Good Sam Club Open Roads Forum: E rated tire with max psi of 65?
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 > E rated tire with max psi of 65?

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Old-Biscuit

Verde Valley

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Posted: 12/01/20 08:20pm Link  |  Quote  |  Print  |  Notify Moderator

2 issues running those tires:

Rim width....you stated your rims are 8" and yet the 'approved rims' are 9=(9.5")-12" (9.5" being the recommended width)
Your rims are too Narrow and running down the hwy or when aired down then can pop off the rims...not too bad when in the sand but can be dangerous on hwy


Max air pressure for those tires is 65#
Running them at 80# is OVER-Inflated ...smaller contact patch, not recommended for 80#
That is a 23% increase

Your own words:
These are way oversized for the truck (spec calls for minimum 9" rim width, mine are 8"
(and when rim width was questioned you replied)
I wouldn't either, but these were on the truck when I bought it.


Change rims and only air up to 65# MAX for MAX Load


Is it time for your medication or mine?


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edbehnke

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Posted: 12/01/20 08:34pm Link  |  Quote  |  Print  |  Notify Moderator

yes, E rated tires do have different psi ratings.


eddie and sandie
3402 Montana 2013
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Grit dog

Black Diamond, WA

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Posted: 12/01/20 10:33pm Link  |  Quote  |  Print  |  Notify Moderator

Well Burb, you’ve seemed to defy the “logic” of the rvnet patriarchs, lol!
Yes the big tires are generally max rated at 65psi. Not to worry. More air volume and particularly more width, holds more weight at the same pressure as a smaller tire.

To maximize tire life though, especially with the narrow rims ballooning the tread a bit, make sure you’re running the lowest safe pressure that you can stand handling wise, when empty.
The Ram we just got sits on 37s and the (very expensive) tires don’t have many miles on them, but the PO ran the pressure too high for the load. He was running 65F/60R And even though the tires are on 12” wide rims and should run as flat as they possibly can, the centers of the treads were wore down 3 to 4 32nds rear and 2/32 front while the edges of the tread is still virtually new.
I’ve got them aired down to a little under 50F and 35R to even out the treadwear.
Tired a bit lower but it drove a bit mushy.


"Yes Sir, Oct 10 1888, Those poor school children froze to death in their tracks. They did not even find them until Spring. Especially hard hit were the ones who had to trek uphill to school both ways, with no shoes." -Bert A.

CapriRacer

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Posted: 12/02/20 04:33am Link  |  Quote  |  Print  |  Notify Moderator

MFL wrote:

Where are all the tire engineers when you need them? My wag is that these tires are designed as onroad/offroad, so even though e-rated, a lesser max pressure is best for the hybrid use, that the tread and sidewalls are designed for.

JMO, but I'd not use a wider tire, than what the rim is designed for.

Jerry


So here I am.

It's a long story why some E Load Range tires have a max pressure of 65 psi, but it deals with the burst pressure - ergo larger sized tires will have the lower pressure. It has nothing to do with onroad/offroad.

This is not unique to E Load range tires.

And just to assure some folks: The burst pressure of a tire is many times the max pressure. Tires do NOT burst based solely on the pressure. They will burst if they hit an object hard enough, regardless of the actual pressure in the tire. They'll also burst if cut deep enough to cut cords!


********************************************************************

CapriRacer

Visit my web site: www.BarrysTireTech.com

BurbMan

Islip, Long Island

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Posted: 12/02/20 06:56am Link  |  Quote  |  Print  |  Notify Moderator

I thought there was some kind of standard that said D rated aired to 65 and E rated aired to 80, just because I've never seen any deviations from that, but it just goes to show that you don't know what you don't know....I'm always learning new stuff here on the forum and I appreciate the comments and expert opinions.

Buying a used truck is always a compromise...I was willing to accept the 1.5" coil spring spacers ("leveling kit") and oversized tires to get a truck with no rust, documented dealer service over 5 years from a single owner, no accidents, no evidence of aftermarket tuning, and overall really clean.

I was expecting to be hugely disappointed with these tires in terms of traction (contact patch too large), noise, vibration, and squirm under load. To my surprise the truck is quiet and smooth as glass at 70 mph, very stable with 3100 lbs of camper in the bed, and very sure-footed on wet roads. Snow performance is TBD...

There is evidence of rubbing on the front trailing arms at max steering angle (full lock) but no wear or damage to the inside sidewalls.

The rims are OEM and in great shape, no scratches or pitting at all. I haven't decided whether to get wider rims or narrower tires, but I probably have another year to figure it out.

The leveling kit makes the truck look badazz when empty, but it sags a little in the rear when loaded with the camper. I can't lose the leveling kit without first going to smaller tires, and my alternative is adding air bags in the rear if I stay with this size and go with bigger rims with the proper offset to avoid rubbing.

My main concern was running fully loaded at only 65psi, but sounds like I'll be OK for now.


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MFL

Midwest

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Posted: 12/02/20 07:25am Link  |  Quote  |  Print  |  Notify Moderator

CapriRacer wrote:

MFL wrote:

Where are all the tire engineers when you need them? My wag is that these tires are designed as onroad/offroad, so even though e-rated, a lesser max pressure is best for the hybrid use, that the tread and sidewalls are designed for.

