Is There an Ideal Rear-End Ratio for Your Used Truck?

4 April 2022
 Categories: , Blog


If you're about to purchase a used truck for your business, you're probably looking for a vehicle that offers the ideal combination of reliability, affordability, and profitability. While you can't customize a used truck right from the factory, you still need to consider the specs of any vehicle you purchase. While there are plenty of specifications to think about, rear-end ratio is among the most critical.

Of course, this begs the question: which ratio is ideal? While a straightforward answer might make life easier, the reality is that there's no such thing as a single set of specifications that are ideal for all applications. Likewise, the best rear-end ratio for your truck will depend on your business requirements, and you may even find that you'll need to choose between several compromises.

How Do Final Gear Ratios Work?

You'll typically see references to "short" and "tall" ratios when discussing gear ratios. A truck with "tall" gearing will have a numerically smaller final drive (or rear-end) ratio, while one with "short" gearing will have a numerically higher ratio. The general rule is that tall ratios work better for keeping your truck's engine at low RPMs during highway driving, while short ratios provide more power off the line.

While this rule sounds straightforward, there's more to choosing an appropriate final drive ratio than considering how much time you'll spend on the highway versus local roads. For example, other factors can also affect your effective final gear ratio, such as the size of your tires. Running larger tires is one way to effectively increase the final gear ratio of your truck.

Why Should You Prefer a Specific Ratio?

Remember that tall (numerically lower) ratios help keep your engine at a lower speed while cruising, helping to prevent you from maxing your RPMs under usual driving conditions. As a result, taller ratios can mean less fuel consumption when traveling on long, flat roads. These ratios often work well for typical, over-the-road trucking.

On the other hand, tall gear ratios can make it more challenging for heavy-haul truckers to get up to speed. These ratios are not well-suited to heavy traffic or mountainous terrain, where a tall gear ratio may lead to difficulty traversing hills. The rest of the drivetrain also matters, and trucks with less power typically perform more poorly with tall final drive ratios.

Is There An Ideal Choice for Your Business?

Ultimately, there's no single gear ratio suitable for all trucking operations. You'll need to consider the loads you're hauling, your typical driving conditions, and time spent on the highway versus local roads. If you do a lot of mixed driving, you may need to choose a compromise that will offer the best fuel economy possible for most of your routes.

Your truck's final drive ratio can significantly affect its profitability, so you shouldn't ignore this critical specification because you're buying a used truck. Always consider the options available on the lot and choose the one with the best specifications for your business's unique hauling needs.