New guy with tire/axle ratio question

[Kurt_W]

Hey all,

Nice forum. Glad I found it. There seems to be a wealth of information here.

I have a '91 4Runner I just purchased. It failed the MD safety inspection for brakes, exhaust and tires. Decided to replace the rotors up front. Bearings and seals too after I found out what was involved. New Idler arm, and exhaust from the manifold back.

After doing a little searching on this site, I found the stock tire size for this car was the 225/75r15. There are 235/75r15 tires on the vehicle now. Earlier this week I ordered tires from tirerack, and their website says the stock tire size is 31 x 10.5 r15.

Doing a little more homework here I found out I have .410 axle ratio w/4 pinions. From what I read here vehicles with stock 31 x 10.5 tires had .456 axles.

My question is: What effect will this have on the performance of the vehicle? Should I just try and return the tires or is this something I'll be able to live with?

Thanks in advance for any help, and hope I can be a contributing member here.

 

[Quakefire]

There were two tire sizes on the 4runner, and only using the right size will give you the factory end gear ratio. My truck is a 1990 SR5 which means it has the 31's on it. If your truck began its life with the other size, then atleast for now, i'd keep them that way. If you start doing a bunch of off roading thats when i'd switch to a larger tire, but i'd go bigger then a mere 31

 

[fourwd1]

Hey all,


My question is: What effect will this have on the performance of the vehicle? Should I just try and return the tires or is this something I'll be able to live with?

As you increase tire size (diameter) you will notice some power loss. Will you notice it going from a 225 to a 235, no.
Going to a 33" tire yes, but many, many people do it and find they can live with it. So for a 31" tire, you'll notice a little power drop, but you should be able to live with it easily.

That's based on a 4 cyl/5 spd/stock 4.10 gears.

 

[mikes4runner]

BTW for most light off roading the 31's are quite capable.


Mike

 

[regularguy412]

BTW for most light off roading the 31's are quite capable.


Mike

Hey Mike,,

What are the size / type / brand of tires you run most of the time?

Thanks,
Mike in AR

 

[mikes4runner]

Hey Mike,,

What are the size / type / brand of tires you run most of the time?

Thanks,
Mike in AR

BFG AT's 31X10.5 I love them


Mike

 

[mikes4runner]

Hey Mike,,

What are the size / type / brand of tires you run most of the time?

Thanks,
Mike in AR

BFG AT's 31X10.5 I love them


Mike

 

[Quakefire]

I'm running Goodyear Wrangler Silent Armors in a 31 10.5 R15 and they are a fantastic tire, quiet and good grip. Plus they integrate kevlar into the tread (i think their 6 ply tires) durable sidewall and all. They ate through the side of a cavalier with very little damage to them so I'm quite happy

 

[Tobi-Wan]

I have been running 33x12.5's on my 87' 4runner, i put 1inch spacer's on as well, for clearance w/ the upper a arm on the ifs up front. They are Dayton Timberline mt's, and i have been satisfied with them. Aggressive tread pattern, and they clean out very well. the compound is soft, not like wrangler mtr's or anything, but softer than normal, and i believe they are only 3-ply walls, but i have not had any problems with them. took it to Tellico, and they were the bomb! good luck! by the way, they definitely slowed me down some, but,. it's not like the 4runner was ever that fast to begin with! lol