this is referred to as toe in, or positive toe. Should the wheels at the front or rear of the vehicle be pointing outwards, this is known as toe out, or negative toe. “Rear toe assists the straight-line ability of a vehicle, as it is based around an axle that experiences no directional movement. Should the wheels not be set equally on both sides, a thrust angle is introduced. Both front and rear toe are crucial to reduce wear on wheel and suspension components, where tensions can be built up without the correct geometry angles. “Vehicles with toe in or toe out problems will experience increased tyre wear across the whole of the tread. This is due to the wheels experiencing a slight sideways force as it travels forwards, effectively ‘scrubbing’ the tyres across the road surface. If drivers are reporting that tyre life is shorter than expected, the toe angles are a good place to start any investigation. “The thrust angle is the angle of the central line of a vehicle in relation to the rear axle. This should equate to 90-degrees from the rear axle which, in turn, means there is a zero-degree thrust angle. If the thrust angle is greater than zero, this will start to affect the relationship between the front and rear axles. With the rear axle helping to keep a vehicle travelling straight, this deviation would require compensation with the driver experiencing their steering wheel pull to the left or the right, a situation that leads to ‘crabbing’. To counter this, technicians need to amend the front toe values, commonly referred to as the ‘thrust angle compensation’. “Another common issue experienced by drivers is inconsistent tyre wear on the inside or outside shoulder of the wheel. This can be an indication of issues around camber. Wheels should sit vertically, without any lean inwards or outwards. Any deviation leads to more pressure on the edge of the tyre, as it presses into the road, while the opposite side experiences less force against the surface. “Camber is set to help vehicles when cornering, keeping the centre of the tyre in contact with the road. These angles must be equal on each side of the vehicle, or the driver will experience drifting to the left or right without steering correction. Negative camber sees the top of a wheel leaning into a vehicle, and affects the inside shoulder of the tyre. Positive camber means a wheel is leaning away from the vehicle, affecting the outside tread. Spotting these trends can offer an insight into misaligned geometry.” “Finally, for wheel alignment geometry to remain as 40 AFTERMARKET APRIL 2024 WHEEL AND BODY ALIGNMENT www.aftermarketonline.net consistent as possible when a vehicle is moving, a castor angle is built in. This is the angle at which suspension components sit, leaning back from the vertical line of a wheel to push when in motion and reduce tension on components. Castor angle is only adjustable in a few vehicles, and problems are likely the result of accident damage. Both castor angles on vehicle wheels do not need to match, as UK vehicles are often set with the left castor slightly higher than the right, to compensate for road camber.” Julia added: “Supertracker is dedicated to offering customers wheel alignment systems and support to suit their individual needs. With a simple, yet accurate range of laser and computerised wheel alignment systems, backed by a nationwide aftercare support team, we can help advise on the right equipment for you, with training and demonstrations available in our new dedicated training studio.” For more information, visit: www.straightset.co.uk/news/post/wheel-alignmenttraining-studio Ideal On the body repair side, and the need for quick-pulling kit, Tri-Sphere director Jim Masterson said: “If your bodyshop isn’t using a smart quick-pulling system yet, the new GO MAX could be well worth considering. Just introduced by Tri-Sphere, it’s ideal for sill dents, rectifying low velocity impacts to doors or wings and almost any visible dent on the bodywork. He continued: “A range of safety features and the highbuild quality design ensures the GO MAX can be used immediately, with little or no training. A quick return on investment is forecast. The vacuum pump secures the pulling tower to the floor. A thoughtfully placed vacuum gauge indicates when the tower is secure enough for the pulling procedure to begin. An anti-slide counter plate, that fits underneath the vehicle, prevents lateral or forward movement during the procedure. It gives maximum traction to the 600kg pulling chain.” “The pulling panel is secured to the vehicle either by stud weld, or high-quality glues. These alternatives provide garages and body repair specialists with additional degrees of working flexibility. Optional extras include a down pulley, a height extension and a sill clamp plate. The down pulley converts a direct lateral pull into a downward pull. The sill clamp plate provides additional stability, while the height extension allows work to take place much higher up on the vehicle body, such as on A, B or C pillars.” Left: Tri-Sphere GO MAX Above: According to Supertracker, understanding wheel alignment geometries can lead to increased work
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