265 tires and 245 spare???

[marlinsdmax]

What are the consequences if any, for running 265 tires and a 245 spare. I've been told never to run spare in 4WD. Is that all???

[Jimamatic]

Marlinsdmax, I'm not an expert here on the dpage but, I do think running a 245 spare with 265s is'nt a great idea, especially if you have a long distance to drive and or need 4x4. If it's in the back and your Eaton locker (if you have it)engages from wheel spin it will start to bind. Not good.
When I converted to 265 75R 16Es I traded my unused 245 spare in for a used 265 spare. No use having a brand new tire that never gets used. All it has to do is get me to a tire shop. The important thing is that it will be spining at the same rpm as the rest of the drive train...

[DmaxMaverick]

I carry a 245 spare and have 285's on. I've had to use the spare (on the rear) once and had no problems. I didn't have the time to switch the front/rear good tire. I wouldn't suggest 4x4 unless absolutely necessary, as powertrain wind up would certainly be evident. The Eaton locker didn't notice the smaller tire. I had to drive about 60 miles and speeds were up to about 60 MPH. The rear end didn't seem to heat up more than normal that I could tell. The tire size difference wasn't enough to lock the rear end, but the differential speeds would probably cause problems with the side gears over a much longer distance. I changed the lube immediately after the trip and didn't notice anything different with the lube.

I'd do it again if I had to, but if time and resources allowed, I'd switch the spare to the front.