{"id":4022,"date":"2020-01-06T16:31:08","date_gmt":"2020-01-06T15:31:08","guid":{"rendered":"http:\/\/en.advancedfleetmanagementconsulting.com\/?p=4022"},"modified":"2020-01-06T16:31:08","modified_gmt":"2020-01-06T15:31:08","slug":"how-speed-weight-and-grades-affect-brakes","status":"publish","type":"post","link":"https:\/\/advancedfleetmanagementconsulting.com\/eng\/2020\/01\/06\/how-speed-weight-and-grades-affect-brakes\/","title":{"rendered":"How Speed, Weight and Grades Affect Brakes"},"content":{"rendered":"

How Speed, Weight and Grades Affect Brakes<\/h3>\n

It’s not enough to simply inspect your brakes regularly. To insure top performance, you need to understand how operational factors impact brake performance.<\/p>\n

We are all familiar with brakes. We use them to stop. That’s their function, but in engineering terms, a brake is a device used to convert kinetic energy (motion) into thermal energy (heat) through friction between stationary parts (brake linings) and moving parts (brake drums or rotors). The brake drum and the lining material are designed to dissipate that converted energy, but too much heat that cannot dissipate quickly enough will\u00a0eventually overwhelm the brakes design capacity rendering them less and less effective, and eventually useless.<\/p>\n

The normal operating temperature of a properly functioning brake is about 500\u00b0F. A hot brake that produces a distinctive odor usually accompanied by white or blue smoke is about 800\u00b0F. Dangerously overheated brakes can reach temperatures of\u00a0\u00a01,800\u00b0F\u00a0or higher. These will glow cherry- to bright-red and there’s serious risk of a wheel-end or tire fire.<\/p>\n

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\u00b0F.<\/p>\n

On top of that, cast iron brake drums expand as they get hot. The diameter of the drum can increase by as much as forty thousandths (.040) of an inch when it’s really hot. An accepted rule of thumb suggests that for every .020 of an inch the drum expands, the push-rod has to travel an additional 1\/4 inch to maintain lining-to-drum contact. If a brake was not properly adjusted to begin with, things can go downhill (sorry about that pun) pretty fast.<\/p>\n

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.<\/p>\n

In practical terms, that means a fully loaded truck descending a hill at 60 mph\u00a0will 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.<\/p>\n

\"Even
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Even small increases in speed can make a big difference to the demands on the brakes. Chart: Jim Park<\/p>\n<\/figcaption><\/figure>\n

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.<\/p>\n

*Much of the technical detail here comes from a book called “Air Brakes from the Driver’s Seat” by Allan C. Wright, published in 1999. It’s now out of print, but in 2004 he assigned the book\u2019s copyright to the Insurance Corporation of British Columbia, and it\u2019s since been incorporated into the ICBC publication \u201cDriving Commercial Vehicles\u201d.<\/p>\n

by Jack Roberts<\/a><\/p>\n

\u00a0Source: https:\/\/www.truckinginfo.com<\/a><\/p>\n

FLEET MANAGEMENT AUDIT<\/h3>\n

Fleet management is the use of a set of vehicles in order to provide services to a third-party, or to perform a task for our organization, in the most efficient and productive manner with a determined level of service and cost.<\/p>\n

Fleet management activities are shown in the following graph 1:<\/p>\n

\"fleet<\/p>\n

Graph 1: fleet management activities<\/p>\n

The proposal audit analyses and assesses all fleet management activities shown in the graph 1, and its main goals are:<\/p>\n