JMO, but I'd not use a wider tire, than what the rim is designed for.

Jerry


So here I am.

It's a long story why some E Load Range tires have a max pressure of 65 psi, but it deals with the burst pressure - ergo larger sized tires will have the lower pressure. It has nothing to do with onroad/offroad.

This is not unique to E Load range tires.

And just to assure some folks: The burst pressure of a tire is many times the max pressure. Tires do NOT burst based solely on the pressure. They will burst if they hit an object hard enough, regardless of the actual pressure in the tire. They'll also burst if cut deep enough to cut cords!


One of our hundreds of tire engineers showed up! Thanks for chiming in. While you SAY burst pressure the reason, then add that burst is many times the max pressure, it would seem that 80 psi rather than 65 psi, would not cause burst.

I disagree with the off/road design, as provided in OPs link, not being a factor. In my experience with off/road motorcycles and the oem tires, they are designed to use lower pressure.

Not sure if CapriRacer has off/road experience, or schooled knowledge of this particular tire, or just making a wag of his own?

Google, our modern day TE may have best answer, for anyone wanting to search! [emoticon]

Jerry





garyp4951

TN

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Posted: 12/02/20 07:58am Link  |  Quote  |  Print  |  Notify Moderator

The Nitto 295/70/18 rated 4080# would seem to be a better choice for a truck camper, and would fit your wheels.

Grit dog

Black Diamond, WA

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Posted: 12/02/20 09:20am Link  |  Quote  |  Print  |  Notify Moderator

^Agree, from a functional standpoint.

However the real lesson in this thread is all the nay sayers that bemoan those “hooligans” with their big loud ill proportioned tires and how they “must” be horrible for doing truck stuff like towing and hauling big loads and are a danger to themselves and society....... can now pipe down.

We now have a real world review from a real person hauling a real camper who isn’t beating his chest about how cool his brodozer is, but rather now realizes that big tires aren’t the horrific doom n gloom that is generally portrayed here!
(And to top it off, they’re on too narrow of rims, and still do just fine!)

These are things that some of us already know and others refuse to believe.

* This post was edited 12/02/20 03:18pm by an administrator/moderator *

Grit dog

Black Diamond, WA

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Posted: 12/02/20 09:25am Link  |  Quote  |  Print  |  Notify Moderator

MFL wrote:

CapriRacer wrote:

MFL wrote:

Where are all the tire engineers when you need them? My wag is that these tires are designed as onroad/offroad, so even though e-rated, a lesser max pressure is best for the hybrid use, that the tread and sidewalls are designed for.

JMO, but I'd not use a wider tire, than what the rim is designed for.

Jerry


So here I am.

It's a long story why some E Load Range tires have a max pressure of 65 psi, but it deals with the burst pressure - ergo larger sized tires will have the lower pressure. It has nothing to do with onroad/offroad.

This is not unique to E Load range tires.

And just to assure some folks: The burst pressure of a tire is many times the max pressure. Tires do NOT burst based solely on the pressure. They will burst if they hit an object hard enough, regardless of the actual pressure in the tire. They'll also burst if cut deep enough to cut cords!


One of our hundreds of tire engineers showed up! Thanks for chiming in. While you SAY burst pressure the reason, then add that burst is many times the max pressure, it would seem that 80 psi rather than 65 psi, would not cause burst.

I disagree with the off/road design, as provided in OPs link, not being a factor. In my experience with off/road motorcycles and the oem tires, they are designed to use lower pressure.

Not sure if CapriRacer has off/road experience, or schooled knowledge of this particular tire, or just making a wag of his own?

Google, our modern day TE may have best answer, for anyone wanting to search! [emoticon]

Jerry


No, Capri is knowledgeable and correct.
And real world, Burbs tires aired up a bit over max, while not the healthiest for tread wear maybe, likely handled better than at 65psi.
I’m no tire engineer, just a dumb gear head civil engineer who has been thrashing light duty trucks for a lot of years in construction. And as part of that, when I have a new 1/2 ton with piddly P or XL tires and am hauling heavy trailers, I’ll air up the 44 or 50 psi rear tires about 10 psi or so over max and enjoy the better handling aspects of a stiffer tire with the load.

That said, I do understand buddy pressure anecdotally and realize that there’s an increased chance of a blowout from a road hazard.

MFL

Midwest

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Posted: 12/02/20 11:26am Link  |  Quote  |  Print  |  Notify Moderator

We are all knowledgeable, but does not mean correct every time! If you read Burb's link, it has some good info, concerning his tires, tread, etc. It does show a little more on road capable, than off.

Do you truly know Capri, or just read of his own drum beating? Hope no relationship involved![emoticon] Roger Marble was more knowledgeable, and also had more RV type experience. Too bad, he was banned here!

Grit...just curious...why does it often take a day or more, for your posts to show up? Your post above, did not take that long, but was blank for a while? BTW...you are a knowledgeable gear head, and like me, a person who has over used trucks, and tires, while I don't recommend either.

Jerry

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