Selection of Special Trailer Tires for 5th Wheel Trailer to Avoid Blowouts

Question:

I have a 43foot 5th wheel. The axles are Dexter 7000#. The rigs GVWR is 15,800#, and the hitch weight is 2900# I haul it with an F350 dually diesel. I have been running with Goodyear Marathons ST235/80R16 load range E that are rated at 3420#. I rigorously check the tire pressures cold @ 80 psi, and use a TPMS system. The road speed never exceeds 62-63mph. Yet I have had 2 blowouts within the past 3 months with these tires. The RV forums suggest either Michelin XPS Rib LT235 /85 R16 rated @ 3086 # or Maxxi ST 235/80R16 rated @ 3420#, The LT Michelins seem to get a real positive rating by users, but I have concerns about the Max Load rating. The ST Maxxis also get pretty good ratings and have a higher load rating. Finally my question: Will the Michelins handle the weight of my rig? Thanks for any guidance or opinion.

asked by: Fred C

Expert Reply:

Most critical to trailer tire performance and durability are 1) proper inflation 2) observance of the tire's rated load capacity and 3) observance of the tire's speed rating. If either of these factors is off the mark then the tire will tend to overheat and heat is what usually causes tire failure. It sounds like you have a good handle on proper inflation and speed.

It is perfectly fine to use a tire that is over-rated for the application, say using a load range F tire when an E-rated one would suffice. This tends to result in a lower operating temperature which, generally speaking, is always a good thing when we're talking about special trailer tires. Cooler-running tires typically last longer. And there is really no down-side to using a higher-weight-rated trailer tire.

Since we don't carry the specific tire brands you referenced I do not have direct experience with them. But the linked page will display all of our available 16-inch radial special trailer tires in the two sizes you mentioned, ST235/80R16 and LT235/85R16. The highest-rated among these are the Load Range G Provider # TTWPRG235R16 and the Westlake # LHWL410.

Both of these tires have a 4400-lb load limit at their specified 110-psi cold pressure, and both carry an M speed rating, which allows operation up to 81-mph. If you select tires that are over-rated in terms of both load rating and speed rating, they will operate at a lower temperature and tend to provide a longer service life.

expert reply by: Adam R