Bendix has lended its expertise to explain how tyre tread patterns can affect braking
In addition to suspension setup, the type of tyre used on a vehicle and its tread pattern significantly influence consistent braking performance.
SEE MORE: Car news
For four-wheel drives, upgrading suspension and tyres are among the most common modifications made by owners beginning their modification journey. When suspension is too soft, excessive body movement during braking can destabilise the vehicle, leading to uneven weight distribution and potentially reducing traction.
Conversely, overly stiff suspension can diminish tyre contact with the road, resulting in longer braking distances. Furthermore, increased ride height can also impact braking due to a higher center of gravity. Swapping tyres beyond the original equipment manufacturer (OEM) specifications and altering tyre bias can have substantial effects, as evidenced by local testing conducted last year by a prominent tyre manufacturer.
Keeping tracks
Utilising VBOX diagnostic equipment on a closed circuit, the company tested a range of road, all-terrain, and mud tyres, including those from several competitors. The tests were performed with 265/65R17 tyres – the most commonly fitted size on vehicles sold in Australia—executing braking manoeuvres on a skid pan from speeds of 70 kms per hour to a complete stop under both wet and dry conditions.
In each instance, the stopping distance varied by roughly five metres (equivalent to a typical car length) between road tyres and mud terrain tyres, with all-terrain tyres falling in between. Some of the decreased on-road braking performance observed was due to the mud terrain tyres featuring a harder, chunkier tread with greater spacing between the lugs (resulting in a smaller contact patch with the road to facilitate self-cleaning). Additionally, mud terrain tyres are generally heavier, even if they share the same specifications. This extra weight, which can exceed two kilograms, results from thicker sidewall construction and tougher tread, thereby increasing the rotational mass of the tyre.
It is noteworthy that mud terrain tyres, despite being labeled 265/65R17, can sometimes be taller than indicated. Rotational mass encompasses all components that rotate with the wheel assembly, such as tyres, wheels, and lug nuts. The farther away the mass is from the axis of rotation and the heavier it is, the greater the rotational mass, necessitating more force to halt the rotation.
Mitigating the effects of rotational mass
An ideal solution for four-wheel drive owners is to maintain a second set of wheels and tyres for challenging terrains, although this can be costly. A practical compromise might be to opt for all-terrain tyres, sacrificing some braking performance in exchange for enhanced off-road capability.
Another alternative is to explore brake upgrades, which can be implemented in various stages based on the owner’s needs and budget.
Improved Friction Materials
The simplest and most economical initial step is to replace the original equipment (OE) brake pads and shoes (for vehicles with rear drum brakes) with high-performance alternatives such as Bendix’s Ultimate 4WD™.