I have a 2000 4runner and in running 35 inch tires. I changed out the stock 373 gears for 529s but my mpg has actually Decresed a little bit. Just wanting a little insight on some reasons this could have happend. Everything i have read said that 529s with 35 inch tires on my year 4runner would take it back to stock mpg. What am i overlooking here?

 

Changing the gears and/or tires changes the formula for calculating the MPG because the odometer will be out of calibration.

Did you make any adjustments?

 

No, but im only getting around 9mpg so im guessing something is way off on my 4runner.

 

Your speedo is about 20-30% higher than stock. Use a gps with a trip meter and odometer to get your true readings.

No way you're getting 9mpg.

Also, forget "getting back to stock."
That ain't happening. You added a load of weight and pushed your brick at least a few inches taller which in turn kills all aerodynamics.

My guess is you're getting 14-17.

 

That makes since bavause when i put it in 4 low my speedometer is way off

 

Getting the right gears to match your tire size will bring the RPM's at a given speed back to stock at a given speed, but once you put on 35's nothing will bring your MPG's back to stock

 

529 gears are kinda steep for 35's for running the hwy. 4.56 would have been a Lil better choice. But 5.29 gears are the better of the two when it comes to running trails and playing on the rocks. Like I was told years ago, are u building the rig for the hwy, or building it for the trails? Can't have the best of both worlds!!!!

 

I run 529's and 35's and put about 30K miles on my truck per year.
They are not too low for highway use. I do 80 and get 16 on a straight highway tank.

 

This. Imagine how bad it'd been without a gear change. I'll bet you are doing fine on mpg, for 35s.

 

Hope you mean 4.88's and 35's ,,, 4.56 is a good gear for 33's, but is to high for 35's even with a 5VZ.

 

on road performance + off road performance = dual cases, 35's 4.88's - 5.29's (depending on motor)

 

winner winner chicken dinner... however, not everyone is willing to go that route. Not only $$$ but you don't see a lot of 3rd gen'rs going where they'd need dual cases. Me on the other hand, I need duals bad

 

No, I meant 4.56, but ur right on ur gearing for tires!!!! Every yota I've built I went straight to 5.29 gears, but all my builds where trailer queens! They weren't built to run on the hwy! I don't run smaller than 38's on any of my builds

 

I got 16mpg doing 75 towing a uhaul with 5.29s....