Tyre Learn

Many off-the-road trucks can be fitted with different size tyres, different strength ratings, and different tread depths. While it is normal practice to apply 100 level, E3 tyres, initial fitment of a larger, deeper tread tyre can often result in substantially reduced operating costs. The most economical time to determine tyre requirements is “prior” to vehicle purchase. In this way, the most appropriate tyre size, tread depth, and ply rating can be specified. This can help to prevent expensive field modifications, such as wheel/rim changes, should larger tyres ultimately be required.

Performance improvements are documented at specific job sites. Your results may vary, depending on your operating conditions.

Radial or Bias Tyres?
Historically, bias tyres have been applied to most new haulage trucks. These tyres usually offer good service in a multitude of different working environments. In many instances, however, lower costs per hour of operation can be realized through utilization of radial tyres. Consider, for example, the following advantages of radial ply tyres:

  1. Longer tread wear for reduced operating costs.
  2. Cooler running for higher speeds, increased fleet output.
  3. Excellent traction.
  4. Penetration resistance for reduced down time.
  5. High flotation for superior mobility.
  6. Better vehicle cushioning, resulting in lower maintenance costs.
  7. Superior operating economy through a 5-8% reduction in fuel consumption.

GROSS TYRE LOADS - Gross Tyre Loads are based on the highest individual wheel load determined by the distribution of the Gross Vehicle.

Weight (GVW), including weight transfer. The maximum GVW shall include, but not be limited to, the following:

  1. Net Weight - Actual weight of the vehicle with standard equipment including the maximum capacity of engine fuel, oil, coolant and operator.
  2. Accessory Weight - The combined weight of all optional items installed on the equipment not previously considered in Net Weight. These include such items as air conditioners, special cabs, body liners, side boards, special reinforcements, etc.
  3. Payload - The total weight of the material being carried.
  4. Tyre Ballast - If used, must be included in determination of GVW.

Service Conditions:
Earthmover (Haulage) - A haulage cycle where equipment self-loads or receives a load from loading equipment, then transports this load to another location and returns unloaded. Transportation usually occurs over unimproved surfaces at medium speeds, up to 40 mph (64 kph), and short distances, up to 2.5 miles (4 Km), one way. Equipment in this category is mainly haulage trucks and scrapers.

  1. Loader - This is a work cycle where the equipment is used to pick up material and relocate a short distance away. Tyre loads fluctuate depending on the conditions involved when the equipment picks up the load. Transportation speeds are low, up to 5 mph (10 kph), and distances are short, a maximum of 250 feet (76m), one way.
  2. Load and Carry - A work cycle where equipment primarily intended for loader service picks up a load and transports this load to another location and returns unloaded. Transportation usually occurs over unimproved surfaces at low speeds, up to 15 mph (24 kph), and rather short distances, up to 2,000 feet (610m). Equipment in this category consists mainly of Ioaders, log stackers and material handling equipment.
  3. Dozer - A working condition where equipment is used to move materials (usually earth) by pushing, dragging or grading. Tyre loads are relatively constant and speeds are low, up to 5 mph (10 kph). Travel distances vary depending on work situations.
  4. Grader -A working condition where equipment is used in construction and road maintenance. Tyre loads are relatively constant during the work cycle. Equipment speeds are slow during working periods with maximum transportation speeds reaching 25 mph (40 kph). Travel distances vary depending on work situations.
  5. Creep - Is movement of equipment at a very slow speed (not over 200 feet (61m) in 30 minutes). During creep motion, loads on the tyres are very high and consideration must be given to the type of surface over which the equipment is traveling.
  6. Drive -Away - Is a term used to define movement of a vehicle from one location to another under non-working conditions. This movement occurs during transportation of equipment from site to site.
  7. Smooth Floors and Runways - are defined as paved or protected operating surfaces which are free of undulations, obstructions or discontinuities.
  8. Maximum Speed - The peak speed attained by the vehicle during any part of a cycle (loaded or unloaded).

Conventional - The cross-section shape of the tyre has an aspect ratio (ratio of section height to section width) in the range of .95. Conventional tyres are also referred to as narrow base tyres.

  1. Wide Base - The cross-section shape of this tyre has an aspect ratio in the range of .83.
  2. “65 Series" - This is a low profile tyre with the aspect ratio in the range of .65.

Suffix letters are included, when necessary, as part of Tyre Size Designations to differentiate between tyres suited for service conditions which may require different loads and inflations and/or tyres suited for and must be used on different types of rims.

NHSNot for highway service.
TGTractor-Grader tyres - Not for highway service.
MLMining and Logging Tyres used in Intermittent Highway Service.
DTTyres primarily suited for use in sand service.
KCompactor tyre for use on drop center or semi-drop center rims.

