Keep ’em movin’

Proper maintenance of tires and tracks will allow your operation’s mobile vehicles and mobile plants to stay on the go.

With companies drilling down on all costs these days, every aspect of the operations and equipment is under close scrutiny. Saving money, in many instances, means looking at the total value proposition of the operations including maintenance practices and procedures. Tires and tire maintenance are aspects that can add significant savings to the bottom line. Proper selection and maintenance can also prevent expensive downtime. Here are a few tips, which should be considered to get the most out of the tire asset.

Maintenance program
Maintenance managers should always have a good written maintenance policy in place. This policy should be specific to the equipment, site conditions, operating conditions, loads carried and other pertinent factors. Once formulated, make sure to follow the recommended tire maintenance schedule.

Safety is ultimately the number-one priority. The equipment maintenance manager needs to start with a comprehensive program. If it is not done by company personnel, then hiring a dealer to administer the program should be considered. The money spent can be saved many times over by avoiding the tire maintenance issues caused by under- or over-inflation or neglect of damaged tires. Results should be provided in writing. This allows a comparison and will point out any discrepancies or trends that may need to be handled.

Tire selection
Tire manufacturers know their business. The tires they manufacture are highly complex and engineered for specific applications and conditions. These experts provide the best experience to give the proper recommendations. Don’t let “I’ve always done it this way” stand in the way of improving tire performance. Getting some advice on selecting the best tire for the application could dramatically reduce your tire costs.

What can a maintenance manager do to ensure he is getting the most out of his vehicles’ tires? The answer is simple: Evaluate tire wear on a routine basis through tracking tire life and always matching tire depths according to the OEM’s recommendations for better wear and less stress on the equipment.

Environment
Another important element impacting overall tire life is keeping the worksite area clean of potential tire dangers. The worksite can have a significant impact on tire life. Supervisors and personnel should pay special attention to road surface/worksite conditions, as well as the cleanliness of loading and dumping areas to eliminate potential tire damage hazards.

Slopes of 10 percent or more, sharp curves or high-speed curves can also have a great impact on tire life. These extreme haul road features can shift the load placed on tires and create an overload situation. Grades of 10 percent or more should be reduced; extreme corners should be changed to have an increased radius or be banked to lessen the effect of load transfer on the tires. If the haul road is difficult to change, having the operator slow down when negotiating these sections can often alleviate most of the problems.

Inspection
Unless there is a suspected problem, checking air pressure can be done once a week. There is no need to check it every day. In comparison, engine oil usually gets checked every day. During these daily inspections, the tires should be checked for damage, visual inflation discrepancies or any other issues that may cause that asset to come out of service.

Get vehicle operators involved during the walk-around inspection of the vehicle before beginning operation. Or, if a walk-around inspection is not currently being done, implement one. The routine inspection of a rim and tire helps to minimize and detect any issues in a timely manner. It helps ensure that problems are dealt with before becoming major maintenance issues or passing the point of serviceability.

If tire damage or problems are discovered during inspection, do not operate the vehicle until a trained service technician can diagnose the severity of the situation and make the proper repairs. Never allow untrained personnel to attempt repairs. Visual inspections familiarize the operator with proper tire appearance at proper inflation pressure. They usually allow the operator to detect more serious inflation pressure issues with a quick inspection.

There are two main areas to check when evaluating tire wear – the tread and the sidewall. Start with a visual inspection of the vehicle’s tires, looking for signs of irregular wear, deep cracks, cuts or other major problems in the tread or shoulder of the tire. Look for signs of cutting, chunking, stone or debris penetration and rubber tearing. These are signs of over- or under-inflation, or poor site maintenance. Determining the root cause will be the first step in addressing the concern and mitigating or eliminating further damage.

Inspect the rim hardware for any signs of cracks or flange damage. It is also important to check the valve hardware for signs of damage or wear. If a dealer or tire manufacturer representative inspects the tires, join them on one of their inspection to learn more about what to look for.

Tire pressure
Tires need the right amount of air pressure to function at their optimal performance. Any radial or bias earthmover tire that is either over- or under-inflated is vulnerable to potential downtime. Therefore, proper tire pressure is critical to a tire’s performance. Check tires for correct pressure regularly with an accurate gauge and with a visual inspection daily as mentioned above.

Determine precise tire pressure or PSI for the tires based on the manufacturer’s requirements and vehicle application. The most important step is to properly maintain the manufacturer’s recommended tire pressure for the loads being carried. This will maximize tire life and productivity. Establish a recommended tire maintenance schedule to help maintain proper inflation pressures.

