Okay to leave spare flat?

Upgrading tires but want to keep spare in stock location. Will it be ok for the spare (305/70 or 295/70) to be kept under the truck partially deflated? The tire will be stuffed under there and won’t be uniformly round. Is that ok for the tire in the long run? I have on board compressor, if I do ever need the spare.

 

I would be concerned about it permanently deforming and making it thumpy.

No different than parking a vehicle for years sitting on the tires.

If your okay with only using it in emergency situations and then replacing it with the new tire, then i think it would be ok.

 

Other than as message board-fodder, what's the advantage of doing this?

 

It won't fit inflated.. the benefit is it fits.

 

I've seen it done before and I've done it on customers cars that had aftermarket exhaust where the spare was touching the exhaust pipe, so we lowered the pressure

 

Less weight? Dropping to 2 psi vs 35 psi saves a lot of weight. Over the life of the vehicle, this could add up to a lot of gas savings.

Sorry, I'm joking.

You won't hurt anything, but I would recommend leaving a little pressure in the tire to make sure the bead remains seated. It would suck to find out you needed that tire but you couldn't get the thing inflated with your onboard air or similar compressor

 

thats when you bust out the brake cleaner and start spraying and hope you dont over spray and create a pressure bomb

 

I still seat the beads that way, it just takes a bigger squirt of spray, since the new stuff is so weak.