English loads and inflations are TRA (USA) standards. Metric loads are ETRTO norms except where a size or ply rating is not covered by ETRTO. In these cases, TRA (USA) SI standards are used. Metric inflations are Goodyear recommendations. English and metric loads are not directly convertible. Rated loads are based on cyclic operations.


CodeTread TypePercent Tread Depth
E-4Rock deep tread150
CodeTread TypePercent Tread Depth
G-4Rock deep tread150
CodeTread TypePercent Tread Depth
L-4Rock deep tread150
L-5Rock extra deep tread250
L-4SSmooth deep tread150
L-5SSmooth extra deep tread250
CodeTread TypePercent Tread Depth

The Ton-Miles-Per-Hour formula (average tyre load multiplied by average tyre speed), is designed to help you achieve optimum performance from Goodyear earthmover tyres. lt helps you calculate the load-speed-time factor that’s within safe tyre temperature limits. Use the TMPH formula to avoid premature tyre removal due to excessive heat.

All Goodyear earthmover tyres have been assigned a TMPH limit. Earthmover haul jobs operate at various TMPH rates, depending on the load, distance and time involved in round trips. Thus, each job’s haul rate must be determined to compare it with each tyre’s TMPH rate limit. (For more information go to your Goodyear Off-The-Road Tyres Manual)

Heat is a tyre’s worst enemy - the increased thickness and higher load carrying requirements of Dozer and Loader tyres necessitates the use of a tyre limitation system – the WORK CAPABILITY FACTOR SYSTEM.

The Work Capability Factor rating system provides the guide lines to select the correct Goodyear tyre for the job requirement. Years of controlled testing and field studies have culminated in a valid and practical means of establishing capabilities of Dozer and loader tyres when used in “Load and Carry” Service.

The factors of Load and Speed have long been used for evaluating the limitations of transport tyres. For tyres used in transport service on loaders, additional factors such as more stops, starts and turning must be considered. These additional operational factors produce higher stresses on the tyre components, resulting in increased tyre heat build-up.

The WCF formula heIps you select the right Dozer and Loader tyres for the job – before you buy. lt’s another customer service at Goodyear, producers of the industry’s Work Capability Factor rated Dozer and Loader tyres.

(For more information go to your Goodyear Off-The-Road Tyres Manual)


  • SAME AXLE on any vehicle - Bias and radial tyres must not be mixed on the same axle of any vehicle (drive, steer or trail).
  • Haul Trucks - When mixing tyre constructions, radial tyres should be used only on the front/steer axle and bias tyres should be used only on the rear/drive axle.
  • Loaders, Container Handlers, Reach Stackers, Forklifts - Bias tyres can be used on one axle and radials on the other axle.
  • Graders - Bias or radial tyres can be used on the front axle. Bias or radial tyres can be used on the rear axles.
  • NOTE: The tandem axles must have tyres of the same construction - all radial tyres or all bias tyres.
  • Articulated Dump Truck (ADT) - Do not mix bias and radial tyres on an ADT. Use only radial tyres.
  • Scrapers - Mixing of bias and radial tyres is not recommended. Use only bias tyres or only radial tyres.
  • Mobile Cranes - Due to differences in cornering force characteristics and spring rates, good tyre and vehicle performance will be obtained by applying tyres of the same size and construction (radial ply or bias ply) to all vehicle wheel positions. However, different tyre constructions are permitted on the steer, drive, and trailer axles of two-axle, tandem, and multiple-axle combinations when the following rules are observed.
    • Never mix different tyre sizes or tyre constructions on the same axle.
    • If radials are mixed with bias tyres, better handling will be obtained with the bias tyres on the steer axle.
    • Bias or radial tyres may be used on either axle of two-axle vehicles, providing the vehicle has dual rear wheels or is equipped with Super Single wide-base tyres.
    • Either bias or radial tyres may be used on the steering axle of vehicles with three or more axles. Either all bias or all radial tyre should be used on the nonsteering axles.
    • Never mix bias and radial tyres in a tandem or multiple axle combination.

Always check with the vehicle manufacturer before changing tyre size or tyre construction on any vehicle. Carefully evaluate performance changes caused by tyre size or tyre construction changes before putting the vehicle back into service.

  • Other vehicle types – Contact the vehicle and tyre manufacturer for tyre mixing options.

NOTE: Ton Mile Per Hour (TMPH) and Work Capability Factor (WCF) must be considered for proper fitment to all positions.








1. Tyre Size.

Bias 45/65-45.
Section width: 45”.
Aspect ratio: 65.
(“) Bias construction.
Bead heel diameter: 45”.
Radial 23.5R25.
Section width: 23.5”.
(“R”) Radial construction.
Bead heel diameter 25”.

2. Play or star rating.
3. Goodyear Tyre Name.
4. Tube type or Tubeless.
5. Casing construction type.
6. Industry Code (if applicable).
7. Goodyear custom compound/construction type.