Poppie51

Hi, I have a 1988 Toyota 4Runner with a 4cyl. engine and automatic transmission. I am in the process of purchasing tires but undecided which size to go with. I am leaning towards the 31X10.5X15 because I think they would look better although I do have a 4cyl. engine. Would the 225X75RX15 be a better choice. They are a little smaller in diameter which would allow me to have more power. I go off road although i'm in south Mississippi so there are no hills just backroads which has a few mud holes so there will be no steep hills or rock climbing where the extra power would be benificial although I don't want to harm the vehicle engine and transmission just because I think the larger tires looks better. What are you guys thoughts? Thanks

muddpigg

iTrader: (1)

What gearing do you have??

Poppie51

I'm not sure. How do I find out?

muddpigg

iTrader: (1)

If your open dif, lift one rear tire. Mark a spot on your drive shaft. Turn the lifted tire one revolution and count the number of times it turns. 4.10 slightly more than 4, 4.88 almost 5, ...

If your not sure if you have a locker, lift both tires and turn one if the other tire turns in opposite direction it is open. If the same direction it's got a locker. Obviously you'd know if you had a selectable.

If you have a locked dif lift both rear tires off the ground. Mark driveshaft and spin tire as mentioned above.

Think that 4.88s are recommended for 31s with an auto. Matter of fact there was a that can stock with 4.88s and 31" tires.

combatcarl

If you haven't changed gearing, and it doesn't appear to have been modified, you're probably stock, and the door jamb nom plate will have an axle code that can be cross referenced to determine the factory ratios. (May not apply if thirds have been monkeyed with) I have an 89 22RE 5spd, and had 235/75s on it for a long time. Ran well, had power. Put 30x9.5s on, same. Two months ago, put 31x10.5s on, and it's a noticeable difference above 3rd gear. Definitely requires a 5-4 downshift on a hill, on bad ones, a 4-3 shift. I have 4.10s, and am hunting for 4.56s, or 4.88s. An auto with 31s will do best with 4.88, manual with 31s, 4.56s. Anything over 31" tires pretty much requires 4.88s with any trans, to maintain any power on road. I haven't noticed any real power difference in L4.

Poppie51

Thanks for the advice. I'm fairly sure it would be stock. I'll look on the door panel but will also lift the rear wheels and perform the test you both mentioned to be sure it is stock. Thank you both for the advice. The people on this site who offered advice has made it much easier getting this 4 runner back on the road. Thank you all for the help and quick response.