Over the last two decades the trucking industry has made some major changes in the equipment it runs.
Trucks, tractors, and trailers are now spec'd with emphasis on fuel economy, which means more lighter-weight and fuel-efficient components and more aerodynamic devices used than ever before.
We've seen the adoption of wide-base tires used in single applications grow significantly in regular dry freight-hauling operations as well as the use of aluminum wheels.
Aluminum wheels were at one time used only by fleets that were extremely weight sensitive, and by owner-operators who wanted to trick out their trucks. Most fleets couldn't justify the expense of these spiffy wheels unless they could carry more payload with the saved weight.
Today the economics have greatly changed. Aluminum wheels can be found in almost every type of operation. In fact these wheels are now on 60 percent of the new tractors and 22 percent of the new trailers being produced this year. As a result, instead of encountering aluminum wheels only occasionally, technicians now are routinely servicing them.
One of the most common conditions found on aluminum wheels is rim-flange wear. This is abrasive wear and/or pitting that is found on the top of the rim flange. This wear can become quite severe and sharp.
This type of wear is caused by abrasion from the tire chafer and sidewall on the flange that occurs especially when the tire is underinflated and/or overloaded. It also can be caused by using a rim that is too narrow for the tire and can be exaggerated by corrosive or abrasive environments and applications, like tanker operations, in which the load shifts frequently.
Rim-flange wear can damage tires when a tire is being demounted from a wheel that has a severe case and exhibits sharp edges.
The sharp edges of the rim flange can slice slivers of rubber out of the bead about 3 to 6 inches on either side of the tire tool as the bead slides over the rim flange. And, as we all know, bead damage can lead to other tire conditions such as sidewall separations.
Michelin North America Inc. has come up with a helpful hint that is easy to use when you encounter this situation: When you encounter an aluminum wheel with rim-flange wear, lubricate the tire and wheel with a thick coat of slippery bead lubricant when demounting a truck tire from a rim.
(If you are using lubricant concentrate that is mixed with water, this may not be slippery enough.)
Then find an empty plastic bottleperhaps the one that the lubricant comes in. Remove the top and bottom of the plastic jug so that you have a long strip of plastic about 4-6 inches wide.
Cut that in half so that you have two strips of plastic (See photo at right).
Using a tire-changing tool, raise the rim off the tire bead and slip the plastic strips at about four inches on either side of the tire-changing tool.
After pushing down on the tire tool, the top bead should come off the wheel without any damage.
To remove the other bead, reposition the tire-changing tool between the bead and the rim flange and again place the plastic strips about four inches on either side of the tool between the bead and the rim flange.
Slowly remove the bead and Voila!you have one intact tire to which there is no need to make bead repairs.
OK, so what do you do now?
You don't want to mount another tire on this wheel, nor do you want to scrap the wheel yet. Instead, you have to do some proper maintenance to the wheel to remove the rim-flange wear and prevent damage to the next tire that gets mounted on it.
First, if it is a dual wheel, always check it to ensure it has the proper contour. Wheels can shrink due to exposure to high heat such as from brakes and running flat.
Check the wheel by either rolling it a minimum of 10 feet on a flat surface and ensuring it rolls straight, or by using a carpenter's square.
If using a carpenter's square, place the long leg of the square across the center of the disc side of the wheel and extend the short leg across both rim flanges. The short leg should touch both rim flanges.
If a distance greater than the thickness of a credit card appears between the short leg and the rim flange, the wheel should be removed from service and scrapped.
Do this at four locations around the wheel.
Always check all wheelssteel or aluminumfor contour deformation prior to mounting tires on them. If they have been shrunk by heat or mounted with flammable liquids, the next tires mounted on them may blow off during inflation.
Then, according to the Wheel Service Manual from Alcoa Inc.'s Wheel and Transportation Products unit, check the rim flange with an Alcoa rim-flange wear gauge to determine if the wheel should be removed from service due to excessive flange wear.
If you don't have one of these gauges, call Alcoa at 800-242-9898 or go to the company's websiteat www.alcoawheels.comto obtain a gauge at no charge.
Alcoa recommends that the sharp edge on the rim flange be removed by using a metal file, an air- or electric-powered sander, or an air or electric grinder.
Any of these tools can be used effectively to remove the edge, but the powered tools obviously will provide a quick and efficient removal operation. However, be advised that grinding pads may gum up from the aluminum that is removed.
If you use a powered grinder, make sure it can operate at at least 11,000 rpm. It should be used with a medium to fine grit grinder wheel, wire brush or purple disc. Always wear safety glasses, work gloves and hearing protection. During this process, power tools generate metal filings and sparks and have edges that are sharp and may become hot during usenot to mention the excessive noise the process produces.
Whatever tool you use, work the tool around the wheel's circumference, removing only enough material to remove the sharp edge and make sure you remove metal as uniformly as possible and avoid gouging the wheel. If both rim flanges have sharp edges, perform this work on both flanges.
Then check the rim flange height with the Alcoa rim flange wear gauge again to make sure there is adequate height remaining to safely support the tire. Move the gauge all around the wheel's circumference to make sure that no area of the flange is below the acceptable limits as indicated by the gauge.
If the entire wheel flange is within acceptable limits according to the rim flange wear gauge, then you are good to go with mounting the next tire on the wheel.
When people first noticed rim flange wear, they got all upset and thought they had to scrap their expensive aluminum wheels. But this is not always necessary.
However, it is necessary that proper maintenance procedures are followed to ensure these wheels have a long life and cohabitate well with their mounted tires.
The use by fleets of aluminum wheels will continue to increase in the trucking industry. Your know-ledge of the proper techniques required to service them properly must grow, too.