Proper trailer tire inflation

[QC]

Re: Proper trailer tire inflation

UIS and The Crazy One,<br /><br />Thanks for clearing up your respective logics. Now that I think it through with your latest comments I am completely on board with your recommendations. The semantics of "inflate to" and "max load at" make sense too.

 

[cp]

Re: Proper trailer tire inflation

Guys - I'm not trying to tell anyone to run their tires underinflated, just the opposite - tires need to be inflated sufficiently to support the load placed on them. That's what the Goodyear chart says: "Tire load limits (lbs) at various cold inflation pressures..." Of course this being the USA, each individual is free to do as he sees fit. <br /><br />I think one of the benefits of forums such as this is the general increase in knowledge stemming from open objective discussion. So with all due respect to the learned opinions of others and at the risk of getting flamed, let me just say that I spoke with a Goodyear dealer who confirmed that the chart gives the minimum inflation required to support the listed load per tire (divide total load by number of tires to get individual tire load, hence minimum inflation per tire). So, as recognized by some of you, the total weight of the boat and trailer must be known if the tire is to be inflated to something less than max, although inflating it to the max is eminently acceptable. For those who don't know the weight of their rigs or who have barely enough tire, certainly they should inflate to the max (and pray that's enough). By the way, look closely at your tire sidewalls...nowhere does it say to "inflate to 50 psi". What it says is "Max load 1760 lbs at 50 psi cold" which is not a requirement to inflate to 50 psi, just a statement that the tire can carry max load of 1760 pounds when inflated to 50 psi.<br /><br />I agree that, as many have said, most tire failures other than physical damage from punctures, etc. are due to underinflation (psi too low for load) or overloading. I've towed for over 29 years with zero failures on tires inflated less than max but more than enough to carry the load. My 5420# boat/trailer runs on four load range C tires inflated to 40 psi (4x1530#=6120#) with no problem. Proper tongue weight prevents any sway and I've never had such problems, even when someone-with-less-than-full-mental-capacity cuts in front of me and forces a panic stop. At least in my experience it isn't an absolute necessity to inflate tires to max psi, but it is an absolute necessity to inflate sufficiently to carry the load.<br /><br />Lots of good discussion. Peace and Aloha.

 

[Silvertip]

Re: Proper trailer tire inflation

PC - you said, "By the way, look closely at your tire sidewalls...nowhere does it say to "inflate to 50 psi". What it says is "Max load 1760 lbs at 50 psi cold" which is not a requirement to inflate to 50 psi, just a statement that the tire can carry max load of 1760 pounds when inflated to 50 psi."<br /><br />You are half right and half wrong. I checked four trailers in the immediate area. Two specify "inflate to" and two indicate "max load xxxx @ xx PSI cold". Three of the four had GoodYear tires and I don't remember what the fourth had but it was an off-brand.

 

[QC]

Re: Proper trailer tire inflation

I just checked and my Carlisles say Max Load at . . .

 

[cp]

Re: Proper trailer tire inflation

Didn't cite above that my sidewall inspection showing the "Max load xxxx lbs at yy psi cold" statement was based on looking at Goodyear Marathon, Delta, and Carlisle trailer tires and Michelin, Goodyear, and Uniroyal car tires. UIS - Looks like some manufacturers may not be fully complying with tire marking requirements. 49 CFR 571.119 section 6.5 states that "...each tire shall be marked on each sidewall with..." "(d) The maximum load rating and corresponding inflation pressure of the tire, shown as follows: Max load _____ lbs at _____ psi cold."<br /><br />Oh well, wouldn't be the first time a company didn't comply with government regulations. As long as we all have enough psi in our tires to support our boat/trailer weight, we're all good to go. <br /><br />Aloha

 

[Silvertip]

Re: Proper trailer tire inflation

I don't know how old 49CFR 57.119 is but I suspect the age of the tire may have something to do with this issue. My new trailer does specify max load @ xx PSI. Regardless -- it doesn't alter my position.

 

[polyb]

Re: Proper trailer tire inflation

Most trailer tyre failures are due to underinflation and overloading. Obviously the load capacity is related to the pressure. Now therefore if you are under the maximum load you can get away with less pressure. As others have mention they are benifits in this eg less bouncing around.<br />There is a surefire way of working out the optimum pressure. Fisrt start with the pressure you think will be adequate (going by the sidewall load rating). Take a note of the cold pressure of the tyres. Then go for a good drive, preferably at highway speed. The idea is to warm the tyres to full operating temp. Then re-measure the pressures. They should have risen by 4 psi. If the change is less then you can get away with less pressure. If they have risen by more than 4 psi then they are overheating and you need more pressure. If in the second case you have started with the maximum pressure then the tyres are not up to the job.

 

[jspitzer]

Re: Proper trailer tire inflation

as alot of you pointed out you will get sidewall flex. and if you have looked at tire you will notice that the sides are tinner than the bottom. I fill them to the max not only will your tire handle better but it will last longer. lowwer psi willcup your tires and cause them to wear improperly.

 

[BillP]

Re: Proper trailer tire inflation

Underinflation is way worse than filling to max pressure. Max gives treadwear in the center, less heat, less sway and more load capacity. Underinflation gives treadwear on the edges...plus more heat, more sway and lower load capacity. Why take chances on underflating?

 

[dajohnson53]

Re: Proper trailer tire inflation

Just bought a trailer tire from a reputable tire store because one of the two I bought three years ago really is worn poorly (uneven with near bald spots) and I have a long, remote trip coming up. I haven't really put that many miles on the tires, and the other tire is evenly worn and has plenty of tread, probably will finish next season. Because of the odd wearing and this discussion, I asked them about inflation pressure (I thought the worn tire had been neglected by me in the pressure). They said: inflate to the max pressure indicated and don't load above the stated load limit per tire. Two simple facts: inflate to max pressure, don't overload. There was no option for lower tire pressure for lower loads.<br /><br />Looking at the tire they said inflation pressure could have been a problem, but the tire guy and my trailer mechanic (who does a lot of trailer work from moving vans to snowmobile trailers) both told me that it could just be the way it is with my trailer - they feel boat trailer tires can wear poorly sometimes even with properly balanced and inflated tires because of the relatively crude suspension on a boat trailer - no shocks, difficult or impossible to finely align. I'll do what I can to correc the "problem", but the bottom line is that I'll probably have to replace that side tire more frequently than the other, or rotate side to side every couple thousand miles. For me, it's probably the difference between needing new tires every three years instead of every five which really isn't that big of a deal in terms of "boating bucks" (two tires cost 1 1/2 boating bucks).

 

[craze1cars]

Re: Proper trailer tire inflation

Another good alternative for even tire wear in such a situation is to rotate all 3 tires on your trailer (assuming single axle), not just the two.<br /><br />You'll get max treadwear life, and your spare will not become neglected or dry-rotted from sitting there unused, which has the potential to render it useless when you really need it.

 

[dajohnson53]

Re: Proper trailer tire inflation

Yea, Craze1cars - I'll probably do that if/when I get three new tires at the same time. Right now, the spare is a decent leftover from a previous change - good enough for a couple hundred miles forced duty if needed, but not good enough to put in the rotation.

 

[KRS]

Re: Proper trailer tire inflation

Max PSI means Maximum.... If you choose to go up to that absolute maximum pressure, be sure you don't go over it.