Cannot determine tire pressure

muelldawg

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Feb 7, 2016
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Just "topped off" tires on boat trailer. Required pressure is 90 psi. My hand gauge and compressor did not get a read on pressure in tire. This is a small boat trailer carrying a dinghy that weights less than 200 lbs. The gauges work on my truck tires. What is happening here ? Do my boat trailer tires have some special valves?
 

rallyart

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No special device. Sometimes the valve is just a little further in so some gauges don't activate the valve to read it correctly. A different gauge is likely to give you a clear reading.
 

Thalasso

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No your trailer doesn't have special valve stems
Does your gauge read that high?
If your using one that's made for cars it won't go that high. How much air does your truck tires take? 45lbs.
You need a truck tire gauge to get that high. One that goes to 120-150lbs
 
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H20Rat

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This will probably start all kinds of debate, but when you have a very light load, you absolutely do not need to run the tires at their max PSI. By doing this, especially with bias tires, you are drastically reducing the tread pattern, and running the tire far outside its performance envelope. Only the very center of the tread is actually in contact with the pavement, tires are meant to run with the entire tread on the pavement. Also, that much pressure will beat your load on every bump.
 

Thalasso

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This will probably start all kinds of debate, but when you have a very light load, you absolutely do not need to run the tires at their max PSI. By doing this, especially with bias tires, you are drastically reducing the tread pattern, and running the tire far outside its performance envelope. Only the very center of the tread is actually in contact with the pavement, tires are meant to run with the entire tread on the pavement. Also, that much pressure will beat your load on every bump.

:thumb:
 

NYBo

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This will probably start all kinds of debate, but when you have a very light load, you absolutely do not need to run the tires at their max PSI. By doing this, especially with bias tires, you are drastically reducing the tread pattern, and running the tire far outside its performance envelope. Only the very center of the tread is actually in contact with the pavement, tires are meant to run with the entire tread on the pavement. Also, that much pressure will beat your load on every bump.

It seems the debate is rather one-sided. Why is he running 90 PSI with that load was the first thing to cross my mind.
 

naturelover

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I'd agree, I'm running around 10 psi (maybe less) in my 4.80x8 Jon boat trailer tires with no ill effects. Seems to help with the ride and with wearing out the center of the tire. Now this is probably not more than 200# gross trailer weight (I can pick up the boat and trailer from the rear and move it), if one is running at or near rated load, then inflate to recommended pressure.
 

JimS123

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I'd agree, I'm running around 10 psi (maybe less) in my 4.80x8 Jon boat trailer tires with no ill effects. Seems to help with the ride and with wearing out the center of the tire. Now this is probably not more than 200# gross trailer weight (I can pick up the boat and trailer from the rear and move it), if one is running at or near rated load, then inflate to recommended pressure.
Whoa.....an accident waiting to happen. 10 psig may not even keep the bead sealed to the rim.
 

JimS123

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It seems the debate is rather one-sided. Why is he running 90 PSI with that load was the first thing to cross my mind.

MY first thought was why is he running high capacity / high pressure tires on that low weight trailer?

Everybody knows that trailer tires are to be inflated to the pressure listed on the sidewall, regardless of the capacity. The key is to match the tires to the load.
 

lckstckn2smknbrls

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Just "topped off" tires on boat trailer. Required pressure is 90 psi. My hand gauge and compressor did not get a read on pressure in tire. This is a small boat trailer carrying a dinghy that weights less than 200 lbs. The gauges work on my truck tires. What is happening here ? Do my boat trailer tires have some special valves?

What size tires and what's the load rating?
 

naturelover

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Whoa.....an accident waiting to happen. 10 psig may not even keep the bead sealed to the rim.

Well, haven't had any problems. I may have 15 or so in it, but seems if there is any more than that in them, it runs on the center(at least looking at the tracks pulling out of the water).

All I have on it is the aluminum boat, I don't even trailer the motor, and 200# is probably a good bit of an overestimate. (I'll have to weigh it next time its out).

I honestly think I could run them with no air at all and be just fine, but won't be putting that to the test.

I don't do this with the ST trailer tires on my utility trailer, the unloaded weight and taller sidewall could lead to the tire popping off the rim. I pump up my 4.80x8 4x8 utility trailer tires up to inflation pressure too, because it's loaded weight isn't constant (and it probably weighs more unloaded than the loaded boat trailer) But for this extremely light load with a set weight, with very little possible side to side forces able to be applied to the tires from the load, and stiff, short sidewalls, I'm not sure the the bead could pop off without actually trying to.

It just seems to put such a pounding on the boat too, there's no other way to ease that either that I can see, as theres only one spring leaf, unless I added a lot of weight to the trailer or something.
 
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rallyart

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When you take your tire temperature readings with the pyrometer you keep lying around you will be able to tell if the tire is working correctly. Just have both sides of the tread at the same temperature as the centre after you have towed it down the road for at least 15 minutes. That's the best way to ensure that you are running at the correct tire pressure. It can also tell you about your alignment. Okay, so you don't all have an extra pyrometer lying around but I do, and this works for any tire. Your fuel mileage will be better if you raise the pressure above that level but you will wear your tire a bit more.
If I had to I would definitely take Maxxis or Goodyear advice ahead of Carlisle. The likely reason for Carlisle's statement is that the negative affects of to low a pressure are serious. The negative affects of too high a pressure are small. It's okay to have more pressure in the tire than you need, within the design limits. It's not okay to have less pressure in the tire than you need.
 
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NYBo

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The Carlisle document doesn't seem to address the issue of tire pressure vs less than full rated load, and the Goodyear document provides a handy chart of inflation vs load capacity. I think I would go Goodyear, so to speak.
 

bruceb58

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The likely reason for Carlisle's statement is that the negative affects of to low a pressure are serious. The negative affects of too high a pressure are small. It's okay to have more pressure in the tire than you need, within the design limits. It's not okay to have less pressure in the tire than you need.
I believe you hit the nail on the head. For some people, it's easier to have one simple rule to follow than to expect them to go out and weigh their load and use a chart.
 
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