I just love all the speculation on this thread.

No tire or jeep damage resulted from this experience. (running undersize spare on the front)

You will not damage a tire running at low psi unless you just plain act stupid. I frequently run 5-8 psi back from the trail. I have done this for over 25 years and have had ZERO tire failures!

NONE!

There have been plenty of threads on this and not 1 single person has posted up saying they had serious damage to their jeep as all the fear mongerers on here have stated.

A 33" spare will be fine if running 35s, open diff, front end. It will also save your tail gate.

 

Yeah....I totally agree. Nobody has said how they tore up their jeep because they did this. Besides......just because a 35 is stated 35 doesn't mean it is 35 inches tall.......it could be closer to 33". And the other way is true also. The 33" tire could be closer to 33" than the stated 35 is to 35". The difference "may" only be minimal.

 

All these different opinions is what the forum is all about.

In making a decision, it's good to consider the entire spectrum, including both ends.

You read all the material, and make up your own mind.

 

If you run a tire at a low psi then it will create heat and eventually cause a blowout. This is a FACT. A spare doughnut is usually the same height as the other tires, it is narrower though. You could run a smaller tire on the front IF you had to but I think it would be wise to invest in a full size spare. Who wants to play musical tires beside the road in the middle of the night?

 

Of course, everyone has an opinion and is entitled to share it. Just be sure to take those opinions (including mine) with a grain of salt.

CJ7nvrstk is running 36" tires and an undersize spare. He's also running those 36" tires on an auto JK with 3.73 gears. That setup is far from what would usually be considered "best practices". Just because it happens to work for him doesn't mean it's right.

Plenty of people have been stranded on the trail because the didn't have a proper spare. They're lack of preparation requires other people to take their time to help save their bacon. It's foolish and selfish.

Why does every car manufacture provide a spare that is the same diameter as the rest of the tires? Why does every off-road capable vehicle come with a spare the has the same capability has the rest of the tires?

If one can't afford to do something right they should seriously consider if they should be doing it at all.

 

No one will argue that running a matching full size spare is the definitive way to go. But, you can run a slightly off sized tire in case of an emergency. This is if you're running open diffs. Run it up front and only use 4wd when you absolutely must. Keep the speed down and the distances short.

By the way, doughnut spares are NOT the same diameter as operating rubber. And yes, running a tire that is low on pressure at higher speeds WILL wreck the tire due to the excessive flexing of the sidewall creating heat

 

They don't. Most space saver spares are shorter than the tires they are meant to replace. Literally millions and millions of automobiles use space saver spare tires for one reason, ... they work.

And some manufacturer's don't even include spare tires. Our 2008 Challenger SRT8 does not have a spare tire, and our 2010 Grand Cherokee SRT8 does not have a spare tire.

 

Point well taken... one should never use absolutes. Space saver spare tires of smaller diameter were much more common in the past before widespread use of electronic stability systems. However, compromised performance spare tires are only found on light duty road vehicles, not trucks and sport utility vehicles.

My Corvette didn't come with a spare either. This meant that except for a narrow range of circumstances, self-recovery from a flat tire was not possible. Do you really want that situation 10 miles down a trail in your Jeep?

The argument against having a full size (and full capability) spare on a Jeep is the very definition of penny wise and pound foolish.

 

i wouldnt reccomend running it in 4wd with a smaller tire. just make sure youre in 2wd and have the same size tires on the back. my spare is smaller than my other 4...although ive never had to use it

 

Exactly.....and that's what spares are for....an emergency. And a smaller tire WILL work in case of an emergency.