Carbon road bikes explained: What really matters when choosing a performance frame from the Halfords range

Carbon fibre is used to construct the majority of high-performance road bikes. But not all carbon fibre is the same and there are key qualities to look out for in a top-tier carbon bike, such as the Boardman SLR 9.8 Carbon.

We’ll run through what makes a quality bike frame, the modern features to look for and how to keep your carbon road bike running at its best. Boardman Bikes carries the name of one of the UK’s greatest cyclists, Tour de France yellow jersey wearer Chris Boardman, and has produced a long line of affordable, quality road bikes.

A bike needs to be made with the right mix of carbon fibre grades in the right places to ensure that it’s strong, light and comfortable to ride. The bike’s geometry – the frame angles and tube lengths – need to be chosen to meet the ride quality objectives, while the tubes' shapes are carefully chosen to make the bike more aerodynamic.

Look after your carbon bike and it will last for years. Halfords can help you to keep it maintained well, offer checks, and keep you rolling.

How carbon lay-up influences ride feel and stiffness

You’ll see carbon bike frames described as ‘high modulus’, but no frame is exclusively made from a single type of carbon fibre.

High modulus carbon fibre is very strong along its length, but also brittle and it doesn’t absorb road buzz well. Due to its strength, smaller quantities of high modulus carbon fibre can be used in a bike frame, so a frame with a greater proportion of high modulus carbon is typically lighter for a similar stiffness.

But the skill of a bike designer is in mixing high modulus carbon fibre where it matters with other grades of carbon fibre to give the frame a more comfortable ride and greater impact resistance. How the different carbon layers are laid up is also important to ensure that there’s strength in the right directions in high stress areas of the frame.

Higher modulus carbon and wider tube shapes are typically used in the head tube, down tube, bottom bracket and chainstays to ensure that the frame offers a stiff pedalling platform.

Lower modulus, high strength carbon is a better choice for areas such as the seat tube, seat stays and fork blades, where compliance and vibration absorption are more significant to ensure a comfortable ride.

Boardman’s C10 carbon used in its premium bikes, including the Boardman SLR 9.8 Carbon, is a mix of mid-modulus carbon fibre with strategically placed higher modulus carbon. It gives the ride characteristics needed for performance, without sacrificing comfort.

Why frame design affects weight, handling and aerodynamics

The right mix of carbon fibres will result in a bike frame that’s lightweight but retains rigidity and compliance where needed in order to increase ride comfort.

Beyond that, the frame’s geometry is an important factor in bike design to ensure that the bike handles as expected.

Different bikes are designed for different purposes and it’s important to choose a bike that suits your ride style.

A race-oriented bike will usually have a more edgy ride thanks to steeper frame angles, particularly in the head tube and fork area. Shorter chainstays provide a more lively ride feel and the head tube is usually shorter, so that the rider sits more forward in a more aerodynamic position.

Other bikes are designed for longer distance endurance rides. They’ll usually sit the rider in a more upright position thanks to a longer head tube, so there’s less pressure on their neck and shoulders. Less steep frame angles and longer chainstays and wheelbase will make for more stable handling and the carbon mix and frame design will ensure better ride comfort by absorbing more road chatter.

Almost all modern road bike frames are designed with aerodynamics in mind. A round tube produces significant drag even at lower speeds, whereas a more aerodynamic tube profile will cut through the air better. A teardrop shaped tube, with the blunt edge hitting the wind first, has good aerodynamic performance but the tail makes it heavy, is harder to manufacture and affects the tube’s strength.

In practice, aero bikes typically use truncated aerofoil tube shapes, where the back of the teardrop is cut off. It’s been found in wind tunnel tests that these shapes perform similarly aerodynamically to a tube with a longer tail and they are lighter and stronger too.

The Boardman SLR 9.8 includes truncated aerofoil-shaped tubes in its down tube and seat tube, as well as the fork legs, seat stays and seat post, as these are all areas that face the wind when riding. As a result, it’s 5.7 watts more aerodynamic than the previous generation bike.

Carbon bike frame durability and maintenance

If you keep your carbon frame well maintained, you can expect it to last for years. Carbon fibre is relatively inert, so it won’t rust or decay, although it’s important to keep the bike clean and dry to avoid any galvanic corrosion between the frame and components, particularly if you’re riding on salted roads in the winter.

It’s also important to have any damage to the frame professionally inspected, as internal damage to the inside of frame tubes cannot always be seen and can weaken the frame, in extreme cases causing it to fail.

Modern road bikes typically have internally routed hydraulic brake hoses and wireless electronic groupsets fitted. Often, as with the Boardman SLR 9 carbon bike range, the brake hoses and gear cables are routed through the handlebars and the stem, so that the bike is more aerodynamically efficient.

Why expert retailer support helps cyclists understand increasingly complex bike technologies

It’s important to keep your bike well maintained, which is where Halfords’ quality servicing comes in.

The external parts of your bike, the chain, cassette, derailleurs, brakes and tyres need to be serviced regularly. Wear isn’t always apparent and worn parts need to be replaced to keep your bike running smoothly, which is why Halfords offers a free health check for your bike, as well as affordable tiered service options.

Less visible parts of your bike such as bearings should be inspected and replaced when worn. They should be tightened if they’re loose, particularly the headset bearings that hold the fork in the frame and allow the handlebars to turn.

There’s increasing complexity in higher-spec bikes, with hoses routed internally, hydraulic disc brakes replacing cable-operated rim brakes and electronic parts replacing mechanical cables. It’s not always obvious when components need to be tuned, brakes need to be bled, and worn out items need to be replaced, and many jobs require specialist tools too.

Halfords mechanics have the tools and expertise to help keep your bike running at its best, so Halfords should be your first stop for quality bike maintenance.