Replacing 14" Marathons with 15" Marathons

Originally Posted by fcatwo

We've been away but in scanning the last few pages of this thread I don't see any mention of garage door heigth problems. Everything about the TM is a compromise of some sort and adding lift kits and larger tires can make those with roof air so tall they don't fit through some garage doors. Not a problem for most but something to keep in mind.

I put my TM in the garage a couple of weeks ago so that I didn't have to winterize between camping trips. With the lift kit and 15" "C" rated tires, the low profile AC just barely cleared the rubber seal around the door frame and the electric door opener, but would not clear the electric door opener arm. I propped the door open with a C clamp in the track, removed 2 pins, and took the arm off. So the TM will still fit with the mods., at least in my garage, which has just a standard height door......7' door, ~82" to the door frame trim, ~81" to the rubber seal around the trim.

Chap

[Bill]

A quick update on the performance of my new (thanks to wmtire) 15-inch Marathons. Just got back from a 2000-mile trip from Scottsdale to Joshua Tree NP, then up to Santa Barbara, the Pacific Coast Highway to Monterey, then up to Napa/Sonoma. A leisurely trip. Then a fast return to Scottsdale via I-5 and I-10. Fun trip - I'll describe it in another forum.

The tires performed flawlessly. We are now above 10,000 miles on these in less than a year, and I'm very pleased. I'm running them at about 60 psi. What I like especially is that I check the sidewall temp every time we stop, and they run stone cold. The old 14-inch Marathons used to run warm - never hot, but warm.

We'll do another 1,000 miles later this week, down to southeastern Arizona. I don't expect anything to report, but if something comes up, you'll hear about it here.

Many thanks, Bobby.

Bill

You know, for a bbs we are paying to be a member of there should be some sort of regulation on members. Maybe a user level for Trail members where their posts are moderated.

[Bill]

Just to keep the experience base up to date, I am here to report that we returned to Maine from Arizona, via Rocky Mountain National Park, arriving about 10 days ago. The trip totalled just about 3000 miles, most of it Interstate at 65 mph. That brings the total miles on my 15 inch Goodyear Marathon retrofits to about 15,000, over a bit less than two years, with no sign of any troubles. As always, I ran them at 60 psi, and checked temperature with my fingertips at every stop. They run pretty much stone cold, unlike the 14 inch Marathons that always ran a bit warm - not hot, but a bit warm.

I'm beginning to think these may be keepers. Thanks, Bobby!

Bill

[hhoenig]

Is it possible to upgrade to 15" rims without the lift kit?

[Bill]

Check this thread. I think that the answer is in post #16.

http://www.trailmanorowners.com/foru...ead.php?t=6750

Bill

Originally Posted by Freedom

The sprung weight didn't change, just the unsprung weight. I don't think the new tires will affect the total weight by more than a few pounds. Unless you're referring to the thought that "Hey now that I have bigger tires, I can carry more junk!" Now that could be a problem with some people, but I don't think it would be with Bill. He seems to be pretty level headed - to me any way! I think this was all in an effort to cure an already existing problem.

Where would you carry more "junk"? LOL

[fourteener]

Bill / Dave / Bobby,

First off, THANKS for all of your help, you are all outstanding!

I just noticed under the "More Marathon Failures" post, Andromeda (David) just posted that he has heard Goodyear is releasing a ST205/75R14 Class D, although it may be backordered currently. Can anyone verify that for me (come on wmtire, help me, help me :-).

Secondly, I was getting ready to make this upgrade this next weekend, and thought I best raise my camper and see if I have the required clearances for the 15" wheels and tires. My '07 2720 Trailmanor appears to have some challenges. First the aluminum blocks in-between the axle and frame looks to be factory installed, but I don't seem to have the 3" of clearance that is recommended for the upgrade. I only have between 2-2.5" of clearance at the top of the tire to the black plastic wheel well. Also the aluminum block that I thought was the 'lift kit' is only 1.5" thick. See pictures below. Please note that the camper is on the axle in the photo, not jacked up, so in these pictures the axle is under load.

Can you tell me, if I am to order the lift kit, does it come with the 4 longer bolts and the two blocks required to do the work? Also, do I leave the aluminum blocks in place and simply add the lift kits?

Again, if Goodyear is coming out with D rated 14" Marathons, I would like to hold off and save myself a bunch of un-needed expenses and time (ie hunting down tires and rims, installing a lift kit, retro-fitting the spare tire rack, etc, etc.) that I could be accomplishing other work.

Any update is much appreciated.

Thanks Again,
Mitch

[ShrimpBurrito]

Originally Posted by fourteener

I only have between 2-2.5" of clearance at the top of the tire to the black plastic wheel well.

That may be enough. You don't say what tires you have, but a Goodyear Marathon 205/75R14 is 26.1" in diameter and has a load capacity of 1740 lbs (http://www.tirerack.com/tires/tires....wall=Blackwall. My 225/75R15 Carlisle tires (not my ideal choice in brand, but as I said, this was an unplanned upgrade in the middle of a trip) are 28.3" in diameter and have a load capacity of 2830 lbs - they are load rating "E" (http://www.carlisletransportationpro...wables/tires43). So they are 2.2 inches larger in diameter, but of course, only half that extra size is measured on each side of the tire. That means that if you mounted that tire, you'll have 1"-1.5" of clearance at the top. Have the tire shop add the lift kit from the factory if you don't want to do it, and that gives you an extra 1", and you are back up to the clearance you have now (I am nearly certain the lift kit I got was 2.5" tall). Then you're done. Piece of cake, no more tire worries.

Originally Posted by fourteener

Can you tell me, if I am to order the lift kit, does it come with the 4 longer bolts and the two blocks required to do the work?

Yes. Or at least mine did.

Originally Posted by fourteener

Also, do I leave the aluminum blocks in place and simply add the lift kits?

I suppose you probably can, but I wouldn't if the lift kit alone gave you the necessary clearance. Why?

Originally Posted by fourteener

Again, if Goodyear is coming out with D rated 14" Marathons, I would like to hold off and save myself a bunch of un-needed expenses and time (ie hunting down tires and rims, installing a lift kit, retro-fitting the spare tire rack, etc, etc.) that I could be accomplishing other work.

Don't overthink this -- it's not hard to do, and it shouldn't take much time. The rims are nothing special - any decent tire dealer should either have them in stock, or be able to get them on short notice. I did the upgrade in the midst of a cross-country trip -- which you don't want to do -- but it simply involved me sitting in the parking lot for 4 hours. Most of that time was me being paranoid about measurements like you are now, making posts to this forum and waiting for responses, etc.

If you can close to the same weight rating of a 15" wheel with a 14" wheel, than go for it. But my guess is you can't. If I were you, having been down this road and having tried the "I want to try to get by with 14 inch wheels" approach, I would put in the extra effort and do it right the first time. But that's just me.

Dave

[trailbiker]

I recently purchased Kumho 205 14 R tires. They are D range tires. I found it very difficult to find any 14" trailer tires in load range D. Kumho and Maxxis were the only brands available and only online. I had to send the first set of Kumhos (purchased from TireRack) back because they were 18months old when I got them. The only place I could get Maxxis tires was direct from the factory. I called Maxxis several times to see if they could tell me if the tires they were shipping would be less than 1 year old and my calls were never returned. They are expensive and so is shipping to the Northeast. I think that there are a lot more options available for 15" wheels and that alone makes it worth doing.

P.S. I am still planning to get the lift, but it seems my dealer is having problems getting the kit from Trailmanor.