Tire pressure

[Rweb]

Hey everyone, need a little bit of help. I just put new tires on the trailer that I purchase at Kal Tire. They are 10 ply tires. Now the sticker on the side of our trailer say to keep them at 65 PSI. Kal tire only put them to 60. I phoned over this morning to find out what to put in and they said there rated for 80 psi.... I am so confused. I ran 65 in the old ones, that's what our dealer had told us at the time. Could anyone offer some advice?


Thanks.

On a side note, thanks to everyone on this great forum, I have learned a lot of great tips, ideas, and valuable information.

[SAABDOCTOR]

I WOULD RUN THEM @ 80PSI. That presure will give the the max load. they will run cooler too. did you have them balanced too? if not go back and have it done. Your tires wheel bearing shocks and axles plus everything inside will thank you enjoy them.

[chuckster57]

I usually run trailer tires about 5 psi UNDER the molded max on the sidewall.

[Desert185]

Since SAABDOCTOR mentioned balancing...

The owner of the company that manufactured my car hauler told me to not balance trailer tires. Seems like bad advice, but then he's in the business. Opinions?

[gearhead]

Sounds like you had 8 ply tires originally, now you have 10 ply. The max air pressure is molded onto the sidewall of the tire. Usually fairly small print. It most likely is 80 PSI cold. Try to find on the back side of the wheel if it is rated for 80 PSI. If the wheel is good for it, I would run max air pressure, 80 PSI.
I can't imagine any mechanical reason to not balance tires on any trailer.

CWtheMan is all over it. Good info.

[Bob Landry]

The armchair engineers usually turn these tire pressure threads into discussions bordering on the rocket science level, but that isn't needed. Some people are constantly adjusting tire pressure to meet some published load/pressure table. I don't. I have gotten and still get the best longevity from running tires on all of my vehicles at the maximum rated pressure stamped on the tire simply because there is less rubber touching the road and they are going to run cooler.. There's no need, IMHO, to fill it with less to compensate for heat and higher pressures because th tire manufacturers have already factored that into the design. it works for me, YMMV.

[W.E.BGood]

Desert185 said, "The owner of the company that manufactured my car hauler told me to not balance trailer tires. Seems like bad advice, but then he's in the business. Opinions?"

The guy who owns the company that built my house told me not to change the filter in my furnace...now there's an "expert's" opinion if I ever heard one. .

Per my friendly local/been-in-successful-business-for-many-years chief tech, they recommend balancing any wheel operated at highway speeds, particularly if any weight point is over 1/2 ounce...like my TST507 sensors with brass high-pressure stems.

[TomHaycraft]

Originally Posted by Desert185

Since SAABDOCTOR mentioned balancing...

The owner of the company that manufactured my car hauler told me to not balance trailer tires. Seems like bad advice, but then he's in the business. Opinions?

This gets debated from time to time. For those who have been dogmatic about not balancing trailer tires, I have asked the question about how the physics of trailer tires are different than your TV tires. No one has been able to give me an answer. There has been isolated talk about centering the wheel on the balancer, that trailer wheels are not built centered on the center hole, but rather the studs? I can't quite wrap my head around that.

Regardless, we balance the wheels/tires on our TV because if we don't, we'd feel the vibration and be worried about integrity of the tires and suspension. Back to my question about physics. Same action is going on with the trailer tires, we just don't feel it going down the road.

Next question ... how much might an unbalanced trailer tire, lead to the self-destruction and blow outs so commonly discussed on these boards?

[Desert185]

I agree. Trailer tires should be balanced, but I didn't argue the point with him. Sometimes it just isn't worth the effort.

[kellydog98]

Simply put...Balanced and @80psi cold in the morning.

[CWtheMan]

The current Keystone Owner’s Manual does not address tire balancing. This is a quote from the owner’s manual, “Keystone RV does not administer the warranty for tires.” And it then gives all the phone numbers for their OEM tire suppliers.

