proper tire psi,.transon ties,bow stop??

[alumapompano]

Have another dumb question ,but I just want to be safe! Had my boat on the trailer jump a bit more than I like on sunday.The transom ties were not too tight and the bow was not all the way up to the bow stopI Just bought new tires (5.708) the max psi is 50.. I had them set cold at 42 psi ,I think that was a bit high... Im thinkn more like 35-38psi ... What do u guys think ? Any advice would be more than helpful .... Thanks....... Ps. The tires I purchased are the same size as the originals.....

 

[oldjeep]

You run trailer tires at max psi - they should be set at 50psi

 

[foodfisher]

Winch tight and snug transom ties. Loose ties and you give the boat a running start in an emergency stop.

 

[Starcraft5834]

set tires to 50.. no shortcuts or secret to it..under inflation will cause them to run hotter in the sidewalls.. you dont want that.. snug tight to bow stop, snug transom ties.. happy trailering....

 

[Expidia]

not a lot of info here regarding boat weight, trailer etc but the first place I would start is take your rig to a truck stop that has drive on scales. Park boat and trailer on scales and drive vehicle off the scales. They charge like $10 to give you the weight of boat and trailer. Then when home take a bathroom scale with a board on it and place tongue on it. proper tongue weight should be in the range of 10-15%. http://auto.howstuffworks.com/auto-parts/towing/towing-capacity/information/tongue-weight1.htm Then move the boat back or forward on the trailer to achieve correct tongue weight. This should eliminate the bounce if your tongue weight was the issue. You might have to move trailer axle back a hole or forward is trailer has extra holes. This is where I would start to isolate your towing issue.

 

[kjsAZ]

yes, total trailer weight and load rating of the tires are missing.
It's an old internet fairy tale that you run trailer tires always at full pressure. Get the load ratings from the specific tire manufacturer and inflate to the correct PSI's for the actual load. If you have a low weight trailer with tires capable of a much higher load and fully inflated they not only wear out in the centre but the trailer also jumps a lot more and shakes the boat more then required. It also tends to have more sway.
If you go to the link in my signature and look at the trailer-myth write up you can find the load rating curve for Goodyear trailer tires. Others may be identical or similar but it's not guaranteed.
The tongue weight of 10-15% is also a (North American) internet fairy tale which became the truth after some dummy companies even adopted it . US trailers are supposed to be designed for 8-10% (single axle) and 5-7% for tandem and more. Some of the major trailer manufacturers meanwhile publish the design parameter for their trailers and several saw the light and design now for 5-10% for single axle.
Lower tongue weight when the trailer stability criteria are met means a better overall geometry of the vehicle trailer combo. My last trailer was modified to meet European requirements (<2.5% tongue weight) and handled a lot better after that. It actually bounces a lot less.... Currently working on getting my current trailer there (much longer tongue mainly).

 

[alumapompano]

That's what I thought !! If u set the tires at max psi when they are cold ..Wont they go over when they are hot?????? I think ill run then round 42 -43... I really think the main issues this time was I did not have the transom ties tight and most of all did not crank the bow of the boat into the bow stop... My old tires which are the same size as the new ones ..I never ran them at max psi which was 50 and never had an issue .......

 

[JASinIL2006]

Interesting. Carlisle, in presenting a load/inflation table recommends running at max p.s.i., stating, "The above table DOES NOT endorse the reduction of air pressure. It is to be used as an example of the relationship between air pressure vs. load or lack there of. Carlisle Tire and Wheel only recommends and only warrants tires maintained at the max air pressure while in service."

They go on to say, "Maximum load range is attained only when the tire is at 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." (http://www.trailmastertrailers.com/pdf/proper_tire_care_safety.pdf)

So max inflation thing is not entirely some Internet myth, but it does lead me to wonder why publish a load limit vs. inflation table if the intention is to run at max PSI.

 

[kjsAZ]

you have to read the fine print! They are talking about the maximum load. In addition most of this brands tires are CCJ as I call them (Cheap Chinese Junk) and they may not even know how the curve is supposed to look like. And as I wrote: some of these manufactures better called Chinese retailers just adopt the wrong stuff but please do your own research NOT on the internet but by contacting the appropriate real tire manufactures like Goodyear and others.
It's the easiest for Carlisle to spec it that way as there are to many out there which would not be able to get the correct values. The tire naturally does fine as a tire when on full pressure.

To alumapompano: tire pressure is ALWAYS specified as the pressure in a COLD tire. The tires are designed to handle the increase in temperature. That's why you have to check tire pressure on cold tires ONLY. If you don't know the real weight and don't have the derating curve inflate to the spec on the tire side wall at cold.

 

[oldjeep]

Jeeze - Goodyear makes the worst trailer tires you can currently buy. Every trailer tire mfg I have ever seen outside of goodyear says to inflate to max psi.

 

[kjsAZ]

well, when I looked for tires I got the values from several manufacturers including the Chinese Greemax (good tires by the way too)....... I only took Goodyear as an example because they have a PDF on their website with the numbers for all tire sizes. For the other companies I only have the numbers for my ST205/75R14 tires. Interestingly they were all identical except for one company but the difference was just 1PSI at my load.

