14" marathon blow outs

Originally Posted by jcjim4

More confusion! is there an increased safety factor in changing to a 225-75R15 rather than a 215-75R15? or other advantages?

You can get some more load capacity, with the 225/75R15. You can find more of the 225/75R15's in a Load Range D (8ply rating) and Load Range E (10 ply rating).

Most of your 215/75R15 tires are going to be Load Range C (6 ply rated), but you may be able to find some in a Load Range D (but will probably be hard). Another thing is, a 215/75R15 size ST trailer tire is kind of an anomoly. A lot of manufacturers skip this size in their lineup. They go from a 205/75R15 directly to a 225/75R15.

This extra capacity may be overkill, but more can't hurt.

[Bill]

Ragmopp et al -

Many of the questions are covered in the original thread regarding this conversion. See especially the first few posts in
http://www.trailmanorowners.com/foru...ead.php?t=6245
The new wheels are cheap and commonly available (or quickly obtained by) a tire dealer.

Regarding the spare tire holder, the thicker tire can make a difference in the spare tire holder, although apparently Scott didn't experience it. There is a discussion, and a couple different mods, described here
http://www.trailmanorowners.com/foru...ead.php?t=5828

Bill

[gjc-99]

I had two 14 inch Marathon tire failures this fall -- both were original tires on our 2005 TM and were manufactured in late 2004. Our TM is garaged (no direct sunlight), I estimate 12000 miles total on the set of three (rotate each season), all three were balanced, the tires are up in the winter, and I frequently check tire pressure. I had planned to replace them this year or prior to spring 2010.

I believe that there may have been a material or manufacturing defect with this vintage of Marathon tires -- my tires should not have failed. Anyone with 14 inch Marathons of this vintage should consider replacing them.

Originally Posted by gjc-99

I had two 14 inch Marathon tire failures this fall -- both were original tires on our 2005 TM and were manufactured in late 2004. Our TM is garaged (no direct sunlight), I estimate 12000 miles total on the set of three (rotate each season), all three were balanced, the tires are up in the winter, and I frequently check tire pressure. I had planned to replace them this year or prior to spring 2010.

I believe that there may have been a material or manufacturing defect with this vintage of Marathon tires -- my tires should not have failed. Anyone with 14 inch Marathons of this vintage should consider replacing them.

I replaced mine in July 2008, when one failed on the freeway. My tire age and usage was similar to yours. I was expecting to get another year out of them.

[CAmark]

Two quick things...my TM is a year newer than those of the last two posts...right now I want to think I am wise enough to learn from your misfortunes and get new tires before the season starts...secondly, increasing tire capacity will not increase the axle capacity -- you only gain margin for blowout avoidance rather than the ability to greatly increase the over all load...right?
Mark

If you check the tire charts for the max load per tire on the Load Range C tires vs a load range D tire, you will find that you gain some margin of safety, Not a great deal. Unfortunately much of that margin can get eaten up by a false sense of security that causes you to load even more stuff into the TM than before.

Mark: You are exactly correct. The object is to increase the margin of safety, not eat it up by loading more and more stuff!

[Bill]

Mark -

As you point out, increasing the tire capacity does not increase axle capacity. On the other hand, this board has heard many stories of failures on the 3500-pound tires, but never a failure on the 3500-pound axle. Dunno why.

Bill

Originally Posted by Bill

Mark -

As you point out, increasing the tire capacity does not increase axle capacity. On the other hand, this board has heard many stories of failures on the 3500-pound tires, but never a failure on the 3500-pound axle. Dunno why.

Bill

Driving at 55mph in 105 degree temperatures, I think, can impact the longevity of the tires a lot more than the longevity of the axle. Also hitting a California pothole under those conditions has little effect on the axle.

I suspect there is little difference between the 3500 vs 5000lb dexter axles. Like a 1/2 vs 3/4 ton truck. They can have the same axle but the suspension is dialed in to carry different amounts of weight and maintain ride. I think firmness is the issue over strength.