Spare Tire Rack Modification

I decided to modify the spare tire holder on our 2720sl after a wrestling match to remove the tire for balancing and after seeing the holder's indentations in the tire's side wall. Apparently, some members' spare tires have been permanently damaged by the supporting framework after long term storage in the rack. I read about the modification sometime back in a post from another member. I'm not sure if what I did exactly conforms to the original recommendations. I'm attaching some photos of the simple modification. I used two, 3 x 3 inch steel plates that were 1/8 inch thick to increase the length of the rack's vertical metal supports by 9/16 inch (on only the curb side). I chose to drill the holes BEFORE cutting the vertical supports. Just be sure you allow for the gap you wish to produce before aligning and drilling your holes. If I had it to do over again I would have produced an 11/16 inch gap. There was still a slight compression of the sidewall when I remounted the rack. It was not enough to do damage -- but it still offered some resistance to remounting. I really can't imagine why the factory doesn't make the modification. The bars' compression on a fully inflated tire's sidewall is unnecessary.
I used 5/16 inch, stainless steel bolts with both lock washers and castle nuts. I didn't want anything to vibrate loose over time. Of course, I painted the raw metal pieces before I mounted them in place.
Oh, one of my three tires required quite a few weights to provide proper balancing. Now I've installed mud flaps, balanced the tires, modified the spare tire rack, and done a thorough inspection of the tires. We're ready for more summer adventures. Wish and yours -- safe and memorable TM moments.

[Bill]

Aha! You made the mod to the rack part of the assembly. I was going to do it to the ledge (frame mounted) part of the assembly, but I think your way makes more sense.

Bill

[rickst29]

My version uses weaker aluminum as the 'extender', but since I've got aluminum bar are on BOTH sides of the original steel, there's not gonna be any 'torque' forces created by the offset of the single plate in your version.

With strong steel and 4 bolts, yours ain't going anywhere either-- it's exactly what I was thinking when I first pondered a one-sided solution. We even chose the same bolts! I'll definitely take your advice to leave a space of at least 11/16. Maybe a full inch, because my "squashed sidewall" solution took away 1/8 inch AND I've got the 225/75-R15 tire, which is wider than yours.

I'm betting that you figured this out without looking at that Thread, because you didn't do my "squashed sidewall" fix-up at the same time you had it down for this job. (At least, I don't SEE a wide plate under the tire in your picture. That's the main thing I put into the Thread Bill pointed at, this idea appeared only as the very last post.)

Nice idea, and nice work!

[Bill]

As noted in the TiresTiresTires forum, I've made the move to 15" tires. These tires are a bit wider than the OEM 14" tires, and therefore even less tolerant of the cramped vertical dimension of the spare tire carrier. Eric Larson made a great mod to the carrier (shown above in this thread). As part of my move to 15" tires, I tried a different mod. It is not better than Eric's mod - just a different approach.

I dropped in at my local welding shop, and asked the guy to give me a 10-inch piece of 3/16" X 1" x 2" channel iron, with 4 holes drilled in it. One side of this piece is attached to the carrier's hanger loop with a couple 1/4" bolts and nylock nuts. The rest of the story is in the pictures attached below.

Pic 1 is a schematic of the original spare tire hanger.
Pic 2 is a schematic of what I was trying to accomplish. The vertical scale of the extender is exaggerated - it is actually less high than it is wide.
Pic 3 is the actual channel iron that I got from the welding shop.
Pic 4 shows the channel iron bolted to the carrier's hanger loop.
Pic 5 shows the modified carrier hanging in place under the TM.

At the dimensions shown, this mod provides about 5/8" of drop, which turns out to be just about right. The new 15" tire fits nicely on the carrier, and can be raised into place by hand. The advantage of this approach over Eric's is that the channel iron carries the weight, rather than any bolts. The bolts simply keep the channel iron in place. Also, it requires no hacksaw work. The disadvantage is that it is a bit harder to put the safety clips in and out of the retainer pins. And it is more expensive. As I say, I think it's a wash.

