ATV Diff Locks Explained: Are They Worth the Investment?

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When you’re in the market for a new ATV, one important decision is whether you want a bike with a differential lock (diff-lock) or not.

A diff lock can be beneficial in challenging off-road or wet and slippery riding conditions. If your budget permits, it’s a valuable investment.

This post looks at what a diff lock is, what it does, and what situations they are worth having. 

What Is Diff Lock on an ATV?

Diff is short for differential, referring to the front and rear axle differentials or the center diff.

The differential consists of a set of gears contained inside a metal housing. It aims to transfer the rotational forces from the prop shaft connected to the engine and out to the wheels via the drive shafts. 

How differentials are designed allows power to be transferred from the engine to the wheels while allowing the wheels to rotate at different speeds when required. This is known as an open diff. 

differential
The fundamental principles of an open differential.

The downside of having an open differential is that when one wheel begins to spin, all engine power goes to the wheel with no traction. 

A diff-lock mechanically interlocks the left and right driveshafts on the same axle, forcing them to rotate at the same speed regardless of which wheel has the most traction. 

This helps maintain optimal performance in rugged terrain.

If one of the wheels leaves the ground or enters a soft spot where traction is low, the diff lock ensures that the opposite wheel still spins at full power.

How to Use the Diff Lock on an ATV

Not all ATVs come with a diff-lock. On some models, they are optional. 

If your ATV does come with a differential locking feature, you must know how it works and when to use it.

First off, a diff lock is a low-speed, straight-line feature. 

When the diff is locked, the ATV becomes hard to steer to either side, and turning with the diff lock engaged on a paved surface will increase tire wear and may damage the ATV drivetrain. 

Also, using the diff lock at higher speeds is not recommended due to its effect on handling and potential vehicle damage. 

There are two main types of diff-locks: automatic and manual.

An automatic diff lock engages when it senses that one of the tires is losing traction and releases as soon as it is no longer required. 

A manual diff lock is engaged and disengaged manually by the rider with a switch or lever. 

For an experienced rider, having the ability to operate the diff-lock manually provides complete control over vehicle performance under challenging situations. 

However, for a beginner, having an automatic diff lock allows the rider to focus entirely on the riding while leaving it to the ATV to ensure optimal traction.

Related: Why Aren’t All ATVs Four-Wheel Drive? 2wd vs. 4wd

When to Use an ATV Diff Lock

The diff lock is to be used when you ride off the road in rugged terrain, and you need additional traction not to get stuck or maintain control up a bumpy hill. 

Only engage the diff-lock when you anticipate needing it, and remember to disengage it once you’ve successfully tackled the challenging terrain.

Here are a few common scenarios when having a diff-lock may come in handy:

When Riding up a Rough Hill With Ruts and Loose Rocks

When facing a challenging hill climb that feels too rough, using the diff lock can help you maintain complete control of your vehicle to the summit.

What typically causes losing control over an ATV when riding up hills is when one of the wheels begins to spin, and the vehicle starts to slide from side to side, struggling to maintain traction.

With the diff lock engaged, the wheels are more likely to maintain a constant speed regardless of the terrain, making it easier to tackle tricky parts of the trail in a controlled manner.

When Riding Over Soft or Wet Turfs Like Mud, Snow, and Sand

Driving in soft or wet conditions with poor traction and a high chance of sinking in can be challenging. 

With no diff lock, when a wheel loses traction, it begins to spin and dig in while the other wheels stop turning. 

A diff lock ensures that the wheel with traction keeps turning regardless of whether the other wheel spins. This ensures you remain forward momentum and reduces the risk of digging in and getting stuck. 

When Riding in Rocky Terrain

When passing through rocky parts of the trails or stretches containing deep ruts, one of the wheels is likely to come off the ground.

With the diff locks engaged, you can maintain a slow and steady pace across the bumps without losing traction. 

On the contrary, with no diff-locks, you might need to utilize speed to get across, increasing the risk of tipping or getting stuck.

When Riding on Slippery Surfaces

If you’ve ever tried riding on slippery surfaces like packed snow and ice, you know how easily one of the wheels begins to spin. 

Once again, the diff lock comes to your rescue and ensures optimal traction on all four wheels.

This can be incredibly useful when plowing snow or crossing a small stream covered in slippery rocks. 

A word of caution on driving up icy or slippery hills tho. 

With the 4×4 and diff locks engaged, you will get farther up the hill than there is friction to keep the vehicle from sliding down. If you don’t make it to the top but stop halfway up, there is a high chance the vehicle will begin sliding uncontrollably downhill. 

Please don’t ask me how I know.

To Get You Out of a Difficult Situation

It is not always easy to know how your ATV will handle a specific situation, and if you misjudge, before you know it, you find yourself in a tricky spot with no way out.

One solution is to bring out the winch, but more often than not, flicking the diff-lock is all it takes to bring you back on track. 

While this may not seem like a big deal, having this ability to gain extra traction is like having a get-out-of-jail-free card those times you unintentionally put yourself in a bad spot. 

Is Having a Diff Lock on Your ATV Worth It?

Locking differentials are crucial for serious off-road driving and can make a world of difference in specific situations.

The main benefit of having diff-locks is their ability to bring much more power to the ground in rugged, soft, or slippery terrain. 

In practice, an ATV with a diff-lock can get through stuff where an ATV without won doesn’t stand a chance. 

In other words, an ATV with a diff-lock can go much farther before getting stuck and is well worth having if you ride a lot of off-road with your ATV.

On the other hand, if you primarily spend your time on smooth trails or putting around the farm, the added cost of diff-locks may not pay off.

Undoubtedly, diff-locks improve off-road performance and traction on slippery surfaces, but if this is something you need, it will ultimately be up to you to decide.

Related: Power steering (EPS) on an ATV; is it worth it?

Haavard Krislok
Haavard Krislok
Haavard Krislok is an ATV and off-road enthusiast with a rich background spanning two decades in owning, maintaining, repairing, and utilizing ATVs for farming, logging, and hunting. Outside his professional life as an engineer and project manager, he cherishes recreational trail riding and is the creative force behind BoostATV.com, serving as its owner, editor, and content creator.

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