So I checked out two of the references. The TowMax trailer tire warranty does not mention tire balancing. On the other hand, the Uniroyal Laredo - used as OEM by Keystone in the past - does mention balancing.

Those are two completely different designed tires and the LT has to perform well on steer and drive axles.

CW

[Rweb]

Thanks everyone for the replies. I will put 80 PSI in the tires.

I did check the sidewall of the tire, and it does also show 80 PSI. I attached the picture as well.

[CWtheMan]

Originally Posted by Rweb

Hey everyone, need a little bit of help. I just put new tires on the trailer that I purchase at Kal Tire. They are 10 ply tires. Now the sticker on the side of our trailer say to keep them at 65 PSI. Kal tire only put them to 60. I phoned over this morning to find out what to put in and they said there rated for 80 psi.... I am so confused. I ran 65 in the old ones, that's what our dealer had told us at the time. Could anyone offer some advice?


Thanks.

On a side note, thanks to everyone on this great forum, I have learned a lot of great tips, ideas, and valuable information.

The correct air pressure for the replacement tires depends on their design. Replacement tires need to provide - at the minimum - the load capacity the Original Equipment (OE) tires provided at 65 psi. (That's not my standard. That's the tire industry standard. Others may, and often do, dispute it. I do not).

Replacement tires for RV trailers become complicated when they are not the same size and design as the OE tires.

When replacement tires are of the same size but have a higher load range they will provide the same load capacity as the lower load range at the same psi. Here is where it gets complicated. Special Trailer (ST) tire manufacturer's always - maybe a little less than 100% - want that tire design to be operated at full sidewall pressures. Some may agree to a lower air pressure if it's recommended by the vehicle manufacturer. Another tooth puller situation.

Bottom line; Use the air pressure depicted on the ST tire's sidewall as correct when using that design as replacement for the OE tires. Use the air pressure necessary to equal the load capacity of the OE ties when the replacement tires are LT.

Always check wheelwell clearances. Always check the distance between tires - 1" minimum. Make sure the new tires do not exceed the load capacity of the rims. Make sure the replacement tires correctly fit the rim dimensions.

CW

[chuckster57]

Tire pressures are best checked "cold" meaning not driven on. If you took them to the tire dealer OFF the trailer, and then put them back on the trailer your fine to add air now.

[CWtheMan]

The subject of tire pressure always seems to be a controversial subject with many opinions.

There is a single source for the correct air pressure to be put into your tires. That’s the vehicle manufacturer. That’s right, the vehicle manufacturer. They built the trailer and by federal regulations they are directed to set the correct air pressure for the Original Equipment (OE) tires and put that information in the vehicle owner’s manual and on the federal certification label/tire placard.

Tire manufacturers provide load inflation charts to assist vehicle manufacturers with tire selection and load inflation. They often recommend increasing tire pressures beyond the vehicle manufacturers’ recommendations for load conditions but they never recommend tire pressures below a vehicle manufacturers recommendations.

The vehicle manufacturers’ recommended tire pressures are the minimum standard for all subsequent tire replacements, even plus sizing with like designs or other designs. The amount of air pressure recommend for the OE tires equates to the amount of load capacity the tire will provide with that air pressure. That load capacity is what the vehicle manufacturer has set as a minimum safety factor for the OE tires. The tire industry will not knowingly recommend replacement tires unable to provide that minimum load capacity.

Here is a current generic reference (4/2014) for Keystone trailers. Tire info starts on page 18.

http://www.keystonerv.com/media/8945...-19_-_1545.pdf

Here are a few references that support the statement about minimum load capacity.

http://www.tirerack.com/images/pdf/warranty/GY0513.pdf

http://us.coopertire.com/Tire-Safety...-Capacity.aspx

http://www.maxxis.com/sponsorship/au...ve-tire-safety

CW

[Festus2]

CW

While Keystone is federally regulated to set the pressure on OE tires and that pressure may be found in the manual or on labels and stickers attached to the RV, once the owner removes the OE tires and replaces them with something different, then Keystone is out of the picture. I can't see anyone checking with Keystone when setting tire pressure.

