Uneven tire wear (also known as one-sided tire scrub) is a common fault for HOWO mining dump trucks operating under heavy-load, bumpy, curved and stony mining conditions. In most cases, the issue does not stem from the tires themselves, but abnormal tire pressure, misaligned chassis parameters, worn components, operating conditions and improper maintenance. Specific causes categorized by wear patterns are listed below:

1. Abnormal Tire Pressure (Most Common & Fundamental Cause)

Mining dump trucks require precise tire pressure under heavy loads. Imbalanced tire pressure directly changes the force distribution on the tire contact patch and leads to regular uneven wear, which is often overlooked.

1. Underinflation: Excessive compression deforms the tire sidewalls. The tread caves in the middle, and only the two shoulder areas bear the load. Long-term operation results in even wear on both tire shoulders. Sidewalls are also vulnerable to crush damage from broken stones, and wear accelerates drastically when running over bumps under heavy load.

2. Overinflation: The center of the tread bulges excessively, shrinking the contact area and concentrating pressure on the tread center. This causes rapid wear at the tread centre. The tread hardens with reduced grip, prone to chunking and groove wear on stony mine roads.

3. Inconsistent pressure on the same axle: Large pressure difference between left and right tires on the same axle leads to unequal rotating speed and load. It triggers one-sided wear and may further cause axle stress offset over time.

2. Misaligned Wheel Alignment Parameters (Key Fault Cause)

Continuous heavy impact, frequent uphill/downhill operation and rough mine surfaces easily knock camber, toe and kingpin angles out of factory specifications. The tires run with persistent lateral force, causing continuous uneven wear, which is the main source of sawtooth or feathered wear.

1. Improper toe: Excessive toe-in makes the tire inner shoulder rub continuously, creating sawtooth or feathered wear on the inner shoulder. Insufficient toe-in or toe-out wears the outer shoulder; steer axle tires may develop S-shaped wear tracks.

2. Deviated wheel camber: Positive camber wears the outer shoulder as the tire tilts outward. Insufficient camber tilts the tire inward and heavily wears the inner shoulder, usually seen on one or both tires of the steer axle.

3. Uneven wheelbase and bent axle: Heavy impacts in mines may shift rear axles or slightly deform the frame. Wheels on the same axle become non-parallel and left-right wheelbase differs. Tires are dragged and rubbed while driving, causing irregular one-sided wear mostly on rear tires.

3. Worn or Loose Chassis & Running Gear (Frequent Mine Truck Issue)

With heavy loads and strong road impacts, chassis wearable parts degrade far faster than ordinary trucks. Excessive clearances, looseness or deformation destabilize wheel movement and induce irregular uneven wear.

1. Steering system failures: Worn kingpins and bushings, over-cleared or loose steering ball joints cause wheel wobble during travel. Alignment parameters dynamically shift, resulting in S-shaped wavy tire wear, accompanied by excessive steering play and vehicle pulling.

2. Hub and bearing faults: Worn hub bearings with excessive clearance or out-of-round hubs create wheel runout and wobble, leading to spotty or blocky localized tread wear. Loose hub bolts worsen wheel shaking and wear.

3. Brake malfunctions: Out-of-round brake drums, seized calipers or dragging brakes keep wheels partially braked while moving. Local friction generates heat and causes rapid localized one-sided tire wear, together with hot tires and abnormal noise.

4. Leaf spring and suspension faults: Broken leaf springs, aged rubber bushings or loose brackets unbalance vehicle load and tilt the body. One side tires sustain constant overload and develop fixed shoulder wear over time.

4. Mining Operating Conditions & Driving Habits

Mine environment and operator habits continuously accelerate tire wear and lead to recurring problems.

1. Improper operation: Frequent sharp heavy-load turns, stationary steering and high-speed bumpy travel sharply increase lateral friction and aggravate shoulder wear. Consistently driving on one side of the road or rolling over potholes and crushed rock creates irregular wear.

2. Harsh road conditions: Stony, uneven, sloped and muddy mine roads create uneven tire loading with continuous impact, dragging and squeezing, which brings local wear. Long-term operation on one-way ramps shifts the vehicle centre of gravity and overloads tires on one side.

3. Overloading: Operating beyond rated load drastically increases tire deformation and unbalanced contact force, passively shifting alignment parameters and accelerating overall wear, aging and cracking.

5. Improper Assembly & Maintenance (Hidden Human-Induced Causes)

Non-standard daily maintenance and assembly errors are hidden triggers for uneven tire wear and are easy to ignore.

1. Lack of tire rotation: Front/rear and left/right tires bear different loads on mining trucks. Staying in fixed positions concentrates stress and creates differential wear.

2. Tire assembly defects: Deformed, cracked or out-of-round rims, poor tire seating cause wheel wobble during operation and irregular wear. Mixing new and old tires or tires with different tread depths on the same axle creates different rolling radii and drag wear.

3. Inspected maintenance gaps: Failure to regularly check tire pressure, chassis clearances and wheel alignment allows minor faults to accumulate and eventually develop severe uneven wear, shortening tire service life.

Quick Reference: Wear Patterns and Corresponding Root Causes

• Uniform wear on both sides of tread: Long-term underinflation

• Wear concentrated at tread centre: Long-term overinflation

• One-sided shoulder wear: Abnormal camber, collapsed suspension or tilted vehicle body

• Sawtooth / feathered wear: Incorrect toe setting

• S-shaped wavy wear: Loose steering components or deformed rims

• Spotty localized wear: Dragging brakes, hub bearing faults or wheel runout