Is it OK to have a spare tire size of 265/65/R17, when the four driving wheels have 265/70/R17 tires? This is for a 4th gen 4x4 4runner.

 

It will be okay as long as it is very temporary. Get your original tire repaired/replaced & back on your rig ASAP.

 

try to make sure its on the front of the vehicle and 4x4 is not engaged as a lot of newer vehicles come stock with an lsd and a mismatched sized tire can make havoc happen to the clutches in an lsd

it would just be a better idea to get the same sized spare...

 

Don't worry about it, you will probably never use your spare.