Tire pressure

[ultra_1968]

Single axle trailer, 18' foot bowrider I/O, tire size 215/75/R14.

Tires look a little low, and I don't want to tow with out a sufficient pressure.

What should the pressure be when hooked onto the SUV (Expedition) and just resting without being hooked up?

Thanks again, as usual.

 

[oldjeep]

Re: Tire pressure

Look at the sidewall of the tire - it will say max load xxxxlbs at xxpsi

Fill the tires to what the psi says. It is irrelevant if the boat is attached to the truck or not.

 

[ultra_1968]

Re: Tire pressure

Thank you sir.

 

[dazk14]

Re: Tire pressure

+1 as oldjeep said. fill when cold, not after driving and avoid the temptation to put in less air to "lower the stress". Once you start driving with less pressure the tire will run much hotter and that's when the trouble starts.

 

[wbc1957]

Re: Tire pressure

Look at the sidewall of the tire - it will say max load xxxxlbs at xxpsi
Fill the tires to what the psi says. It is irrelevant if the boat is attached to the truck or not.

Bull! Come on and think about it. Just like you are supposed to inflate the tires on your vehicle based on the door panel tag of that vehicle, you should look at the inflation rate of max pressure of the tire/max load, and equate the rate of pressure based on the weight of your boat. Can you imagine inflating full pressure on a super light boat and trailer, just because someone told you to use max pressure of off the tire? Use common sense please.....

 

[oldjeep]

Re: Tire pressure

Bull! Come on and think about it. Just like you are supposed to inflate the tires on your vehicle based on the door panel tag of that vehicle, you should look at the inflation rate of max pressure of the tire/max load, and equate the rate of pressure based on the weight of your boat. Can you imagine inflating full pressure on a super light boat and trailer, just because someone told you to use max pressure of off the tire? Use common sense please.....

I'd suggest that you look at any trailer tire manufacturers page and read what it says. Trailer tires are designed to be used at sidewall pressure, not adjusted for load.

 

[BoatNoobie]

Re: Tire pressure

Bull! Come on and think about it. Just like you are supposed to inflate the tires on your vehicle based on the door panel tag of that vehicle, you should look at the inflation rate of max pressure of the tire/max load, and equate the rate of pressure based on the weight of your boat. Can you imagine inflating full pressure on a super light boat and trailer, just because someone told you to use max pressure of off the tire? Use common sense please.....

Those ratings are for whatever tires that came with the vehicle.

So if you got tires that are rated for 50 PSI, but your trailer only says 35 PSI. Running those new tires at 35 will destroy your tires due to flex and heat.
Use common sense please....

 

[dazk14]

Re: Tire pressure

Bull! Come on and think about it. Just like you are supposed to inflate the tires on your vehicle based on the door panel tag of that vehicle, you should look at the inflation rate of max pressure of the tire/max load, and equate the rate of pressure based on the weight of your boat. Can you imagine inflating full pressure on a super light boat and trailer, just because someone told you to use max pressure of off the tire? Use common sense please.....

You are starting a different topic here and there are instances where lower pressures can be useful or appropriate...but, you would need to ask more questions about his SPECIFIC tires, trailer, actual loading, driving conditions, tow speeds, and towing issues well before you use the "Bull!" comment. Is he hauling a,"Super light boat and trailer"? Really? with an I/O...

To the OP - 18' I/O probably ~2100lbs dry(if 4cyl),+ loaded(fuel,batteries, etc.) ~400LB, +trailer ~700lbs = 3200lbs. MINIMUM. All of these could easily be...Much higher...

2 "C" rated tires likely 1760lb ea. +3600 capacity MAX at 65mph at Maximum sidewall pressure - AT LEAST 3200lbs loaded weight yields...

the obvious answer that you'll hear over and over...

I can assure you that a blowout at 50mph is no small event.

 

[Frank Acampora]

Re: Tire pressure

Yeah! Please wbc 1957, let's not compare apples and oranges, or in this case trailer tires and auto tires. The auto tire pressures are set by the manufacturer for a number of factors, one of which is comfort of ride, another is handling, and another is tire life. It is a compromise.

Running for example two 8 inch trailer tires rated at about 900 pounds each and 60 psi with a 1000 pound load, by your reasoning, the tire pressure should be reduced to about 35 psi which even at the reduced load will eventually result in damage to the tires. And we don't care about the boat's comfort level. They all do very well on the trailer if fitted correctly.

PS: I may be wrong, but I always run my auto tires at the max inflation pressure specified on the tire. I lose a little comfort amd handling but I do gain a small measure of fuel economy and tire life. Right now I have 90,000 miles on a set of Tiger Paws and they will still pass inspection.

 

[wbc1957]

Re: Tire pressure

Yeah! Please wbc 1957, let's not compare apples and oranges, or in this case trailer tires and auto tires. The auto tire pressures are set by the manufacturer for a number of factors, one of which is comfort of ride, another is handling, and another is tire life. It is a compromise.

Running for example two 8 inch trailer tires rated at about 900 pounds each and 60 psi with a 1000 pound load, by your reasoning, the tire pressure should be reduced to about 35 psi which even at the reduced load will eventually result in damage to the tires. And we don't care about the boat's comfort level. They all do very well on the trailer if fitted correctly.

PS: I may be wrong, but I always run my auto tires at the max inflation pressure specified on the tire. I lose a little comfort amd handling but I do gain a small measure of fuel economy and tire life. Right now I have 90,000 miles on a set of Tiger Paws and they will still pass inspection.

Yes, you may be wrong and are. Plus whether it be trailer tires or auto tire, the load decides the inflaton rate. Any trailer can have adaptations to the point of too many plys or too many load ranges. This is just another reason why load determines inflation. So, whether you all like it or not, you are wrong.

