When was the guide first written?

In the early 1990s, the National Transportation Safety Board (NTSB) recommended to the wheel industry that they standardize procedures for both informational and training purposes. For help in putting those practices in place, the wheel industry came to TMC for assistance.

The TMC set up a task force of wheel manufacturers, fleets and other industry experts to put together the first User's Guide to Wheels and Rims.

Like the new edition that came out last year, the first guide was a consensus of the opinions and practices of the task force, and not one manufacturer's mandate.

So everybody agrees on the best practices?

Yes, and that's what makes the TMC User's Guide to Wheels and Rims so ideal. Whether it's a maintenance supervisor initiating maintenance practices, a manufacturer adjusting a warranty or the Tire Industry Association referencing DOT-regulated installation procedures, the entire industry has adopted the information that's in the guide as its primary source.

Tell us about the new guide.

The first guide was introduced in 1994. An update task force got together and went through the manual page by page, looking for ways to improve it.

The new guide, which came out in winter 2004, offers maintenance procedures in greater detail, more conditions and clearer photographs.

What else is new?

First of all, the photographs are in color - the book, too - so wheel conditions are easier to identify.

Some wheel damage - for example, cracks - depend on the scope and severity of the condition to determine whether a wheel should be removed from service and scrapped.

Of course, scrapping a wheel is expensive, so the more information a fleet has to make that determination - like photographs that show a lot of detail in them - the easier they can determine if the size, length and location of a crack warrants wheel replacement or continued visual inspection.

Same with corrosion.

That has to be a big problem.

Modern de-icing chemicals help clear roads of ice and snow, but they are really hard on wheels. Some states, such as Colorado, use a particular chemical that is very difficult to wash off - in fact, it adheres more than other brine solutions.

The new guide features more photographs so fleets can identify different types of corrosion problems. Plus, there are additional pages with recommendations on coping with corrosion.

What do the code numbers on each page mean?

Those are the Vehicle Maintenance Repair Standard, or VMRS, alpha and numeric failure codes. TMC members requested that the new guide include those codes so they don't have to reference a second source when inputting failure codes into their fleet maintenance software. Not only is it more convenient, it reduces errors, too.

Which wheels are referenced in the guide?

The guide addresses wheel conditions that affect heavy-duty, class 6-8 vehicles.  There are three types of wheels used in this industry: the older spoke demountable rims, stud-piloted disc wheels and hub-piloted disc wheels.

The most important thing to know about these three types of wheels is that the parts, especially the fastening systems, cannot be interchanged.

What could happen?

Fasteners for hub-piloted disc wheels and stud-piloted disc wheels are different. For example, hub-piloted wheels use flange nuts. If the parts get interchanged, you could experience broken studs, cracked wheels - or the wheel could fall off.

Plus, each wheel system uses a particular sequence for tightening the nuts. You'll find a chart at the bottom of page 21 for tightening hub-piloted wheels; if you're working on stud-piloted disc wheels, the chart is on page 22. 

If you need help training your technicians in proper wheel maintenance, TMC also offers a video called Tires & Wheels: Wheels and Rim Inspection. It's a good companion piece to the book because it shows why a wheel should be removed from service and explains the differences among wheel types.

So, can wheels wear out?

Of course. Corrosion. Cracks to the handhole or bolt holes. Improper torque. Overloading. Under-inflation. All of these can cause wheels to wear out and possibly fail.

How can we order these materials?

To order the User's Guide to Wheels and Rims or the video Tires & Wheels: Wheel and Rim Inspections, call TMC MarketPlace at 1-800-282-5463 or visit the online store at www.truckline.com/store/index.