Interply Shear Question - 15" XL vs 16" LT

[jcanavera]

Originally Posted by CapriRacer

Jack,

I know you addressed this to Roger, but I hope you don't mind if I comment on some things I found interesting in your post.




I suspect the reason the tires were physically larger was that the Maxxis's had cap plies and that's what prevented the tread detachment that you experienced earlier with the Goodyear Marathons. That is, both tires suffered belt leaving belt separations, but the cap plies acted like a bandage. It may also be the reason why you were at season 4, where previously you were at season 3.

Cap plies reduce the amount of centrifugal movement - and therefore that amount of stress the belt edges experience.

However, cap plies, in and of themselves, are not sufficient to prevent belt leaving belt separations.



From a tire engineering perspective, this change was also a load carrying capacity increase, just like the change from LR D to LR E you did the step before. This is on top of the change from ST to LT and the change from Maxxis to Michelin. Statisticians would say that those 3 things are "confounded" - meaning you can't figure out which change is significant given the data in front of you.



I really dislike the way they did that statement. I think they were very awkwardly trying to explain that the number of cycles loaded (revolutions) plays a role in a tire's life and that one should not expect a tire to last forever.

However, they seemed to imply that ST tires are different than other types of tire in this regard. They are NOT! ALL tires have this property. It's a part of the way this works - a "Laws of Physics" kind of thing. In engineering terms, this is called "Fatigue".

CapriRacer,

One of reasons I specifically chose the Maxxis as my replacement for the Marathons was that cap ply feature. Obviously I was hoping that the belts would have less tendency to separate.

With the fact that we went to load rated E tires and a belt cap and still had belt separation at close periods withtwo different brands of ST tires would now point out the fatigue issue? Going back to my contention that there may be a direct relationship between the amount of weight that tire has to bear and its life expectancy?

There seems to be a plausible theory to me that a Michelin LT in the E rated 16” version has some attributes, construction, materials, etc. that seem to resist the fatigue factor caused by my Classic slideout’s higher weight. Considering the cold inflation levels I keep, my favorable storage conditions, and towing speeds, no road or sidewall damage or abuse, I fail to come up with any other smoking guns.

Jack


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[tjdonahoe]

Originally Posted by jcanavera

CapriRacer,

One of reasons I specifically chose the Maxxis as my replacement for the Marathons was that cap ply feature. Obviously I was hoping that the belts would have less tendency to separate.

With the fact that we went to load rated E tires and a belt cap and still had belt separation at close periods withtwo different brands of ST tires would now point out the fatigue issue? Going back to my contention that there may be a direct relationship between the amount of weight that tire has to bear and its life expectancy?

There seems to be a plausible theory to me that a Michelin LT in the E rated 16” version has some attributes, construction, materials, etc. that seem to resist the fatigue factor caused by my Classic slideout’s higher weight. Considering the cold inflation levels I keep, my favorable storage conditions, and towing speeds, no road or sidewall damage or abuse, I fail to come up with any other smoking guns.

Jack


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Look and see where these maxis tires are made.....

[jcanavera]

Originally Posted by tjdonahoe

Look and see where these maxis tires are made.....

Last time I checked they were Taiwan I thought. Maxxis is a well respected manufacturer in the market.

[Tireman9]

Originally Posted by SailorSam205

Roger,
I understand the inspection, but did you really mean every 2,000 miles? For me, that would have me jacking up my trailer multiple times per trip. I've got a trip planned to the Grand Canyon and Albuquerque that is about 5k miles...

Not all folks pulling trailers travel that much. Aome claim to only travel 3 - 4000 a year in multiple short trips.


I would certainly check before leaving and as soon as you return from your long trip. My point was that the inspection is not a one time thing but it can be good insurance.