From 14" to 15" Wheels and Tires

[angerlo]

I changed from 205 75 R 14" Good Year Marathons to 15" Maxxis tires and 15inch wheels after several blowouts on my '97 3023 TM. The following website was most helpful in measuring the rims to get an exact similar rim one size larger. The site is:
https://www.rsracing.com/tech-wheel.html
This site on wheel technical information discusses how to measure bolt patterns and how to measure back space. The backspace (distance from highest part of bolt circle to top of outer lip of wheel) on my 14" rims was 3.5inches. This means my offset was "0" as indicated in the Backspace to Offset Conversion Chart. I purchased two 15" wheels by searching for them on the Internet. Look for Trailer wheels.
The M 8008 ST Radial 205 75 R 15 Maxxis tires (part No. TL15703000) are 1.1" taller than the 14" Good Year Marathons. They are 8 rather than 6 ply and rated to carry a load of 2040 lbs at 60 psi and a load of 2150 at 65 psi. At 65 psi is load range D. I sure hope these tires are a better fit for our well engineered and cared for TM. Load range for the Good Year Marathons was 1760 lbs per tire.
Since I have had at least one, perhaps two blow outs due to poor valve stems made in China, I opted for all steel valve stems. They are solid and available. (Nappa Part #90-416 Tubeless Clamp-In Tire Valve TR 416
1 and 1/4" lenght, Fits .453 and .625 rim holes).
Hope this info is helpful to anyone looking for a tire-wheel upgrade.
Happy camping!

[Wavery]

Thanks and welcome to the forum........that's very helpful information.

[RejoiceWay]

Thanks for the posting. We just ordered a lift kit yesterday and will be converting to 15" soon, so this information will be very helpful. Really appreciate sharing you experience!

[Wavery]

Thanks for the posting. We just ordered a lift kit yesterday and will be converting to 15" soon, so this information will be very helpful. Really appreciate sharing you experience!
You may find this thread helpful for the lift kit installation.
http://www.trailmanorowners.com/forum/showthread.php?t=10292&highlight=lift+kit+installation

You will find that your axle is welded to the frame. Be prepared to cut those welds. I used a 4" angle grinder with a steel cutting wheel. Also, carefully mark the location of the axle by scribing a mark down the frame and the axle with a square up against the trailer floor. Before tightening your new bolts, be sure that the scribed mark lines up by again placing the square against the trailer floor and lining up the scribe marks.

I would recommend having the lift spacers welded to the frame after installation (to keep it from moving fore & aft on the frame). It shouldn't be necessary to weld the axle to the spacer.

[RejoiceWay]

We'll be sure to check out this link when we receive the kit. It'll probably be a while before we get the kit installed, but will let you know who it came out.

[tgpmd1]

Thanks for the posting. We just ordered a lift kit yesterday and will be converting to 15" soon, so this information will be very helpful. Really appreciate sharing you experience!

RejoiceWay,

May I ask about how much the lift kit from the factory was with shipping?

Thanks!

Theresa

[Bill]

Are you sure you need a lift kit? By 2006 (the year of my TM), I think every TM that left the factory had a lift pre-installed. It might have been in the form of a lift "kit" (a length of rectangular steel tube bolted between the axle and the frame on each side), or it might have been in the form of a higher-angle axle.

Adding a lift kit to a trailer that is already lifted won't hurt anything (assuming you can still get it into your garage), but the higher center of gravity and increased wind resistance are not necessarily good things.

Bill

[RejoiceWay]

This lift kit w/harware was $40, but we had ordered a bunch of other stuff so can't say what the freight costs would have been just for the kit. We did end up taking it to a shop and had it installed at a cost of $187.50. When we took it to the shop we had printed out instructions from this forum and they really appreciated the detail.

[tgpmd1]

Are you sure you need a lift kit? By 2006 (the year of my TM), I think every TM that left the factory had a lift pre-installed. It might have been in the form of a lift "kit" (a length of rectangular steel tube bolted between the axle and the frame on each side), or it might have been in the form of a higher-angle axle.

Adding a lift kit to a trailer that is already lifted won't hurt anything (assuming you can still get it into your garage), but the higher center of gravity and increased wind resistance are not necessarily good things.

Bill

There is no lift kit and it has what appears to be original 14" Good Year tires. When we bought from the original owner, they advertised and we bought what we thought was a 2005, but that's when they ordered it from the factory. It was a 2006 model on the title.

[Scott O]

Thanks for the original post angerlo. Since so many TM owners have shifted to 15" and metal stems, seems the number of wheel problems has diminished. Don't know which factor was most important, but the results seem positive. Good luck with yours...

