tire pressure

[Scott'n'Wendy]

I've never understood the "cold" tire inflation number on the tire. Cold for me on an August morning in Arizona may be 90°F. But a person in West Yellowstone may be at 40°F. If we both inflate to 80 PSI, our tire pressure will be quite a bit different if I drive to a cooler climate, or they drive where it's warmer. I wish the tire manufacturers would specify an actual temperature. For example, 80 PSI at 70°F. And then you could use a compensation table to properly inflate the tires.

I believe the tire manufacturers take that into account and the tire can handle the added pressure no matter where you start and where you end up. But you do need to check cold inflation each morning if you are changing regions.
I don't know because the tire manufacturers don't put it out there, but I'll bet a tire with a max cold inflation pressure of 80psi can probably handle 105-110psi. So, as long as you monitor your cold (ambient) pressure you will be good.
I don't air down my tires to match whatever I weigh because I would never be able to do any better than guess at my actual tire loading. I don't start each day at a CAT scale. And unlike some other people I can't tell any difference in towing experience between 65psi and 80psi. My butt accelerometer has a large deadband..lol

[Scott'n'Wendy]

I run what the manufacturer sez for the weight. Empty I rum 35 PSI.

I run 35psi on my snowmobile trailer......

I'm curious though. Got a pic of what tires inflated to 35psi look like on a 15,000# Solitude?

[Crespro]

I believe the tire manufacturers take that into account and the tire can handle the added pressure no matter where you start and where you end up. But you do need to check cold inflation each morning if you are changing regions.
I don't know because the tire manufacturers don't put it out there, but I'll bet a tire with a max cold inflation pressure of 80psi can probably handle 105-110psi. So, as long as you monitor your cold (ambient) pressure you will be good.
I don't air down my tires to match whatever I weigh because I would never be able to do any better than guess at my actual tire loading. I don't start each day at a CAT scale. And unlike some other people I can't tell any difference in towing experience between 65psi and 80psi. My butt accelerometer has a large deadband..lol

Hi,

I tend to agree with Scott and run at near max cold pressure. My pressure for the "G" rated tires is usually about 106 PSI cold and 124 to 128 PSI warm. The rated pressure for a 310GK with about 3,100# per tire and a 4,080# max tire rating is about mid 80's, so this is well above the minimum.

This is anecdotal evidence, but I suspect there are 100 tire failures for underinflation for each failure due to overinflation. I think running near the top rating both answers Jim's temp question and is safer.

Best,

Charles

[Skilletface]

I run what the manufacturer sez for the weight. Empty I rum 35 PSI.

X-2, love these discussions because in the end I’m not sure an OP’s question gets answered. Here is one way to consider what is the proper inflation psi “ for your rig “ not mine yours.
Get a loaded axel weight, refer to manufacturers psi recommendations for the weight to be supported, adjust recommended psi up approximately 10 - 15 % to account for temperature fluctuations and generally try to accomplish this when your region is + or - 10 degrees of your average temperature. Cold psi is generally accepted as first thing in the morning before being moved.
Then over time monitor tread wear with a tread wear gauge at the wear indicators found in the tire tread. ( That is almost a tongue twister )
The goal here is to get as much the tread face to contact the ground evenly as possible, more ground contact = better traction, over and under inflating = less traction and abnormal tire wear
In closing, going by the manufacturer’s recommendation and adding 10 - 15 % will take care of temperature differences down to just above freezing and just below triple digit temps.

And I’m back out!

[Cate&Rob]

As mentioned earlier in this thread, weight by axle will not tell you the significant side-to-side weight difference on many towable RVs. My Reflection 303 has an 800 lb difference and a 337 is more like 1000 lbs. I run label pressure which happens to be the same as tire side wall spec. This cold 80 psi will typically climb into the mid 90s when towing. If this was over pressure for the light side of the trailer, I would expect to see the centre of the tire tread wearing faster. There has been no evidence of this across three sets of tires and many thousands of miles.

Rob

[BlueSky]

Happy New Year!
I have the H rated Coopers on my Solitude which I inflate to 120 psi cold which provides significant extra load capacity above what I need. I do that to minimize the impact of interply shear on the tires and to maximize the life of the tire. I have about 15000 km on them and the wear looks good so far.
When I bought our Solitude I scaled the truck and trailer in multiple scenarios…..lightly loaded through to loaded to the GVWR. This included each RV axle (front and rear) as well as the CS and SS axle weights. On ours there is about an 800 lb difference between CS and SS. The time at the scale was well worth it for me.

