We’re about to hit the road for several months, so I wanted to do this before we left. What an excellent opportunity to talk about tire safety, proper inflation, proper maintenance, and what to look for to avoid a blowout. I also wanted to cover things like the difference between an ST (Special Trailer) tire and an LT (Light Truck) tire, plus some best practices for going to the tire shop and replacing your tires or wheels.
This article is specifically about towable RVs. RV owners need to understand this information for themselves. Consider an article like this as a way to consider specific ideas so that you can further investigate and understand them to make the right decision for you, the RV you’re towing, where you’re going, and how you’re storing it. We’re going to get into all of that.
Take ownership of understanding tires for your towable RV because it’s the most essential thing in the entire setup regarding safety and RV safety. Now, let’s talk about what you should look for in your tire to ensure it’s in good condition to hit the road. Before you go on any long trip, you want to inspect the tire thoroughly.
Stuff to look for: cracking on the sidewall is a significant indication that you need to get the tire looked at by a professional or replaced. Equally important is uneven wear on the tire. We’ve discussed proper inflation in this video, but if you’re overinflated to the load, you will be running on the center of your tire, which could be worn there. If you’re underinflated, it will be riding on the tire’s sidewalls, which is terrible because that generates more heat. Heat kills a tire and creates a blowout, so you’ll ride on the sidewalls and get uneven wear there.
If you have an axle or bearing problem, you’ll notice uneven wear on the tire. Uneven wear indicates that you may have a bigger problem or are not running the proper inflation. So, look for cracks, uneven wear, and anything else you think is peculiar. Just pop into a tire shop, have them check it out, and see if you need to replace that tire before you get going.
Another big question is when it’s time to replace the tire. The first thing you have to do is find the DOT date stamp on the tire. It’s a four-digit number. It’s weird how it reads, but when you look on the side of your tire and find the DOT stamp, you’ll notice a four-digit number. The first two digits are the week the tire was manufactured, and the second two are the last two digits of the year.
In this case, it looks like 0919, so the ninth week of 2019. I contacted Jack, who was the previous owner of this RV. I asked, “Hey, when did you put these tires on?” He said March 23, 2019. He even showed me a picture consistent with the date stamp on the tire. These tires are just a little over three years old, and as you can tell, they’re in excellent condition. There’s no cracking whatsoever. The wear There’s no uneven wear on the tire, and I’m probably replacing this tire based on how it looks a little too soon. But I also know that we’re about to hit the road for several months, and this is not something I want to do while we’re on the road. So, I want to take care of it now while we have the time. I’m upgrading from the 15-inch rim to a 16-inch one, giving me more clearance. For those reasons, I will go ahead and do it now.
The most significant factor in determining when to replace the tire is how you’ve maintained and stored it. We once had an RV and put brand-new tires on the trailer. We parked it out for the summer, and four months later, the tires were shot entirely because when a tire is not in use, it must be covered from the sun. Otherwise, the sun will dry out the tire, and you’ll go one mile, and they’ll disintegrate.
These tires, three years old, have never been covered up. As you can tell, they’re in excellent condition. The reason is we’re using this RV all the time. When you’re towing you tow your RV, it regenerates the rubber compound inside the tire and keeps it fresh. Think of it like dough: it stays excellent if you knead it. It gets dry and complicated when you stop kneading it and leave it out. The same is valid for tires.
At a campsite, I often see people covering up their tires. While it provides peace of mind, it’s not necessary if you’re using the tires. Protecting the tires from the sun is critical when storing your RV and not towing it. You can use a board to shield them or buy covers over the tires. Additionally, it’s essential to maintain the proper PSI in the tires during storage to prevent flat spots.
On the way, I want to discuss the difference between ST and LT tires. If you have a new or new-to-you RV, making a mock tire change at home is a great idea. This ensures you have the proper four-way or lug nut wrench and the correct jack for your RV. Each RV is unique; some may sit too high for standard jacks. In such cases, you can purchase a bottle jack from another tool suited for your setup. It’s far better to figure this out in your driveway than on the side of the road.
Two topics often spark debate regarding towable RV tires: proper tire inflation and the ST versus LT tire debate. Let’s start with ST and LT.
ST stands for “Special Trailer,” and LT stands for “Light Truck.” To be blunt, ST tires were not very good before the Goodyear Endurance tires. They were only rated for speeds up to 65 mph and often had various issues. As a result, many seasoned RVers switched to LT tires and swore by them. However, around six years ago, Goodyear introduced the Endurance tire, an ST tire rated for speeds up to 87 mph that addressed many of the prior shortcomings.
My truck is 72,000 miles, and about half of those who tow this RV on 15-inch E-rated tires had zero issues. I researched the ST versus LT debate deeply and consulted tire manufacturers to understand the differences and proper applications. Most tire manufacturers strongly recommend ST tires for trailers. ST tires are specifically designed to handle the unique challenges of towing. They mitigate heat (a critical factor), have stiffer sidewalls for better handling during tight turns, and feature a tread pattern optimized for towing. LT tires, by contrast, are built for steering, cornering, and accelerating—functions that trailers don’t typically perform.
However, you might face resistance if you want to use a Michelin tire on your towable RV. Some discount tire shops refuse to install LT tires on towable RVs, sticking strictly to ST specifications. You may need a shop willing to step outside these parameters in such cases.
