tire pressure

[floater212]

quick question, when filling tires up on boat trailer, is it better to have boat off or on for the pressure? I would think maybe on because a 3500lb. boat would change pressure and make it higher if it was at pressure empty. my tires are 10 ply and need 80psi and that by itself makes me a little afraid. Make sense??

 

[Horigan]

It doesn't matter. The change in volume in the tire when on the ground doesn't change enough to affect the pressure appreciably.

 

[Bondo]

Ayuh,.... Correct, it don't matter in the least,.....

The tires should be 80 psi, loaded, or empty,....

 

[Scott Danforth]

Pump em up, go boating

If pumping them up without the boat on, makes you feel better, then that is between you and your irrational phobia

 

[PITBoat]

I've wondered such a thing, in a passing way at least, but not connected to the boat trailer.

If you check the pressure with one tire in the sun on a hot day, and the other in the shade, there's a small difference.

Logically, if you could push down on your (vehicle, boat trailer, whatever) hard enough with an imaginary force, and if the sidewall profile was tall enough to keep the rims from bottoming out first, you'd eventually burst the tires.

Also logically though, it's not practical to have to remove your tires to set the correct pressure. And the pressure number is tied to a max load rating.

 

[PITBoat]

I've run across something related in the last year or so that's a problem - pressure gauges with significantly different readings.

I've always used the stick kind, and they seemed accurate enough, but I got a 12v pump with a dial gauge some time back, and it reads significantly higher. It's on the order of like 20-25% if I remember right. But the gauge action is so smooth and steady that it seemed like it'd be more accurate than a stick gauge.

I bough another push on dial gauge with a pressure relief valve, and it was junk - didn't seem to read high enough, and had to push it too hard to get the reading. I don't think it read as high as the stick even.

I went back to a stick (Slime brand? for what that's worth), and added air to my trailer tires this season based on that, and they look better now. 50psi using the stick was probably 35psi (stick) if I used the nice pump with the built-in dial.

 

[matt167]

I've run across something related in the last year or so that's a problem - pressure gauges with significantly different readings.

I've always used the stick kind, and they seemed accurate enough, but I got a 12v pump with a dial gauge some time back, and it reads significantly higher. It's on the order of like 20-25% if I remember right. But the gauge action is so smooth and steady that it seemed like it'd be more accurate than a stick gauge.

I bough another push on dial gauge with a pressure relief valve, and it was junk - didn't seem to read high enough, and had to push it too hard to get the reading. I don't think it read as high as the stick even.

I went back to a stick (Slime brand? for what that's worth), and added air to my trailer tires this season based on that, and they look better now. 50psi using the stick was probably 35psi (stick) if I used the nice pump with the built-in dial.

Most stick gauges are about as accurate as a good guess. Use a good professional quality digital gauge like an Accutire. They are accurate down to 2% for $12 or so

 

[lprizman]

As mentioned good gauge and I wouldn't max out...75 psi is fine....
No boat on it just makes easier for the pump to fill it...since less pressure..

Great day all!!?

 

[floater212]

thanks for all the info, as i originally thought, on or off 80psi, or close to that depending on your gauge!

 

[jhande]

I hope you don't take the tires off you're car to fill with air!

 

[Scott Danforth]

I use a 2.5" wika tire pressure gauge. Its much mire accurate than the spring loaded sticks