First rule in shopping for a carbon bike: All carbon fiber is ABSOLUTELY NOT created equal. Even if the actual unfinished carbon-fiber materials are exactly the same, there are multiple characteristics and processes critical to the stiffness, ride feel, durability and overall quality of the finished bike frame – more so than any other common bike material. That’s partially because builders get access to the material earlier in the manufacturing process, and there is really no limit to how it can be placed, layered, angled, etc., within a frame layup. Therefore the opportunity to use carbon to ‘get it right’ is unprecedented – but so is the opportunity to make a genuinely terrible bike. Here’s how Alchemy GETS IT SO RIGHT:
Why Alchemy Premium Carbon:
Alchemy’s Premium Carbon frames are, as the name suggests, sourced from the highest quality carbon fiber sheets, which are then processed, laid up, epoxied and finished entirely by the hands of extremely knowledgeable and highly experienced engineers and builders. Every step of the process, from choosing the material to laying up the carbon tubes to the finish coating of the frame, is meticulously researched and executed for each different carbon model we produce.
Four Key Factors:
You may have heard about the ‘modulus’ of the carbon sheets used in a particular bike, and indeed using higher or lower modulus carbon is an important factor. But what exactly does it mean? The modulus of a carbon sheet is simply how stiff the carbon is once laid up and hardened. The higher the modulus, the stiffer the tube, and vice versa. However the tensile strength – in lay terms how easily it can crack – along with the vertical compliance are inversely proportional.
Alchemy takes all of this into consideration of course when selecting the right carbon for each bike. While we definitely want to make laterally stiff bikes – which are more efficient at transferring power and handle more nimbly – we also want to make sure our consumers remain comfortable and don’t fatigue too much on their outings. For this reason we generally employ custom blends of different modulus carbon in different parts of each model’s frame to get the exact ride characteristics for that particular bike. A large majority of our carbon is medium or standard modulus, with high modulus only used for appropriate applications – simply because too much high modulus carbon yields bikes with extremely unforgiving, and therefore uncomfortable, ride quality. That said, for riders who happily sacrifice comfort for pure performance, our Au bikes feature more high-mod carbon to be as stiff and light as possible.
Another key characteristic of carbon fiber sheets is the directionality of the fibers. Carbon sheets are extremely stiff in one direction but flexible in another. By using unidirectional carbon in specific areas and layups, and say a 3k-weave in others, we can make a bike stiffer and highly responsive or slightly more compliant and predictable, or any combination of the two. but Alchemy uses approximately 99% unidirectional carbon for maximum ride performance. We only use weave where it is better suited for the task such as dropout interface, head tube cups, BB cups, because weave plies are stronger and are better for the extreme forces in those areas.
Even using the exact same modulus carbon can result in different ride qualities depending on the layup, weave and directionality of fibers. Carbon tubes are literally made from strips, squares and other carefully designed shapes of raw carbon sheeting, which are then laid up in a mold and hardened to create a tube. Vastly different ride qualities and performance aspects can be achieved by altering the weave, positioning, directional orientation, combination and number of layers used in a particular tube or even part of a tube.
Our engineers and fabricators painstakingly design layup ‘schedules’ for each tube on each bike, based on the desired stiffness, strength, weight and ride quality. Each Alchemy frame has about 500 individual pieces of carbon cut, oriented and layered into its build – a process that takes about 10-14 hours per frame – to give you the best combination of ride qualities, strength and durability possible.
Custom Frame Construction:
On all our custom-made carbon road and gravel bikes, we use a tube-to-tube construction concept: Each frame is made as a connected series of tubular carbon sections and other parts. This gives us total control over frame geometry, enabling more sizes and even custom frame design, such as our Atlas, which can be ordered with choice of rear triangle clearance. This process also allows us to minimize the use of epoxy at the points of connection between frame tubes and sections, instead utilizing a carbon overwrap process to finish every joint. Thus the strength and characteristics of the carbon itself define the resulting ride feel and resilience, rather than the glue holding it together.