Bill

[lorianne6]

This is my first post. I bought a 2008 2720 SD this past month and I love it. It is in excellent condition, in fact it must not have been used much at all and kept in a garage. Maiden voyage with me and my sister went well, traveled almost 1000 miles with it and learned plenty from other campers, and reading the manual and hands-on. So, even the tires look fantastic, but from reading through this forum I found out that they are time bombs. Their date is from 2007. So they are being replaced and I'm going to 15 inch rims and tires. Now I have to get the spare tire carrier mod done, and my question is: Why are the mods only adding 5/8" or 9/16" and not an inch. The 14'' tire in the spare carrier now is totally snug to bottom of the trailer. Aren't 15 inch tires an inch wider than 14 inch tires. Maybe a dumb question, but I'm not doing the mod myself (since I'm a girl ha! and bending steel and drilling holes in it is way beyond me) and will be having it done somewhere. Thank you everyone who posts here. If I hadn't read this forum I'd still be taking the TM out with these 2007 14" Goodyear Marathons. I think I was lucky they got me home safe on my first trip.

[Padgett]

Depends on the tire. the first numbers are the section width in mm, the second the aspect ratio in % (section width x aspect ratio =diameter) and the third the wheel diameter.

So my 205x75R15 LRD (2150 lbs at 65 psi) are 10mm or about 4/10" skinnier and 8/10" taller than the 215x75R14 LRC (1850 lbs at 50 psi) that came on it.

15" wheels are an inch taller than 14" and mostly come in two widths for 5x4.5 trailer wheels, 5" and 6". I would want at least 6" wheels rated for the same load as the tires.

Wheels, tires, and axles are an area that I feel that TM may have cut a few corners & am seriously thinking about swapping in a 5k #11 Dexter axle with a 22.5 degree drop (stock is a 3500 lb #10 axle with what appears to be a 10 degree drop and does not leave enough clearence in the wheel wells IMNSHO). This may require 6x5.5 wheels. I do not believe in just raising the coach .

[lorianne6]

Thanks for the info. I will figure out a way to add the appropriate space. And I am hoping the 15" tires will be an adequate fix for me. From reading all the posts on here, the 15" tires seem to be performing better, and I haven't seen much of anything about them failing. As for me, this is where I'm drawing the line, no new axle for me.

[Bill]

The forum's tire guru, WMTire, reminded me a few years ago that the nominal "size" of a tire (14-inch, 15-inch, etc) refers to the size of the hole in the middle of the tire. Nothing else. So you can have a 14-inch tire that is quite narrow, or really really wide. And it can have huge diameter like a tractor tire, or a diameter that is not much more than 14 inches. If you have seen pictures of cars called "low-riders", you have seen this.

Bill

You rascal --- I like it !

I installed my 15” wheels and tires last year, but I was still using the 14” spare. But with the opportunity to sell all three of the old 14” wheels and Marathons, I finally had to get a new 15” tire mounted on a previously bought new wheel. After carrying that puppy in the back of the truck on a recent trip to OBX, I decided to break down and use 1 of the excellent ideas in this thread. Figuring that Eric’s modification might save me a trip to the machine shop, I decided to try that 1……with a twist. I bought a 3’ section of 3 x 1/8” steel flatbar (they didn’t have a 2 ½” width similar to the TM spare tire mount) at Lowe’s, with the intention of bending it at home to fit around the current spare tire hanger. After several attempts of bending that puppy with a sledge hammer in a vice, I realized that I needed to have a machine shop to bend that for me so that it would be straight across. I then sized things up, drilled the holes, and installed the new piece over the old hanger, allowing for about a ¾ to 5/8” drop. That allows for the far side of the spare to fit snug up against the bottom of the TM, but the closer side still has a little gap……a compromise of sorts. I didn’t want to do it any tighter, and maybe spring the whole thing. And instead of using pins and cotter keys, I decided to use 3/8” bolts double nutted through the existing hanger, just in case there was a failure in the modified piece, the bolts would hopefully hold things together. Cost for everything, including the machine shop bends and cut was about $35.

After an 850 mile round trip to TM factory in Lake City Tn. this week, everything seems to ride OK.

Chap