 

[bassman284]

Re: Tire pressure

Hot Dog! Tire pressure fight! I've gotta go get me some popcorn and a beverage.

 

[2300max]

Re: Tire pressure

Hot Dog! Tire pressure fight! I've gotta go get me some popcorn and a beverage.

Uh oh!!! I kind of agree regarding apples and oranges.....I stick with what the Veh. Mgr. suggest on my vehicles and go with the info on the tires on my trailers..... Folks get confused and over inflat vehicle tires all the time and wonder why they have wear issues. I had my vette inspected and they checked the tire pressure and the service guy wanted to put 45 lbs in the tire. I had to explain to him I run between 29-30 lbs. He thought I was crazy until he looked at the door sticker.......

 

[V153]

Re: Tire pressure

Call me crazy but I inflate my truck & boat trailer tires to what is recommended on the sidewall. Plus mebbe a psi or two. No problems.

 

[NYBo]

Re: Tire pressure

Call me crazy but I inflate my truck & boat trailer tires to what is recommended on the sidewall. Plus mebbe a psi or two. No problems.

Okay: You're crazy.

My son used to have a Ram pickup. When he bought it, the ride was terrible. It turns out the previous owner had done just what you do. But it had large, high load rated tires with a maximum PSI of something like 81. When he lowered the pressure that Dodge recommended (35 or so, IIRC), it rode fine.

 

[H20Rat]

Re: Tire pressure

Running for example two 8 inch trailer tires rated at about 900 pounds each and 60 psi with a 1000 pound load, by your reasoning, the tire pressure should be reduced to about 35 psi which even at the reduced load will eventually result in damage to the tires. And we don't care about the boat's comfort level. They all do very well on the trailer if fitted correctly.

PS: I may be wrong, but I always run my auto tires at the max inflation pressure specified on the tire. I lose a little comfort amd handling but I do gain a small measure of fuel economy and tire life. Right now I have 90,000 miles on a set of Tiger Paws and they will still pass inspection.

Your 35psi # is wrong... It isn't a straight line formula to determine correct tire pressure...

Anyway, yes, it is absolute appropriate to run lower PSI IF you have a reduced load. Before jumping on me, let me explain why... Your overall goal is to keep two things the same, no matter the load. You want the sidewall deflection angle the same, and you want your contact patch consistent. The only way to do that is to adjust the pressure. No, it won't wear your tires out, the point of reducing pressure is to actually EXTEND your tires life. People mentioned it will ruin the sidewalls. Re-read my paragraph if you still think that is a concern. (for a recap, the goal is to maintain the same sidewall deflection irregardless of load)

As far as max PSI on car tires. Dangerous and in most cases, you will reduce the tire life. What happens is that the center wears down to the wear bars, even though the outside is fine. Go check your tires with a wear gauge and make note of what it is in the center vs the edge. I have a feeling you might be to the wear bar at the center, and it just hasn't been caught because people usually only look at the edge.

As far as handling, running max PSI instead of rated can dramatically increase dry and wet surface braking distances. Hate to get into an accident because you ran max psi instead of oem recommended.

 

[beagleboy]

Re: Tire pressure

Max pressure on the side of the tire is just that. Depending on the weight of your vehicle the pressure varies. As an example my Ford Escape calls for 30 psi all around but when I'm towing the boat or other trailor I'll bump the rears up 5 psi. When finished its back down to 30. Bottom line look at your vehicle door post for psi hot or cold. note air expands when hot. Tires have a max weight rating and psi max. If you want to go over that you must get different tires. Example is people with SUV's buying car tires instead of LT or light truck tires.

 

[Frank Acampora]

Re: Tire pressure

As I said, at 90,000 miles the tires still pass state inspection. And here in Pa, that means that the inspector sees NO wear bars showing. I stand by my right to inflate to max pressure. Ohhh! Tire fight! let's argue about oil and ethanol too! LOL

 

[dazk14]

Re: Tire pressure

So, whether you all like it or not, you are wrong.

In normal use, comparing automobile tires(rated at 100mph+) that are, stress wise - loafing - IS comparing apples to oranges in the boat trailer world where 65mph max is generally specified. For the record, MY shop installs Kuhmo 857's when the correct fitment(14" only), because they are Q(98mph) speed rated at load, but that is another discussion.

Let's get back to the topic at hand...

Since wbc opened his mouth, please give the OP and answer to his question - A SPECIFIC PRESSURE. Fire away with needed data from the OP. What if he unknowingly hits 70MPH? What if it's a very hot day - Uh-oh.

To the OP, if you would like to use your boat and be safe...while we all wait for a wbc answer... fill cold to the tire max pressure on the sidewall, due to the math I indicated in an earlier post.

The simple fact is underinflation is the most common cause of tire failure in boat trailers.

And guess what, running it under-inflated for load and speed CAN DAMAGE a tire - without showing ANY visible signs.

 

[bigdee]

Re: Tire pressure

This is what the manufacturer says about MAXIMUM PSI?

"Carlisle Tire recommends and only warrants tires maintained @ the max air pressure while in service.
Maximum load range is attained only when the tire is at its maximum air pressure. There is no
advantage to taking air out of the tire. With maximum pressure, the tire will perform and wear better, and you will get better gas mileage. Reduce the psi, and you compromise the functionality of the tire. This is the position that we take on this".

There are ultimately three keys to avoiding tire trouble while towing: (1) Make sure your rig is

equipped with the proper tires; (2) Maintain the tire meticulously; and (3) Replace trailer tires every

three to five years of service, whether they look like they?re worn out or not.

 

[dazk14]

Re: Tire pressure

WBC1957 - we are still waiting for you to enlighten us with the correct pressure for Ulra_1968. Please get calculating, time is running out for a Mother's day Boat cruise...tic,tic.tic..