The subject of gearing has come up reciently. With out getting too crazy I wanted to give a brief statement about my experiences with gearing. Once before most of you knew me I had a 98 tacoma. It came with 27" tires and 3.58:1 axle gears. It had good power and I got 21 mpg with it. I then upgraded to a 31" tire It became a gutless turd and my speedo was way off. I eventually changed the axles and had the factory 4.30:1 gears with the 31" tires. It had good power this way and I got around 20 mpg and the speedo was close. I eventually moved up to a 33" tire. I kept the 4.30's but the power was gone and my good mpg was gone too. The engine was just working too hard for what I was trying to make it do. Later I bought my current 4runner it came with 4.10's and 31's. It had good power that way and was enjoyable to drive on the road. I moved to 33's and the 4.30's I swapped my taco axle and found a front diff with matching gears. The feel stayed the same as stock. Later I moved up to 37's with the 4.30's the truck was now undriveable! I had to ride the hell out of the clutch to get it going and 5th gear was useless and 4th wasn't much better. I regeared the axles to 5.29's. There is a 5.71 ratio that no one uses since the pinion gets really small. My truck was driveable but not by much. 4th gear was good but 5th dosent get used too often. So what happened, did I not use a low enough axle gear? nope. In fact it is slightly under drive. The extra weight of the wheel and tire combo I have is harder to factor in. The lesson is that nothing drives like stock even with the numbers look stock. Infact, playing with this gear ratio calculator. http://www.grimmjeeper.com/gears.html If my truck were stock at 3000 rpm in 5th gear It has me at 79 mph, my current setup I must be at 3300 rpm to do 79 mph. By regearing you/I are attempting to restore lost power and lessen the strain on other drive train components. These could include universal joints, clutch, torque converter, brakes maybe some other things too. Higher rpms do not always mean lower mpg. Infact if your engine isn't working so hard you will increase your mpg. Automatic tranny's will hide the need to regear to a extent. The same goes for a engine with power to spare. The need is still there and I encourage everyone to look into doing this. Yes, it will likely set you back 1k or more, but so will a roof top tent that you wont use nearly as often. If anyone has somthing to add or point out where I am wrong please do.