Why do I do I need to have my large wheels and tyres certified on my four-wheel drive?

There are a number of reasons. Larger wheels and tyres are heavier which have greater rolling diameter that effects the safe handling of the vehicle. Larger wheels require larger brakes Vehicle stability is compromised as the centre of gravity changed to the manufactures design height. The height change affects road handling, front zone crash protection, bumper heights to other vehicles, side protrusion protection, air bag crash sensors, electronic stability control and in some cases wheel track. Statutory requirements limitations, VSB 14, ADR,s, brake assessment manual & suspension manual requirements.