Our bikes are conceived and designed for maximum rider benefit. That goes beyond just speed – our bikes are fast, of course, but we look for balanced performance.
We pay huge attention to every part of the ride, balancing often-contradictory requirements. For example, to make stiff frame, more material is required, either to make higher-volume tube sections or to make tube walls thicker. More material means more weight, so stiffness and weight are always a trade-off. It’s possible to use stronger materials, which let you use less material for the larger tubes, but that introduces the additional axis of cost.
It’s a similar scenario when it comes to aero features. A tube with a deep aero cross-section inevitably uses more material than a round tube. It’s a question of balancing the benefits of reducing drag against the weight penalty. Aero tubes are also stiffer along the long axis of their cross-section, which often seriously compromises frame comfort and ride quality. We spend a great deal of time testing and assessing all these axes of performance to achieve the ideal balance.
We pay particular attention to the ride quality, deliberately setting out to achieve a ride feel comparable to the very finest steel bikes of the mid 1980s, when steel was the dominant frame material. The geometry, feel and characteristics of 853 and 753 Reynolds frames that Mark rode as a professional left a lasting impression on him.
This tubing marked the last generation of steel frames before aluminium, and then carbon fibre, took over as the primary material for high-end road bikes. But Mark was underwhelmed by most carbon fibre bikes, and this drove him to launch SwiftCarbon. “My experience of carbon in the past had always been not necessarily that good,” he explains. “Numb, slightly over engineered, or very unsettling, twitchy and nervous, hard and unforgiving. People without pre-carbon experience take these handling characteristics as a given for how bikes usually feel. Having ridden some of the best steel bikes in the world I knew the benchmark for handling and ride quality was much higher.”
For Mark, carbon fibre had masses of unrealised potential. It was light, and strong, and could, in theory, deliver the best ride attributes of steel in a stiffer, lighter frame (if tuned correctly). It became his goal to create bikes that combined the undoubted weight and stiffness advantages of carbon with the lively, interactive ride quality of the best steel frames. He wanted comfort and confidence as well as stiffness and low weight – handling and acceleration to win races from frames you can ride all day.
The unique ride feel of a SwiftCarbon frame should instil complete confidence in the rider. It's a sensation that comes from being totally relaxed and comfortable on the bike. When a bike is predictable yet agile, stiff under power yet damps out road buzz, with spot-on fit for its intended purpose, that rider feels utterly at home on it. A relaxed rider is an efficient rider, and an efficient rider is a faster rider. The feeling of confidence may be almost subconscious, but the speed will be clear to see.
So how do we achieve this unique balance? Time. Also, there's a great deal of design, engineering and testing work that goes into each model. The key is to recognise that different parts of the frame are stressed in different ways, both in terms of direction and magnitude. In a hard sprint, for example, a rider's efforts exert forces that twist the bike along its length – the head tube tries to go one way and the bottom bracket tries to go the other. Conversely, in the saddle, vibrations and shocks from the road are transmitted upwards and excessive vibration at the contact points makes for an uncomfortable, fatiguing ride – this must be minimised for greatest efficiency and speed.
This is where the balance comes in. We identify and quantify the stresses and loads at different parts of the frame, and use that knowledge to tune the construction of those zones. We work to enhance stiffness in the appropriate direction while maintaining a balance between stiffness and compliance. Using carbon fibre makes it possible to very finely adjust the characteristics of every part of the frame – the key is to do that while retaining a balanced whole.
An example is the contrast between the high-volume head and down tubes, bottom bracket area and deep chainstays, and the slender seatstays. The backbone of the frame is stiff to make the most of the rider's power. The sections that support the seated weight are engineered for vibration control. It’s the best of both worlds.
As well as frame construction, geometry and components have a big part to play. Some bikes have the back wheel pulled in for an ultra-short wheelbase, but we use a slightly longer back end. That adds comfort and stability, with the extra stiffness of the frame – especially in the head tube and bottom bracket – keeping the bike lively on climbs and accurate in turns. And we use 27.2mm diameter seatposts – these are more compliant than larger ones, offering an extra element of vibration control.
Our bikes have a signature look, standing out in the bunch while remaining understated. And characteristic design details are carried across the range – a SwiftCarbon bike looks like a SwiftCarbon bike, whether it’s a road racer, TT bike or MTB. But the key element is, and always will be, the ride.
Just as there are different alloys of aluminium and steel, so there are numerous types of carbon fibre. So many, in fact, that saying that a frame is made of “carbon fibre” really doesn’t reveal very much. No one can ever tell exactly what kind of carbon a frame is made of just by looking at it, regardless of the finish on the surface.
