I'm looking to compare gas mileage and performance on and off road. I have 33" tires so the closer you are to that the better.
Every page I find has people back and forth between 4.56 and 4.88.
So list your engine, transmission, tire size, vehicle, gear ratio and your corrected gas mileage.

I currently have a 3.4 in a 91 4runner with 4.10's and 33/12.50r15 tires and am getting 19 mpg on the freeway corrected by my scangauge 2. I can get 19 in town too but thats accelerating like a grandma and with normal acceleration I am more like 14-16 in town. I have been able to babyfoot 21mpg out of it going 60-65 on the freeway. I blew up my elocker so I am looking to regear to 4.56 or 4.88 and am looking for a comparison.

 

you'll be over geared with the 4.88s, 33s and a 3.4. 4.30s or 4.56s would be almost exact on the speedo if thats what you're going for. 4.88s might be a bit high for freeway driving as well.

 

If you're getting mileage like that, I'd keep the 4.10's haha. If anything, with the 5spd, I'd go up to 4.56, no more than that though. I've got a 3.4 Auto with the same size tires, getting re-geared to 4.88's within the next few weeks, just gotta drop the diffs and take them to the shop.

 

I have a different truck that gets 50 mpg for longer trips so I don't care much about 1 or 2 mpg loss. When towing heavy loads the truck drops out of the powerband. I figure 4.56 will be good and that is what I will probably get but the 4.88's might be better for towing. I just want to hear what people with first hand experience say about the gears they are running in a 5 speed 3.4 with 33's

 

You're going to want the lower gear for towing.
Buddy of mine wishes he went to 4.88's instead of 4.56's. His truck is an 04 ext. cab Tacoma 3.4 5 speed.
Though, he wheels pretty hard, so the lower gears would be better for him.

There's only about a 250 rpm difference between 4.56's and 4.88's.
People think RPM's are what makes or breaks mileage, but engine load and throttle position has more to do with it than RPM.

 

Amen.

4.56 imo.