[Jkwilson]

As mentioned earlier in this thread, weight by axle will not tell you the significant side-to-side weight difference on many towable RVs. My Reflection 303 has an 800 lb difference and a 337 is more like 1000 lbs. I run label pressure which happens to be the same as tire side wall spec. This cold 80 psi will typically climb into the mid 90s when towing. If this was over pressure for the light side of the trailer, I would expect to see the centre of the tire tread wearing faster. There has been no evidence of this across three sets of tires and many thousands of miles.

Rob

Good data point Rob. I hadn’t thought before about that being a test of how higher inflation pressure does or doesn’t affect tire wear.

I’ve had vehicle alignment issues and bent trailer axles damage tires before, so I check my tire tread with a gauge a few times a year. I test each edge groove and the center groove. Record them and compare to each other and my last measurement. Usually check over the winter while piddling in the shop, but with camper, truck and boat I often check before and after longer trips. Some of it just curiosity when I do that. Run it 2300 miles and see how much tread wear!

My boat trailer wears the right front just a little more than the other three, so when I service the bearings, I move it to another spot.

But back to the RV, I do not see any notable uneven wear side to side. Occasionally there will be a small deviation either within a tire or between tires, but it doesn’t generally repeat year to year. On my previous set of tires, my fronts or rears (Can’t recall which way) were slightly more worn than the others, but I suspect it was greasy brakes, and I rebuilt all four at the same time I changed tires which seems to have corrected that.

[Scott'n'Wendy]

X-2, love these discussions because in the end I’m not sure an OP’s question gets answered.

LOL..threads like what's the best tow vehicle......... or what oil should I use......or what's the best grease to use in my bearings......come to mind

[ThePowells]

If I can catch the right time, I will do a side to side and have exact weights on each wheel. I don't want to keep paying for reweighs on a CAT scale, especially with other drivers wanting to use it. My pressures when towing are above what the MFG chart recommends. Hopefully in the near future I can complete a complete weigh and will post it on youtube. The low pressures are about spot on for bobtail. The actual /32 measures are perfect with the exception of the LF as I have identified an alignment issue there. The problem with the single reweighs is much simpler with a spotter to splits the axles. If I can perform it as I want, most trucks will be avoid this set of scales.

[howson]

If I can catch the right time, I will do a side to side and have exact weights on each wheel. I don't want to keep paying for reweighs on a CAT scale, especially with other drivers wanting to use it. My pressures when towing are above what the MFG chart recommends. Hopefully in the near future I can complete a complete weigh and will post it on youtube. The low pressures are about spot on for bobtail. The actual /32 measures are perfect with the exception of the LF as I have identified an alignment issue there. The problem with the single reweighs is much simpler with a spotter to splits the axles. If I can perform it as I want, most trucks will be avoid this set of scales.

Jerry,
An option is the method Cate&Rob showed us a few years ago (reposted below).



For full context, see https://gdrvowners.com/towing-and-hi...g-helpful-info

Howard

[Jlawles2]

Howard,

With some of the reviews on those weigh systems, I'd be a bit cautious and suggest using a bottle jack instead to minimize side loading of the scale.

This is after watching BTBRV and the issues he had with the one he was using. He was even using the tongue jack to raise and lower getting different results each time.

[ThePowells]

howson Actually my plan is to use a set of state scales and weigh completely on the scales, then reweigh with left side on the same scales and right side off, then again reweigh with the right side off. HOPEFULLY the next move will be in the next month and I can use the platform scales since they are usually closed at the time I usually go through going to my home away from home.

[Jlawles2]

Too bad they do not make these in a reasonable price range for the axle loads trailers have: https://www.summitracing.com/parts/pro-67644

[Cate&Rob]

In figuring out how to get repeatable weight measurements using my Sherline scale (process in the post that howson Howard linked) I learned how important it was to keep the trailer at exactly its towing ride height. Tipping the trailer, even slightly, from one side to the other, changed the measurements significantly. Unless the surface beside a commercial weigh scale is exactly level with the scale platform, weighing just one side of the trailer this way may be less than accurate. It would be interesting to learn whether the two sides sum to the total weight as measured by the same scale.

Rob

[Jlawles2]

If these were not so expensive, someone could make the cost back quickly at a couple of rallies weighing rigs with a couple of them and some 3/4" plywood.

http://www.scaleline.com/haenni_wheel_weigher.htm Note that is the price each. We have a set of 4 at work, easy to move and 2 fit in a pelican box.