Quote:
Originally Posted by tractors1
Distributing the trailer load over 4 tires means each tire carries 1/4 of the load instead of 2 tires each carrying 1/2 the load, so for a given weight the tire pressures need not be as high - which results in a smoother ride for the trailer.
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Yes, but tires come in a wide range of sizes, so for this purpose one could just use two larger tires... and most people (including everyone following Escape's recommendation) inflate the tires to 50 psi anyway, so they don't get this benefit.
On the other hand, trailer manufacturers like to use ST tires (again, what the buyers expect), which greatly restricts the choice of sizes. In common ST tires, the lowest pressure to have sufficient capacity for 4000 pounds of axle capacity (what an Escape 21 would need with only a single axle) without resorting the excessively tall ST235/80R16 would be 45 psi in an ST225/75R15... still 10 psi more than needed in the stock setup of four ST205/75R15.
Quote:
Originally Posted by tractors1
I know some 17LD casita folks who run 65 psi in their Load Range D and E tires that complain about drawers coming out and doors falling off hinges.
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The Casita 17 is a classic case of the trailer manufacturer running the smallest possible tires, thus putting them at their limits, so owners often run them with insufficient inflation and many have had failures. Many owners have responded by choosing tires which have higher capacity by allowing higher inflation pressures - thus the harsh ride. Small tire diameter with high pressure is a jarring combination. Casita used 14" wheels on even their heaviest trailers for a long time, although they have since moved up to 15"
Escape follows the opposite approach, using larger tires which then don't need to run close to their rated load capacity, avoiding these problems. The Escape 17' (which is lighter than a Casita 17') moved up from 14" wheels to 15" years ago.
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