Running spare tire w/more tread question

I've got a set of Wrangler RTS tires with about 30k on them. Have been doing only 4 wheel rotation.

Blew one out today. Tire not repairable. Put the spare on which is brand new.

The other 3 tires have about half tread left on them.

Anybody see any problem with running one tire with full tread and the others at half tread, for about 20k to get me through the life of the remaining 3 tires?

Trying to cheap out and get the most out of these tires.......

NP242 selec-trac case. Daily driver. In 4WD only in heavy snow.

Thanks guys....

which axle is the spare tire currently mounted on?

If you have a rear locker or limited slip I'd put the spare on the front. If not, it probably doesn't matter much.

Suggest to get one new tire to match spare, brand, size, etc., and put both on the same axle.
Use one of the worn tires for spare.

Not sure, but as I recall, there is something about the 242 Xfer needs to have tires close to the same diameters or gets into binding issues.

X2 on limited slip- needs to be close on diameters.

Good Luck,
Orange

The spare with more tread is currently mounted on the rear.

I know the locker is sensitive to this issues, but I don't have that. Stock 242 t-case.

Just 2 cents.., lol, and really.., just 2 cents! One thing I have noticed on two lane asphalted roads that have a noticeable convex surface, for water drainage, etc., that what helps my rig maintain a straight forward line of travel is to add a pound of extra air in the right side tires, front and back. Hence, if I were running a larger diameter tire, i.e., same tread, new versus old, I'd place the newest one in the rear right side, especially if I was pressed for cash preventing me of obtaining another tire, or a set, etc., and add that pound, or maybe two into the front right side tire.

When I bough my Jeep - a '99 with a 242 case - it was difficult to shift back into 2wd from full time 4wd. One front tyre was new and one was half worn. Since then I have replaced all four tyres and it shifts in and out of 4wd no problem.

yea i would not use full time with tires that have mismatched sizes.

Update:

Tire that I blew out was not repairable. Tire shop found a used tire of the same brand, model, size, and close in tread depth for $40 so we bought it. Goodyear Wrangler RTS. I know these aren't great tires, but I've honestly had very decent luck with the last 3 sets of them for a daily driver.

I rotated tires at the same time as I did this tire swap.

The new (used) tire is now on the left front. Wouldn't you know it, it now has a very noticeable vibration ONLY between 58-62 mph.

This vehicle, for the past 60k, has been very susceptible to a vibe at this specific speed range. It's very fussy about everything being good, both mechanically and tire related or it will vibe there.

Anyways, this new (used) tire on the left front did have some slight cupping on it. Not real bad, but we could feel it. I just talked to the tech at the shop and the consensus is that this cupping must be the cause to trigger the 58-62 vibe, as it didn't have it before today. So it has to be tire related.

The options to me look like this:

1. New tires. Tire shop of course is quick to come up with some quotes!

2. Drive it for a while to see if the cupping related vibe changes with some miles. Which I may do, but if that doesn't help.....

3. Swap that left front to the right rear maybe? The suspect tire is LF, so does getting it to the back make some sense here and then maybe schedule my next rotation a little sooner?

Any other options I might consider here?

Thanks guys.......