Description

Book 5: Gears and Lockers

Mention gear ratios or differentials around a group of off-road drivers and it probably won’t take long before numbers start flying.

3.73.
4.10.
4.56.
4.88.

Then someone starts talking about lockers, limited slips, open differentials, tire sizes, crawl ratios, and suddenly a new off-road driver may be wondering whether they accidentally wandered into an engineering class.

It doesn’t have to be that complicated.

At their core, gears and lockers are tools designed to solve problems.

Understanding those problems is where Gears and Lockers begins.

Welcome Back to the Campfire

The Offroading101 Campfire Series was created to help new off-road drivers understand what’s happening inside and underneath their vehicles without requiring an engineering degree to participate in the conversation.

This isn’t a drivetrain textbook.

Think of it as pulling up a chair after a day on the trail and talking about what we experienced.

Why did one vehicle crawl slowly and smoothly while another needed more throttle?

Why did changing to larger tires make a vehicle feel different?

Why was one tire spinning while the tire on the other side seemed to be doing almost nothing?

Why did engaging a locker suddenly change what the vehicle could do?

Those questions are much more useful than simply memorizing terminology.

Once you understand why something is happening, the hardware designed to change it becomes much easier to understand.

What Do Gears Actually Do?

Your engine produces power, but that power has to travel through the drivetrain before it reaches the tires.

Gearing helps determine how that power is delivered.

That’s important on the highway, and it becomes particularly noticeable when you’re trying to move a vehicle slowly and deliberately over uneven terrain.

Then we start changing things.

Put larger tires on the vehicle and you’ve changed part of that relationship. The vehicle may accelerate differently. Transmission behavior may change. Highway manners can change. The amount of control you feel at low speeds can change.

Suddenly those mysterious gear-ratio numbers have a reason for being part of the conversation.

The goal of this book isn’t to make you calculate gear ratios around the campfire.

It’s to help you understand why gearing matters enough to ask the right questions.

Bigger Tires Change More Than Appearance

Larger tires are one of the most common modifications made to off-road vehicles.

They can provide additional ground clearance, change the vehicle’s capability, and certainly change the way it looks.

They also change the mechanical advantage the drivetrain has at the tire.

That’s something that’s easy to overlook when you’re choosing a tire based primarily on size.

A vehicle designed around one tire diameter may behave differently when significantly larger tires are installed.

That doesn’t automatically mean you need new gears.

It means you’ve changed something, and it’s worth understanding what that change did before deciding what needs to happen next.

Once again, we come back to the same philosophy we’ve used throughout the Campfire Series:

Understand what changed before deciding how to fix it.

Why Does One Tire Spin?

This is where differentials enter the conversation.

Your left and right tires don’t always need to travel at the same speed.

Turn a corner and the outside tire has farther to travel than the inside tire. The differential allows that to happen.

That’s extremely useful.

Then you get off road.

Put one tire on a surface with good traction and another somewhere with very little traction, and suddenly the behavior of that differential becomes much more noticeable.

A new driver may see one tire spinning and wonder why the tire with traction isn’t simply pushing the vehicle forward.

Understanding that moment is the beginning of understanding why lockers exist.

What Does a Locker Change?

A locker changes the relationship between the wheels on an axle.

That can be incredibly useful when terrain causes one tire to lose traction or leave the ground.

Engage a locker in the right situation and a vehicle that was struggling a moment earlier may suddenly move forward with surprisingly little drama.

That’s powerful.

It also doesn’t mean a locker should be the first solution every time a tire slips.

Line choice matters.

Tire placement matters.

Tire pressure matters.

Throttle control matters.

Your four-wheel-drive and traction-control systems matter.

The driver still matters.

A locker is another tool available to you. Understanding when that tool helps is more useful than simply knowing where the button is.

Technology May Already Be Helping You

Modern 4x4s can be remarkably good at managing traction.

Electronic traction-control systems can recognize wheelspin and use braking or power management to help move torque toward a tire that can use it.

Some vehicles have selectable lockers. Others have automatic systems. Some combine several different approaches.

That means two vehicles sitting beside each other on the same obstacle may solve the same traction problem very differently.

Instead of worrying about which system is “best,” start by understanding what your vehicle has and what it’s trying to do.

The more you understand its tools, the better you can work with them.

A Locker Doesn’t Replace the Driver

It’s tempting to think of modifications as ways to eliminate problems.

Install a locker and traction problems disappear.

Add the right gears and every obstacle becomes easier.

Off-roading rarely works that way.

A locker can’t choose your line.

It can’t decide whether you’re approaching an obstacle too quickly.

It doesn’t know whether the tire should be six inches to the left.

It can’t tell you when it’s smarter to back up and try again.

Those decisions still belong to the person behind the wheel.

Sometimes the best demonstration of good driving isn’t watching someone use every capability the vehicle has.

It’s watching them get through an obstacle without needing all of it.

4LO Is Part of the Conversation Too

Before spending thousands of dollars changing drivetrain components, it helps to understand the gearing already available to you.

For many new drivers, simply experiencing 4LO for the first time can be surprising.

The vehicle feels different.

Throttle response feels different.

Speed changes.

Control changes.

On steep terrain, the relationship between the engine, transmission, transfer case, and tires becomes something you can actually feel from the driver’s seat.

That’s one reason the Campfire Series keeps bringing the conversation back to experience.

You can read about gearing all day.

Sometimes you need to feel what gearing does before the numbers begin making sense.

Written for the New Off-Road Driver

You don’t need to know your ring-and-pinion tooth count.

You don’t need to calculate crawl ratios.

You don’t need to understand the internal workings of every differential.

You don’t even need to know what gear ratio your vehicle has before opening this book.

That’s why we’re having the conversation.

If you’ve wondered why people regear after installing larger tires, what a locker actually does, why one tire spins while another doesn’t, or whether you really need any of this equipment for the kind of off-roading you want to do, you’re in the right place.

The goal isn’t to turn you into a drivetrain specialist.

It’s to help you become a driver who understands enough to ask:

What problem am I actually trying to solve?

Printed by Offroading101

The printed edition of Gears and Lockers is printed and bound by Offroading101.

These aren’t mass-produced books coming from a large publishing or fulfillment company. We print and assemble them ourselves in small quantities.

The format is intentionally simple and practical: a comfortable 5.5″ × 8.5″ book that you can keep at home, toss in your vehicle, or bring along on your next adventure.

More Formats Are Coming

Looking for another format? We’re still working!

The Campfire Series is being released in Digital PDF, printed, MP3 audiobook, and PDF + MP3 editions. If the format you’re looking for isn’t available for this book yet, we’re working on publishing it.

As additional formats are completed, we’ll make them available here.

Pull Up a Chair

Gears and lockers can seem complicated when the conversation starts with numbers, acronyms, and parts.

Start with the problem instead, and things become much clearer.

What is the vehicle doing?

What do you want it to do differently?

What tools does it already have?

Could experience, tire placement, pressure, or technique solve the problem first?

If the answer eventually leads to gears or lockers, you’ll understand why.

That’s a much better reason to modify a vehicle than simply being told you need something.

The goal isn’t to have every tool available.

It’s to understand the tools you have, recognize when they’re useful, and know when the vehicle might need something more.

Book 5 of the seven-book Offroading101 Campfire Series.