Full size spare necessary?

[BRubicon84]

Question from a first-time Jeep owner. I've got a 2019 JLU Rubicon and have been planning upgrades over time. About to install a lift, and will follow up with bigger tires. I am planning on going from the the stock 33 BFGs to 37s. I plan on keeping the stock wheels (due to cost, weight, and I also like the look), so I am wondering if it is really necessary to buy the 5th 37in tire for the spare? Reading about the extra care/cost to have the larger spare I wonder if it is even necessary. Correct me if I am wrong, but upping the tire size means I should add reinforcement to the tailgate, relocate the brake light, and of course, pay for another tire. I understand if I have a flat, it'll be an awkward drive to get the tire fixed/replaced, but is that the only issue to be aware of? I don't wheel heavily, and don't expect to. I appreciate the help! Please help me understand if there is something i am missing.

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[rickinAZ]

Cosmetics? Plus...I don't think that you can drive safely with that disparity in size, so you might be in for some inconvenience. That said, I've never had an on-road flat in a Jeep.

 

[BRubicon84]

Cosmetics? Plus...I don't think that you can drive safely with that disparity in size, so you might be in for some inconvenience. That said, I've never had an on-road flat in a Jeep.

Good point... cosmetics is another element in the decision, albeit minor. I worry more about the safety of driving on different sizes like that. Seems like a lot of other vehicles have tiny donuts instead of full size spares. I understand Jeeps are not the same as cars.... just an observation.

 

[jdubya421]

Once you buy all 5, if you stay with the same tires and don't rotate your spare, you only need to buy 3 tires next time and will have 4 spares.

 

[OldGuyNewJeep]

 

[BadAssBumbleBee]

Good point... cosmetics is another element in the decision, albeit minor. I worry more about the safety of driving on different sizes like that. Seems like a lot of other vehicles have tiny donuts instead of full size spares. I understand Jeeps are not the same as cars.... just an observation.

With all the computers in your JL, not to mention 2 differentials, if you try to drive your Jeep with 3 37" tires and a 33" tire, your Jeep is going to freak out before you get more than 10 feet.

Most modern vehicles will allow some discrepancy in tire size from front to rear (1-2% difference in height), but it typically has to be less than 1/4" or you'll start getting all kinds of warning messages or worse.

 

[BRubicon84]

lol exactly. think of all the money he saved only having to buy 4 of those tires!

 

[Tar Heel Wrangler]

Once you buy all 5, if you stay with the same tires and don't rotate your spare, you only need to buy 3 tires next time and will have 4 spares.

I'm going to rotate all 5 and when I need new tires, I'll keep the tire with the most tread as my spare. Then I will not rotate the spare. I'll get a little more life out of the set the first go around.

 

[BRubicon84]

With all the computers in your JL, not to mention 2 differentials, if you try to drive your Jeep with 3 37" tires and a 33" tire, your Jeep is going to freak out before you get more than 10 feet.

Most modern vehicles will allow some discrepancy in tire size from front to rear (1-2% difference in height), but it typically has to be less than 1/4" or you'll start getting all kinds of warning messages or worse.

Right on, makes sense.

 

[Black Jeep Convertible]

If you do 5 tire rotations, you'll gain an extra 10-15k miles of tread life. That's another 1-3 years for some people. For me that will be another 2 extra years before I have to get new tires and by that time, it'll be racing against tire degradation.

 

[rickinAZ]

Good point... cosmetics is another element in the decision, albeit minor. I worry more about the safety of driving on different sizes like that. Seems like a lot of other vehicles have tiny donuts instead of full size spares. I understand Jeeps are not the same as cars.... just an observation.

Difference is that those tiny donuts are the exact same diameter as the full size tires. Your approach has vastly different diameters. I think that you'll feel differently about the cosmetics after you see the mismatched setup for the first time.

 

[BRubicon84]

Thanks for the info and help everybody. I'll go with 5 new tires, and rotate them over time.

 

[Nomod]

The manual states the factory spare tire, although it appears to be the same as the four on the ground, is a temporary tire. I'm aware the manuals are often used for different vehicles so I'm asking if anyone knows for certain if the spare is or isn't temporary.

 

[Rico1111]

All 5 tires are exactly the same and that is why when you go in for an oil change at the Dealer...They ask...4 or 5 tire rotation( if you are having that done which you should every oil change). So it includes the 5th which helps to keep all tires evenly worn and there is a specific rotation to include the 5th.

 

[jmr]

On my Willys JL the spare tire is the same as the other 4 tires.

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