Cooper Tires Chart--load verses psi

**ForBruce** · 03-14-2023, 06:39 PM

i have enclosed a chart for the tires that come on the solitude.

but i do have questions concerning it .

My trailer loaded has a rear wheel weight of 13,460 lbs . If i divide by 4 tires the weight on each is 3,365

But we know that is not true; as the left and right side are not the same .

The refrigerator weighs about 425 loaded and the stove is about 150lb. The pantry loaded is about 150 lbs..... all together 725lb extra on passenger side of the trailer.

So What tire pressure ,according to the chart below would you set the tire to and why ?

**ajg617** · 03-14-2023, 07:03 PM

Interesting question. As delivered, ours is 600lbs heavier on the street side to start with empty. Add pantry items, dishes, etc. and that goes up. The washer/dryer is on the curb side and I try to load heavier pass-thru items on the curb side as well but I know I'm still heavy on the appliance side. I've been keeping all at 125 cold. What I noticed during travels last year was that curb side tire pressure and temps were higher at interstate speeds than street side. I suspect some of that is due to slight crown in the roadway but really not sure.

**Hoopy Frood** · 03-14-2023, 07:06 PM

Well, you definitely got the tires to handle the weight.

I think I would start at max inflation pressure, put things on the countertop, preferably non-breakable, and see how they ride. And also consider how the trailer feels over rough roads and bridge approaches. If things get thrown around I'd lower the pressure until things started riding better and the trailer towing felt better. You may find the it tows just fine at max pressure.

**Calbar** · 03-14-2023, 07:39 PM

Originally Posted by ForBruce

i have enclosed a chart for the tires that come on the solitude.

but i do have questions concerning it .

My trailer loaded has a rear wheel weight of 13,460 lbs . If i divide by 4 tires the weight on each is 3,365

But we know that is not true; as the left and right side are not the same .

The refrigerator weighs about 425 loaded and the stove is about 150lb. The pantry loaded is about 150 lbs..... all together 725lb extra on passenger side of the trailer.

So What tire pressure ,according to the chart below would you set the tire to and why ?

I have been running my tires on my 378MBS at 110PSI. I did a calculation on axle weight with one side being heavier and then added 25% margin to come up with the 110PSI. I prefer to err on the safe side and if there is more than 4400 lbs on one tire then I will have bearing issues as well.

Rob

**Gronk1** · 03-14-2023, 08:34 PM

[QUOTE=ajg617;472739]Interesting question. As delivered, ours is 600lbs heavier on the street side to start with empty. Add pantry items, dishes, etc. and that goes up. The washer/dryer is on the curb side and I try to load heavier pass-thru items on the curb side as well but I know I'm still heavy on the appliance side. I've been keeping all at 125 cold. What I noticed during travels last year was that curb side tire pressure and temps were higher at interstate speeds than street side. I suspect some of that is due to slight crown in the roadway but really not sure.[/QUOTE]

The temps & pressure on mine will increase on whichever side the sun is shining on.

**ajg617** · 03-14-2023, 08:43 PM

[QUOTE=Gronk1;472751]

Originally Posted by ajg617

Interesting question. As delivered, ours is 600lbs heavier on the street side to start with empty. Add pantry items, dishes, etc. and that goes up. The washer/dryer is on the curb side and I try to load heavier pass-thru items on the curb side as well but I know I'm still heavy on the appliance side. I've been keeping all at 125 cold. What I noticed during travels last year was that curb side tire pressure and temps were higher at interstate speeds than street side. I suspect some of that is due to slight crown in the roadway but really not sure.[/QUOTE]

The temps & pressure on mine will increase on whichever side the sun is shining on.

That also but last year at least half of our travel days were in rain or cloudy weather.

**huntindog** · 03-15-2023, 09:53 AM

Originally Posted by ForBruce

i have enclosed a chart for the tires that come on the solitude.

but i do have questions concerning it .

My trailer loaded has a rear wheel weight of 13,460 lbs . If i divide by 4 tires the weight on each is 3,365

But we know that is not true; as the left and right side are not the same .

The refrigerator weighs about 425 loaded and the stove is about 150lb. The pantry loaded is about 150 lbs..... all together 725lb extra on passenger side of the trailer.

So What tire pressure ,according to the chart below would you set the tire to and why ?

I have those tires and my momentum is a tripple axle. i set them at 125. i am not anal about though if my tpms is happy, so am i. those cooper are stout. almost like a semi tire. semis do not adjust their tires for the and neither do i

**Hoopy Frood** · 03-15-2023, 09:57 AM

Originally Posted by huntindog

I have those tires and my momentum is a tripple axle. i set them at 125. i am not anal about though if my tpms is happy, so am i. those cooper are stout. almost like a semi tire. semis do not adjust their tires for the and neither do i

While that may be true, most semi drivers are not concerned how the contents of their trailer ride.

And they have a few more tires to mess with too. And likely no TPMS to help them be aware of what their tires are doing. RV'ers vs semi drivers is kind of apples and oranges comparison.

**ForBruce** · 03-15-2023, 11:19 AM

Originally Posted by Calbar

I have been running my tires on my 378MBS at 110PSI. I did a calculation on axle weight with one side being heavier and then added 25% margin to come up with the 110PSI. I prefer to err on the safe side and if there is more than 4400 lbs on one tire then I will have bearing issues as well.

Rob

exactly---i run mine at 110 -112lb cold.. glad to know i am not the only one

**Riverbug** · 03-15-2023, 11:47 AM

Back to the original question. If you were going to set the PSI based on the table of recommended inflation, you would know the actual weight of each tire (think Smart Weigh through Escapees), then you would set all tires to the highest pressure required for the load. So in your example, if the heaviest side is 4,000#, then you would set all tires to 100 PSI (or what the table says related to 4,080#). Always rounding up, not down. But as you can see from the responses, most people ignore those tables and go based on what "feels" right, what they've been told or heard, or whatever.

I'm in that same boat. Based on my 22MLE a year ago I did the Smart Weigh thing on all individual tires (which was well worth it in my opinion). But with those weights I set my PSI based on the manufacturer's inflation table for Goodyear Endurance 205/75/R14. The tires had a max pressure of 65psi. But the recommended PSI for my highest weight (slide side) was 35PSI. So, I set them all to 35PSI. I mean, that's what the manufacturer recommends and that's the way you're supposed to do it right? By the time I drove halfway across the country I noticed that I had scuffing on the sidewalls as if the tire was rolling onto the sidewalls and I had one flat. I can't assume the flat was due to inflation necessarily. Anyway, I went back to running at 60PSI and didn't notice the sidewall scuffing anymore and just "felt" like it was a more appropriate pressure. So now I just go a bit under max PSI and don't think too much about it. It was all fine after that. Plan to do the same with the new trailer, but looking forward to getting it and the new truck weighed at each tire. I just find it interesting.

Take that for what it's worth.