Was just wondering what you guys thought about this.

Im going on a good length drive later in the year pulling a small trailer. I have 30" BFG's all the way around now. If i get a flat would it be ok to use the OEM spare (good condition) or should I get another 30. Did not now how much size difference there was and if it would make a difference if it was not much. Its a 99 4x4 Explorer. I think the OEM size is 235 but not positive.

As long as you don't have a locker in the rear, the OEM will be just fine. With a locker in the rear if you have two different size tires, the smaller one will want to spin faster than the larger one. for the front it's not a problem either way unless you have a locker and use it while the different size tires are on it.

I guess even if you do have a locker in the rear and you got a flat in the rear you could switch one of the front tires to the rear and use the spare on the front. So it looks like either way you will be fine. Have a great trip.

I could be wrong but using a different size tire could cause your control-trac to kick in and out,it might be ok for a short distance but id prefer all tires be the same size.Especially if driving a long distance.

just dont run in 4x4 with it..atleast thats what my owners manaul says.

EDIT. you have auto 4x4.you might wanna do the brown wire mod. cause my manaul says running a different size tire with auto 4x4 will screw up the computer.

It is not a good idea to run a different size tire on a 4x4. The transfer case may bind up and not get out of 4x4, which will cause horrible on-road manners. I would try and get the same size/brand 30" tire to be safe. The 29" tall will be okay, but it's really not a good idea. Good luck.

-Drew


EDIT: if you do run the 29" tall tire - run higher pressure in it to give it more height (it may wear bad if you drive on it for a long time, but you run a less chance of messing up your Xfer case or worse)

How about a first gen with 31's? Should I be ok running the stock spare if I needed it? I have no lockers or anything. I don't see a problem since many cars have mini spares.

I have a first gen have (open rear diff) and used the oem spare with bfg 30s without any issues.

Check this thread out: http://www.explorerforum.com/forums/showthread.php?t=131673

Thansk for all the info guys, sounds like I might just go ahead and buy a new BFG for the spare instead of taking any chances of messing anything up. My X does have the AWD system so might be best to buy a new spare. :)