PROPER MATCHING AND SPACING OF DUALS
Paired tires should be of the same size designation, construction, and tread design and be as close as possible to same outside diameter. Mismatching duals forces the larger diameter tire to carry an overload, causing it to overdeflect and overheat. The smaller diameter tire, lacking proper road contact, wears faster and irregularly.
Note: Determine the actual difference in diameter by measuring the tires (with a steel tape) at least 24 hours after initial inflation. Matching should be done before installing tires on the vehicle. Applies only if tires are of the same tread.
Using the same tire size and construction that was specified as the original equipment for that vehicle will normally produce the best performance from the vehicle and the tires. However, there are times when mixing of different tire sizes and constructions on a vehicle is necessary. Some mixing of tires can be allowed, if certain rules are followed:
- Never mix different tire sizes or construction types on the same axle.
- Bias ply tires can be mounted on steer axles and radial tires on single-axle drive positions of two-axle vehicles. Reversing these positions may result in handling problems.
- Either bias ply or radial tires can be mounted on the steer axles if the vehicle has multiple drive axles.
- All multiple-drive axles should have the same size and construction tires.
- Tires mounted on trailers may be bias or radial, as long as all tires on each individual axle are the same size and construction.
- No mixing of tire sizes and constructions are allowed on four-wheel-drive type vehicles (4WD).
Use of Bead Lubricant
Preferred materials for use as bead lubricants are animal- or plant-based and mixed with proper water ratios per manufacturer's instructions. When dry, the lubricant should have no residual lubricity and should not flake from the surface upon which it is applied. To avoid damage to tires and rims, the following should be avoided: petroleum oils or grease, improper ratios of approved lubricants and water, silicone oils and emulsions, and solvent-based lubricants.
Use of Sealants
Yokohama does not recommend, endorse, or prohibit additives installed in the interior chamber of its mounted tires, provided the material is not flammable and or injurious to the tire chamber or structure and does not replace air pressure as the tire’s primary inflation medium. The Yokohama Standard Limited Warranty remains in effect with the use of these additives, providing the additive is not the cause of a tire condition submitted for a warranty claim. Damages attributed to the use of an additive will be denied warranty consideration.
MOUNTING DIRECTIONAL TIRES
When mounted properly, directional treads prevent block squirm, effectively reducing irregular wear and improving treadlife.
Direction of Rotation
When viewed from the top, the tread pattern should face in the following direction:
Directional treads should be mounted facing opposite directions to ensure their “direction of rotation” arrows are each pointed to the front of the vehicle. This arrow can be found on the sidewall.
RUN-OUT AND MATCH MOUNTING
Yokohama places red and yellow marks on the sidewalls of some truck tires to enable the best possible match mounting of the tire and wheel assembly. There are two methods to ensure they are mounted properly:
When performing uniformity match mounting, the red mark on the tire, indicating the point of maximum radial run-out, should be aligned with the wheel assembly’s point of minimum radial run-out, which is generally indicated by a dimple somewhere on the wheel assembly (consult manufacturer for details).
When performing weight match mounting, the yellow mark on the tire, indicating the point of lightest weight, should be aligned with the valve stem.