- Location
- Surrey/ Kent Border, UK
your rules are far different to the uk then, and do you really need 70% minimum ?
In the uk a HGV running at 44 tonnes gross, or any HGV for that matter,
only needs 50% minimum to pass an MOT on service brakes
and it is hard to get a HGV to have a braking efficiency above 70%
you must have a big scrap yard
Most cars, HGV's and the very best Ag trailers have a braking efficiency of just about or slightly over 50% braking efficiency. The regulations for Ag trailer brakes are for a 25% efficiency unless towed over the 40k limit by either a fastrac or mog. However the best tractor braking efficiencies can hit nearly 80% ( normally involves oil immersed brakes in front hubs ) and it would be impossible to exceed this without breaking the laws of physics. This is why, with decent brakes on tractors and poor trailer brakes, there were so many tractor brake failures, they were just being overloaded. Generally the message has got out and more people have spec'd better braking systems on trailers reducing wear and increasing safety.