When I replaced ours with Maxxis, I referred to their data and recommendations as well as the wheel manufacturer not Keystone.

[CWtheMan]

Originally Posted by Festus2

CW

While Keystone is federally regulated to set the pressure on OE tires and that pressure may be found in the manual or on labels and stickers attached to the RV, once the owner removes the OE tires and replaces them with something different, then Keystone is out of the picture. I can't see anyone checking with Keystone when setting tire pressure.

When I replaced ours with Maxxis, I referred to their data and recommendations as well as the wheel manufacturer not Keystone.

The vehicle manufacturers’ recommended tire pressures are the minimum standard for all subsequent tire replacements, even plus sizing with like designs or other designs. The amount of air pressure recommend for the OE tires equates to the amount of load capacity the tire will provide with that air pressure. That load capacity is what the vehicle manufacturer has set as a minimum safety factor for the OE tires. The tire industry will not knowingly recommend replacement tires unable to provide that minimum load capacity.

That is a snip from my previous post. There are not many references on the WWW to support the industry standard for plus sizing tires. I do have one. I can post it but it requires in-depth reading and selections of the sections/portions of the pdf that fit the circumstances.

CW

On edit: This reference from Toyo may say it best.

http://www.toyotraining.com/toyo_fund_8.php

[CWtheMan]

I probably dig a little deeper into reference materials than most other tire researchers. To the best of my ability my posts about tire regulations and industry standards are factual. In other words, I don’t adlib my posts.

During the 2007 tire rules committee discussions prior to making the most recent changes to the manufacturers regulations (2007), it was determined that the federal certification label must reflect the actual tire size installed on the trailer at the time of first sale. By insuring that particular element of the regulation is consistent insures the buyer and all subsequent owners of the vehicle are aware of the vehicle manufacturers’ original tire selection.

Many first and second owners change tire sizes without regard for tire industry standards and use inferior replacements in size and load capacity. There are always tires that will meet the minimum requirements the trailer builder set with the OE tires. There are many reasons why owners will not play it safe and stay within the industry standards with replacement tires. I could describe many of them but it would just light a fire under those that have strong convictions about their own tire selections.


BA

p.s. When researching such documents as FMVSS 571.120 it will lead you to a chain of other FMVSS topics. Chief among them is vehicle certification. The reader of FMVSS regulations pertaining to RV trailer manufacturers must remember that those regulations were written for the vehicle manufacturer to abide to. Not the end user.

[ocbms]

As most of you have found, Each RV seems to have axles and tires that nearly matches the maximum gross of the RV. That being said I carry the max pressure, 80 psig at about 60 degrees. When the morning temperature is 80 degree, I have over 80 psig. I also use a tire pressure monitoring system, don't drive other 65 mph and slow down if the tire pressure approaches 100 psi.
So Far so good for 3500 Trailer miles.

[Desert185]

I'm attending a gathering with a number of trailers and motorhomes in attendance. Since I've been on this forum I've been more aware of tire brands and air pressures and I am surprised at the number of aging and obviously under inflated tires I see. One trailer looked like one of the tires was down to 25 PSI. I asked a friend about his Maxxis tires on his 5er and he mentioned they were the original tires on the eight year old trailer.

To read some of these tire threads one could become seriously motivated to rid themselves of the "china bombs", buy a TPMS and religiously maintain 80 PSI. Seeing how many don't pay attention to their tires and are obviously complacent due to not having issues could counter that motivation, but I still can't take the chance on my Power Kings. Right now, Maxxis 235/80-16's are in the future before the next big trip. Even at 100# less per tire I'll still have tires capable of the 326's GVW.