The correct tire pressure for a radial tire can vary widely between brands and can be significantly different from that of a bias tire, depending on the machine type, manufacturer model type and weight. Naturally, the best method would be to consult the tire manufacturer with actual measured load per tire for the correct pressure. While this is the most precise method, it is not often realistic unless there is a known tire performance issue. Your tire dealer or tire manufacturer representative can help pinpoint the exact recommendation for your application and loads carried.

Always use sealing valve caps, which have a sealing washer, to retain tire pressure even when the valve core is partially open owing to dirt infiltration.

Tire changes
Deflate the inner and outer tires of a dual fitment before removing any rim fixture from the hub of the vehicle. Damage to the inner wheel assembly could cause injury when the outer is removed by releasing pent up energy that could dangerously propel wheel parts.

Avoid lifting tires through the center with a crane hook. This can damage the critical bead area. Instead, lift the tire under the tread by using flat straps. Flat straps are recommended over steel slings or chains because they are less likely to cause cuts or abrasions.

Avoid mixing tires on your vehicle, such as normal tread depth with deep tread depth or a bias-ply tire with a radial. Using two different types of tires could damage the vehicle’s internal components because the tires do not work together to provide the same rolling circumference, traction or handling performance.

Precautions
Never weld or apply heat to a wheel or wheel parts. Due to the potential hazardous nature of tire fires, any wheel work should be done with the tires dismounted and removed from the wheel/rim. If a wheel requires repair, it should be inspected and repaired by the wheel manufacturer.

Never operate a vehicle that has a flat or near-flat tire, damaged or distorted rims or wheels, missing bolts or cracked studs. Safety is key.

When not in use, store tires in a cool, dry place away from direct sunlight to avoid premature aging. Prevent exposure to ozone sources such as sun, arc-welders and mercury vapor light bulbs, as well as ultraviolet rays and inclement weather. Store tires standing upright on the tread (but supported to avoid injury or death from falling tires), and avoid stacking.

Training
Establish a training program for the machine operators to ensure they are properly trained. This training should include visual tire inspection, avoiding damage-causing obstacles when operating equipment, reporting obstacles that need to be removed from the site or repaired, and using the proper operating speeds in corners or grades.

Following these simple steps will help productivity and add significant savings to the bottom line by reducing tire costs and ensuring safe operation.

Take note
Supervisors and personnel should pay special attention to road surface/worksite conditions, as well as the cleanliness of loading and dumping areas to eliminate potential tire damage hazards.

Steve White is market segment manager for Michelin Earthmover Tires.

Maintain your tracks
By Mitch Peltomaa
Daily maintenance checklists for most tracked equipment generally include pre-shift inspections of the tracks themselves and the track gearbox. Operators who ignore these inspections are tempting fate.

Depending on the type of failure, it could take four to eight hours to fix a broken track and up to two days to remedy a final drive failure – if the parts are handy. Even worse, ignoring damage to a track gearbox can run from $15,000 for small machines up to $60,000 or more for larger machines, with associated costs and profit loss for two days’ labor and downtime.

The typical crawler rig’s pre-shift inspection includes track and track gearbox checks similar to those described below.
■ Check track tension: Monitor track sag. A track that is too tight increases the wear on both the front idle wheel and sprockets of the final driver. If it’s too loose, the track could fall off, damaging the lower rollers and bushings. Adjust them to measurements prescribed in the manual. This usually involves putting the rig up on lifts and gauging the distance between two reference points.
Investigate unusual noises such as grinding and popping. Be alert to any high whining noise, which could indicate insufficient oil.
■ Torque bolts/nuts: Use a common torque wrench to set bolt/nut tension. Correct bolt torque is generally 420 ft.-lb. (+/- 50 ft.-lb.), but always check the manufacturer’s recommendations. This secures them as tightly as possible without threat of having them break under normal operational stresses. Track pads can fall off or break the track rail if nuts are too loose. Final drives can become loose and leak oil, leading to environmental issues and, ultimately, partial seizure.
■ Maintain oil levels: Keep oil levels to owner’s manual specifications to prevent damage and to extend useful life. Service the oil on schedule – often prescribed for every 250 hours – and immediately upon discovering any leak.

Mitch Peltomaa is national service manager, CMT store operation, Atlas Copco Construction Mining Technique USA.