When buying a road bike (or a racing bike, a term twice as many people actually use, according to the great all-knowing entity that is Google), one of the number one considerations is ‘what frame material should I go for?’.
There are four very distinct options: carbon, aluminium, steel and titanium.
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Modern day trends err very much on the side of the first two fabrics of bicycle construction. However, the latter two have their merits and are often retained for the ultimate ‘N+1’ bike, ‘one bike to rule them all’ – the one the rider wants to keep forever.
There is no one ‘best’ material – but there is certainly a best for you, based upon your riding plans, requirement and budget.
Useful links for road bike shoppers…
Carbon road bikes
Carbon is the frame material you’ll find in the pro peloton, and on most club rides during the summer months.
Raw carbon fibre comes from a handful of companies, and most of it goes into the aerospace industry. However, it’s how the raw material is treated – how it’s heated, resin used, layering of the carbon and direction of the fibres – that determines ride quality. Every major bike brand has a special name for its own carbon.
On its own, carbon fibre is very brittle, so it’s mixed with resin to create a composite. There are assorted different levels of carbon fibre – it’s rated by the Japan Carbon Fiber Manufacturers Association (JCMA) based on stiffness and durability. Brands layer sheets of carbon – up to 500 in one frame – to create the perfect blend of stiffness, compliance and strength. The angle and carbon grade are altered to achieve stiffness and compliance at the desired areas.
Pros and cons of carbon frame material
Carbon can be made incredibly stiff whilst remaining very light. It’s also malleable – brands can layer sheets of carbon into any shape they desire, making aerodynamic tubing much more attainable and effective.
Carbon’s downfall is that it’s not always immediately obvious when it’s damaged – which can lead to failure under stress. Therefore, a carbon frame needs to be very carefully assessed after a heavy crash.
Aluminium road bikes
Aluminium was the leader when it came to frame material before carbon become more accessible. It’s a relatively light and stiff material and generally cheaper to produce than carbon.
When it comes to bike frames, aluminium is ‘alloyed’ with another metal.
In order to achieve a greater strength to weight ratio, quality aluminium bike frames are butted. The more butting, the better. Single butting means that one end will be thicker, double butting means the tubes are thicker at both ends and triple butted tubes are thicker at both ends and thinner in the middle.
Straight gauge tubes are not butted at all – but in this case a product description is likely to simply say ‘aluminium alloy frame’ as opposed to ‘triple butted aluminum alloy frame’ – the former will be notably heavier and less responsive as there will be less give in the frame.
Taking it one step further, tubes can by hydroformed into a specific – eg more aerodynamic – shape.
Once butted and formed to the desired extent, the tubes are welded together. Ideally, the weld should be smooth – an uneven, bumpy line can be a warning sign of questionable handy work, though some brands may be open about doing this to save money for the consumer. Most manufacturers use TIG welds, where the same material is used across the frame and welds to create an even join.
Pros and cons of aluminium frame material
Aluminium road bikes – save for some custom designs – are fairly inexpensive. The material is light and stiff. It could be said that it’s not quite as light and stiff as carbon – but aluminium technology has progressed in recent years and good aluminium often trumps cheap carbon.
The downside for aluminium is that it can produce a slightly harsh ride quality – though some riders appreciate this. Though easy to dent, it’s unlikely to fail completely – making it a good choice for road and criterium racers.
Good aluminium can last a lifetime – but it is open to fatigue and corrosion.
Steel road bikes
‘Steel is real’, the saying goes. And there was a time – before the 1970s – when it was simply the only option.
Steel tubes, like aluminium, can be butted to create strength where it’s needed and cut weight where possible.
When it comes to joining the tubes, manufacturers can opt to braze or use lugs. The former is a lot like welding but uses an additional material, whilst using lugs means slotting the tubes into joins – there’s a lot of room for artistry and creativity here.
There are two key families of steel frame – Hi-Tensile and Chromoly. The latter is an alloy form, and is much more durable than Hi-Ten which is cheaper.
The pros and cons of steel frame material
Steel might be real, but it’s also heavy. However, it also has a notably springy ride quality, which enhances comfort over long miles. Repair is easy too, and steel is very durable – though it is open to corrosion.
All in, steel is often reserved for touring bikes, and winter bikes – any machine where the rider is keen to plod in comfort.
Titanium road bikes
Very much the material of the boutique custom frame builder, the best Titanium is lighter and stiffer than steel, with a a spring in its step – it’s comfortable, light, stiff, and longer lasting than the other metals.
When used to create a bike frame, Titanium is alloyed – often with aluminium. Once the tubes have been created and formed, they’re welded together – like aluminium, though the process is slightly more drawn out as the sections being welded can’t be exposed to oxygen.
Pros and cons of titanium frame material
Sound like the dream material? For many it is. But it’s also expensive, if done right – so it’s really the ideal material for that dream, custom bike you’ll cherish forever.