I'm running Pirelli Scorpion ATR's (came with my rig when I bought it.)
They seem like good tires but one has a nail stuck in the sidewall. I was told that I can't buy just one new tire and if I did it would burn up the differential.
Money is very tight right now but I don't want to risk a blowout (transporting children) or burning up the diff.
Suggestions please.
A little better to do two tires, maybe. If your 4Runner is well maintained (ie diff fluid changed at some point and the diffs are full) buying one tire would be ok.
By purchasing the same size, brand and model you are ensuring the Radius will be within a couple of mm.
Think about it, a minor screw-up on the part of the 'Jiffy Lube team' sets you 31psi in one back tire and 35psi in the other (effectively changing the radius by a couple of mm). There's a chance you may not notice that for months, right? (say "yes")
When was last time somebody blew a diff because of a 4psi differential in tire pressure? Now, back to your situation... 3 Pirelli Scorpions with 'x' miles and one new one. The premise of the sales pitch is "the O.D. of the new tire is bigger than the worn tire and therefore your differential is working harder". I say the couple of mm difference in RADIUS (because that's what really matters) isn't enough to worry about even though the diff is, theoretically, working a little harder.
My advice: Buy one now to be safe with the kids. Make sure it's it's same make, model and size. If you want to buy a second that's your choice. I probably wouldn't as I like to replace all 4 tires at once and put the best old tire as my 'new' spare. Take the money for the second tire (which I know is scarce) and do some preventative maint. If you've never done t-case and axle fluids do those...
:cheers:
PS- You may have noticed I referenced same
make, model and size twice. Even though tire sizes are supposed to be based on math (265mm/65%/17in) there's a fair amount of variation brand-to-brand and even within model lines from the same manufacturer. The best way to insure a very close OD is to get another Scorpion.