Trailer Tires Keep Blowing Out on a 2006 Keystone Cougar 314EFS 5th Wheel Trailer

Question:

Hi I have a 5th wheel 2006 Keystone Cougar 314EFS with a dry weight of 8300 and carrying cap of 3300 The manufacturer recommends 225/75D/15D , 65PSI I am have been using 225/75/15 load E and still having blowouts every couple of trips Please advise Thanks for your support

asked by: Art C

Expert Reply:

An ST225/75R15 load range E trailer tire, such as # AM10303, is rated for 2,830 pounds at 80 psi. On a tandem axle 5th wheel trailer with 4 of these tires, that equals 11,320 pounds which is about 300 pounds under the gross trailer weight.

Trailer manufacturers calculate that some of the trailer weight will be carried by the truck to account for the difference in the weight of the trailer and the axle/tire capacities. But what can happen is if the trailer is riding high in the front, less weight is being carried by the truck and the only place it can go is back on the trailer axles and tires. This can lead to the tires being overloaded and tire failure.

It at all possible, make sure the trailer is level. Most 5th wheel trailer hitches and pin boxes are height adjustable so you may be able to make some adjustments to get a little more weight on the truck side and relieve the stress on the trailer tires some.

Also, trailer tires should always be inflated to the maximum psi indicated on the tire sidewall. This is because trailer tires are built with a thicker sidewall than passenger vehicle tires to handle more vertical load. If under inflated the thicker sidewall generates excessive heat and can lead to failure.

expert reply by: Michael H