It is possible to replace your tires with a different size, in some instances, to increase your load capacity with a different inflation pressure. If there is a reason to replace your tires with a different size, make sure the following checks are made before the purchase:
• Does the replacement tire have the load capacity that is needed for my trailer and will it fit properly inside the wheel well?
• Will the overall diameter difference affect the braking system?
• Is the increase in air pressure compatible with the maximum rated pressure stamped on the rim?
Most trailers are towed at or near maximum loads during hot weather and then left idle for months. In normal use, oils in the tire come to the surface during flexing and protect the rubber from ultraviolet light. But when the trailer tires sit idle too long, natural aging may cause the rubber to crack prematurely, especially in the sidewall area. Trailer tires over five years old should be inspected by a tire expert for cracking and replaced even if it has no apparent tread wear.
Choose a tire adequate for the load. The load rating printed on the sidewall will show the maximum load that can be carried at a defined pressure.
A Goodyear Endurance ST225/75R15 tire inflated to 80 PSI (MAX.) has a load capacity of 2830 lbs.
An ST tire is a Special Trailer tire with a section width of 225 mm, a height-to-width ratio of 75%, and radial construction with a diameter of 15 in. As the width-to-height ratio becomes smaller, the tire has a lower profile.
Do not mismatch wheels and tires.
Axle systems are installed with hubs and drums that are compatible with many wheels used in the recreational vehicle industry that have matching bolt patterns. If the original manufacturer-installed equipment is in need of replacement, the wheel manufacturer should be contacted for proof of compatibility prior to replacement and use. Customers replacing original equipment that has not been tested for compatibility must ensure the replacements are compatible to the hub and drum assembly installed. Such elements of compatibility include, but are not limited to:
• Diameter of the hub-mounting surface.
• Stud length and diameter.
• Location and number of studs.
• Center hole diameter for the wheel.
• Wheel-mounting offset from the rim center.
• Rated capacity of the wheel.
• Wheel fastener torque.
• Wheel nut size and shape.
• Impact of any added wheel accessories (such as decorative center caps) that could affect proper seating of the wheel to the hub surface.