Trailer Tires Splayed

[Springer]

Have a Cougar 327 RES. While pulling my 36' 5th wheel had to turn REALLY tight. I noticed the tires on the left side of my 5th wheel splayed out in opposite directions. I repeated this by backing up sharply. The tires splay out on both sides. Never once noticed it with my old TT. Once I started forward again, they aligned correctly. But my question is, how much stress are these tires rated for? Do I need to worry about anything in particular? Should I be towing art the MAX tire pressure?

I have read that this is "normal". Looks anything but.

Thanks guys.

Springer

[JRTJH]

You're right, it looks "anything but normal" but it is a typical condition of most heavy trailer wheel/tire/axle assemblies when maneuvering in tight conditions. Things do return to "normal" once you're headed in a straight line, which is why you should always pull forward and back up in a straight line once you've got your RV into the space you want to end up. By pulling forward and backing up in a straight line, you will remove the stress from the tires caused by the angled maneuvering.

[Bob Landry]

I also run my tires at the max pressure indicated on the sidewall. The less flexing you subject them to, the better, you'll get less heat buildup and longer tire life.

[Springer]

Thanks John. Have ready many of yours, and the other moderators replies, and they are always very informatative. So much good stuff comes from the other contributors also.

Can't tell you how much I have learned from purusing this site.

Thanks again

[hankpage]

Originally Posted by Bob Landry

I also run my tires at the max pressure indicated on the sidewall. The less flexing you subject them to, the better, you'll get less heat buildup and longer tire life.

X2 JM2¢, Hank

[Springer]

Thanks also to you Bob. Missed your reply the first time. I had to take the 5er in for a problem with the entry steps and, when I mentioned the "splaying" of the wheels, the service writer looked at me like I had three heads.
Guess I expected them to know what you two already seem to know.

Doesn't give me a warm fuzzy about my dealer's service dept.

Thanks again

[Woodsrider]

The splaying will be worse on trailers with a "spread axle". When the distance between the axles is greater, you put more stress on the tires in tight turns. At least that's what my truck driver neighbor says.

[JRTJH]

Originally Posted by Woodsrider

The splaying will be worse on trailers with a "spread axle". When the distance between the axles is greater, you put more stress on the tires in tight turns. At least that's what my truck driver neighbor says.

You're correct Woodsrider, but the OP's Cougar has conventional tandem axles under it

[outwest]

Originally Posted by JRTJH

You're right, it looks "anything but normal" but it is a typical condition of most heavy trailer wheel/tire/axle assemblies when maneuvering in tight conditions. Things do return to "normal" once you're headed in a straight line, which is why you should always pull forward and back up in a straight line once you've got your RV into the space you want to end up. By pulling forward and backing up in a straight line, you will remove the stress from the tires caused by the angled maneuvering.

Good to know, thanks! There's one park I regularly use in Houston (South Main RV Park) that has several spots that you have to make a really tight turn to back in to. I've gone forward and back after getting in it, but just because I'm OCD about it being in square with the spot. Now I know to make sure to give it a decent amount (length) of forward and back once squared up. Thanks again, appreciate the info and education.

[jadatis]

This is all because the tires have to much gripp that it splayes out .
but at low speed the tire can bare more then at normal driving speed.
At normal driving you never make such a curve.

But now , what can we do to give it a lesser gripp so it the treath slides soones and the tire does not spaye out .

Probably your tires are ST (special trailer) tires wich have more maximum load then an LT tire , because they are allowed more deflection at the lower speed of 65m/h they are calculated for.
This more deflection gives thoug more rubber on the road , so more gripp and resistence to let the sidewals bend more.

If you would give them the same deflection , an LT tire would have of same sises, and then even for dual-load, it slides sooner in curves and so splay less.
I once calculated for same sises ST and LT for one sise, that the ST has 15% more maximum load then the LT , and in America sometimes even 9% is substracted from the single-load maximum load to get the dual load maximum load. In Europe thats 7.5% substraction ( so Maxload dual is 0.925 times maxloadsingle).
So to get the ST to deflect and gripp the same as LT you have to do the next sum. So simple calculation gives ( MaxloadsingleST/1.15)* 0,925= 0,804<>80% to get maxload dual LT.

If you then would put that in my motorhome-tire-pressure-calculator wich also uses 10% reserve above this all, it would give probably a pressure close to that pressure written on the sidewall, wich is called the maxloadpressure and is not the maximum pressure of the tire.
Even stiffer TRA allows 10 psi above this for ST and LT but for different reasons. Whatever the reasons are, it proves that its allowed, and we can use this extra for what we want.
Only if calculation comes higher then this maxloadpressure , and you highen it up in a tire that is already damaged by to low pressure, it wil even sooner blow and then you blame the high pressure .
But if you did not make many miles yet , or sertainly when you do it for new tires from the beginning , you are alrigt with that 10 psi higher.
That is the reason why ST tires are kept on "maxloadpressure "as advice.
And the damage to the tires with that more deflection sooner happens by the to much deflection at higher speed, then from the once in a while at low speed curving and spaying.

[jlb27537]

Originally Posted by Springer

Have a Cougar 327 RES. While pulling my 36' 5th wheel had to turn REALLY tight. I noticed the tires on the left side of my 5th wheel splayed out in opposite directions. I repeated this by backing up sharply. The tires splay out on both sides. Never once noticed it with my old TT. Once I started forward again, they aligned correctly. But my question is, how much stress are these tires rated for? Do I need to worry about anything in particular? Should I be towing art the MAX tire pressure?

I have read that this is "normal". Looks anything but.

Thanks guys.

Springer

Hi Springer, You need to run your tires @ 80psi cold....Yes they will look like the axles are bending on a tight 90 degree back in. Normal. You might look into a product by Mor/ryde called X Factor. You can install it on your present trailer and when you move up to a Montana, can take it with you. A bit labor intensive but worth it.

http://www.morryde.com/aftermarket/r...r-ryde-60.html

Might also look on the Montana Owners forum and read the section on tires.

http://montanaadministrator.forumco.com/default.asp

Might want to re-consider the "Made in China" tires you have now.

Jim