ok i have a stock 86' 4runner and i dont know what the stock gear size is but belive it is 4:10 or something like that because other people have said that that was thier size, its a manual tran. i am running stock size tires which are 28' with 6' rims so i think the tires are only 8' wide they are preety skinny. I have an offer lined up for 31'x10.5 tires and 15x8 mikey tompson rims (a good deal if you ask me) anyways two questions here:

*where can i look to find out the gear size(ratio) that is on it stock right now? (i have a chilton manual and owners manuals)

*based off this info can anyone tell me wheather or not i should change the gear ratio for the tires and will it mess anything up if i dont (i probably will only lose power right?)

thanks, john

 

If you have a good, healthy motor you shouldn't lose any power.....I didn't notice any loss.

Did you run a search on gears or gear ratio?

 

you can cross reference the code on the door sticker with the chart on here

 

yea thats where i got sort an idea on my gear size and stuff well i wouldnt say its too great its got 140,000 miles and regular oil changes

 

thook: I hate to argue with you, but going from 28 to 30 inch tires will DEFINITELY make a difference in acceleration/power. I did this a few years ago and it was most noticeable in 3rd gear acceleration. Towing will be greatly affected, too.

 

well the only thing i tow is my own a$$ so i guess im alright there

 

A motor with even 300k on it can still be healthy. But, if yours isn't running great it may just need a tune up whatever size tire.

Anyway, point is I wouldn't worry about regearing for that size, if you are. Unless, you're just unhappy with the power you already have.

 

Oh come on, argue with me....I dare ya. I can take it!

Okay....right. What was I thinking? Probably because I ran 30's when I briefly switched to 31's and noticed no difference and didn't think that you wouldn't either. Except you said 28's and not 30's....which makes me wonder where I left my head this morning. Oh! There it is! In the commode! Pardon me!

 

Yeah, you most likely have 4.10s (I did on my 87 4cyl 5 speed). You will notice a difference going from 28s to 31s particularly when on the interstate and climbing hills (get ready for some 3rd gear climbs). The ideal for 31s is 4.56s. I lucked into a set out of a pickup and swapped them into mine. It feels roughly stock with the 31s. It's just something you have to try and see if you'll be able to live with. I know some people that run 33s and 4.10s and don't have a problem with it but to each his own. I ran 31s and 4.10s for a few months and it bugged the crap out of me. Something I did that helped was running an open air filter. It gave me a little more power to make up for it.

 

31s and 4.10s will be just fine, thats what i have and it worked just fine for me, while my truck is not as quick as my uncles on 235/75(somewhere between 28-29 i think) my truck isnt fast but it still goes just fine down the highway and such, and i think 31x10.50 is a really good looking size for a stock suspension. you will notice a difference but you shouldnt need to worry about regearing unless you go above 32"

 

As well gas mileage but just go for it if you don't like how it runs then swap your stocks back on and keep the 31's for offroading.