Gear ratios

[Rogue Hunter]

Can someone give me a rundown on which gear ratio a person would want for a specific purpose? Gas mileage?

I'm clueless on this issue!

Thanks

[DevinSixtySeven]

For gas mileage, stick with the stock ratio.

For lower gearing, go to a higher numerical ratio. Low gears will help offroad, climbing hills and getting heavy loads started, but will lower your top speed and in extreme cases will lower your highway cruising speed. Around town, lower gearing may improve your mileage, it may not.

The opposite, numerically lower gears for a high ratio, may improve your gas mileage if all you ever drive is flat highway. Around town, it will hurt, same with towing and hauling, and offroad it will decrease your ability to control the vehicle in technical situations.

I don't know what gears your truck runs stock, but Randy's Ring and Pinion has a gear chart showing general ratios for highway & mileage vs power and control.

Don't deviate more than about 10% by speed from your final drive ratio, and remember that the final drive ratio includes both the ring and pinion AND tire size. For example, you change the ring and pinion and tire size, if your speedometer is reading more than 10% high or low, you may have made a mistake. It depends on what roads you drive, your driving style, and your driving needs.

-Sean

[Rogue Hunter]

Thanks for the reply.

I wouldn't be changing the ratio on a truck, but rather, trying to understand it in terms of what model I may want to purchase and what I want the truck to do.

I would be towing a 1000lb boat in the summer and occational 4x4ing during hunting season and winter snow. But, I think gas mileage would be paramount.

Looking to strike a balance.

[kathyricks]

Toyota pickups come from the factory with gearing already optimized for fuel economy.
The most important thing is to get a manual transmission and 4 cylinder engine. The 4 cyl can easily handle a 1000 lb boat. A 2WD Tacoma gets more 3 MPG more than the 4WD.

[DevinSixtySeven]

Yup...factory ratio and tire size is balanced.

If you can swing it, a larger tire will help you offroad only because you can air down and effectively raise the numerical ratio. You'd need a second set of tires, tho. On the road, the same set of tires will hurt your towing ability and in-town mileage because the final drive ratio will be numerically lower.

Likewise, if you get some great tires for towing, stiff sidewalls etc., they'll be a waste offroad...those tires usually have a road-specific tread and aren't meant to be driven at low pressure--standard two ply sidewalls and no sidewall protection--at the least you'll damage the outside of the sidewall, at worst you'll separate the liner inside the tire.

Close to stock is the best all purpose compromise hands down. As soon as you choose a focus, you'll likely decrease the vehicle's capability in other areas.

-Sean