Spare tire requirements

[Ski_Pro_3]

Last year I got a set of Rickson steel 19.5" SWR style wheels and 245/70R19.5 tires. A set of 4. Now I'm looking into the spare. My current spare is a stock 2006 Dodge wheel and tire, neither of which, has the load capacity I need.
So, in my pursuit of attaining a 19.5" spare, I have a few questions;

1. Will a 19.5" tire and wheel of the above mentioned size, fit under a 2006 Dodge 2500 4x4 diesel short bed truck? Is there enough room and will the crank/pulley device support the weight?

2. I can find a Vision Heavy Hauler 81 Series Machined Clear Coat Wheel (19.5x7.5"/8x6.5") on Amazon;
http://www.amazon.com/Vision-Heavy-Hauler-Machined-19-5x7-5/dp/B009F9MF82?ie=UTF8&colid=ZO07J7YSGGZ7...
I'm pretty sure this is the size I need for my truck. Can anyone confirm that?

3. Since I have steel wheels and the Vision wheel is aluminum, will I need different lug nuts for the spare?

4. Will the lug nut torque be the same value as with the steel wheels or is it different?

5. Does the tire have to be the same size as the other 4? I don't plan on rotating it. If I ever use it, it will be only for long enough to fix my original tire or to replace the original tire. I'd like to use a smaller, lighter tire than the running size for a spare if it's safe to do so. Even a used tire if I can find a good one for a good price.

Any thoughts or ideas would be appreciated on the topic. Discussion of the necessity of a spare can be in another thread if that's alright to keep things on topic here. I'm mostly just interested in the pros and cons of using an aluminum wheel and off sized tire for a spare considering my 4 tires in use.

[Bedlam]

From what I have read, the 245/70R19.5 tire will fit in the stock location on the Ram and Ford. The GM's seem to be a little tight and may need to be deflated to squeeze in. I know my F250 could carry that size 19.5 or a 275/70R18 tire even with the larger SuperHitch.

The next question is how you will access the spare. I was able to use the jack extension to reach the crank mechanism to raise or lower the tire. It was easier to disconnect the lift chain and pull the truck forward than drag the tire out, but all could be done with the camper secured (I have a big bottle jack for lifting duty). Those with more than 2' of rear TC overhang need to build a longer extension or relocate the crank to the rear wheel well opening.

[mkirsch]

skipro3 wrote:
I appreciate the feedback. I never thought of using the stock wheel with a taller tire, then rotating to the front if a rear tire fails.

It's just to get me into town and a good tire shop that can get me fixed up right after all.

I guess I gotta go do some homework on what would make a good spare tire that somewhat matches my 19.5 diameter.

If you think about it the only reason you put 19.5's on the front was for looks. There is no way you'd ever need that kind of capacity on the front axle.

That's why just going with the factory spare makes perfect sense. The 19.5's are far tougher than even LT-E rated tires to begin with, so you're not as likely to have a flat to begin with. Having the spare is for that real bad day. Only downside is you're changing two tires instead of one 50 percent of the time you have a flat.

IMHO if you need the spare more than once in the lifetime of the truck, you are doing something very very wrong. You're running those tires way too long, or your road hazard avoidance ability needs improvement.

[Ski_Pro_3]

yes, I have an 'open' rear axle. As I recall, the spare fit just fine up there after I had installed my Super Hitch. Tomorrow I'll stick it back up there and verify, but from I'm hearing, the stock spare should work as a 'spare' until I can get to a tire store and get a failed tire repaired.

Thanks for all the feedback guys!

[Farmerjon]

I'm also for just keeping the stock spare and putting it on the front if you have to use it.
Jon

[Reddog1]

Another food for thought on the Vision wheels. There has been one or more posts on the Vision wheels cracking around the lug nut hole. It appears Vision machined a relief at each hole (back side) to clear a brake drum clip. I do not know if this is true of all Vision wheels. I have not had mine off in years so I do not remember if mine have the relief or not. If I were to buy another Vision, I do not think one with the relief would be acceptable. To be fair, the cracking issue could simply due to improper torque. I do carry a torque wrench in my truck. With the special lug nuts, a special socket is required.

As I recall, you do not have limited slip (Anti-Spin Differential Rear Axle). If true, the only down side with a smaller rear tire would by load capacity.

The instructions (03-12 Dodge RAM 2500/3500 HD Long or Short Bed) on the install of your Super Hitch has a SHORT BED SPARE TIRE ADDENDUM. Among other things, it says "... the spare tire will stow away approximately 2”(5cm) lower than it’s original position." It makes no mention of reducing the diameter of the storage area. If you have not made the modification, we can do that. We can install your spare in the storage area, and see just how large of a diameter tire that will fit.

Personally, I am with kohldad and boogie_4wheel on this one.

Wayne

[Bedlam]

I'm looking at moving my spare to the top of the SuperTruss when I get a larger TC, but the truss will 4' long compared your idea of using a 20".