At the tire shop, the technician used a tread depth reader and confirmed that one of my tires was in poor condition. The inside edge was starting to separate, so it was time for a replacement. This shop has always been accommodating, and it’s nice to know I can rely on them. While waiting, I reflected on how RV life makes situations like these feel manageable—changing a tire while making a sandwich exemplifies the convenience of RVing.
Regarding tire selection, I also learned something new about clearance. The Michelin tires for the 16-inch rims provided adequate space between the front and rear tires, ensuring proper movement. This separation is crucial for safe towing, and it’s likely a significant reason Airstream opts for these tires on its trailers. Meanwhile, the Goodyear Endurance tires work well on 15-inch rims, providing an excellent option for smaller setups.
Raising an RV for tire replacement also requires caution. Some RVs sit so high that a standard floor jacwon’t’tjack won’t reach the frame. The alternative is to place the jack under the axle, as close to the wheel and U-bolts as possible. There are designated jack points, but using the actual jack point is critical—not just the label showing where the jack point is located. Misplacing the jack can cause significant damage to the RV.
Finally, I want to touch on tire pressure monitoring systems (TPMS). While technically not necessary, they are incredibly convenient. Many people don’t check their tire pressure as often as they should, which can lead to safety risks. With a TPMS, you can quickly spot tire pressure or temperature discrepancies, identifying potential problems before they escalate. For example, if all your tires read 66 PSI except one that reads 84 PSI, you know there’s an issue. This convenience and real-time monitoring are why many RVers, myself included, rely on TPMS systems.
A great feature of a tire pressure monitoring system (TPMS) is its ability to switch between units. For instance, you can toggle it to Fahrenheit and check your tires. If you see three tires at 95 PSI and one at a different pressure, you can identify an issue and take action before it becomes a blowout. Early detection is a crucial advantage of TPMS. The other benefit is convenience. You’re not out there every morning checking pressures manually, especially when it’s cold.
Vehicles follow the manufacturer’s recommendation for door jambs. But with RVs, this information isn’t always available. Many RVs run near their max capacity, so technicians often inflate to thtire’s’s max cold pressure. However, a placard shows the recommended PSI based on the trailer’s gross vehicle weight rating (GVWR) of 8,800 pounds. It suggests inflating E-rated tires to 65 PSI.
For my setup, I prefer running the tires at 67 PSI. When I told the technician, he suggested 80 PSI, the maximum cold rating. However, I explained that 67 PSI works better because it balances load-carrying capacity with a smoother ride. Overinflating to 90 PSI, for example, creates excessive rigidity, unnecessarily stressing the trailer.
Proper tire inflation is crucial for both safety and comfort. Overinflated tires can make the ride harsh, causing items inside the RV to shift or break. Conversely, underinflated tires won’t carry the load effectively, risking tire damage. Inflating to 65-67 PSI meets the required payload for nearly 9,000 pounds while providing enough cushion for a smooth ride.
The same principles apply to the tow vehicle. While you could inflate your truck tires to their max cold PSI, this often results in a rigid ride. You’ll notice it immediately—hitting a speed bump or pothole becomes jarring. Instead, I lower the PSI to balance comfort and performance, ensuring the tires can handle the load while maintaining a smooth driving experience. There’s an ongoing debate about whether to inflate tires to their maximum cold PSI. One argument is that if you don’t know the exact weight of the tires, max cold ensures you’re within the safe payload range. However, it’s relatively easy to determine the weight. You can stop at a CAT Scale, which accurately reads your RV’s axle loads. This information helps you inflate your tires according to a load inflation chart, ensuring a safer and smoother ride without overinflating.
When discussing RV weight distribution and tire inflation, it’s essential to understand the setup. On a CAT scale, you typically see three weight pads: one for the steer axle (front), one for the drive axle (middle), and one for the trailer axle. For a double-axle trailer with four tires, you can estimate the weight of each tire by dividing the trailer axle weight by four. It’s a rough estimate, though, as weight distribution. For example, a refrigerator on one side may create uneven weight distribution.
After estimating the weight on each tire, consult a load inflation table from brands like Goodyear or Michelin. These tables provide the appropriate PSI for a given weight, helping you balance the load-carrying capacity and ride comfort.
Dispelling Inflation Myths
There are common misconceptions about tire inflation, especially regarding max cold PSI. Contrary to popular belief, max cold PSI is not the maximum pressure a tire can handle. It refers to the maximum recommended pressure when the tire is cold, usually in the morning. As the tire heats up during use, the pressure naturally increases beyond the maximum cold PSI without causing damage.
Some believe they should underinflate tires in hot climates to leave” “or “m” f “r” pr” s “ure increases due to heat. This is incorrect. If your tire requires a max cold PSI of 80 to handle the load, inflate it to 80. The tire is designed to accommodate the pressure increase caused by heating.
The Role of TPMS
A tire pressure monitoring system (TPMS) is invaluable for maintaining proper PSI. With a TPMS like the i10, you can monitor all tire pressures and temperatures in real-time. For example, if three tires read 80 PSI but one shows 100 PSI, it signals a potential issue. The same applies to temperature readings. For larger setups, like a Class A RV towing a vehicle, you can monitor multiple tires simultaneously—up to 10 on one screen.
Conclusion: Proper tire inflation and weight distribution are critical for RV safety, comfort, and longevity. A TPMS can simplify monitoring and understanding load inflation tables to help you make informed decisions.
