My tires are rated at 45 lbs max. Is that for the trailer only? When loaded, would there be less pressure as the weight would add pressure and make the tires be at 45 lbs?
Should I put in the 45 lbs with everything in the trailer?
Posted 2005-06-09 2:55 PM (#26282 - in reply to #26278) Subject: RE: Correct Tire Pressure
Expert
Posts: 1416 Location: sc
45psi all the time, loaded does not add tire pressure. also the tires should be checked when they(the tires) are "cold" (have not been drive)and technically tires should be checked at the coldest part of the day, as 10 degree change in ambient temp changes tire pressure by 1 psi. warmer increses tire pressure, colder decreses. yes they may go over the max psi a few pounds in the heat of the day but they will also go over under load. underinflation is the enemy, less psi = less ablility for the tire to cool itself = tire failure.
Posted 2005-06-10 12:50 AM (#26305 - in reply to #26278) Subject: RE: Correct Tire Pressure
Member
Posts: 39 Location: Covington, Louisiana
Yes you should run the maximum listed tire pressure in your trailer tires. The previous answer was correct and accurate. One of the leading causes of trailer tire failures is running with low pressure. Your tires can carry their maximim load only at the maximum listed pressure. Lower the tire pressure and you lower the load it can carry. On your truck keep the tire pressure at the truck manufacturer's recommended pressure (which may be less than the maximum pressure listed on the tire sidewall) The link below might be of interest about the importance of maintaining maximum rated tire pressures in your trailer tires. It is from the Carlisle Tire site but Goodyear and some other trailer tire manufacturers have the same recommendations. http://www.carlisletire.com/product_care/proper_tire_care_safety.pd...
Posted 2005-06-10 11:43 AM (#26328 - in reply to #26278) Subject: RE: Correct Tire Pressure
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Posts: 2689
I disagree with a couple of previous posts on this.
I think the advice on the Carlisle site is ABSOLUTELY WRONG and that running tires at their maximum pressure is not appropriate when they are not loaded to their maximum rating. This is likely to lead to a contact patch that is too short and a ride that is too harsh. Some of the effects are similar to putting wide tires on a truck and inflating to the same pressure as the stock size tire, i.e. a short wide contact patch.
I'm not saying that Carlisle makes a bad tire, but I think the folk who wrote that article need to check what they wrote with their company's tech people (-:
Sidewall flex is the primary contributer to tire temperature build up in an underinflated tire, a secondary cause is braking. For trailer tires there is not the heating due to acceleration as there is in the driven wheels of a car or truck. Heat typically "escapes" through the metal of the rim (one reason that some aluminum alloy rims are "better" than steel) and through the rubber. Sidewall flex is some inverse function of pressure. Pressure rises with temperature, so to some extent slight underinflation will warm the tire enough to increase the pressure to an acceptable level - not good, but acceptable.
Other tire manufacturer's sites recommend inflation pressures for each tire size by application and by load. I don't have URLs for them handy, but as I remember it Dunlop, Michelin and Goodyear ALL recommend less than max pressure for less than max load. You can probably find tables via their web sites.
BTW, a working definition of a COLD tire is one that hasn't been driven for more than a mile in the previous 3 hours (courtesy of GM).
I'd just add that if it has been standing on hot black tar in blazing sun for those 3 hours it might not be considered to be cold (-:
Posted 2005-06-10 12:09 PM (#26330 - in reply to #26328) Subject: RE: Correct Tire Pressure
Extreme Veteran
Posts: 326 Location: Palmdale, CA
I'll second what Reg said. My tires are spec'd at 80lbs but I typical run them with around 60-65psi. Reason, my trailer is never loaded to capacity and doesn't come close the maximum weight possible. Second, it gives a softer ride to the horses, third, my tires wear more evenly. At 80lbs, if you have no tire compression from the max weight, the tires will wear more in the center.
Posted 2005-06-10 1:18 PM (#26338 - in reply to #26278) Subject: RE: Correct Tire Pressure
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Posts: 1416 Location: sc
well im going to have to disagree with both of you, sort of. the max pressure advice given by the tire manuf. is given for the "rule" that being: the proper tire with appropriate load rating (GVWR / 3) for the trailer is in use. and yes most mauf. will talk with you about your load and recommended psi. but what you guys are refering to is the "exception", being "overtired" would be the only time acceptable to not runthe max psi. of course then youll need the manuf. inflation/load/psi chart to make sure youre not underinflated for your given load. and it gets difficult to be "overtired" with single tires on axles over 7000#.richb, i hope you have that(inflation chart) and arent just guessing, not saying you are of course. i do know what youre talking about though, i have tires rated to a GVWR 7000 tralier at 50 psi, but im only at 5200 on the axles loaded. i could use as little as 35 psi and still be within the load rating (GVW / 3).
