A Look at Aircraft Tires and Wheels

Tasked with absorbing brutal landings and carrying hundreds of tons, aircraft tires and wheels operate under some of the most extreme conditions in aviation. Both vital for basic aircraft functionality and to protect the safety of passengers and crew, these components have to be designed to strict standards. In this blog, we cover all the basics you should know about aircraft tires and wheels, ranging from the types of stresses they face to the maintenance practices that keep them ready to perform.

The Conditions That Aircraft Tires and Wheels Accommodate

• Tensile, Compression, and Shear Forces: Multiple mechanical forces act simultaneously on tires and wheels, including tensile stress from inflation and rolling loads, compression from vertical weight bearing, and shear forces caused by factors like uneven runways or crosswind landings.
• Thermal Extremes: Braking can generate a lot of heat, while external temperatures can become freezing cold.
• Centrifugal Forces: As tire rotation speed increases, centrifugal forces build up within the tire structure, placing outward stress on the casing and reinforcing plies.
• Frequent Operation: Aircraft may undergo numerous landings and takeoffs in a single day, increasing cumulative stress.

How Aircraft Tires and Wheels Are Constructed

Tires

As the portion touching the ground, aircraft tires are built with:

• Multi-Ply Casing: Multiple layers of nylon cord plies are arranged in alternating angles to form a cross-ply or bias-ply structure in the tire, offering exceptional flexibility and the ability to readily absorb heavy loads and impacts.
• Reinforced Treads: To resist damage from friction and foreign object debris, the tread area of the tire is heavily reinforced with thick rubber compounds. Additionally, these treads are designed to channel water, improve surface grip, and manage wear. The most common pattern is the ribbed tread, which consists of circumferential grooves.
• Tubeless Design: These days, most aircraft tires feature an airtight inner liner built into the tire itself that eliminates the need for a separate inner tube. In turn, this makes them more lightweight and lessens the risk of sudden deflation.

Additionally, tires are typically inflated with nitrogen rather than ambient air as it is less reactive, provides more consistent pressure across temperature ranges, and reduces the risk of combustion under high-heat conditions.

Wheels

Meanwhile, the wheel serves as the structural base for tire mounting, as well as interfaces with the brake and landing gear systems. It is built with:

• A Split-Hub Design: Aircraft wheels are built in two halves called the inboard and outboard sections. These are bolted together around the tire, facilitating easier tire replacement and preventing overstressing the tire during installation.
• Torque Bolts: High-strength bolts securely fasten the two halves together, keeping them structurally stable.
• Protective Coatings: Anti-oxidation coatings are applied to the wheel surfaces to protect against corrosion and chemical exposure.

The Deceptive Compactness of Tire Dimensions

Aircraft tires are more compact than many might assume. For example, Boeing 737 tires tend to be around 27 inches in diameter with a 7.75-inch width. Meanwhile, the wheels have an approximately 15-inch diameter. Instead of size, much of their strength comes from the tire’s internal construction.

Threats to Tire Safety

Despite being carefully constructed to hold up to repeated stress, tires remain vulnerable to hazards like:

• Controlled Deflation: This type of pressure loss occurs gradually and does not result in a sudden failure, but it has to be detected and addressed early.
• Explosive Failure: A tire may disintegrate or explode due to overheating, excessive internal pressure, or severe impact with debris or runway imperfections, posing a serious risk to nearby systems and those onboard the aircraft.
• Foreign Object Damage: Although their construction aims to mitigate this, sharp debris on runways or taxiways can still puncture or cut through tires. If the damage penetrates the casing, it can cause a full tire burst.

Necessary Maintenance and Inspection Practices

To keep aircraft tires and wheels flight-ready, technicians and operators should perform routine checks and servicing, encompassing:

• Pressure Monitoring: Tire pressure should be checked daily or before each flight to ensure safe load distribution and tire longevity.
• Visual Inspections: Visible signs of damage in the tire such as cuts, cracks, bulges, or notable tread wear indicate the need for repair or replacement. Meanwhile, wheels should be inspected for corrosion, cracks, or fastener issues, especially at the bolt holes and mating surfaces.
• Tire Retreading: If the casing remains in good condition, the worn tread can be replaced to extend the tire’s service life and avoid full replacement costs.
• Cleaning and Protection: Keeping tires and wheels clean of hydraulic fluids, oils, and de-icing chemicals helps prevent rubber from deteriorating and metal components from corroding.
• Scheduled Overhauls: Tires and wheels should be removed and thoroughly inspected at defined usage or lifecycle intervals, regardless of visible wear.

Just NSN Parts: Your One-Stop Shop for Aircraft Tire and Wheel Assemblies

Aircraft tires and wheels are far more than simple rubber casings and rims, being precisely designed to operate in hostile environments. As such, if you need to replace any aspect of this assembly, you must turn to a reputable source. On Just NSN Parts, a platform operated by trusted distributor ASAP Semiconductor, we present various high-quality wheel and tire parts that suit diverse aircraft models.

Sourcing products exclusively from leading manufacturers and suppliers while abiding by a strict NO CHINA SOURCING pledge, you can rest assured that you will only get the best when you shop on this website. Along with benefitting from a top-tier inventory, our customers will always have their unique specifications catered to with competitive procurement options. Bearing this in mind, get in touch with us at any time to see how we can help you secure all you require for your aviation endeavors.