[tgpmd1]

This lift kit w/harware was $40, but we had ordered a bunch of other stuff so can't say what the freight costs would have been just for the kit. We did end up taking it to a shop and had it installed at a cost of $187.50. When we took it to the shop we had printed out instructions from this forum and they really appreciated the detail.

Thanks so much! Sometimes it's worth just taking it to a shop than trying to do it yourself if you don't have all the equipment. We found a very good truck and RV shop not far from us. Everyone told us that we wouldn't be able to find a place to get the TM inspected anywhere near D.C., but I kept looking around and finally found this shop. They seem very knowledgeable and we just had them do work on the TV. Their prices seem very fair. I love this forum!!! Like a big TM family. :)

[moaboy]

North of DC -about 10 miles south of Thurmont MD (which by the way is the turnoff for Camp David) on highway 15 there are two very large and comprehensive RV dealers. Endless Mountain -the one you see first going north is my favorite and their prices are better. Plus near Thurmont is a pretty state park if you wanted to go to a dealer and go camping. Beautiful country especially in the fall.

[tgpmd1]

North of DC -about 10 miles south of Thurmont MD (which by the way is the turnoff for Camp David) on highway 15 there are two very large and comprehensive RV dealers. Endless Mountain -the one you see first going north is my favorite and their prices are better. Plus near Thurmont is a pretty state park if you wanted to go to a dealer and go camping. Beautiful country especially in the fall.

Are you referring to Cunningham Falls State Park? We tent camp there all the time both with the Cub Scouts and our family. Love it!

We've only had our TM out for three camping trips since we bought it in July. One trip to the KOA in Hagerstown and two trips to VA (Natural Bridge and Luray). May need to take a trip up North and visit those dealers. Not sure if they or mail order is the way to go on the 15" rims and tires.

I've been to Camping World in Northern VA or Queenstown RV in College Park for supplies. Seems cheaper to mail order from Camping World if we need something right away. Also found some Walmarts have a few general supplies. The selection varies from store to store.

[Steppy]

You may find this thread helpful for the lift kit installation.
http://www.trailmanorowners.com/forum/showthread.php?t=10292&highlight=lift+kit+installation

You will find that your axle is welded to the frame. Be prepared to cut those welds. I used a 4" angle grinder with a steel cutting wheel. Also, carefully mark the location of the axle by scribing a mark down the frame and the axle with a square up against the trailer floor. Before tightening your new bolts, be sure that the scribed mark lines up by again placing the square against the trailer floor and lining up the scribe marks.

I would recommend having the lift spacers welded to the frame after installation (to keep it from moving fore & aft on the frame). It shouldn't be necessary to weld the axle to the spacer.


I'm changing from 14" to 15" wheels on my 2004 2720SL. I'm also replacing the brake assemblies and bearings & races as well. Yesterday after pulling the old the curbside brake assembly, I glance up at the place where the axle is bolted & welded to the frame and got a big shock. The forward bolt was gone, and the forward weld holding the axle to the frame was broken. If it were not for the fact that I was replacing the brake assemblies & installing a lift kit, I doubt that I would have detected this problem.

I guess the moral to this story is to inspect your axles to make sure they'll stay on your TMs regardless whether you're installing a lift kit or not!

As you'll see from the attached pic, I have a little frame repainting to do as well. Oh the joy! :)

Happy camping!!

[Bill]

Now that is truly scary!

Bill

[TM Pilot]

angerlo,

How have your Maxxis 205/75R15 8-ply load range D tires been for you the last 3.5 years? A few months ago, I upgraded from 14" to 15" rims & tires on my TM2619 and I chose those very tires as well.

[Speckul8r]

Steppy,

I'm sure that did not give you a warm fuzzy at all!! Glad you found that 1 b4 something ridiculous happened.

I changed over to 15" 225 75R15 E rated Maxxis tires this Spring and am very satisfied with the results. Our last trip was only 600 mi but everything seemed to run cooler and smoother than with the 14s.

[tentcamper]

I'm not sure you can conclude it was the wheel size that made the difference. One of the articles I read by a tire experts that is a professional witness. It indicates goodyear changed the thickness of the rubber between the belts or maybe it was between the belts and tread, and that was the cause of the de-lamination problem. Goodyear will not confirm that being the issue or that they had an issue. But they confirmed they change the specification and have gone to a thicker rubber between the layers.

Not sure I have the dates even close, but it seems everyone was having issues with tires made for about 4-5 years. Somewhere in the mid/late 2000's to around 2011 or so. I think Goodyear is past the issue.

So was it 15" tires, different tire manufacture, or the changes that goodyear made.