14" marathon blow outs

[ThePair]

Originally Posted by Scott O

Additional note: I was told that the '09s come with 15" wheels. Can anyone confirm this?

Although I have not yet taken delivery of my new 2009.5 2720SL, I have confirmed with the factory that it will come with 15" wheels as standard.

They have also moved to a lower profile Carrier AC unit to make up for the difference in height. In fact, they told me that the new TMs are a little bit shorter (like 1-2 inches) as a result.

[SCBillandJane]

I read about Marathon tires before buying our 2003 3021KS with 15 inch tires in Feb. 2008. I live in SC, and traveled to Tampa, Fla. to pick it up. Following the advice of the forum, I decided I woudn't leave Tampa until I replaced the 6 year old tires including the spare.. Thanks for the advice. The tire store employees thought I was crazy for replacing tires that looked brand new especially the spare that had never been on the ground.
I chose Brand B for replacement tires because I hadn't read any good news about Marathons. Brand B was the only brand that this tire store had in the right size that wasn't Marathons. Not a very scientific choice. I kept the Marathon spare as a second spare since I planned a trip to Alaska. The second spare rode in the back of the the truck on a 9 week trip to Alaska. When I returned and removed the spare from the truck bed, the rubber was gummy and coming off the tire leaving my hands black. It had still never been used. I took it to the recycle center.
The Brand B tires have been from Tampa to SC to Myrtle Beach to Alaska down to Washington back to SC to Key West, Fla. and back to SC. The total milage is close to 20,000 miles in one year with no problems under a variety of conditions. When I replace the current tires, I will choose Brand B unless I can find good information that says Brand C is best.
I would have liked to have had a "scientific" or a reasonably reliable recommendation on which brand would give me the best chance not to have a blow out with all the related damage. Maybe I just got lucky with the three Brand B tires I bought. Is there such a place that has reliable information about 15 inch trailer tires?
In any case, thank you forum members for the information about tire balancing, tire age, inflation, speed, and over loading. I feel that your information saved me from an unpleasant surprise.

I didn't measure carefully, but the new tire/wheel combo is less than 1" higher than the 14" stock wheels, eyeballing it looked to be about 3/4". I was surprised the difference was so little. My garage has limited clearance also, so I was prepared to let some air out if necessary. But happily it was a non-issue for me! The Kumhos seem to be a good choice also, but they are rather hard to find and my dealer recommended I stay with the Marathons.

Note to The Pair: The new AC unit is indeed very short. It hardly sticks up at all! Indeed the new trailers must be at least a couple of inches shorter that previously. Enjoy your new rig and keep us posted as to your opinions and experiences.

Note to Bill and Jane: My dealer (Custom RV in Anaheim) told me he had seen only 2 cases of Marathon failures. One was obviously caused by improper use of a weight distributing hitch. The other was probably a failure. The problem is that blame is really hard to figure...improper loading, hit a pothole last month and forgot about it, valve stem failure, sat too long and got out of round, improper storage, or plain old tire failure. In reality, I'm not sure how prevelant this problem is, and how many can be blamed on the tires. But since there have been so many reports I decided to err on the side of caution. Also, what is Brand B?

[Bill]

Switching from a 14-inch tire to a 15-inch tire should add only a half inch of height to your TM, of course. Although the diameter increases by an inch, the radius (that is, the distance from the ground to the axle hib) increases by only half an inch.

Bill

Originally Posted by Bill

Switching from a 14-inch tire to a 15-inch tire should add only a half inch of height to your TM, of course. Although the diameter increases by an inch, the radius (that is, the distance from the ground to the axle hib) increases by only half an inch.

Bill

Bill is absolutely correct as always. There can be a little more difference if you change the section width/aspect ratios of the tire sizes between a 14 and 15 inch rim.

If you change from a 215/75R14 tire to a 215/75R15 tire, then is only 1/2 inch different radius, since the 215 section width and 75% aspect ratio (or height) are the same.

Now if you change from a 215/75R14 to possibly a 225/75R15, then the radius will be a little more. 75% of 225 is a little more than 75% of 215.

The only reason I threw that out there (besides the fact I am a sadist and like to confuse the situations ) is that the two predominant tire sizes we keep discussing are a 215/75R14 and a 225/75R15.

Now more questions....

What about the spare? Any problems placing the 15 incher in the spare tire holder?

Also, where do you get the wheels? The Goodyear dealer?

If the 15 inch wheel really doesn't cause any necessity for modifications on my 2720SL then I really might consider this....

Mike Anderson

Originally Posted by Bill

Switching from a 14-inch tire to a 15-inch tire should add only a half inch of height to your TM, of course. Although the diameter increases by an inch, the radius (that is, the distance from the ground to the axle hib) increases by only half an inch.

Bill

With my 14 inch wheels, I have about 1/4 inch of clearance.

Taking out the 2 inch lift kit is not viable, because I have scraped the ground once with the battery tray on the front.

The shorter a/c will help newer owners. Mine is now 4 years old.

ragmopp:
CustomRV got both the wheels and tires for me. I think they said from Big O Tires but I wasn't really paying attention so I'm not positive. The studs on the spare holder (the posts the lugs fasten to that hold the wheel in place) were too short. Dealer just replaced them with slightly longer ones (required a bit of welding which they didn't charge me for) and all fit just fine.

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

Not really.