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SERIOUS RISKS FROM REPAIRING WHEELS AND RIMS FOR TRUCKS AND BUSES
Unlike processes used to increase the life of tires, wheels should never be repaired where repair and retreading are expected.
No wheel manufacturer, whether of steel, aluminum, or special band, recommends any kind of process of wheel repair for breakage, cracks, bulging, or ovalization.
This Bulletin was prepared by the Latin American Tire and Rim Association (ALAPA) of which Alcoa is a member. The purpose is to alert users to the dangers of this practice, which may lead to very serious or fatal accidents.
We note that Alcoa wheels have a five-year warranty starting from the date of sale (consult the warranty policy in the Safety and Service Manual -- Alcoa website).
For further clarifications, contact your Alcoa representative or call Alcoa Rodas de Alumínio Ltda.- After-Sales Department - Phone 011 3611 3086.
The Latin American Tire and Rim Association (ALAPA) disapproves of the practice of REPAIRING WHEELS AND RIMS and explains:
Breakage through fatigue
A wheel is planned to meet particular requirements of the vehicle for which it is intended. The main parameters are the maximum work load, vehicle speed, and type of the road to be traveled.
Over time these factors cause extremely high cyclical stresses at some points on the wheel. The points most affected are the ventilation holes and the disk attachment holes, the flange, and the edge of the rim.
Wheel material subjected to continuous stresses suffers deformations that lead to the appearance of gradual cracks if the demanding conditions continue.
Traveling overloaded at speeds incompatible with the loads transported, and on poorly paved roads, are factors that lessen the life of a wheel.
The more travel that takes place under such conditions, the less durability there will be.
Repair of the Disk
The disk is damaged by fatigue cracks or deformation in the ventilation holes or mounting holes, or ovalization of the attachment holes.
Wheels with a damaged disk, or with cracks or deformation in the mounting holes, may not be repaired or used in service.
Repairing them by welding the cracks or placing rings in the damaged holes, or by re-drilling, will cause new cracks to appear in the welded areas, circumferentially around the holes.
Example of wheel with cracked disk.
Repair of the bead
The bead on the rim is responsible for retaining the ring or rings, depending on the type of rim. It becomes damaged basically through wear or fatigue cracking.
Repairing it by turning and welding does not assure tight tolerances of radial and lateral eccentricity of the ring and of ovalization of the rim.
Since there are no correct tolerances in the bead/ring inset, it will be left in an unbalanced condition after the tire is inflated, with serious risk of it dislodging from the ring.
Similarly, the welding of the bead will quickly lead to fatigue cracking, and in this case the risk will be for the tire to blow out while the vehicle is moving.
Repairing the Rim Flange
The flange normally breaks due to fatigue. It starts with a crack that quickly spreads around the circumference of the rim.
Replacing this flange by welding on a new flange does not eliminate the possibility of new cracks appearing, primarily in the welded region.
Moreover this area has a ramp with a 5º to 15 º inclination, depending on the type of rim, for properly attaching the bead of the tire, which is difficult to reproduce by repairing. In this case, the tire will tend to spin incorrectly over the rim, seriously affecting vehicle safety.
The Brazilian Rim and Tire Association is always concerned with safety and standardization, and is available to those interested for any further clarification on this matter.
Example of a wheel with a crack in the flange region.
According to the international standards reproduced below, wheel repair is also disapproved in various countries in the world.
ETRTO (European Tire and Rim Technical Organization) RECOMMENDATION Tires and Rims
Damaged or distorted wheels should not be repaired or used in tire mounting.
Cracked rims or disks must never be welded under any circumstances, as the weld will crack again after a short space of time under the dynamic stresses involved.
OSHA STANDARDS 29 CRF 1910 - OCCUPATIONAL SAFETY AND HEALTH AGENCY
Letter F - Operational Procedure - Multiple Piece Wheels Item 9
Cracked, broken, bent, or otherwise damaged rim components, shall not be reworked, welded, brazed, or otherwise heated.
TIRE MANUFACUTURERS - USA - SAFETY NOTICE
Air pressure in an inflated truck tire mounted on a rim or wheel creates an explosive energy.
This pressure may cause the tire to explode with such great force that a person may be hit with a piece of the rim or tire, possibly leading to serious injury or death.
AVOID SERIOUS OR EVEN FATAL ACCIDENTS BY FOLLOWING THESE RECOMMENDATIONS
- Do not heat wheels in an effort to "soften" them to facilitate the process of repair from blows or strong impacts.
- The special band used on Alcoa wheels is heat-treated, and uncontrolled heating may undo the wheel's mechanical properties.
- Never submit an Alcoa wheel to any filling operation by welding.
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