Tire pressure

[zippy83]

Hi all,

My trailer tires state the following.

Maximum load 1045LB at 80PSI. My setup is approx 900LB and when I checked the tire pressure it is at 45psi. I feel like if I go to 80PSI that the tires might blow.

Should I go up from 45 to 80?

Thanks
Zipp

[WIMUSKY]

Re: Tire pressure

First, nice musky! If your tires are rated for 80# they will not blow if you max them out. Considering your approaching max load with 900#s, I would put 80#s in the tires......

[Bondo]

Re: Tire pressure

Ayuh,.... The safest tire pressure is the pressure stated on their sidewalls,....

[JB]

Re: Tire pressure

+1^^

[roscoe]

Re: Tire pressure

Trailer tires use air pressure for sidewall strength and rigidity.
If you run low air pressure, you risk a blowout if you hit something, like railroad tracks or a curb.
Low air pressure also causes the tires to run hot, and can cause premature failure.

Per TireRack: The stiffer sidewalls and higher operating pressures common with Special Trailer (ST) designated tires help reduce trailer sway.


From Carlisle Tire:
Underinflation is the number one cause of trailer tire failure. Low
inflation pressure elevates tread temperature, especially as speed
increases. Operation of a
trailer tire that is 30 percent under-inflated can reduce tire lifespan by
approximately 55%. An underinflated tire creates abnormal tire
flexing and excessive heat causing the following:
– Tire damage and failure.
– Ride and handling disturbance.
– Reduction of tire life.
– Decreased fuel efficiency by as much as 10 percent.
– Maintain air pressure at the maximum PSI recommended on the
tire sidewall.
– Check tire pressure when tires are cold and in the shade.

[NYBo]

Re: Tire pressure

Yes, inflate them to 80# for safety and tire longevity. Note that the weight capacity is per tire, so the set will be good for up to 2090 pounds. Don't worry too much about the increased pressure transmitting impacts to the boat: reducing that is why you have springs on the trailer.

[MH Hawker]

Re: Tire pressure

Hi all,

My trailer tires state the following.

Maximum load 1045LB at 80PSI. My setup is approx 900LB and when I checked the tire pressure it is at 45psi. I feel like if I go to 80PSI that the tires might blow.

Should I go up from 45 to 80?

Thanks
Zipp

Some thing dose not sound right, a 1045 pound load range is a load range C rating and that is normally around a 45 to 50 psi air pressure. a 80 to 90 psi tire is a E load range. Mine are E rated at 90 psi at 1650 pounds. I would take a real close look at the side wall ratings. 80 psi in a C rated tire can blow up in your face.

[zippy83]

Re: Tire pressure

I got it now at 70psi. The spare reads max load 845lb at 60psi

[lckstckn2smknbrls]

Re: Tire pressure

Some thing dose not sound right, a 1045 pound load range is a load range C rating and that is normally around a 45 to 50 psi air pressure. a 80 to 90 psi tire is a E load range. Mine are E rated at 90 psi at 1650 pounds. I would take a real close look at the side wall ratings. 80 psi in a C rated tire can blow up in your face.

I have 8" and 12" load range C tires and they are 90psi.

[bassman284]

Re: Tire pressure

If a tire isn't meant for 80 psi, they wouldn't mention it on the sidewall. He didn't state tire size or brand. The tire manufacturer determines the pressure they need to be run at.

[ricohman]

Re: Tire pressure

I got it now at 70psi. The spare reads max load 845lb at 60psi

Run them at max pressure. They will gain some psi anyway during use. I can't see any reason to run trailer tires at anything but the max pressure.

[JimS123]

Re: Tire pressure

If a tire isn't meant for 80 psi, they wouldn't mention it on the sidewall. He didn't state tire size or brand. The tire manufacturer determines the pressure they need to be run at.

Pressures are universal based on the load range. The print is real small and the chinacrap tires aren't all that readable at times. Use a mag glass and look again. Then load it to the rated psi.

Obviously, the spare is a lesser grade tire. Better be sure it'll handle the load.

[NYBo]

Re: Tire pressure

Obviously, the spare is a lesser grade tire. Better be sure it'll handle the load.

He said the whole shebang weighs around 900 pounds, so the spare is fine.

[H20Rat]

Re: Tire pressure

So two things... First, keep in mind rims have a max pressure also. You do NOT want to exceed that, unless you enjoy metal shrapnel... I've seen rims with max psi less than 80 psi...

Second, the OP is less than half the max load. I know people often disagree with this, but give me a second... Imagine your tire at max load, max psi. The angle of sidewall and size of footprint is what the tire is designed for. You want those two variables to be the same, no matter what the load. The only variable you control is the psi in the tire. Running max psi when a tire is loaded to less than half of capacity puts the tire way outside of its design spec. Your footprint on the ground is miniscule, you will wear the center of the tire extremely quickly and the available traction is greatly reduced. (assuming bias ply, radials are actually much more tolerant of higher psi when compared to load.)

So i'm curious, why do vehicle manufacturers never, EVER recommend max tire psi on the doorpost placard? Because your ride would suck, tire lifetime would be greatly reduced, and you would not have nearly as much control. But yet for some reason people think it is ok with trailer tires that are at half their max load.

[NYBo]

Re: Tire pressure

Second, the OP is less than half the max load. I know people often disagree with this, but give me a second... Imagine your tire at max load, max psi. The angle of sidewall and size of footprint is what the tire is designed for. You want those two variables to be the same, no matter what the load. The only variable you control is the psi in the tire. Running max psi when a tire is loaded to less than half of capacity puts the tire way outside of its design spec. Your footprint on the ground is miniscule, you will wear the center of the tire extremely quickly and the available traction is greatly reduced. (assuming bias ply, radials are actually much more tolerant of higher psi when compared to load.)

Your theory sounds right, but the problem is figuring out what pressure to use. Is the relationship linear (i.e. half pressure for half load)?