Proper air pressure for PWC trailer

seapea

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Jan 5, 2022
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I have a single PWC trailer with 4.80x12 5 lug wheels. The trailer decal says to inflate to 60 PSI, and my old tires said the max PSI was also 60 PSI. However, I just replaced with new tires that have a max PSI of 90 PSI. So what's the proper pressure to use now? 60? 90? Something in between?

BTW, I'm about to tow 2500 miles (southern route, so hopefully no freezing temps).

Thanks
 

Alumarine

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Welcome.
The max psi stamped on the tire is for the max load they are rated for.
What are the tires rated for and what is your total weight?
 

H20Rat

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Mar 8, 2009
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You will probably get a slew of answers saying run max PSI, but that is very likely pushing the tire outside its operating envelope for a light load. If the trailer is lightly loaded, it wears the center of the tire prematurely and you have very little traction.

With any luck, you can find a load rating chart for the tire from the manufacturer, but that is somewhat uncommon for a smaller tire but do some digging, might be out there.
 

seapea

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Welcome.
The max psi stamped on the tire is for the max load they are rated for.
What are the tires rated for and what is your total weight?

Load Range: C (6-ply rating)
Max. Capacity: 990 lbs. each
Overall Diameter: 20.5"
Maximum PSI: 90 lbs.

Trailer + PWC is about 1200 lbs.
 

Scott Danforth

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your old tires most likely had a lower load range than your new tires, hence the lower pressure.

nothing wrong running your tires to max, however your trailer will bounce a bit more if not loaded enough

running too little pressure and you risk damaging a tire from overheating the sidewalls due to too much flex. this causes a blow-out

I would probably start at about 75 psi in with your tires/load. if it bounces a bit, lower the tire pressure to about 70. if the tires are a bit squishy looking increase the pressue to about 80. I would also take tire temperature readings on the two outer edges of the tread and the center. the temperature should be close all the way across. that is a good indicator of proper inflation.
 

robert graham

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If tire says 60 psi at max load then run at about 50psi cold so when the tires heat up at highway speeds you’ll be about 55 psi….
 

Scott Danforth

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If tire says 60 psi at max load then run at about 50psi cold so when the tires heat up at highway speeds you’ll be about 55 psi….
his new tires are 90 psi max, old tires were 60 psi max. Hence the OP's question
 

robert graham

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Like I mentioned, if tire says 90psi on sidewall, then inflate at about 80psi so when tire heats up at highway it won’t overinflate causing tire wear, hard ride….
 
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