Gettin new tires

[boatman]

Does anyone know of a link to a chart or something that shows what pressure tires should be inflated to for a given weight. I am going from load range D to load range E tires so I am thinking that I will not need to inflate to max cold pressure?

[Dave_Monica]

Here's a link to a chart on Michelin's site... Michelin North America RV Load & Inflation Tables

Dave

[wyo700]

In my experiences working in tire shops for about 8 years no matter truck, car, or rv tires. If its a p rated which is passenger tire the max inflation pressure is either 35, 41, or 44 psi never more. Every load range c tire was max pressure of 50 psi. Every load range d tire was 65 psi max pressure and every load range e tire was 80 psi max pressure. From everything I can remember they were all the same.

[thebrakeman]

I understand your point. That being if I needed load range C for XXX weight, and I get load range D, I can leave them underinflated and get the same performance.

To answer your questions, I do not think you will find such a chart. The scale probably is not linear, so it's not that simple. What's more, a D-tire at 50psi may wear faster than a C-tire at 50psi, even though they may or may not support the same weight.

Just inflate them to the maximum, and be done with it. If they are rated higher, then perhaps you don't have to be a judicial in keeping them fully inflated. But I would not intentionally under-inflate them.

[BarryD0706]

Originally Posted by thebrakeman

...
To answer your questions, I do not think you will find such a chart. The scale probably is not linear, so it's not that simple. What's more, a D-tire at 50psi may wear faster than a C-tire at 50psi, even though they may or may not support the same weight.

Just inflate them to the maximum, and be done with it. If they are rated higher, then perhaps you don't have to be a judicial in keeping them fully inflated. But I would not intentionally under-inflate them.

What are you talking about?!? Dave have a link to the chart in post #2. Over-inflation of tires causes them to wear unevenly.

[Pipeman]

I have XPS Ribs on my 5er. I always inflate to 80 psi. About 13,000 miles on them and no sign of wear. My truck is the same when hauling the 5er. I've had one hard top camper, two TTs and two 5ers and have never had to replace tires because of wear, just age. Always inflated to maximum.

[thebrakeman]

Barry,
RELAX!
There are obviously 2 schools of thought here. Personally, I read that Michelin chart, and I see them covering their own butts, showing only their own tires (16" and larger!), and making statements like:

Industry load and inflation standards are in a constant state of change, and Michelin continually updates its product information to reflect these changes. Printed material may not reflect the latest load and inflation standards.

The RV industry has historically recommended to keep trailer-rated tires inflated to the max sidewall pressure. Perhaps tires on motorhomes are more like passenger vehicles, and you run them per the manufacturers rating.
But the recommendation from me (and others like Pipeman) is to run them at the max. I've done this on 2 sets of tires on my Coleman popup, and I'm doing the same with the up-rated tires on my Surveyor hybrid.
The reality is that the only ones who replace tires for wear are full-timers. Those that underinflate get blowouts.

PS - Running at max pressure on trailer tires is not "overinflation". That is what they are intended to run, to get the rated load capacity.

[OldCoot]

Originally Posted by thebrakeman

... Running at max pressure on trailer tires is not "overinflation". That is what they are intended to run, to get the rated load capacity.

Agree wholeheartedly, if you don't inflate to max stated on the sidewall, why buy heavier load rated tires? Max pressure does not cause abnormal wear.
It might if you had a tire rated for 3000# and only had 1000# load on it, but that is sure not the case with rvs. Trying to adjust the pressure to match the exact load is a time consuming exercise and IMO you get no benefit.

[BarryD0706]

Originally Posted by thebrakeman

Barry,
RELAX!
There are obviously 2 schools of thought here. Personally, I read that Michelin chart, and I see them covering their own butts, showing only their own tires (16" and larger!), and making statements like:

The RV industry has historically recommended to keep trailer-rated tires inflated to the max sidewall pressure. Perhaps tires on motorhomes are more like passenger vehicles, and you run them per the manufacturers rating.
But the recommendation from me (and others like Pipeman) is to run them at the max. I've done this on 2 sets of tires on my Coleman popup, and I'm doing the same with the up-rated tires on my Surveyor hybrid.
The reality is that the only ones who replace tires for wear are full-timers. Those that underinflate get blowouts.

PS - Running at max pressure on trailer tires is not "overinflation". That is what they are intended to run, to get the rated load capacity.

I need to relax? You're the one that's YELLING.

You're entitled to your opinion, but claiming that there's no such chart when Dave has posted it is not an opinion. Perhaps you wanted him to post one for every brand?

OC agrees that in the extreme case, over-inflation (for the load) causes wear. This is like weighing: How do you know that you're not over-inflated (for the load) if you haven't looked at the chart!!! I'm not advocating putting 63# in them (if that's what the chart says) instead of 65#, but if it's significant, then use it. I know it's hard for some people to use scientific methods to think thru things, but you really should try.

