tire pressure

The friendliest place on the web for anyone with an RV or an interest in RVing!
If you have answers, please help by responding to the unanswered posts.
See posts with no answers
A

amigobob

Member
Joined
Jan 6, 2008
Posts
7
I have goodyear G670 275/80/22.5 tires on my coach. I weighed it on a truck scale and got 10,300 lbs on front axel and 18,680 lbs on rear axel . stupid question is what should my tire pressures be?  Thanks for your help.  Amigobob
 
According to the Goodyear RV inflation table, the front tires should be run at 90psi and the rear duals at 90psi, both at the minimum for that tire.  You can get the inflation table from the GY web site at this page.
 
I have been searching past posts to get an answer on proper tire inflation for my 5er.  In your answers to other posts several of you have recommended PSIs to operate at.  My question is :  Are the manufacturers PSI you are talking about the one on the label that is affixed on the trailer or the maximum PSI found on the sidewall of the tire?  My 5er has 65PSI on the tire inflation tag affixed to the trailer and 80 PSI  (max) on the tire?  So when I read maintain 5 PSI over,  which one should be used?  Thanks Tom
 
Rules for trailers are same as any other vehicle.. Two pressures all but guarenteed to be WRONG are the pressure on the sticker and the pressure moulded into the sidewall of the tire

the only way to get the proper pressure is to park the wheel on a scale (one scale per wheel, note duals are one wheel) and visit the tire maker's web site and find out the proper pressure for the tire you have. FOR THE LOAD THE WHEEL IS CARRYING

NOTE: May be different for each wheel.
 
John In Detroit said:
NOTE: May be different for each wheel.
Click to expand...

Always inflate the tires on one axle to the same pressure.  If the weights are different, use the higher weight to determine the inflation pressure.  I would treat tandem axles as a single axle and inflate all tire to the same pressure, but the trailer experts may have more to say on that situation.
 
The psi shown on the tire sidewall is the pressure required to support the tire's maximum carrying capacity. It will say xxxx lbs at yy pressure. This psi is generally well in excess of what is required or desired unless the tires were not sized well for the job they are doing.

The psi on the trailer tag/sticker will be the pressure needed to support the trailer at its maximum rated weight, which is usually the axle's GAWR. That's a "safe" pressure, as long as you are not exceeded the trailer GVWR (and you should not be).  Use the sticker psi until you get the trailer weighed and can look u p the actual weights in the tire manufacturers inflation tables and use the correct psi for the actual weight. We usually recommend got 5-10 psi above the inflation table, to allow for some growth in the actual weight. Like people, trailer tend to gain weight between diets.  :D
 
RV Roamer said:
The psi shown on the tire sidewall is the pressure required to support the tire's maximum carrying capacity. It will say xxxx lbs at yy pressure. This psi is generally well in excess of what is required or desired unless the tires were not sized well for the job they are doing.
Click to expand...

Gary,

If I remember correctly, A-Weigh-We-Go several years ago published the results of a thousand or so weighings that they had done over the previous several years. They indicated that something like 65-70% of the rigs which they had weighed were over weight at least one wheel position or perhaps one axle. To me this means that one should go with the maximum on the tire when in doubt and it is possible that one or more wheel position "could be" over weight. Use this pressure until the actual wheel weights are known and then air up the tires to what the manufacture recommends.  If your rig is empty or partially loaded, the sticker ratings may be OK.

The pressure rating on the tire will give you a somewhat harsher ride but unless you are over the GVRW your tires will not be under inflated.

Richard
 
Go with the max on the tire until you are absolutely sure you can run at a lower psi for the axle weight.
 
They indicated that something like 65-70% of the rigs which they had weighed were over weight at least one wheel position or perhaps one axle.
Click to expand...

My recollection is that those 65% of "overweight' rigs were those whose actual weight exceeded the tire pressure at the time of the weighing. In other words, their tires were underinflated but not over the tire max spec.  However, RV Safety & Education (RVSEF,  previously known as Aweigh-we-go) reported in the July, 2007 FMCA magazine that 10% of all RVs weighed exceeded a tire rating. Here is their exact statement:

One RVSEF finding is that 10 percent of the RVs its teams have weighed exceeded a tire rating without exceeding the GAWR.
Click to expand...

For the entire article, see RVSEF.

So yes, I guess the safest course of action is to go with the tire max. However, even that is not enough if the actual weight in fact exceeds the tire rating.

Nearly all RV manufacturers are inflating to the pressure they indicate on the FDOT rating plate by the driver seat.
 
Richard

IIRC, your recollection is correct. The A-Weigh-We-Go quote related to overweight AND underinflated tires. There is a major issue with tires not regularly checked and properly aired up.
 
Caution is advised if inflation tires to the maximum pressure found on the sidewall.  This Maximum pressure can be in excess of what the wheel is rated for.  Seen this a few times.
 
Ned said:
Always inflate the tires on one axle to the same pressure.  If the weights are different, use the higher weight to determine the inflation pressure.  I would treat tandem axles as a single axle and inflate all tire to the same pressure, but the trailer experts may have more to say on that situation.
Click to expand...

Not a trailer expert but I am opinionated none the less.  Trailers have no steering wheels and no drive wheels.   What they have are simple dead axles, oxcart geometry if you would.   The tire must bear the dead vertical load of the trailer's weight.   Because the axles are simple the tires most bear considerable lateral twisting of the sidewalls.  Just observe a trailer's tires in a short radius 90? turn in your drivers side mirror.   They assume remarkable shapes as they twist around the turn.

To me this demands good sidewall strength and load bearing capacity. Ride smoothness is a minor consideration. That spells ST or LT tires at maximum inflation -- the number printed on the sidewalls.

.
 
Hmmm. Max inflation makes the sidewall stiffer, but I'm no sure it gets any stronger. One could even argue that max stiffness makes the tire less able to contort as it does in sharp turns.  I would have to assume that the tire manufacturer has considered sidewall flex and loading when they establish the psi vs loading tables. Now, what is it they say again about ASSuming things???  ;)
 
You must log in or register to reply here.

Latest posts

Members online

Total: 803 (members: 31, guests: 772)

Forum statistics

Threads
132,122
Posts
1,390,689
Members
137,839
Latest member
Hagen Joshua
Back
Top Bottom