor Leggero front derailleur

More expensive bikes might instead have electronic derailleurs. These rely on battery-powered servo motors to do the heavy lifting. Controlled by either electronic cables or wirelessly, they're otherwise mechanically similar.

Road bike brakes

Road bikes use either rim brakes (sometimes referred to as caliper brakes) or disc brakes. Typically fixed high on the bike, rim brakes directly clamp the wheel rims to slow you down.

Disc brakes are located closer to the bike's axles and use a separate rotor attached to the hub as a braking surface. Generally more powerful and consistent, disc brakes provide better stopping but are slightly heavier.

Other key components

Road bike saddle and seatpost

The bit on which you sit and the post which supports it. Compared to other bikes, road bike saddles are generally relatively narrow and minimally upholstered.

Allowing for freedom of movement, they work best with padded cycling shorts.

The saddle is fixed by a clamp at the top of the seatpost, and saddle height is adjusted by moving the post up and down in the frame. The angle of the saddle can be adjusted at the clamp, as can the fore-aft position

Road bike handlebar and stem (or cockpit)

One of the things that makes a road bike a road bike is a pair of drop handlebars. These allow riders to adopt multiple positions, including getting low down, known as riding 'in the drops'.

The width and shape of the bar can vary to match different styles of riding or fit riders with broader or narrower shoulders.

The stem is the part that fixes the bars to the top of the fork. It allows you to steer the bicycle, while its angle and length affect how the bike fits. It can also be changed to adjust the handling of the bike.

The bearing assembly that connects the fork to the frame and allows steering is the headset.

Road bike pedals

The part you put your feet on. While you can put any pedals you like on a road bike, most riders opt for ones you clip your shoes into, often confusingly referred to as 'clipless' pedals, a hangover from the days of toe-clips and straps.

The pedals thread into holes at the end of the crank arms, and feature a mechanism that engages with cleats fixed to the soles of your cycling shoes.

The most common road bike pedals are single-sided, meaning you can only clip in on one side of the pedal. Wahoo Speedplay road pedals are the exception to this, offering double-sided entry.

Many road and gravel cyclists opt for mountain bike-style pedals instead of pure road ones, as these are all double-sided and the smaller cleats mean the matching shoes are usually much easier to walk in than road shoes.

Got it, so what road bike should I buy?

Now that you're an expert on the parts that make up a road bike, read our guide to choosing the right type of road bike or, if you've already got an idea of what you're after, head to our buyer's guide to the best road bikes. Looking for something a bit more versatile? A gravel bike might be even more fun than a road bike. Read our beginner-friendly introductory guide to find out if a gravel bike is for you, and don't miss our guide to the best gravel bikes

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