Help, Im Fishtailing (and other first trip encounters)

[mcbrew]

Originally Posted by Jim Bennett

Actually, Francesca's post is quite true.

I have pulled literally 100's of different trailers, big and small, and have never seen a recommended pressure anywhere as low as 20 lbs. I am curious as to where you have seen it recommended by either a tire, or trailer, manufacturer to go this low with a tire rated for 50 psi.

Two places: one on each side of my Scamp (manufacturer's sticker) and also in the Goodyear documentation for ST tires.



My Scamp 13's tires are the top row... Same as the original ones that it came with. The loads listed a for EACH tire, not the total axle weight. So you can see that 20 PSI is the proper inflation so long as there is not more than 795 pounds per tire.

[Francesca Knowles]

Hmmm...

Can it be that I've once again proven the wisdom of Josh Billings' famous saying:
"It ain't the things you don't know that gets you in to trouble- it's the things you know for certain that just ain't so."

That "inflate-to-the-max" rule has been in my head for simply EVER...and it's beginning to look to me as if I've been...dare I say it?... WRONG.

I distinctly hear the ripping sound of a Hole Being Torn in The Fabric of My Universe.

Mind you, I'm not quite ready to throw in the towel, especially since reducing the pressure on my present tires may not be wise since I've been running them at 50 for several years.

They're probably as stretched out as the "size 5" jeans I keep cramming my size 10 self into.

BUT
I'm just about due for new trailer tires, and when I get them I'm going try the lower pressure. That is, IF my trusted Tire Guy at Les Schwab concurs...

Thanks, I think!

[Thee Jimbo]

Thanks for the smiles Franchesca and the table McBrew! Called arrow trailer 270 for a new axle with brakes and 235-290 to install. (I'm going to assume 290 or 600 total)

Any other recommendations for the El Lay area?

[Bob Miller]

My local RV dealer, Richardson's in Riverside, sends all of it's axle and frame work to Arrow. Tell em' that Mike and CJ sent you, maybe that will get you a free cup of coffee..... Let us know your experience.

BTW: be sure to get somethuing that improves your ground and wheel well clearance

[Byron Kinnaman]

Originally Posted by mcbrew

Two places: one on each side of my Scamp (manufacturer's sticker) and also in the Goodyear documentation for ST tires.



My Scamp 13's tires are the top row... Same as the original ones that it came with. The loads listed a for EACH tire, not the total axle weight. So you can see that 20 PSI is the proper inflation so long as there is not more than 795 pounds per tire.

Please re-read this chart. At the TOP... it says "Load Limits at various inflation pressure"... It DOSE NOT SAY "Recommended inflation pressure at various loads" as has been interpreted by many here.

[Bob Miller]

The rest of the story:
I have talked with the engineering staff at Yokohama a number of times about loads, inflation pressure and ageing on tires used on RV's and their general recommendation is to inflate RV tires to at least 90% of the max pressure shown on the sidewall to provide best tracking, wear and sidewall life. They have told me that while lower pressures will support less weight, it can also cause additional heat build-up in the side walls leading to earlier side wall failure. That's Yokohama's take, but as some one will mention, they don't make tires for our application.
That said, this clip is from the www.goodyear.com/rv site:

"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."

But this topic, like several others, are neverending stories.

[cpaharley2008]

So another way of looking at the chart is @ 45 psi every tire(except for 2) is able to carry the maximum it was designed for. By decreasing the psi you decrease the capability. Gives new strength to the old argument- use maximum on tire and you will be okay.

[Bob Miller]

EXCEPT for the "B" rated tires that top out with a maximum inflation of 35 psi. Again, always read the information on the sidewall.

[Jim Bennett]

Originally Posted by mcbrew

Two places: one on each side of my Scamp

Scamps owner manual says "Tire inflation is the most important factor in tire life. Inflation pressure should always be as recommended by tire manufacturer (as indicated on tire)." This kinda contradicts what they have posted on your trailer saying to use 20 psi.

I have never heard from an industry professional, whether in the RV or tire industry, to use anything but from near max to full maximum tire pressure as indicated on the tire. From everything I have heard, and from using my form of logic, this would seem to be true in my way of thinking (though my way of thinking has been questioned many times before ).

