Replacing Underrated Tires on a 42 Foot Montana 5th Wheel Trailer

Question:

I have a 42’ Montana 5th wheel with wt of 17k. Purchased 235/80-16 14ply tires with load cap of 3200 lb/tire. Max pressure of 105 cold. Do I need a bigger tire?

asked by: Vernon B

Expert Reply:

Fifth wheel trailer manufacturers assume that some of the weight of the trailer is carried by the tow vehicle. So it often seems like the tires on them are underrated for the gross trailer weight. And that is true. However they also assume that the trailer is going to be towed perfectly level which isn't always true. So if you were towing the trailer nose high for example there would be more weight on the trailer axles and that could overload the tires.

It would not hurt to go to 235/85-16 tires. They fit the same wheel size as the tires you have now and they will be stronger. You could go to a 235/85-16 and also step up to load range F such as the Kenda Karrier # AM1050. It is rated for 3,960 pounds at 110 psi. Using 4 of these would have a total capacity of15,840 pounds which is an increase of 3,040 pounds. This tire has a speed rating of 81 mph. We do not have any of this size tires in a load range E.

And the highest load range, G, # TTWPRG235R16, will be rated for 4,400 pounds at 110 psi for a total of 17,600 pounds; an increase of 4,800 pounds. This is the route I would take so that no matter what the tires cover the gross trailer weight.

expert reply by: Michael H