Tire pressure to use for Sundance

loafer

Well-known member
not tire monitoring related but wondering what tire pressure to run in our 225/75 /15 inch mission brand tires on our brand new 24.5 xlt sundance 5th wheel. they have 50 lbs from the dealer but tire says max 65 on sidewall.
any comments appreciated as we are newbies to the rv world
thanks Bill
 

jmgratz

Original Owners Club Member
The best way to find out is to ask a reputable independent tire dealer. Remember the side wall is the maximum psi for the tire. You should use the maximum tire pressure when the maximum load rating is approached. To be sure you need to weigh the unit where you know how much weight each tire is carrying. Then you can determine if you can use less than maximum pressure. Remember heat is a tire biggest enemy and low pressure can cause a tire to overheat very quickly even though it gives a smoother ride. If I was unsure I would use what is on the sidewall as that is the tire manufacturers recommended pressure. I sure others will have opinions also
 

StevieWonder

Well-known member
65psi is the max COLD pressure ... NOT max pressure
BIG difference
The pressures will elevate rather dramatically after time on the road, particularly when the road surface is hot (summer in Arizona?)

If you're like most of us, you probably have enough stuff on the trailer to be at or very near the max weight. I've dragged big trailers (see my signature) down to motorcycle trailers from coast to coast to coast and into Canada. Set the tire pressure at or near the cold maximum. The heat buildup is what destroys the tires and the sidewall flex is what builds up the heat. More pressure means less sidewall flex which means less heat build up which means a lower likelihood of a catastrophic tire failure.

Make sure you check the spare too ... it's of no value if it's at 30psi when you need it.
 

jmgratz

Original Owners Club Member
65psi is the max COLD pressure ... NOT max pressure
BIG difference
The pressures will elevate rather dramatically after time on the road, particularly when the road surface is hot (summer in Arizona?)

You are very right I forgot to mention the important COLD pressure. When I set mine at 110 psi cold (G rated) in the summer they will get up to about 128 while on a hot road. Sometimes that increase is kind of scary, however the Goodyear factory rep told me they are designed for that increase and not to worry about it. I have also found by using a digital thermometer there might be a 15 degree difference in the sun side versus the shade side and a 10 psi difference also. Tire pressure is a funny (strange) thing. I would also recommend a TPMS (tire pressure monitoring system) such as Pressure Pro or Doran TPMS. They are both excellent and reliable systems. Personally I have the Doran system and it has saved us a number of times.
 
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