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Tire Rack Tire Tips - 12 Tips: About Tires

What You Should Know Before You Buy

Larry S. Saavedra
Sep 1, 2009
How much do you really know about your tires? If you said “very little,” don’t worry, you’re not alone. Although more than 11 million passenger car tires were sold last year by auto dealers, a majority of us still can’t distinguish one tire from the next. What we do know is that not all tires are created equal, especially for RVs and trailers.
Photo 2/4   |   Michelin displays tire loads per axle end in the load and inflation tables at For control of your RV, it is critical that the tire pressures be the same across an axle while never exceeding the maximum air pressure limit.
To learn more about tires, we contacted the guy who seems to have all the answers, Matt Edmonds at Tire Rack, and we talked shop. Edmonds is Tire Rack’s go-to guy whenever we have a question, and this time we had twelve of them. Specifically we wanted to know about tires for people with tow vehicles or motorhomes, because there are some unique differences between standard passenger car tires and light- or heavy-duty tires.
Why Tire Rack? For starters the company is one of the largest online distributors of tires in the country. Also, Tire Rack has its own tire testing facility on site, which gives it an advantage in determining what works and what doesn’t before a product is sold to the consumer. You can find more in-depth explanations about tires at
Q: Do tires for RVs, tow rigs, or trailers differ from standard passenger car tires?
Matt Edmonds: Most tires for RVs and tow rigs are LT, not P-metric. Trailer tires are definitely different in that they are designed to handle additional stresses and loads being towed.
Q: How do you find the correct tire for recreational vehicles, and do their speed ratings or load ratings really matter?
Look in the owner’s manual or the tire sticker that is required to be on the driver’s doorjamb of the vehicle declaring tire size and proper air pressures. Speed and load ratings are just as important to these tires as they are to passenger vehicle tires.
Photo 3/4   |   The XRV radial is Michelin’s all-position, Highway Rib Summer radial designed for recreational vehicles and motorhomes.
The load range or ply rating branded on a tire’s sidewall helps identify its strength and ability to contain air pressure. While specific load ranges are assigned to passenger tires, load ranges are identified in ascending alphabetical order for light truck tires (the higher the letter is in the alphabet, the stronger the tire and the greater amount of air pressure it can withstand and load it can carry).
Before load ranges were adopted, ply ratings were used to identify the relative strength of light truck tires, with higher numerical values assigned to tires featuring stronger, heavier-duty constructions.
Q: What’s the story on weighing your RV to get proper tire inflation?
The reason to weigh your vehicle is to determine the load your tires are carrying. Once you know the load you can adjust the tire pressure within the allowed pressure range for that tire (noted on sidewall) to properly support the weight.
Q: Does long-term storage of an RV affect tire life?
It’s what the tires are exposed to during storage that affects them the most. Since heat and exposure to the elements are the important factors that influence a tire’s aging, drivers can prolong their tires’ life by minimizing this impact. Keep the tires shielded from the sun and keep them clean, cool, and dry, and don’t use any tire dressing on them while storing.
Q: Is it safe to mix tire types? What if you have a tow vehicle and trailer and need tires for both?
Tires are vehicle-specific based on the jobs they must perform. Do not mix tires between trailers and tow vehicles.
Photo 4/4   |   Continental HDR commercial tires were developed for single and dual application use on the drive axles of medium-duty vehicles. The Continental HDR is designed to provide on/off highway service depending on conditions.
Q: Are all tire brands created equal?
As with any product, there are tiers of manufacturers. Generally top-tier manufacturers tend to be leaders in engineering and technical advancement.
Q: Why are some tire brands so much cheaper than others?
Many times the cost is related to engineering time put into the tire and thus value you receive, but again like other products, marketing investment varies from brand to brand.
Q: How often do you need to check your tires for air loss?
Tires should be checked at the minimum monthly. If you have dual tires and are traveling, it is important to check them more frequently since a tire that is low can be concealed by the adjacent tire.
Q: Why do we need to rotate our tires? How often?
Tire rotation can be beneficial in several ways. When done at the recommended times, it can preserve balanced handling and traction and even out tire wear. Tire rotation can even provide performance advantages.
Many tire mileage warranties require tire rotation to keep the warranty valid. When should tires be rotated? We recommend that tires be rotated every 3,000 to 5,000 miles even if they don’t show signs of wear.
Tire rotation helps even out tire wear by allowing each tire to serve in as many of the vehicle’s wheel positions as possible, hopefully promoting even wear across the tire tread pattern.
Q: If tires have a load rating, what about wheels?
They do have a load capacity; it is stamped or cast into the wheel. The wheel must have enough load capacity when compared to the gross axle weight rating of the vehicle.
Q: Is there a break-in period for new tires?
Tires are comprised of many layers of rubber, steel, and fabric. Due to these different components, your new tires require a break-in period to ensure that they deliver their normal ride quality and maximum performance.
When tires are cured, a release lubricant is applied to prevent them from sticking in their mold. Some of the lubricant stays on the surface of your tires, reducing traction until it is worn away. Five hundred miles of easy acceleration, cornering, and braking allows the mold release lubricant to wear off, allowing the other tire components to begin working together.
Q: Is there any way to know how old your tire is?
In addition to the tire’s brand and line names (tire model), there is a lot of information provided by the manufacturer on the sidewalls. Since 2000, the week and year the tire was produced has been provided by the last four digits of the Tire Identification Number, with two digits used to identify the week immediately preceding the two digits used to identify the year.
Some of the branded information provides the tire’s basic dimensions and identifies the week it was produced. Other branding lists the types of materials used internally to reinforce the rubber, along with the tire’s maximum inflation pressures and loads. And others confirm that the manufacturer certifies that the tire meets various industry standards and measures up to the government regulations of the nations in which it will be used.



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