In Part 1 of this discussion, we outlined getting started, getting acquainted with your rig and making a practice run in a parking lot prior to hitting the road. One of the most essential maintenance items you can conduct for a safe and enjoyable road trip is checking your weight ratings and know proper tire inflation and maintenance.
Understanding weight ratings and knowing what your rig, tow vehicle, and towed vehicle actually weigh is essential to prevent excess brake wear, axle problems and tire blowouts!
- Gross Vehicle Weight Rating (GVWR)
This is the maximum weight your rig can weigh with everything inside going down the road including personal items, propane, water, and people the case of a motorhome. Today’s new RVs have a weight sticker that tells what the rig weighs “dry”, and Cargo Carrying Capacity (CCC) meaning how much you can put inside before hitting GVWR. Most owners have no idea how much weight they are carrying. They see all the huge compartments and think they can fill them up! Not so. Once you get your rig loaded, take it to a CAT Scale and get it weighed.
CAT Scales are available at most major truck stops like Pilot or Flying J, or visit www.catscale.com and find one near you. For $10 you can use the platforms to put the front wheel on the first platform, back wheels on the second, and towed vehicle on the third. This will not only tell us the GVWR when we add the two axles, it will tell us GAWR as well.
2. Gross Axle Weight Rating (GAWR)
The GVWR is the weight the entire rig can weigh, however, each axle has a weight rating that must not be exceeded as well. Usually, the front axle is the lightest and most abused by RV owners. You should have a data plate inside the vehicle or on the tongue of a trailer with the GVWR and GAWR posted. Trucks, cars and trailers should put the front wheels of the tow vehicle on the first platform, the drive or back axle on the second, and the trailer or 5th wheel on the third. This will give you axle weights on individual axles and tell you if you might have too much weight on the back end of the tow vehicle. This is a common mistake with 5th wheel trailers as owners tend to fill the large compartment under the bedroom and put items in the bed of the truck as well.
It is also recommended to have your rig weighed by individual wheel position as some rigs will have over 1000 extra pounds of “accessories” on one side or another. The only way to accomplish this is to have individual platforms such as those provided by The Recreational Vehicle Safety and Education Foundation (RVSEF). Visit their site at: www.rvsafety.com to find weighing locations in your area.
Tire Maintenance and Proper Inflation
Tires are the most vulnerable component on our rigs and the most neglected. A small percentage of owners actually know how to determine proper inflation. It’s not the marking on the side of the tire – that’s maximum inflation at maximum weight. If you are not fully loaded to GVWR, your tires will be overinflated and have less tread on the road. The only way to find proper inflation is to weigh the coach which we just talked about and refer to the tire manufacturer’s tire chart.
Once you find the weight on the individual tire, refer to the chart, find the tire size, dual or single application, and the weight. That is the proper tire pressure for your tire! My truck tires are a good example which recommend 61 psi at maximum load. During normal driving I don’t have a truck bed full of dirt or drywall so 61 psi would be overinflated and my truck would ride like Fred Flintstone’s car with rock wheels! I drive with about 35 psi.
Another issue is underinflated tires. If your tires are just 10 psi lower than proper inflation, it reduces carrying capacity by 25%! Your tires should be checked every day you hit the road, not just glanced at or hit with a “trucker’s bat”! Make it part of your pre-trip inspection list or get a Tire Pressure Monitoring System (TPMS).
Check the sidewall of the tire periodically for signs of cracking known as weather checking. Exposure to UV rays will dry out the material and make it crack. If you are letting your rig sit for more than a day exposed to the elements, cover the tires.
Finally, as you are driving, check the temperature of the tires, the axle, and the brakes. I carry an Infra-red laser temperature tester and when I stop for fuel I test the temperature. It typically will run about 20-30 degrees hotter than ambient temperatures which is normal. However, if I see a spike, then I know something is wrong! Could it be starting to lose pressure and it’s working harder? If the hub is hot, do the bearings on my trailer need to be repacked? If the brake rotor or drum is hotter than normal, are the brakes set too high? Once you get a few readings, you’ll know what is normal and what is excessive. Also, if one side of the rig runs consistently hotter than the other…it’s time to get the coach weighed by individual wheel position as it might be too heavy on that side and everything is working harder. You might need to move some items to the other side.
About the author:
Dave Solberg: Managing Editor, RV Repair Club
For the last 25 years, Dave has conducted RV maintenance and safety seminars, developed dealer and owner training programs, written RV safety and handyman articles, authored an RV handbook reference guide and logged over 100,000 miles on the road in an RV.
RV Repair Club is your go-to online resource for enthusiasts who want quality RV maintenance, repair, and upgrade information – a community where passionate RVers can come together to gather knowledge and share their experiences.
Karl P. UT~ “Kurt from Quality Tire was exceptional. He came and pulled both sets of back tires. The inside tires on both sides of our motor home had 0 pressure. Both Valve stems had been damaged for some reason. He replaced the valve stems on both tires, checked and filled all 6 tires to correct pressure. He was a pleasant and pleasurable person to work with. We were called by Coach-Net several times to make sure everything went as it was supposed to. Thank you to all the Coach-Net Representatives and to Kurt from Quality tire. It took something that was a pain and made it a pleasure.”