OK to run spare tire with different backspacing?

This may be a dumb question, but I'm wondering if it's okay to run a spare tire on a wheel with different backspacing than the other three wheels?

I have a '91 XJ, RE 3.5" lift, 31" BFG A/T's on 15x7 aftermarket aluminum wheels (American Racing AR-23). I have not measured my particular wheels, but I looked them up online and apparently the backspacing is 3.75". Whatever it is, they definitely stick out a bit further than the stock 15x7 alloys did.

I have been running around town with no spare tire, but with a 12 hour road trip coming up I finally got a hold of an extra 31" BFG. I was planning on mounting it on one of my old stock alloys, but the difference in backspacing just now occurred to me. Will it be okay to run the spare on this wheel, should I need to actually use it? Or will it cause weird handling issues? I could order another AR-23 to match, but I'd rather save some money as long as I'm not going to compromise safety.

other than rubbing issues because of lack of backspacing it should be fine to use as a spare

X2^^

IIRC, the factory space saver spare doesn't even place the centerline of the tire/wheel in the factory location. You'd be fine for a quick trip or two on a differently backspaced wheel.

I have driven with a different offset spare a few times, no troubles. Coudn't even tell oddly enough. At the time my wheels were 4.5 BS and the spare was 3.75, it looked stupid but drove fine even on the front

only time you might notice is in heavy rain if the backspacing is excessively different

Tacedaddy, can you elaborate? Heavy rain is definitely a possibility living in the NW.

I assume I shouldn't have any real rubbing issues with a 31X10.50R15 on a stock alloy wheel. If there's a little loss of turning radius it's no biggie as it'll only be used as my spare. I'm more concerned with how it'll affect handling at highway speeds. Of course I would drive a bit more cautious knowing the spare is a different offset, I just don't want any unpleasant surprises should I have to dodge someone cutting into my lane at 60 mph. I'll be driving through some pretty remote stretches of central California on this trip and it may be 2-3 hours to get to a tire shop should I get a flat.