Effect of weight on braking for trucks.
Instead of further morphing the other thread, I thought it would be interesting to discuss the effect of weight and speed for trucks since we obviously increase our weight when we add TCs.
Obviously, it is talking about drum brakes, but I think the principles apply. It seems like improving the linings and doing things to decrease heat would be helpful.
My source is https://www.truckinginfo.com/347664/how-speed-weight-and-grades-affect-brakes.
Several things happen to hot drum brakes that will reduce their stopping ability--a condition often referred to as brake fade. Most lining materials lose some frictional capability at high temperatures. Poor quality linings may lose up to a third of their effectiveness at temperatures above 600°F.
The laws of physics work against truck brakes in other ways too. It's accepted that if truck weight is doubled, stopping power must be doubled. But if speed is doubled, stopping power must be increased four times. If both weight and speed are doubled, stopping power must be increased eight times.
In practical terms, that means a fully loaded truck descending a hill at 60 mph will require eight times the stopping power of a lightly loaded truck traveling at 30 mph. Or, the brakes on the faster heavier truck will be doing eight times as much work as the brakes on the slower lighter truck. In other words, the brakes must absorb or dissipate eight times as much heat.
Even small increases in speed can make a big difference to the demands on the brakes. An increase in speed from 50 mph to 60 mph --an increase of 25%--would increase the stopping distance on level ground by 56%. You can guess what happen on steep hills at high speed.
Obviously, it is talking about drum brakes, but I think the principles apply. It seems like improving the linings and doing things to decrease heat would be helpful.
My source is https://www.truckinginfo.com/347664/how-speed-weight-and-grades-affect-brakes.
Several things happen to hot drum brakes that will reduce their stopping ability--a condition often referred to as brake fade. Most lining materials lose some frictional capability at high temperatures. Poor quality linings may lose up to a third of their effectiveness at temperatures above 600°F.
The laws of physics work against truck brakes in other ways too. It's accepted that if truck weight is doubled, stopping power must be doubled. But if speed is doubled, stopping power must be increased four times. If both weight and speed are doubled, stopping power must be increased eight times.
In practical terms, that means a fully loaded truck descending a hill at 60 mph will require eight times the stopping power of a lightly loaded truck traveling at 30 mph. Or, the brakes on the faster heavier truck will be doing eight times as much work as the brakes on the slower lighter truck. In other words, the brakes must absorb or dissipate eight times as much heat.
Even small increases in speed can make a big difference to the demands on the brakes. An increase in speed from 50 mph to 60 mph --an increase of 25%--would increase the stopping distance on level ground by 56%. You can guess what happen on steep hills at high speed.