[OldCoot]

Just a guess, but I would say most trailer tires are loaded within 500#-600# of their load rating and running max pressure is not going to hurt them. Air gauges are not that accurate and can vary 2#-3# very easily, so just got to max and forget it. Dynamic shock loads on the highway will no doubt either approach or exceed the tire load rating anyway, so why chance it?

[garbonz]

Tire inflation pressure determines the tire footprint and wear pattern for a given load. That is a physical fact notwithstanding the real world experiance stated here, which would seem to indicate that it's not a big deal.

i have LR E tires on a camper that was supposed to have D's and so am running at 70 psi, as a compromise, but I have not enough miles to see what that means.

I'd go full max or maybe 5psi less if you want to.

[Herk7769]

This has been addressed several times here (and elsewhere). There is a proper inflation pressure for every load in the range of loads for a give tire's class.

Here are the charts for Maxxis, Goodyear, Michelin, etc.

Run max pressure if you want (provided you are not overloaded of course).

Pressure too high for the load results in center rib wear, excessive tire bounce, excessive trailer frame flex and vibration. Pressures too low result in edge wear, rim damage, flats, run hot and can fail explosively.

You should find the "Goldilocks" pressure for your tire's actual load.

[youroo]

Why don't we throw (Rim-Wheel Width) into the ring also? People go with larger tires,wider tires, tires that require more air pressure,but Don't upgrade their (Rims-Wheels). Game Changer! Youroo!!

[thebrakeman]

Barry,
I'm sorry if you feel this disagreement is personal (for me, it's not), but I see no reason to question anyone's intentions, nor my ability to think. This is a discussion. Nothing more. I hope we can keep this discussion civil and not attack each other.

It sounds like there are those that like to determine the optimum pressure for the required load. I learned something today. I did not know that such charts existed.

For me, I just want to be sure I'm never underinflated, since my tires will always rot with age/exposure before they actually wear out. Because of that, I'm willing to accept some minimal amount of additional wear (?), and simply run at MAX sidewall pressure, assuming I"m not grossly overrated in my tire selection.

In this very thread, I'm hearing both sides of that fence. That's not an inability to think reasonably or logically or scientifically. That's just a difference in priority for different campers.

[shineysideup]

Originally Posted by herk7769

This has been addressed several times here (and elsewhere). There is a proper inflation pressure for every load in the range of loads for a give tire's class.

Here are the charts for Maxxis, Goodyear, Michelin, etc.

Run max pressure if you want (provided you are not overloaded of course).

Pressure too high for the load results in center rib wear, excessive tire bounce, excessive trailer frame flex and vibration. Pressures too low result in edge wear, rim damage, flats, run hot and can fail explosively.

You should find the "Goldilocks" pressure for your tire's actual load.

Interestingly, I found the following information from the goodyear site;

Weighing your RV - Goodyear RV

"Special Considerations
Unless trying to resolve poor ride quality problems with an RV trailer, it is recommended that trailer tires be inflated to the pressure indicated on the sidewall of the tire. Trailer tires experience significant lateral (side-to-side) loads due to vehicle sway from uneven roads or passing vehicles. Using the inflation pressure engraved on the sidewall will provide optimum load carrying capacity and minimize heat build-up."

I pump them to the max and forget about it (not really, I have a temp gun and do check at times)... looks like I'm o.k., at least according to Goodyear!

[OldCoot]

Originally Posted by shineysideup

Interestingly, I found the following information from the goodyear site;

Weighing your RV - Goodyear RV

"Special Considerations
Unless trying to resolve poor ride quality problems with an RV trailer, it is recommended that trailer tires be inflated to the pressure indicated on the sidewall of the tire. Trailer tires experience significant lateral (side-to-side) loads due to vehicle sway from uneven roads or passing vehicles. Using the inflation pressure engraved on the sidewall will provide optimum load carrying capacity and minimize heat build-up."

I pump them to the max and forget about it (not really, I have a temp gun and do check at times)... looks like I'm o.k., at least according to Goodyear!

I inflate to max (65#) engraved on the tire and forget them and rely on the TST TPMS to keep me informed. Don't want to be tied to a Cat scale every time we get ready to go somewhere worrying about tire pressure whether to start with 58#, 60#, 62# etc. We load the camper and the truck the same every time anyway. Storage compartments are never changed. Wardrobe closets may change by 10#-15# if that much, groceries the same.
Altho the trip to Goshen will be a little heavier by 2 cases of beer on the floor in the rear pantry.

[shineysideup]

Ahh... Beer... I'm starting to drool! I don't have enough time be a drunk
!