By Dave Millhouser

Rolling west on Interstate 70, it was always tense as the old Brill approached Foristell, Mo.

We peered into the distance, trying to glimpse the billboard that announced the state weigh station.

Sometimes, hanging from the bottom, there was a little sign that read "Buses Weigh." And, if it was visible, we were in doo-doo.

Fully loaded, the ancient IC41 was overweight on the rear axle, and quick action was necessary. All the passengers in the back of the bus moved forward, and then were forced to squat in the aisle, out of sight of the inspectors.

Back then, Missouri was the only state we crossed that weighed buses.

This is oversimplifying but there are two major ways in which weight matters to law enforcement.

First, the heavier the vehicle the more it thrashes the road. Most jurisdictions are not awash in money these days, and would like their pavement to last as long as possible, so this matters to them.

Currently, on federal highways, motorcoaches and buses are largely exempt from this sort of regulation. But change appears to be in the air.

We can make the case that a single, big vehicle clobbers concrete less than several smaller ones, and that the clever engineering that makes coaches ride nicely for passengers also pampers the pavement. We hammer far less than a truck of comparable weight.

The second concern about weight does apply to us and is important.

The GVWR (gross vehicle weight rating) of a vehicle is the maximum weight it can legally carry. Its generally posted on the vehicle builders plate. The key word in all this is "legally."

Each axle is rated, and theres a maximum for the whole shebang. It is crucial that, when a coach is laden, no axle exceeds its rating.

All kinds of mischief can happen when components are overworked, from extended braking distance, to hardware failure, to blown tires.

Manufacturers determine how much weight an axle can bear by evaluating the components, and like golf, low score wins. If you have a 25,000-pound axle, wheels rated for 19,000 pounds and tires that can handle 18,000 the tires win, and the whole assembly is only allowed to carry 18,000 pounds.

Two critical factors about tires can make a major difference.

First, they are rated to carry "X" pounds at a specific air pressure (pounds per square inch). If theyre under inflated, they run hotter, and can fail.

The weight rating is for a specific maximum speed, again usually determined by the tires capability.

A major manufacturer used to govern one of its models at 71 mph, while another was allowed the dizzying speed of 72. The difference was weight; one model was a tad heavier, so the tires could only safely handle 71 mph at full load.

A full bus thats rolling faster than the factorys electronic engine control setting, is not only speeding, its overweight.

The other thing to be aware of is that a tire rated for 9,000 pounds single (like on a steering axle) is capable of substantially less on a dual. Because it cant shed heat as well on the side adjacent to another tire, its allowed fewer pounds in a dual application. (Dont trust me? Read the side of a tire.)

That being the case, it might be smart to err on the conservative side.

Coach tires spend their lives in a more enclosed environment than on trucks. It stands to reason that, in hot weather, they will have more difficulty shedding heat.

In addition, on some coaches, the rear tires are subject to heat from the engine compartment. Consider tire-pressure monitoring systems, theyll save you more than they cost.

Most 45-foot coaches (as well as two-axle coaches and transit buses) are close to maximum GVWR when loaded with passengers, baggage and freight. That means we need to be vigilant about installing correctly rated tires, consistently checking condition and inflation, and educating drivers on the whole dynamic. We need to be intelligent about how much baggage and freight we allow on board.

In light of some recent crashes where tires are suspected as the cause, regulators are likely to be checking tires and weight, and a coach exceeding its GVWR would not be allowed to continue.

Years ago, one of my favorite people in the coach business cleverly figured out he could save a ton of freight charges by picking up brake drums during Atlantic City day trips.

After dropping his passengers at the casino, hed drive to the parts warehouse and stuff a couple of dozen drums in the belly of his GM4905 while they were gambling.

Many of his customers thought he must have gotten a new bus for the return trip because the ride home was sooooooooooo smooth.

The extra weight smoothed the ride. But, hindsight being 20-20, it might not have been such a good idea.

Dave Millhouser is a bus industry marketing consultant and freelance writer. Contact him via email at Davemillhouser@gmail.com.