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for Harley, Buell and performance V-twin customizers looking to save weight, add strength and improve handling, but for years have been the‘ go to’ for customizers for whom performance engineering has been the driving force in their design decisions at the AMD World Championship of Custom Bike Building. They are made using pre-preg carbon fiber- " preimpregnated " composite fibers where a thermoset polymer matrix material, such as epoxy, is already present. The fibers often take the form of a weave and the matrix is used to bond them together and to other components during manufacture. The thermoset matrix is only partially cured to allow easy handling; this B-Stage material requires cold storage to prevent complete curing. B-Stage pre-preg is always stored in cooled areas since heat accelerates complete polymerization. Hence, composite structures built of pre-pregs will mostly require an oven or autoclave to cure. Pre-preg allows the wheel to be worked on a flat surface, in an industrial process, and then the impregnated fibers are formed to shape later- not something that can be done as well using the alternate hot injection process. Pre-preg also allows impregnation with a bulk amount of fiber and then store it in a cooled area( below 20 ° C) for an extended period of time for curing later. BST makes 5 and 7 spoke designs in aerospace FAR25 qualified materials( as also supplied to Airbus, Boeing, Ferrari and McLaren among others), providing complete aerospace critical standard traceability during manufacturing processes. All wheels are coded and serial-numbered for easy identification. Using fully automatic aerospace nesting and cutting machines, each wheel ' s pattern is cut and partnumbered simultaneously, guaranteeing correctness and uniformity. Far stronger than standard wheels, BST wheels are comfortably over-engineered for road use and they pass all known tests for their rims, corner, radial and torsional fatigue and impact test standards. Carbon wheels deliver at least a 50 percent weight saving over alloy wheels and centralize the weight due to the lighter rim, resulting in improved performance and handling. The smaller radius of
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gyration completely changes the acceleration and braking characteristics. Acceleration is improved and braking is much easier, with improved stopping distances as well,“ improvements that are real and noticed by everybody who rides with our wheels,” says Gary.“ The steering is nimbler too, with the bike changing direction a lot more easily, and because of the lower un-sprung mass, the tire does less rebound work and the springs and shocks work sooner- so whereas going over something like a one-inch expansion joint was a jolt, the bike does not now feel it as much. Quite remarkable to feel and a very noticeable difference.” The end result, according to Gary, is the“ strongest, lightest and most durable wheels available, enormous performance and handling benefits, extended tire life, and improved acceleration, deceleration and braking performance. The bike will handle more easily with much faster turning into corners with absolutely no suspension modifications or adjustments whatsoever required. BST wheels are painted with an automotive grade clear coat( with UV protection) and finish options include matt black, high gloss, satin and even chrome look.
BLACKSTONE TEK Johannesburg, SOUTH AFRICA Tel: + 27( 0) 11 704 0026 marketing @ blackstonetek. com www. blackstonetek. com
The effects of inertia By Gary Turner
Lightweight wheels are without a doubt the best performance product that can be purchased for a motorcycle. Instant performance is gained in all major areas- it ' s something the rider feels immediately – it ' s instant gratification. When comparing wheels and weights, it is not always the overall weight that matters, but rather the weight distribution in each particular wheel which affects the performance of the wheel. A lighter rim means better performance. Carbon wheels generally have much lighter rims and carry the bulk of their weight in the hub – and the hub has little effect on the performance of the wheel. But weight is NOT the only consideration. Lighter wheels will make a major difference to the handling of a motorcycle, but they will also improve your acceleration and deceleration( braking). This is because the weight of the wheels isn’ t at work in isolation. What is even much more important is the Rotational Inertia of the wheels, namely how much weight is close to the axle and how much weight is further away from the axle. Clearly the energy needed to turn wheels obviously comes from the engine. If you need less energy or power to turn your wheels, the available power accelerates the wheel quicker and you will end up with a higher maximum speed. The lighter the wheels, the less your unsprung mass. This means that your suspension has to work less to dampen the wheels and it will therefore track the ground surface much better, giving better control and performance. It is more difficult to move or steer a rotating mass than a stationary mass( try to move a spinning bicycle wheel). If you reduce the mass, and specifically the rotating inertia, the force required to move or steer the mass is reduced significantly. Putting lighter wheels on a motorcycle will reduce the steering forces significantly and therefore have a positive influence on driver fatigue. No other performance enhancing product gives the same benefit / price ratio.
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