Fat guys can’t go fast.. speed and weight

It seemed like the bargain of the (LAST) century. Money was tight, and we'd found a “deal” on some slightly used tires.

The size was right, they had TONS of tread, and the ply rating seemed appropriate. “Ply rating” was the old way of measuring tire strength.. sorta.

So we blithely began mounting them on coaches. We weren't too sophisticated, so it came as a bit of a surprise when one of our genius's noticed that the sidewalls were stamped “DO NOT EXCEED 50 MPH”. We'd bought tires rated for transit use, and all that extra tread generated too much heat to be safely run at highway speeds.

Athletes understand there's a critical balance between weight and speed. If you're fat, it's hard to go fast, and maneuver.

One thing regulators are beginning to take VERY seriously is motorcoach weight, and its’ relationship to speed and safety.

For years most states didn't require coaches to weigh, and as a result we've been living in a bit of a dream world. More buses are now being scaled, and inspectors are going to look closely at weight related factors.

Motorcoach builders and operators have used weight approximations to determine coaches maximum seating and baggage capacity, but those calculations have been based on what our ancestors weighed. The GVWR (Gross Vehicle Weight Rating) placard mounted in every coach is a no-nonsense indication of how much that vehicle can safely carry at its rated speed.

We're chubbier than previous generations (with luck, taller too). Many manufacturers assume that passengers weigh 150lbs, but the average is closer to 200 … and If every seat is occupied, and luggage bays full, the coach is probably exceeding its' GVWR. Pull into a weigh station, or inspection... and there will be trouble.

Just because (obsolete) estimates allow the manufacturer to install 57 seats, doesn't mean the coach will always be under it's designed maximum weight, if they're all occupied. Don't blame the builders... we've pushed them for more capacity.

A vehicle's GVWR is based on a number of factors, including some variables, and makes suppositions about operating parameters like speed and temperature. Manufacturers certify a vehicle assuming it doesn't exceed its rated speed, and presuming that replacement tires and brakes are at least equal in performance to the ones originally installed.

If a builder rates a coach at 71MPH, and it's involved in an accident while fully loaded, at 75MPH, it may have been speeding... but it WAS overweight. Regulators may have figured this out.

Tie governors down to the manufacturers spec.. or lower.

When a coach's specifications call for “H” rated tires, and it's running “G”'s, it's not capable of safely operating at normal weight and speed.

Under-inflated tires can't safely carry as much weight as when they're fully inflated.

Folks... if I know this stuff, surely sophisticated law enforcement people (and crafty lawyers) do too.

This weight thing isn't just about avoiding fines, it really is about safety. Blowouts at the newly increased speed limits and tire fires are serious business.

We can't scale every coach each time it departs (or when another passenger climbs on), however it might be entertaining to check a fully loaded bus. Fill the seats with employees and friends... customers may take offense at being driven over a scrapyard scale. You might be surprised to see how heavy it is.

When the Sumo Wrestling Club charters a bus... leave some seats empty. They only wear loin cloths, in their case, luggage weight might not be a factor.

Double down on tire maintenance and awareness. If coach specs call for G rated tires... installing H buys an extra margin of safety. If some of your coaches call for H, and others G... installing all H's eases administration and reduces opportunities for errors.

Tires last longer and save fuel when air pressure is correct. More important, they're much less likely to fail catastrophically.

Legitimate spare tires need to be properly rated and inflated.

On coaches with tire monitoring systems, make sure they're working correctly, and that drivers and mechanics heed alerts. Sensors need to be mated with the coach the tire is mounted on. Systems get confused when you take a tire from one bus.... and mount it on another without proper introduction.

When the monitor hiccups mid-trip do your drivers know how to check tires?

Other than the Sumo wrestlers, tires seem to be the weight related item operators can control most.

Rather than shop price, find a first rate supplier who can keep you informed on ratings and all the other stuff you know a little about... because knowing A LOT is becoming critical.

If we'd known more, we wouldn't have needed to try selling transit tires as tug boat fenders. Darn few tugs where we were... in Colorado.