Racing wheelchairs have undergone huge developments over the last 20 years, greatly improving race times achieved by wheelchair athletes.
A modern racing wheelchair is actually a tricycle made of extremely light aluminium or titanium. It’s fast and stable. The front wheel pivots for steering and usually has a brake. User positioning in the wheelchair and correct pushing technique plays a large role in performance.
Racing regulations are fairly basic: All racing wheelchairs must have a minimum of three wheels. Only one push rim is allowed per wheel. No mechanical levers or gears to assist propulsion are allowed. No mirrors are allowed, and the athlete must push on the wheel or push rim.
Stability and traction
A race chair is designed for speed, so aerodynamics should be perfect. However, due to the speeds reached – up to 80km/h on a downhill - stability and traction is equally important. Frame rigidity plays a big role in the transfer of energy from the athlete through the wheels. Any flexing absorbs some energy which does not get transferred into speed.
There are two user positions – sitting or kneeling. Sitting is the favourite for beginners as it is more comfortable and stable. It’s also recommended for athletes with poor balance, such as Spinal Cord Injuries above a T10 level. In the sitting position, the feet can be held forward in front of the axle tube and supported by a footplate with the knees strapped. Or the feet can be strapped under the buttocks behind the axle tube. The knees are forward and slightly elevated. This position works well for individuals with lower level injuries and good flexibility. Kneeling puts the athlete into a head forward position, ideal for maximum power transfer through the wheels.
Camber is the vertical slant angle of the rear wheels, which gives the chair stability and minimises arm rubbing. It improves manoeuvrability but slightly reduces straight-line speed. The most popular camber setting is between 11 and 13 degrees, with the latter setting more stable for sharp bends on downhill road racing. A 12-degree camber is the most popular angle for track racing, while 11 degrees is used in marathons by top athletes and those with good balance. Racing chairs don’t have adjustable camber, but an adjustable insert is available that sets the different angles.
The axle position affects the chair’s centre of gravity. If the axle is set too far back, the chair becomes very stable but puts weight onto the front wheel, giving added resistance. If the axle is set forward, there is less weight on the front wheel, making it more efficient but “tippy” and the athlete may tip over backwards. The position of the axle is dependant on the person’s level of injury, i.e. how much balance they have, as well as the height of the person and the weight of their legs. A short person with light legs will have the axle set further back, while a taller person with heavier legs will have the axle set further forward. The kneeling position generally has the axle set further back.
A straight camber tube was introduced in 1995 (the straight bar between the two wheel hubs). This increases the stiffness of the chair and allows rear wheel alignment. The traditional angled camber tube is still an option for users who need more foot room. Wheel alignment is critical for optimum performance, as two wheels that do not run parallel and in line with the direction of movement adds a huge amount of drag.
The overall length of the chair depends on the height of the athlete and their ability to reach the steering bar and brake comfortably, while in the racing position. A longer chair runs smoother and straighter.
The size of the push rim depends on the athlete’s arm length and strength, and influences the amount of speed and power transferred through the wheel. A larger push rim gives more power and less speed, while a smaller push rim gives more speed but less power. Most good racers experiment with different sizes over time to find out what works best on different distance events. The push rim should have a rubber coating to give adequate grip, particularly in wet conditions.
The compensator is a steering limiter device which holds the front wheel in a fixed position while moving around corners or on the straight on the track. This needs to be set before each race according the amount of curve on the corners.
Quadriplegic athletes require a slightly different set-up. Since they have no trunk control, they require a deeper seat and extra support on the backrest to give them more stability. The axle position is set further back to bring the centre of gravity forwards to give added stability. The brake lever is positioned on top of the handle bar so that they can push down with the wrist if they lack finger function.
Products available on the South African market:
Invacare Top End Eliminator
Designed for maximum speed, stability, aerodynamics and traction, the most popular chair amongst top international athletes like Ernst van Dyk and Krige Schabort.
Custom-built 6061 T6 aluminium frame available in sitting (standard) or kneel-only design, with 4 cage choices: U, V, Open V or I cage.
The V cage offers greatest stiffness and aerodynamics, ideal for the kneeling position and racers with longer or thicker legs. The I cage has the most open space but is the least rigid frame.
Integral wrap around fenders and aluminium side panels add stability. Straight axle tube provides rear wheel alignment. Aero bar equipped with caliper brake. Kneeling, amputee or traditional adjustable upholstery is available, and supplied with a precision track compensator system.Specifications:
Weight: 6.3 – 7.2 kg
Seat width: As required.
Frame length: Variable
Weight capacity: 110 kg
Camber Angle: Available in 11, 12 13 and 15 degrees.
Seat height: Rear height 38, 40, 43 or 45 cm. Front seat height is typically 2.5cm higher.
Wheels: 700C or 26 inch rear clincher or tubular 28-spoke high performance wheels with threaded axle. Rubber-coated aluminium push rims. 20 inch tubular front wheel.
Zipp Rear Wheels.
Corima Front wheels.
Carbon Fibre Wheels and push rims.
Price: R38 000.00 Incl. VAT
The low front end and aerodynamic design reduces drag while precision steering provides reliable handling. The integrated fender design creates a narrower, stiffer cage for maximum stability and power transfer.
Custom built 7000 series aluminium frame is extremely light yet strong. Upholstery design allows feet forward or behind, and kneeling for bilateral amputees. Easy-to-reach handle bars. Supplied with cycling computer.
Weight: 7.7 kg
Seat width: 20 – 50cm
Seat depth: 20 – 71cm
Weight capacity: 110 kg
Camber Angle: 12 degrees
Seat height: As required
Wheels: Choice of 18 or 20 inch front wheel. Choice of 26 inch or 700 rear wheels – tubular or clincher available
Push rims: Available in 6 different diameters, 33 – 38cm
Price: from R25 000 – excluding freight costs.
Supplier: CE Mobility
Locally made racing wheelchair designed for both road and track racing is an excellent development racing chair for sports clubs and developing athletes. It has a light, rigid aluminium frame with padded, waterproof, tension adjustable upholstery.
Adjustable footrest, precision sealed wheel bearings, Shimano braking system
Seat width: As required
Weight capacity: 110 kg
Camber Angle: 11, 12 , 13 degrees available as separate inserts.
Seat height: 240mm
Wheels: 27 inch aluminium rear wheels with high performance tires and all-weather aluminium push rims.
20 inch front wheel – choice of Panaracer or Vittoria tubular
Price: from R12 000
Supplier: Able Wheelchairs, Schalk van der Merwe
Schalk is willing to give advice on selecting and importing racing wheelchairs. He has many years of experience as a track and marathon athlete.
SP 2000 sports wheelchair.
Weight: 11 kg
Seat width: 260 – 380 mm
Seat depth: 420 mm
Seat height: 580mm
Total length: 1720mm
Camber Angle: Adjustable
Wheels: Quick release rear wheels 700 x 20C
Price: To be announced
Supplier: Solutions Medical
Pieter Le Roux from Kinetix is presently developing a racing wheelchair. This will be available in SA within months, and priced from R12 000. For more information contact Pieter - Watch this space!