Originally Posted by veraken
To determine what the right tire pressure is for you, you need to weigh your MH. Load your MH as you would for travel, fill you gas and water tanks and then get your MH weighed.
If you can't do 4 corner weighing, this is the procedure to follow:
1. Weigh the coach axles
2. Add 5% to account for possible uneven weight side to side.
3. Divide by the number of tires on each axle.
4. Look to tire chart for your brand to find tire pressure.
5. Add 5 psi for safety
Veraken: So I'm going to try and do the math here and hopefully this example will help everyone.
My tires I bought in 2014 - Hercules H-901 235/85 R16.
Weighed Front Axle:4960 plus 5% (248) = 5208 lbs *Weighed at Flying J
Weighed Rear Axle: 10660 plus 5% (533) = 10893 lbs *Weighed at Flying J
Two tires on front - 5208/2 = 2604 lbs per tire
Four tires on back - 10893/4 = ~2723 lbs per tire
Hercules Tire Inflation Chart:(Chart goes to 110 PSI)
@ 85 PSI - 3170 Single, 2885 Dual
@ 90 PSI - 3300 Single, 3005 Dual
@ 95 PSI - 3415 Single, 3085 Dual
@110 PSI - 3760 Single, 3415 Dual
So according to this I only have the following amount of weight to play around with:
@85 PSI on Front 3170 minus 2604 = 566 lbs additional each side
@90 PSI on Front 3300 minus 2604 = 696 lbs additional each side
@95 PSI on Front 3415 minus 2604 = 811 lbs additional each side
@110 PSI on Front 3760 minus 2604 =1156 lbs additional each side
@85 PSI on Rear 2885 minus 2723 = 323 lbs additional each side? Or do I double that?
@90 PSI on Rear 3005 minus 2723 = 563 lbs additional each side? Or do I double that?
@95 PSI on Rear 3085 minus 2723 = 723 lbs additional each side? Or do I double that?
@110 PSI on Rear 3415 minus 2723 = 1383 lbs additional each side? or do I double that?
I JUST did the math today. Prior to this (Like a total of 3.5 years now) I've been running 90 PSI in the front and 85 PSI in the back as I was guessing.
I'm surprised by the small amount of extra weight I can carry. I'm also nervous about inflating the tires to 110 PSI! Especially since the chart I found on IRV2 here seems to be cut off and I don't know what those letters mean in the parenthesis. 3042(E), 3760(G), etc.
Here's the link: http://www.irv2.com/forums/f258/less...-199994-4.html
One thing I will have to check on is what the max pressure is that is stamped on the side of the tire. I just don't have that info at the tip of my fingers.
**Update - Actually I found that info, see info at bottom
So there you go. Looking at this I might bump my tire PSI on the all the tires up to 95. But again, I guess that depends on what the max is stamped on the tire.
PS: Did a quick search and found these numbers for the H901:
Single Max Load @ Cold Inflation Pressure: @110 PSI - 3760 lbs
Dual Max Load @ Cold Inflation Pressure: @110 PSI - 3415 lbs
Per this site:https://www.herculestire.com/tire-details/Hercules/H-901%20LT
Wish I could talk with a Hercules guy.
**Update: Found this email: firstname.lastname@example.org
, and this phone number:1.844.432.9729