Spare tire smaller than the tires on the truck?

[shortbus4x4]

What about ABS brakes, stability control and possibly traction control issues with a different sized tire on your 19 ram?

This is what would really concern me. Do a trial test run in your neighborhood and make sure your truck will go with that much difference in wheel speed sensors. A skinny tire that is the same diameter or close to it as your 37s is what I would use and mount it in the bed, it won't take up as much room as your full width tires.

 

[Buliwyf]

You can always use a hitch carrier and then keep your small spare in the stock location. That's what I'd do.

Any open rear diff should be able to survive miss matched tires at low speeds for short periods. I'd try to upgrade my OEM spare for a 35 if was running 37's though. At least try to keep them close. When desperate, rotate the spare to the front axle. Although, that moght be more dangerous than mismatched rears.

Maybe an ABS warning light due to ECM seeing weird wheel speeds, but nothing that'll keep you from getting home IME.

 

[jadmt]

Yes like I mentioned, the ABS system, vehicle stability control... it will throw codes.

codes won't hurt a thing. only time any of that is going to come into play is if you are driving too fast on twisty roads etc.

 

[billiebob]

I think you have me confused with the OP.

In an emergency I also wouldn’t be concerned with senseless DOT and/or government regulations.

Most states have laws about modifying/lifting your suspension as well, but we don’t pay any attention to them.


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you are right... how did I do that ?
And quite correct, there are millions of laws rarely enforced.
In BC it is illegal to drive without the doors on a Wrangler. Even tubular doors are illegal in BC.
But I stand by it is terribly unsafe to run an odd sized spare.

As to the tiny donut spares provided by the manufacturer..... those a factory issue with "how to use" directions.
Completely different from saying I'm just doing what the manufacturers do. They have engineering to validate their recommendation.

 

[warrpath4x4]

one question of the OP, did you try to put a fullsize tire in the spare location? just because a tire is sold as a 37" tire does not mean it is a 37" tire. One person online says his 37 wont fit but yet another guy has a different brand and his does.

 

[dreadlocks]

at least be prepared to change yer diff fluid if you end up limping out on a smaller size tire.. but personally I'd of hard stopped at the max size spare I coulda carried.

 

[kiloxraysierra]

I should clarify-definitely not a donut. I mean just using the stock full size spare versus buying another aftermarket wheel with a 37" tire to match the size of the tires on the truck.

Perhaps not relevant to your situation, but for others reading this thread - if the intention is to put an aftermarket wheel and tire in the spare location, best to verify the spare tire hoist will fit through the center hole of the wheel. I wanted to run a Rebel wheel as a spare on my 1500, but can’t mount it on the hoist because the plate won’t fit through the hole.


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[plumber mike]

For me, it would not matter on a long highway trip....id just pull the fuses for the ABS and head to the next town. But if I was in the woods in 4wd and a bead popped, or a tire got destroyed, I'd want a full size matching spare.
If I committed to 37's, and paid to regear, I'd find a way to bring a fifth 37. I think on the Rams, the heat shield(which is removable) and the tailpipe are the limiting factors.
That said, if I was stuck in the mud with a bad tire, I would not want the spare down under the truck anyway.

 

[outback97]

There was a thread on an Xterra forum where this was discussed. One guy tried running pairs of differently sized tires on the front and rear axles. The computers didn't like it much, it threw CEL's and it went into limp mode.

A Twist on the Unmatched Tire Size Debate

www.thenewx.org

Short term use mismatched spare shouldn't cause any physical damage. But ABS and stability control computers might protest.

 

[Buliwyf]

Do those have an AWD mode?

I doubt any domestic fullsize has a limp mode tied to the ABS sensors. Heck, GM's ABS sensors fail quicker than I can eat iguana burritos.

 

[outback97]

Do those have an AWD mode?

I doubt any domestic fullsize has a limp mode tied to the ABS sensors. Heck, GM's ABS sensors fail quicker than I can eat iguana burritos.

No AWD, it’s selectable 4WD with a transfer case and available elocker rear. The rear axle is basically a Dana 44 and the front is IFS.

I didn’t realize this was the specific domestic full-size sub forum, thought it was more general. My bad. I am curious to know if a mismatched spare would trigger codes or other weirdness with the electronics.

Off topic but I rode in a new Ram Rebel the other day and it was freaking out if we tried to back up with the tailgate down or when there were some weeds and brush behind the truck. It would lock the brakes up. Hopefully that type of thing can be disabled. I was surprised at the amount of intrusive tech in that truck, it was off putting to me.

 

[ttengineer]

Off topic but I rode in a new Ram Rebel the other day and it was freaking out if we tried to back up with the tailgate down or when there were some weeds and brush behind the truck. It would lock the brakes up. Hopefully that type of thing can be disabled. I was surprised at the amount of intrusive tech in that truck, it was off putting to me.

100% agree.

I’m in a rental right now as a drunk lady backed into my Ram in a parking lot.


Personally I like my vehicles analog with a nice infotainment system and a few creature comforts like ventilated seats, that’s about it. All the collision alerts, safety stuff, and auto shut off at stop is all very bothersome to me.


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[Explorerinil]

one question of the OP, did you try to put a fullsize tire in the spare location? just because a tire is sold as a 37" tire does not mean it is a 37" tire. One person online says his 37 wont fit but yet another guy has a different brand and his does.

35’s barely fit in the stock location even when aired down, by all accounts I have read, a 37 will not fit... this sucks!

 

[Explorerinil]

This isn't difficult. It's a pickup, put the spare in the bed.

Having ran years with a 37 inch tire taking up a ton of space in my bed I’ll tell you this option sucks.

 

[Regcabguy]

35’s barely fit in the stock location even when aired down, by all accounts I have read, a 37 will not fit... this sucks!

Yeah,my friend crammed a half worn one in there.