We had ST235/80R16 Goodyear Marathon tires on our 2010 Keystone Montana trailer. While traveling south on Route 85 in North Carolina, our driver’s side rear tire blew out with such force that it damaged the side of the RV to the tune of $982. Two days later the front tire blew out on the driver’s side in South Carolina. These tires are rated to carry 3,420 pounds single and are made in China. I check the air pressure every morning for 80 psi in all four tires before we start the day. The shipping weight on the 2010 model 3455SA Montana is 12,270 pounds. The carrying capacity for the unit is 3,290 pounds for a total of 15,560 pounds max weight. The four Goodyear tires rated at 3,420 pounds come to 13,680 pounds.
Am I wrong in saying the tires on my RV are not the correct tires for the unit? I would think the four tires should be rated to carry at least the 15,560 pounds. When I took the RV to the dealer for repair, the body shop manager said he has seen a lot of these tires blow out and cause damage. The tire dealers are recommending a 12- or 14-ply tire for the unit. I’m going to replace all the tires on this unit with 12-ply tires rated at 3,960 pounds single. Goodyear says I must have hit something in the road to blow out the tires. Two new Goodyear tires cost us $442.39. If there was something in the road, why didn’t the truck tires blow out first?
I also replaced the rear passenger-side tire, as it does not look right to me. The tread is uneven and I did not want another blow out. These tires came on the new unit in 2009. The date code on the passenger tire is 1908. We do cover the tires when the unit is not being used and the tires are kept on plywood. We tow with a 2006 Chevy Silverado 2500 diesel. Any advice would be appreciated.
— Dick Jarvela | Palm Bay, Florida
Fifth-wheel trailers are designed to carry about 20 percent of their weight on the hitch, so subtract 20 percent from the 15,560 maximum weight. That calculates to 12,448 pounds, which is how much of the maximum portion of the fully loaded trailer’s weight should be carried by the tires. That figure is well below the 13,680 pounds the four tires are rated for. Tire manufacturers now use load ranges such as E and F, rather than ply ratings. Tire inflation pressure should be determined by actually weighing the loaded RV’s axles on a truck scale and then referring to a load-inflation table from that tire manufacturer (available online or at tire dealers). A date code of 1908 means the tire was made in the 19th week of 2008, so age should not be the cause of failure. It is possible that the tires picked up nails or something, leaked down, got hot and blew apart. I’ve seen it a number of times where the first tires that run over an object stand it up, so a following tire will be punctured. In fact I’ve seen more punctures in rear tires than fronts.
Have a qualified shop check your trailer’s axle alignment. This is an often-overlooked factor in excess tire failure situations. Also, having your trailer tires balanced is a good idea for the same reasons it’s a good idea on your tow rig: The cost is low and you can add miles and years to your trailer tire lifespan.
– Ken Freund
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