Tire Size Upgrade - Surprisingly Successful

I just completed upgrading my unit from 14 inch load range C Marathons to 15 inch load range D Marathons.

After reading all of the postings regarding this exercise, I was convinced that there would be some issues either with horizontal or vertical clearance.

In fact I showed the owner of the wheel and axle shop the postings related to this and the suggested fixes for problems with clearance. There were no problems whatsoever and it was simply a matter of swapping wheels and tires.

There was plenty of clearance on the sides and no interference with the fender skirts. The clearance from the top of the tire to the wheel cover is slightly more than 3 inches with weight on the unit.

I have a 2007 2720SL and along with the tire and wheel upgrade I modified the spare tire carrier and installed a weight distribution hitch as well.

Everything went better then expected and I'm very happy with the outcome. Now that all of the upgrades I wanted to do are complete the unit is sweet and ready for the road. I've done things with extended boon docking trips in mind, so I'm off road ready as well.

All I need to do now is clean the unit thoroughly inside and out and load up my gear. Adios friends!

Dan

2007 2720SL
Solar Panel
Duel Batteries
Electric Stabilizers
Surge Protector & Autoformer
2002 Toyota 4Runner 4x4
Prodigy Brake Controller
Supercharged Engine

I'm guessing that you also must have a lift kit. I wouldn't want other 2720sl owners thinking that what you've done can be accomplished without the lift kit. Alone --- the 22 degree'd Dexter axle does not (from my measurements) provide sufficient clearance. I'm going to be going to the RV show in Phoenix --- hoping to find a deal on 15 inch wheels and Maxxis tires.

I understand that the newer models, of which mine is one, all have factory installed lift kits. I don't know what year TM begin installing lift kits as a standard feature, but I suppose that would be important info for some considering the wheel and tire upgrade.

Dan

2007 2720SL
Duel Batteries
Electric Stabilizers
Surge Protector & Autoformer
2002 Toyota 4Runner 4x4
Prodigy Brake Controller
Supercharged Engine

Originally Posted by saltamonte

All I need to do now is clean the unit thoroughly inside and out and load up my gear. Adios friends!

Dan

Sounds like everything went great for you. Please keep us informed of how the 15 inch marathon tires do. Have fun Dan.

[arniland]

Dan, Bobby, and all the others who have contributed to this thread over the months,

I spent last night reading through this thread as well as a number of others. As I stated several weeks ago, we acquired a new 2007 2720SL which had been sitting on the dealers lot for over a year. While our unit is designated a 2007, it was produced in September of 2006. Yesterday I crawled under the trailer to try to look at the clearances on my tires with the thought of upgrading to 15". When I pulled the cover, I measured nearly 3 1/2" above the tire. This is with an empty trailer, no batter, empty bottles, no fluids, cabinets empty.

I then went in and re-read this thread.

We are planning a road trip in early April which will start with a stop at the factory. I have an appointment to have them go over the trailer and intend to learn which drop axle I have. We will make this trip with the original 14" Marathons and crossed fingers. However, this summer we will be doing a trip to the west coast and back which will probably be 7,000 to 8,000 miles. I want to upgrade my tires before then.

So my big question. Are there any lessons learned yet from the great tire experiment? How did the European sized 14" tires do (with the higher load capacity) or should I just bite the bullet and buy 15" rims and tires, and possibly a lift kit? Not asking you to make my decision, just if there is any new information.

BTW - I've looked at the images someone posted a while ago and my 2007 does not have one.

This forum has been a great help in reaching informed decisions. Bought my battery and mud flaps today.

Thanks to all for their contributions.