 

[Mi duckdown]

I agree with kjsAZ as far as max load. Read the small print on tires The best thing you can do? IS pressure tires to Max PSI and and water the tires or concrete to see what the tire pattern is. Been trailering FOR 50 years.

 

[H20Rat]

Its a simple concept... The tire is designed to have a certain profile given the max psi and max load. That means you have a certain sidewall deflection and a certain footprint on the ground. Running max PSI when at less than max load is actually dangerous. It puts you outside the tire's operating envelope. You have far less footprint on the ground, and the sidewall is no where close to where it would be if you were at the intended max load/psi.

As duck mentioned above, do the water test on concrete. Max load/max psi on the tire, and then reduce the load and see what the footprint looks like. Chances are only the center of the tire is touching, which provides very little traction.

 

[Outsider]

Been trailering FOR 50 years.

So have I, and I've never worn a tire out from over-inflation. Out of alignment? Yep. Road hazards? Sure. Over-weight? Ooops. Old and dry-rotted? Uh, huh. The trailers I've owned that were 'bouncy' were not matched to the boat (one or two), or not snugged to the stop, the trailer was zipping down a road that one should never traverse above a crawl, or the driver was otherwise afflicted with short-term dumb ass syndrome.

For the OP: Most truck stops have split scales. Straddle two platforms with the trailer, unhook and move the tow vehicle, have the weight taken. You will then know total weight, tongue weight (close enough), axle weight, and weight of the boat if you know trailer weight (you should). If your total weight is within 30% of max trailer weight, inflate to max and get on with gettin on down the road, you gain little by playing musical inflation pressures. The 'correct' tongue weight is subjective, and should be the one that produces the tamest ride (likely between 5% and 15%, single axles on the heavier end). Heavier than required, you may find a rocking horse behind you. Lighter than required and it may start to sasche(?) down the road behind. There are some givens with this stuff, but having to refer to a slide rule before pulling out ain't one of 'em ...

 

[Outsider]

Been trailering FOR 50 years.

So have I, and I've never worn a tire out from over-inflation. Out of alignment? Yep. Road hazards? Sure. Over-weight? Ooops. Old and dry-rotted? Uh, huh. The trailers I've owned that were 'bouncy' were not matched to the boat (one or two), or not snugged to the stop, the trailer was zipping down a road that one should never traverse above a crawl, or the driver was otherwise afflicted with short-term dumb ass syndrome.

For the OP: Most truck stops have split scales. Straddle two platforms with the trailer, unhook and move the tow vehicle, have the weight taken. You will then know total weight, tongue weight (close enough), axle weight, and weight of the boat if you know trailer weight (you should). If your total weight is within 30% of max trailer weight, inflate to max and get on with gettin on down the road, you gain little by playing musical inflation pressures. The 'correct' tongue weight is subjective, and should be the one that produces the tamest ride (likely between 5% and 15%, single axles on the heavier end). Heavier than required, you may find a rocking horse behind you. Lighter than required and it may start to sasche(?) down the road behind and shy away from passing cars/trucks. There are some givens with this stuff, but having to refer to a slide rule before pulling out ain't one of 'em ...

 

[jayhanig]

That's what I thought !! If u set the tires at max psi when they are cold ..Wont they go over when they are hot?????? I think ill run then round 42 -43... I really think the main issues this time was I did not have the transom ties tight and most of all did not crank the bow of the boat into the bow stop... My old tires which are the same size as the new ones ..I never ran them at max psi which was 50 and never had an issue .......

The specification stamped into the sidewall of the tire refers to "cold pressure". So run it at the max cold 50 psi. Yes, the internal pressure will increase as the tire heats up but the manufacturer has already considered that in specifying a maximum cold pressure. Charle's Law, loosely described: In a closed vessel, pressure and temperature vary directly, IE, as one factor increases, so does the other.

 

[bigdee]

You run trailer tires at max psi - they should be set at 50psi

Yes,yes and yes. Max pressure ALWAYS and that is a fact and not an Internet myth. The most dangerous condition on a trailer are tires that flex. Anyone who has ever had that horrible feeling when a trailer starts oscillating from side to side and the only way to stop it from getting out of control is to come to complete stop knows what I'm talking about. Who cares about footprint on something being towed? The contact area per psi is still the same. 18 wheelers run max pressure on trailer tires loaded and unloaded AND are required to do so. Life is simple if you follow directions.

 

[bruceb58]

If you are no where near the max load of the tire, you do NOT need to fill them to max PSI.

http://www.goodyearrvtires.com/pdfs/rv_inflation.pdf

 

[JASinIL2006]

I see from those tables that running at less than max psi means your load limit is reduced, but I still haven't seen anything that says running at less than max psi is desirable, even at less than max loads. I'm not trying to be argumentative. I just don't see where it says that running below max is preferred.

 

[kjsAZ]

the internet will stay with that myth for quite some time (at least in North America. can't be found elsewhere) but at least one trailer manufacturer seems to know it now. Came across a Shorelander boat trailer and it had a tire inflation sticker on it (made for a specific boat). First time I have seen one! Low and behold the sticker says to inflate 5PSI less than what's on the tire sidewall as the trailer weighs less than the tires would be able to handle. I am sure he will be told that that's totally wrong and that he should inflate to full pressure. They also spec'd a lower possible tongue weight of 5-10% instead of 8-10% they had before.