Old Blevins said:
Hmmmmm. I have mine over-inflated then. I put Maxxis ST235/80R16 on my Arctic Fox which has an actual axle weight of about 8100 lbs. Those tires max out at 3420 lbs at 80 psi. Looks like I should be running them at around 50 psi, and I have them up near 80. I'll drop them back at least to 60. The scale I used didn't allow me to get individual tire loads, so that'll give me a little cushion for variance.
That wouldn't be a wise move on your part. rvsafety.com below has some excellent advice for those that over tire their trailer beyond recommended 10-15 percent reserve capacity.
I never heard of derating a tires pressure on a trailer till I started hanging out on RV websites.
Carlisle and Goodyear are our oldest ST tire makers and both say use the max sidewall pressure.
In fact using those minimum pressure charts can void your Carlisle tire warranty.
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Goodyear Tire and Rubber .... weighing RVs
Special Considerations
Unless trying to resolve poor ride quality problems with an RV trailer, it is recommended that trailer tires be inflated to the pressure indicated on the sidewall of the tire. Trailer tires experience significant lateral (side-to-side) loads due to vehicle sway from uneven roads or passing vehicles. Using the inflation pressure engraved on the sidewall will provide optimum load carrying capacity and minimize heat build-up.
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And Tireman9
one of our tire engineers also recommends max sidewall pressures says; from rvtiresafety.com his online tire blog;
"The manufacturers do not take into consideration the side to side unbalance, as to do so would require them to provide larger (more expensive) tires. The other thing RV industry does not take into consideration is the forces to the tire structure due to running close axle spacing. Engineering analysis shows that when turning corners the forces trying to tear the tire apart can be over 20% higher in multi-axle applications than with tires at the corners of the vehicle.
The only options for the trailer owner are to up-size the tires (if there is room) or up-rate and increase inflation (if a higher Load Range tire and stronger wheels are available). Lacking the above being sure to run the tire at the inflation shown on the sidewall (i.e. max) will slightly decrease but not eliminate the overload forces.
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Several RV related websites such as;
rvsafety.com
Tire Load and Inflation Ratings
Note: Towable ? Travel Trailer/ 5th Wheel owners Due to the severe use conditions experienced by tires when axles are very close together ? tire industry experts recommend maximum (sidewall) inflation pressure for towable tires unless this causes a sever over-inflation situation (20psi+), often referred to as the ?basketball effect?. If this is your situation allow a 10 ? 15psi safety margin above the minimum required inflation pressure.
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fifthwheelstreet.com
Step #5..
Selecting the Correct Tire Pressure for Your Trailer
We at Fifth Wheel St. no longer recommend adjusting trailer tire inflation pressure below the maximum load PSI rating molded on the sidewall (and only if the wheel/rim is appropriately rated) regardless of the measured scaled weight of individual tire or axle positions for all multi-axle trailers.
However, we do strongly recommend weighing individual trailer tire positions to ensure none of the axles or tire positions are overloaded. Reports have shown that trailers do not have equal weight across all tire positions. Some RV load configurations may reveal as much as 20% difference between the front and rear axle. This especially true for Toy Haulers. It is possible that mismanaged trailer load distribution will cause one end of an axle or a tire to be overloaded. It has been stated, but never confirmed by any RV Weighmaster, that there are many RVs traveling on the road with at least one tire or axle side overloaded. The only way to ensure tires and or axles are not overloaded is to weigh each tire position on your trailer. Unfortunately, attempting to obtain accurate individual tire position weight is practically impossible at all truck scales. View our list of recommend RV Weighmasters here.
- See more at: http://fifthwheelst.com/step5.html#sthash.FIAc3k0Z.dpuf