SwiftCarbon bikes use a combination of T700, T800 and T1000 filaments, originating from Toray in Japan, the world’s largest producer of carbon fibre – much of which is used by the aeronautical and defence industries. We also use filaments from Mitsubishi Rayon, and the combination of Toray and Mitsubishi carbon fibre help us to deliver the superior ride quality that SwiftCarbon bike.
Finite Element Model
One of the unique benefits of carbon fibre is that different types of fibre can be placed in varying orientations within a frame, putting strength exactly where its needed. Using Finite Element Modelling to visualise the loads on frames on computer, we can experiment with different materials, layups and structures without having to build numerous physical prototypes.
With FEM, we can simulate the loads from riding and see exactly how those loads will affect a frame design. This step is essentially Finite Element Analysis (FEA), which not long ago was state of the art. FEM goes further, though, allowing us to add, remove or change material and refine the design virtually, testing as we go along. Once a frame design is performing as we want it in FEM, we know it’s worth making a physical prototype for
Most carbon fibre frames look smooth and seamless on the outside. What’s important, though, is what they’re like on the inside. The conventional air bag moulding process, using inflatable bladders inside the frame to press the carbon and resin into the moulds, can result in ripples or even folds on the internal walls of the tubes which, in some cases, can lead to delamination or premature stress fracturing – every irregularity is a potential stress riser. To avoid these issues, we use our Glide-Tech process.
In conjunction with the EPS Moulding System, we get internal surfaces as smooth and wrinkle-free as the exterior. This increases strength due to the uniformity of the fibres, and greater strength allows us to use less material for a lighter frame. Just to be sure, we use tiny fibre optic cameras to inspect frames internally after production, ensuring that there are no wrinkles, no excess material and no moulding residue.
EPS Moulding System
Making a carbon fibre frame involves compressing layers of carbon weave and epoxy resin into a mould to get the desired shape. Traditionally, inflatable bladders are used inside the frame to force the material into the mould, but because the shape of a bladder can’t be finely controlled there can sometimes be wrinkles or inconsistent thickness in the finished frame. To avoid this, we use expanded polystyrene – essentially the same stuff that helmets are made from.
We can make EPS formers to the exact shape that we want before laminating carbon fibre around them and placing the whole lot in a mould. When heated, the individual beads in the EPS formers swell. Out in the open they’d reach 40 times their original size, but constrained by the mould they exert pressure on the inside of the carbon fibre, pushing it into exactly the desired shape with consistent thickness and no wrinkles. The result is a lighter, stiffer and more consistent final product.
Carbon fibre isn’t just carbon fibre. Woven carbon filaments by themselves aren’t very useful. What turns carbon fibre from floppy sheets to stiff, resilient frames is epoxy resin. The resin binds the layers of carbon fibre together to form a composite structure – really they should be called carbon/epoxy frames. We use Carbon Nano Tech (CNT) reinforcement in the resin for our frames and wheels.
These molecular-level cylindrical structures can strengthen the final product significantly, but success with nanotubes relies on careful manufacturing. It’s easy for the tubes to clump together, leading to inconsistent material properties. Our construction technology gives us precise control of the distribution of resin in the carbon layers, ensuring that the nanotubes can do their job – giving a stiffer and more durable frame.
Boris is one of the most sought-after composite engineers in the cycling industry, with over 20 years of experience. But most of his work goes unnoticed, hidden beneath the sheen of gleaming paintwork. At his happiest working in the back- ground, he thrives on the under-the-skin details. Another of Boris’s key areas of expertise is in test methods and systems, ensuring that SwiftCarbon frames are as safe as they are high-performance. He drives us to constantly improve, to refine and to rethink.
Bikes are Rene’s great passion in life. Trained in industrial engineering at Delft’s Technical University before entering the cycling industry, Rene’s mix of engineering and graphical talents have been sought by some of the biggest names in the cycling world. His bikes have been ridden in the international pro peloton, and claimed a Tour de France prologue victory. Here Rene tests the first working prototype of the Evil Twin.
Before joining SwiftCarbon, Neil held the position of gear editor, testing and rating bikes for South Africa’s biggest selling cycling magazine. He has also raced at a national level on the road, mountain bike and triathlon. Although his official posting is marketing, he’s deeply involved with the development and testing of all new models. He believes that marketing extends to all things related to SwiftCarbon, and that a world-beating product is central to that.
After having completed his university studies in industrial engineering, Adriaan Louw turned to full-time professional mountain biking, focusing on ultra marathon and multiday stage racing. He is based in the Western Cape, South Africa – a region known for its harsh conditions and rugged trails, ideal for real world testing. As a qualified industrial, he has a certain professional curiosity as to how far he can push the limits of our frames. So far so good.
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