Hello guys,

I have searched alot for an answer and I have not found a direct answer.

I have a 2015 F150, supercrew 6.5 box, 4x4, 3.73 gearing, and the limited slip differential.

I put on a set of 275/60R20 BFG KO2 tires.

My question is that if i happen to get a flat tire, can i throw the spare (which is a smaller tire) on as long as it is on the front without using 4x4? Is it safe to drive if I do not use the different sized tires on the rear?

Thanks!

 

There would be no issue running different sizes up front. I wouldn't run the spare on the back for more than a couple miles if I could help it.

 

I wouldnt ever run two different sizes in the back. If i blow a tire in the back, I will swap a front to the back and then the spare to the front.

As long as running the smaller tire up front wouldnt hurt anything.

 

If the tire size difference is too big the ABS and stability control could cause you issues by engaging even if it's on the front tires.

 

Sell the stock spare tire and put an equivalent sized KO2 on the spare wheel. You should be able to fit a reasonable size under the bed.

 

Tire size: 275/60R20
Spare : 265/70R17

Any idea how much difference is to much?

 

This. I recommend that anytime you go bigger just go ahead and buy an additional tire and generic rim for your spare.

 

I did some research and the closest i can get in a R17 is .2 inches smaller than what i have now. Which is a lot better than what is on there right now.