128keaton

Hey folks I finally got big boy tires on and I'm still chasing a vibration. I'm down to axle or rear end. I'd like to know whats the best for highway speeds and 31s. I have a 4.56 I think, but I think its been changed since the tire size on my VIN tag is different and my speedo is near spot on. Thoughts? thanks!

ToyoKev86

4.56 gearing should be able to work fine with 31" tires.

4.10 also works since 31" is just about the maximum practical tire size for that gearing. 33" tires technically work with 4.10 gears as well since that's the combo I have and I can still do 70-75 mph on the highway.

I'm not an expert with gearing, but that's what I do know.

128keaton

Thank you for this info

wallytoo

iTrader: (1)

if you have 4.56s, your truck should handle 31s no problem. my 4r 22re w/4.10s handles 31s, and does well.

se7enine

iTrader: (2)

https://roundforge.com/content/artic...hould-you-get/

dropzone

iTrader: (6)

Hope this a 2wd...

RJR

4.56 was the factory gearing for V6 2nd gens with 31 inch tires, so you should be good. It will run about 3100 rpm at 75 mph.

128keaton

4WD bud. I think that it actually has the stock gearing now that I've had a chance to drive it.

Thank you. Mine is funky since it was wrecked and the owners pieced it together.


Awesome!

dropzone

iTrader: (6)

you said rear diff....

dark_fairytales

The answer is dependent on several factors:
-The use of the vehicle
-Terrain and Altitude
-Desired driving characteristics
-MPG

Everything comes down to the force of torque applied to the road surface.
3VZ-E= 180lb-ft @ 3400rpm - Stock torque value applied too road surface at a 1:1 transmission gear ratio is calculated by multiplying ENGINE TORQUE by DIFFERENTIAL GEAR RATIO and divided by the RADIUS OF THE TIRE; which equate too 52.92lb-ft with 31 inch tires and 4.56 gears B
22re= 140lb-ft @ 3600rpm. - "------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ -----------------------------------------------------------"; which equate too 41lb-ft with 28 inch tires and 4.10 gears

MPG can be kept in check by keeping the engine RPM's within the torque band given all things are equal, such as tire wight and actual distance traveled.
ALTITUDE limits the amount of torque the engine can produce ( all values are estimated at sea level ).
TERRAIN, hills require more torque to the road surface to Travers then flat terrain.
DRIVING CHARACTERISTIC change with different torque values that are applied to the road surface, more torque equal quicker response; however, the torque is multiplied by gear so there would be an increase rpm possible small loss in MPG.

So choose the driving characteristic for the terrain you drive in, run the number with the acceptable mpg's you can live with and select the tire size and gear ratio that works for you.

ZUK

iTrader: (1)

A vibration? Is it a high speed vib like the same speed as the driveshaft? If so, check the driveshaft phasing as that will cause a vibration.

see this

http://lmgtfy.com/?q=phase+of+a+driveshaft

Melrose 4r

Presently running 32" tires with 4.10s on mine. It is ok on highway 65-70mph but you do have to use the rpms, downshifting to 4rth or 3rd for long hills. My truck runs great, just did 100 highway miles yesterday but I would much rather have a 4.56 gear with these tires and then i believe the performance would be closer to factory stock. I like the look of the 32's so i'm thinking about advancing the cam a few degrees instead of changing the rear gear.

Melrose 4r

speedo error will show up greater at higher speeds because it is off by a percentage, not a fixed number of mph.

128keaton

hey man I don’t appreciate that attitude. I’m very sure it’s the passenger rear axle, something is off enough to cause the car to shake, not just vibrate. I will look into phasing after I rule out axles (again).

Melrose 4r

Run it on jackstands and observe. Mine has one tire out of round that is very obvious if you can watch it rotating. Other than that, i can watch the passenger seat try to shake itself loose at 70mph!

128keaton

I have a thread here if you would like to talk more about it: https://www.yotatech.com/forums/f116...haking-301422/

I did run it on jackstands. I'm 95% sure that these axles I pulled from another 4runner are bent in someway. The diff was actually in amazing shape so I'm not touching it.

RJR

The tire size on your door sticker is what was on the vehicle when it was shipped from Japan, not what Toyota intended for operation. In the 90's, the import taxes for light trucks were considerably higher than for passenger cars. So, Toyota imported the SR5 V6 4runner with cheap P225/75/15 (about 29") tires, which qualified it as a passenger car. Then, stateside, before first sale, the dealers installed the 31 inch LT tires and shipped the P225's back to Japan for the next round. The speedometer and axle ratio (4.56) were set up at the factory assuming the 31" tires would be installed. That's why your speedometer is correct even though your tires don't match the sticker.

128keaton

Okay wow--thats really interesting and good info there. I was running 29" tires because thats *what the door sticker said*. Cool. Thank you.

RJR

They did the same thing, btw, with air conditioning. AC qualified the vehicle as luxury, with resultant higher taxes, so Toyota shipped them over sans AC and had the dealers install it. If you inquire about AC parts for your truck, you may get the question, "factory installed or dealer installed?" Apparently there were some different parts involved (probably for ease of installation), so that's why that question is relevant.

It's amazing the behaviors that misguided tax law inspires.