running 285s, what gear ratio should I get for better mpg and speedo correction?

[CWccw]

I made a post somewhere else, facebook or maybe reddit. whichever, I cant find the post now. I have a 3 inch lift, running 285s now and the speedo is off and the mpg is down a few numbers. What gear ratio do I need to look for when searching for a locker rear end?

 

[spartacus]

This has been discussed profusely on this forum. Here is. good one.
Axle Gear Ratio's

 

[Iron duke]

I made a post somewhere else, facebook or maybe reddit. whichever, I cant find the post now. I have a 3 inch lift, running 285s now and the speedo is off and the mpg is down a few numbers. What gear ratio do I need to look for when searching for a locker rear end?

What's your gears now? How much is it off at 75mph? Is it an auto or 5 speed? MPG's will not change significantly.

 

[Bad Luck]

I made a post somewhere else, facebook or maybe reddit. whichever, I cant find the post now. I have a 3 inch lift, running 285s now and the speedo is off and the mpg is down a few numbers. What gear ratio do I need to look for when searching for a locker rear end?

If you have ABS, then regearing will not affect your speedometer. ABS equipped vehicles use the wheel speed sensors for speedometer input. Non abs vehicles use a speed sensor on the transfer case.

Most people with 285's that are automatic regear to 4.88 to account for increased wheel size, wheel weight, and any additional weight from armor and accessories on the vehicle.

 

[phattyduck]

Since you have an SR5, you have ABS - and as the other poster said, gearing will not affect your speedo. You will need to get a speedometer calibrator to adjust the speed signal sent to your gauge cluster then ECU from the ABS computer.

I used the SGI-5 from Dakota Digital, install shown below (on my '99 - your wire colors may be different):

-Charlie

 

[96RedRunner]

Gear Ratio Calculator. good info put in your numbers, Auto - trans OD is off for 1:1 ratio.
285/75-16 10 ply 4.56 gears Auto my RPM's are 3150 I like it for how I use it, lower RPM's.
4Runner OE Lockers came with 4.30 ratio.

 

[Hopeless Diamond]

FWIW, I run 285/75/16 with stock 4.10 gears. Comparing GPS speed and tracking it appears I'm off by ~7%.

 

[96RedRunner]

Wasn't any concern on speedo for me, just kept in mind driving around.

 

[CWccw]

when im doing about 68-69 gps shows 71. Im not sure what my stock gear ratio is.

 

[96RedRunner]

when im doing about 68-69 gps shows 71. Im not sure what my stock gear ratio is.

Says so on B-pillar label AO3A = 4.10 AO4A = 4.30

 

[96RedRunner]

Most people with 285's that are automatic regear to 4.88...

Thought long n hard on this 4.88 seems to be trail street gears, 4.56 street trail with 285's.
4.56's feel like stock performance on 285's with good mpg's, offroad, I'm dual locked so power gain from 4.88's
wasn't worth running higher rpm's where I spend most of my time. No plans for bigger than 285's.

 

[CWccw]

Says so on B-pillar label AO3A = 4.10 AO4A = 4.30

I have AO3A/A340F

If I go to 4.56s would my mpg increase? I used to get 280+ to a tank now im luck if i get 225.

 

[96RedRunner]

You'll get some mpg's back all I can say.