[jefe_4x4]

I've been using dissimilar wheels for years. The most important thing is that the loaded radius be within 2% or so. This means you can run any width tire on any diameter wheel as long as the loaded radius is the same (within the 2%). If you do not plan on running the spare for any length of time, but just as a stopgap, then a skinny, 3860 load rated tire, would be fine. The L.R. is computed with the weight of the vehicle on the tire; measuring from the center of the hub to the ground.
You probably did not take into account the deflection of the tread and side wall making the loaded radius more revs per mile.
My factory spare tire, 16" steel 8 on 6-1/2" rim; -8" wide with 6.25" back spacing, with the stock tire will fit between the frame rails on my 2001 Dodge. Anything larger will not. What happened? I removed the factory trailer hitch and substituted a Class V which has thicker steel and more bracing. I get around that by deflating the tire so as to fit between the rails. I've only used it once in 16 years. On the rare flat tire I've been able to use Safety Seal plugs and my 20 # CO2 tank, and a 12 ton hydraulic jack and jack board to do it all without removing the wheel.

I'm in the throes of deciding where my full size spare is going to go. There are basically three ways to go.
1. Deflate the tire even farther and use a tire iron to swedge it up there while someone cranks it up.
2. fab up a front receiver hitch with a spare tire "L" bracket. Of course, you had better have a great cooling system.
3. Do like Alex (ctraveler2) and fab up a rear, swing away tire carrier that also goes into a Class V hitch. This has it's own problems too, but you won't be running hot in Death Valley..
There is one more possibility with a TC that sticks out beyond the rear bumper at least 18". I think (make that hope) I can lay a tire on top of my 20" hitch extension and fab/weld up a plate with 3 lugs for the spare. This would also be a step up to the door.The added plus is it would be like bumper cars at the carnival if some one rear ended you. 8<)
I don't think one size fits all in this regard. If you need a LOT of approach and departure angle, this would be problematic.
I'm sure some of you have better suggestions. Put 'em on the table.
jefe

[Bedlam]

My math shows that tire at 34.1" tall.

[Ski_Pro_3]

I'm running Toyo M608Z 265/70R19.5
Their website says the tire is 34.4" diameter and 602 revs per mile.
However, checking math here, a 34.4" diameter tire has a circumference of 108.1". One mile is 5280 ft. Doing the math;
108.1" goes into 5280 ft 586 times, or, 586 revs per mile, not 602. To get 602 revs per mile, the circumference would be 105.25" or 33.5" diameter tire.

So, did Toyo mis lable their diameter and it should be 33.5" or did they mislable the revs per mile and it should be 586?
The difference is a 34.4" tire compared to a 33.5" tire.

A handy size for each is;
33.5" diameter tire; 305/70R17
34.5" diameter tire; 315/70R17

I'll be wanting either a 305 or a 315 tire depending on which spec from Toyo I use; their diameter or their revs per mile.

Stupid tire manufacturer's website and their inaccurate data...

I guess I can mark my sidewall, roll exactly one rev and see if it's 105" or 108". Should be obvious...

[Bedlam]

275/70R18 was the same height as my 245/70R19.5 tires. I used that size as my spare. My OEM lug nuts were flat and Vision rims were tapered plus both were a different size nut. Make sure you have the proper nuts and wrenches to swap out a dissimilar wheel. I carry a bottle jack that is strong enough to lift truck and camper rather than unloading the camper to change a flat.

[kohldad]

Newer truck stock tire of 245/70R18 is the 33.1 and the 19.5 should be 33.2. Plus the 18 has a load range of 3450 so gives you a bit more capacity. Plus it will fit in the stock spare tire location since to my knowledge Ram in the spare tire location.

[Grit_dog]

By the calcs, your tires are about 33" tall. Tape measure to verify.
Personally I'd pick up a used, larger 17" tire for the spare. Somewhere between a 285/70-75 and 295/70 17 is what you're after. Plus if you find the right one, they are rated close to 4klbs.
Maybe not the comfort level you're after, but guys run these tires all the time under heavy campers. But as mentioned, in the unlikely event you have a 19.5 go down, your up sized 17" spare will work fine on the front for as long as you need it to.
Also, for slow leak, nail in tire etc, a tire plug and a small air compressor is sooo much easier than changing a rear tire with the camper on. Unless you're prepared for that with a heavier jack too.

[Ski_Pro_3]

I appreciate the feedback. I never thought of using the stock wheel with a taller tire, then rotating to the front if a rear tire fails.

It's just to get me into town and a good tire shop that can get me fixed up right after all.

I guess I gotta go do some homework on what would make a good spare tire that somewhat matches my 19.5 diameter.

[Buzzcut1]

On my Ford the 19.5 Vision and toyo 245/70R19.5 fits underneath just fine. The Visions come with a splined lugnut.