Posted 2005-06-10 5:28 PM (#26356 - in reply to #26278) Subject: RE: Correct Tire Pressure
Extreme Veteran
Posts: 378 Location: Nebraska
Tires are made for many applacations. Pressure should always be what the vechile manufactures recommends, on my Titan trailer it is 80psi, on my f-250 it is 65psi rear and 45psi front
Posted 2005-06-10 6:16 PM (#26357 - in reply to #26278) Subject: RE: Correct Tire Pressure
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Posts: 2689
Here is more than most of us want or need to know about it; http://www.goodyear.com/truck/pdf/databook/loadInflation.pdf
I was a bit surprised to find the speed/load table, particularly table 2 where it shows that you need ever increasing pressure for DEcreasing speeds. This was counter intuitive until I considered that slow moving tires get low/no cooling air past them.
BTW, a lightly loaded tire inflated to it's maximum service pressure WILL be harsh and tend to Hop, though I really don't know whether or not it would cause handling problems on scored surfaces or bridge grids - possible.
The key sentence being, "Remember, the correct pressure for your tire is what the vehicle manufacturer has listed on the placard, NOT what is listed on the tire itself."
Although when a manufacturer decides to lower the pressure for ride improvement reasons tires CAN and HAVE blown at the recommended pressure, rolled the vehicle over and killed people. So I guess the vehicle manufacturers have to do their part PROPERLY !
Posted 2005-06-11 7:32 AM (#26369 - in reply to #26368) Subject: RE: Correct Tire Pressure
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Posts: 1416 Location: sc
The key sentence being, "Remember, the correct pressure for your tire is what the vehicle manufacturer has listed on the placard, NOT what is listed on the tire itself." Although when a manufacturer decides to lower the pressure for ride improvement reasons tires CAN and HAVE blown at the recommended pressure, rolled the vehicle over and killed people. So I guess the vehicle manufacturers have to do their part PROPERLY !
thats true, surely youre not refering to explorer/firestone are you? ive never seen a placard on a trailer though, which is why i hold to the max psi on the tire theory. of course this ass-u-mes the the appropritate tire is in use.
Posted 2005-06-12 12:26 PM (#26401 - in reply to #26369) Subject: RE: Correct Tire Pressure
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Posts: 2689
Originally written by chadsalt on 2005-06-11 7:32 AM
The key sentence being, "Remember, the correct pressure for your tire is what the vehicle manufacturer has listed on the placard, NOT what is listed on the tire itself." Although when a manufacturer decides to lower the pressure for ride improvement reasons tires CAN and HAVE blown at the recommended pressure, rolled the vehicle over and killed people. So I guess the vehicle manufacturers have to do their part PROPERLY !
thats true, surely youre not refering to explorer/firestone are you? ive never seen a placard on a trailer though, which is why i hold to the max psi on the tire theory. of course this ass-u-mes the the appropritate tire is in use.
Well, now that you mention it, I guess the explorer/firestone story MIGHT have relevance, though I forget the details and final outcome - if there is one yet.
I think there is a danger that even if "Joe Average Owner 3rd" sets tire pressures correctly he (or She, Josephine) is unlikely to maintain them at that pressure {beyond the first year of ownership}. A tire that has a max of 45 and should be inflated to 35 for a particular application is in danger of being set to 35 and allowed to leak down to 30 or less. If neglect is likely - and I think it is for 80 or more % of CAR owners - then the risks are lower if it is set to 45 and allowed to leak down to 35.
So I guess owner neglect needs to be factored in... present company, this readership excepted natcherly.
Posted 2005-06-12 12:55 PM (#26404 - in reply to #26278) Subject: RE: Correct Tire Pressure
Extreme Veteran
Posts: 366 Location: Albany, Oregon
Originally written by Jbsny on 2005-06-09 12:37 PM
My tires are rated at 45 lbs max. Is that for the trailer only? When loaded, would there be less pressure as the weight would add pressure and make the tires be at 45 lbs?
Should I put in the 45 lbs with everything in the trailer?
JS
JS,
Lots of reasearch went on here! and all valid points! The 45lbs PSI is for that tire only at that weight rating/tire. There are a lot of variables that will allow you to adjust the preasure. But in my opinion for what thats worth if you want to be safe with all the variables considered run no more than 45psi! You can't go wrong!
Correct Tire Pressure