Arn

I'm kind of surprised that you have 3.5 inches of clearance. I have an '07 2720sl that was manufactured around the same time as yours and it had only 2 inches of clearance. I know for certain that my axle is the 22 degree down, Dexter axle based on confirmation from Dexter (I e-mailed our axle number). I have since added a 2.5 inch lift so I'll have 4.5 inches of clearance before adding the 15 inch wheels. It sounds like you're going to end up with about the same clearance as Bill and, I believe, he's comfortable with how his trailer sits with the 15's. I suppose that deep pot holes could give all of us a headache. I've done a good bit of tire research and I've made up my mind to go Maxxis. I believe it's close to 10 lbs heavier than a comparable Marathon and while heavier doesn't necessarily mean better --- there is a relative scarcity of reports of Maxxis failures. I'm hoping that it's the best choice for the extreme heat of Arizona summers and that its heavier casing makes it slightly less susceptible to catastrophic failures from pressure loss. It's the official "desert" tire for some upcoming event but Maxxis likely bought that claim to fame. I know we're still gathering data and the jury is still out on all of this. I'll going to be one of the Maxxis guinea pigs. Good luck with your decision and keep us informed.
I'm also hoping that Craigslist is going to help take a bit of the sting out of the new wheel and tire purchase. I'll probably run my old fourteen inch wheels and tires for $50-$60 each and a sale would help offset the new rubber.

[Frenchy]

I have used light truck tires on my TM for over four years. I had two blowouts with ST tires before I changed. I bought Cooper tires last time. The dealer said they were a commercial type light truck tire. They were 195R14C, Load Range D 106/104Q with a load rating of 2095 lbs at 65 PSIG. I keep them at 65 PSIG. They are not TT tires however but I have had no problem with them. Ive had them for over four years. They fit and worked very well on my 98 3023 while on four extended trips. One trip to Grand Teton NP (4,500 miles) from southern Indiana. One trip to Alaska (10,000 miles) from southern Indiana. One trip to Carlsbad Caverns (4,000 miles) from southern Indiana. One trip to Grand Canyon, Zion, Bryce, Arches, Mesa Verde (5,000 miles) from southern Indiana. Another trip to Yellowstone (5000 miles). I believe it is very important to have your TM tires balanced and to weigh your TM every time before you take a long trip. I keep the weight on the tires to less than 3700 pounds so the axle rating of 3500 pounds is not exceeded. I never had a problem with the LT tires.

I didn't want to step up to 15"s and checked out the coopers then in my research I just found these load range D 14"s trailer tires at the tire rack Kuhmo 857... Don't know anything other than tire rack has them and they are not too much money... between $70 - $85 depending on size...

http://www.tirerack.com/tires/Sizes....partnum=9R4857

Originally Posted by vrlattu

I didn't want to step up to 15"s and checked out the coopers then in my research I just found these load range D 14"s trailer tires at the tire rack Kuhmo 857... Don't know anything other than tire rack has them and they are not too much money... between $70 - $85 depending on size...

http://www.tirerack.com/tires/Sizes....partnum=9R4857

Vrlattu, First of all I want to welcome you to the trailmanorowner forums. You will never find a better place where everyone will try their best to help you. Feel free to ask any questions you may have or share any advice you have.

ShrimpBurrito and Hsannerud are utilizing the Kumho's on their trailers and can probably tell you much more about them. I think they are extremely satisfied so far with them. We are experimenting with different tires and trying to keep everyone updated on the performance of the tires. If you do go with the Kumho's, we would appreciate if you keep us posted as to how well they perform.

http://www.trailmanorowners.com/foru...umho#post44316

The Kumho 857 specs are located here, in case you didn't see them on the tire rack site.

http://www.trailmanorowners.com/foru...umho#post40920

Thanks

Bobby

[arniland]

After reading Frenchy's experience with the 195R14s and a growing unease with the Marathons my TM arrived with, I had my local tire dealer see what he could find. He came up with Kumho 195R14Cs for a reasonable price. His supplier spoke very highly about them. Three are now mounted, balanced and installed. Count me in on the experiment. Looking at the specs, I picked up a nearly 450 pounds (12%) increase in load rating.

I believe that someone said in an earlier post that the 195s were a little narrower. Well, my spare went back up a LOT easier than the old one came down. To get the Marathon spare down I had to release a bunch of the air and finally pry the rack out with a flat bar. It went back in by hand with a fully inflated (65 psi) tire.

Arn