[dylanear]

Originally Posted by Jim Bennett

I have never heard from an industry professional, whether in the RV or tire industry, to use anything but from near max to full maximum tire pressure as indicated on the tire.

For low profile performance tires, on passenger cars. The max pressure is max, you do not typically want to run that pressure. Poor ride and poor grip and uneven tire wear will likely result.

Not all that relevant to this discussion, sounds like all being equal you do want to run highish pressures on a trailer. I'm just sayin', for the sake of conversation.

[Bob Miller]

Quote: "I have never heard from an industry professional, whether in the RV or tire industry, to use anything but from near max to full maximum tire pressure as indicated on the tire."

On motorhomes and trailers that's pretty much the standard.

But it can been very different on passenger cars. Corvair tire pressure issues basically made, what wasn't a really great car to start out with, into a death trap that liked to turn turtle when tire pressure stickers werre ignored. But I digress.....

[mcbrew]

Originally Posted by Bob Miller

That said, this clip is from the www.goodyear.com/rv site:

"Unless trying to resolve poor ride quality problems with an RV trailer...".

And that is exactly why I run a lower, acceptable pressure. At max pressure, my Scamp bounces a little too much. I find things all out of place inside the camper. I know this is not good for the frame, the camper body, items inside the camper, the tongue, the coupler, and my car's hitch. Lowering the pressure to a safe level, according to both MY Scamp and MY tire's manufacturer smooths out the ride and keeps everything in place.

AS FOR THE HEAT ISSUE: I check my tires with an infrared thermometer, as well as the hubs. Even in 105 degree heat on the highway, my Scamps tires have never been hotter than my car's tires.

[Jim Bennett]

Originally Posted by dylanear

For low profile performance tires, on passenger cars. The max pressure is max, you do not typically want to run that pressure. Poor ride and poor grip and uneven tire wear will likely result.

Not all that relevant to this discussion, sounds like all being equal you do want to run highish pressures on a trailer. I'm just sayin', for the sake of conversation.

As per the discussion, it was trailer tires I was talking about.

[Francesca Knowles]

[Jim Bennett]

Francesca, I have some red pills, and some pretty orange ones. Want one?

[Francesca Knowles]

Originally Posted by Jim Bennett

Francesca, I have some red pills, and some pretty orange ones. Want one?

I'll have to check with the head nurse here...

[Jim Bennett]

Nurse Ratched. You have to know she would give the okay.

[Andrew GPSMapNut]

Raising the tongue changes the weight distribution. Not by a lot but... On your way back... was the propane tank almost empty? Maybe the few missing pounds on the tongue in addition to the raised front caused the fishtailing?
From the pictures, I see that the part that was sometimes dragging was the bottom of the bar's vertical tube. You could just cut off the section that sticks below the ball mount plate - structurally it doesn't do anything for you and it doesn't look like you would be adjusting the ball any lower than it is in the picture.

[Francesca Knowles]

O.K....had a good night's sleep...

But seriously, folks:

I'm quite interested in the whole tire-pressure question, and since I'm about to buy new tires I'm going to conduct some road tests.

I've towed the same combination for thousands of miles with the tires at 50 pounds, and while I've totally mastered the "sway" problem inherent to the rig (without special equipment), I'm not satisfied with the quality of the trailer ride.

I literally cannot carry graham crackers for s'mores as they're reduced to crumbs by the time I get to camp....

The problem in my case isn't the axle or its suspension components, which are in good condition. But the tires are part of the suspension system, too, and certainly major contributors to quality-of-ride.


I'm going to replace my tires with identical new ones, and will experiment with different pressures to see if there's a beneficial effect on the ride WITHOUT any detrimental effect on stability. The timing is perfect since the next several trips we're taking are over roads I'm very familiar with, and I know exactly where the highest sway-potential spots are along the way.

When I've gathered all my Very Scientific Data, I'll post a new thread on the subject.

Thanks to the O.P. for bringing it up, and to the rest of you for making me think about it!

[Donna D.]

Welcome back Francesca.. good night's sleep indeed