Tires?
 

I have 2005 4runner 4wd V8
At 133,800 mileage


I had one tire blowout


Do I need to change all 4 tires?

I'd say probably not as the implication is the other 3 aren't too worn. Putting the new one on front is preferable if you don't have a Limited.

What are the condition/age of the other three tires?
How about your spare?

the 2 tires are about 30,000 miles old, the 3rd tire is 13,800 miles and the 4th is the brand new.

Does this affect the drivetrain just like those AWD Subarus?

Yes and no. Late model Subarus are full time 4wd; asemetrical tires on pavement in 4wd causes slight but constant drivetrain windup.

Your tires with the most mileage are slightly smaller in circumference than those with less mileage (I assume all tires are the same size); there will be a smaller difference in the other two. Off road, these differences don’t make any real difference with your 4Runner in 4wd. Since your truck will be in 2wd most of the time on the road, having a new and old tire on the rear end can be a slight problem if left this way over time.

However, I suggest the tires with the most wear be mounted on the rear. This way they are close in circumfrence for pavement and won’t cause any undue stress to the rear differential in day to day driving.

I think My 2005 4 runner SR5 V8 is a full time 4WD since I don’t see any toggle switch control to alternate it to 2WD and vice versa.

OK, then it likely has a center differential, which will help things. I knew of availability of AWD 4Runners, but don’t know what years they were offered. And I don’t know what ratio split front/rear they normally run (most AWD systems can vary torque split depending on conditions).

Basically what you have is two tires of approximately the same mileage and wear; a slightly used tire and a new one. Given that you maintained them by regularly rotating them you should be OK. Differences in circumference is slight to begin with, but is real and it is there. The center and rear differentials should negate the slightly different turning speeds and circumferences of your various tires on the pavement without undue wear or damage. But over the time before you swap out all four tires it might have an effect in increased wear, even if it is a bit more metal shavings in your differential oils. And your tires will also wear slightly faster. But catastropic failure? No. Unless something’s ready to go already. Given it is a Toyota, I doubt it. They are tough trucks.

It is major differences - large differences in tire size - that can cause damage on the road now or later. Over the decades I’ve seen plenty of vehicles with major differences in tire size front/rear and wince when I think of the circumstances when they pull back on the transfer case lever.

At least change them in pairs. I generally will do all 4 as I am a tire freak and worry about them more that any other part of the car.
I threw out my stock Subaru Legacy GT Bridgestone Potenzas with 5k miles on them as they were dangerous when it rained. I also got rid on my stock 4runner Duelers with 5k as they are garbage in the rain as well. Trying to save money on tires can be deadly. Not worth the risk in my opinion. Save the extra for a spare spare. Just my .02.