Matching Gears To Tires ?

Here is the question. I went from 265-75-16 to 285-70-17, and a cabrac. I use to run interstate at 78-80 mph and got better than 19 mpg, now getting better than 15 mpg running (by speedo) 72-74 mph, I figure thats close to old speed. Rpm's around 2100 flat ground. So if I change the gearing (what size ? ) to match tires will it bring the mpg back? Or is it a weight and drag thing? Is it worth changing gears ? I did a search but apparently didn't do it right. Thanks

 

You auto or stick? I did same tire swap on my auto....then changed from 3.73 gears to 4.10's. Got it back close to same overall gearing as "stock". Got about 1-1/4mpgs back on average driving. No real significant increase at highway speeds. (60mph and above) I'll eventually change up to 35's. May lose gear advantage then. Most people who gear for 35's go with 4.56's or 4.88's

For what it's worth....I'm a typical "old guy" who drives like a grampa...ie slow. My mileage is probably not typical of most drivers. I always got better mileage than everyone else seemed to with a stock Tacoma.

 

Yep. I got 35's and only then did I get new gears which are 4:56. I do a lot of highway and so I went with the less RPM option for gas compared to 4:88s which can eat up gas pretty fast on an auto. Just make sure if you gear up that you really have no intention to go up in size beyond 285s as I at one point never planned to go up from 285s until I wanted to crawl some higher stuff.

 

https://www.discounttiredirect.com/learn/tire-size-calculator

 

Thanks everybody. I will be giving it some thought as to what I want/need to do. I appreciate the input.