gearing/speedo question

[Turbost]

I have a 2.7L 4x4 manual 06 taco and was considering lowering the gearing and increasing the tire size. I think the stock gearing was too tall for the 4cyl (2650rpm at 80mph, where my old v6 4runner would be near 3000rpm at that speed). Plus i get better mileage in 4th. Anyway, my question is i go to a 4.56 what would i need to swap, i'm considering a 265/75/16 tire size. My main concern is the speedo accuracy after the swap, and was wondering if there is a speedo gear i can change? i'm not familiar with how the speed is metered on these trucks, i assume on the trans. Also if anyone has a ballpark of what a gearing swap costs.

[amp2oo1]

no need for new gears for a 265/75r16 tire size. People have said that their speedo is actually closer to being correct with this larger size. Many report of stock tires making the speedo about 3 mph slow.

Plus, as far as I know, no one makes front gears yet for our truck. I could be wrong, havent looked in a while.

And, why would you want higher rpms at highway speed?

[PiercedTiger]

I have 285's on my truck with stock gears. No problems for me. According to my scangauge I still get 17-18mpg, same as stock tires.

[Turbost]

I want higher rpm's at highway to have a little more power there. I'm not as concerned with that as I am with wanting a lower 1st and 2nd. I figure I would have to do something with the speedo since I'd be going to a lower gearing even when compensating for the difference in tire size.

[worthywads]

Originally Posted by Turbost

I want higher rpm's at highway to have a little more power there. I'm not as concerned with that as I am with wanting a lower 1st and 2nd. I figure I would have to do something with the speedo since I'd be going to a lower gearing even when compensating for the difference in tire size.

Seems you've already found your solution by using 4th, why use 5th. I can't imagine how you would get better mpg in 4th though?