Have you ever wondered why ATVs come with thumb throttles like the ones you find on snowmobiles and jet skis and not with twist throttles like on most types of motorcycles?

Being someone who currently owns or has previously owned most of these types of vehicles, I’ve found myself asking this question from time to time. So I decided to do some research on the subject.

So why do ATVs have thumb throttles? A Thumb throttle better allows the ATV rider to shift his bodyweight for optimal vehicle maneuverability while still maintaining precise throttle control. They are also generally considered being a safer option, especially for inexperienced riders.

Honda chose a thumb throttle for the worlds first ATV

When Honda was in the process of designing what is considered today to be the first ATV, their extensive testing concluded that a thumb throttle was the best option for the newly designed machine.

The iconic 3-wheeled vehicle from 1970 was named the «Honda US90», and it was the world’s first all-terrain vehicle by today’s ANSI definition of an ATV.

At the time, the snowmobiles had already been fitted with thumb throttles and was an inspiration to the designers.

This design has been the norm for stock ATVs ever since.

But why did the Honda engineers choose the thumb throttle over the well-known twist style throttle, used on motorcycles?

The newborn ATV was designed with both recreational riding as well as agricultural work in mind.

This meant testing needed to be done in rough terrain, bumpy roads, sandy hills, and slopes as steep as 35 degrees.

ATVs do not lean as motorcycles do

During their testing, the engineers realized that the riding style of an ATV is in many ways very different from that of a bike.

The primary way of turning a bike is by using a technique known as “countersteering,” where you utilize the combined weight of the rider and the bike to lean the bike in the direction you want to turn.

The bike’s leaning enables you to make rather tight turns with a relatively small movement of the handlebar. And when the bike leans with you, the body stays in line with the bike, and the relative angle between your arms and the bars stays almost the same.

On the other hand, when riding an ATV, you cannot lean the machine itself into turns to make it turn.

It is a direct steering machine. The primary way of turning depends on the ability to turn the handlebar. And you still need to lean the body to obtain the right balance.

This requires more active use of the handlebar’s full range of motion, and the shifting body position affects the angle between the arm and the bars to a greater extent.

Hard right turns are particularly difficult to execute. When your body is shifted to the right side, the wrist angle becomes awkward, making it hard to use a twist.

When driving in over rocks, bumps, roots, and steep hills, you really need to have a solid grip on the handlebar to hold on. This is easier to maintain when you don’t have to think about unintended throttle use simultaneously.

Because your body weight is a more important component for turning on an ATV than on a bike, you are likely to transfer some of that weight through the handlebar while leaning your weight on either side. This, in turn, can result in some unintended throttle use.

Another difference in the riding style is the need to constantly shift your body weight from side to side when riding in difficult terrain. This enhances the angle difference between the arm and the bar even more.

In some driving situations, the rider’s body actually needs to be placed totally on the opposite side of where you are turning to maintain balance.

In this situation, it may be enough of a challenge to hold on to the bar, not to speak if you also needed to maintain precise control of a twist throttle.

The thumb throttle’s safe and relatively precise operation is not so dependent on your arm placement relative to the handlebar.

The engineers concluded that a thumb throttle enables the arm to move more freely without affecting throttle control and thereby is the better alternative.

Other reasons the thumb throttle is considered best suited for an ATV

Unintended acceleration or deceleration

Try this: Sit straight on your ATV and turn the handlebars in both directions as if you are turning. Watch your right hand and see how a left turn would decelerate and a right turn accelerate.

This phenomenon happens involuntarily but naturally to everyone, and it especially affects inexperienced riders. With some practice, it is possible no near eliminate it.

This effect increases when the handlebar movement relative to the body placement increases.

With a thumb throttle, what is relevant is the relationship between your hand and your thumb. This relationship will not change as you turn the handlebars, which means the throttle lever will stay in the same position.

Manufacturer’s safety concerns (and maybe some litigation concerns).

Sadly ATVs have a history of many injured and even killed riders after being involved in accidents.

Especially with the introduction of three-wheeled bikes in the early seventies, many accidents occurred. For many years, these bikes were even illegal to produce because of safety issues.

And because a thumb controlled throttle is widely acknowledged as the safer option, today’s manufacturers will not take any risks by fitting a different type of throttle controller on their latest models.

If they were to change one of the main components for operating the ATV now after thumb control has been the norm for about 4 decades, and someone had an accident, they would risk many unwanted lawsuits as a result.

One other aspect is a phenomenon commonly nicknamed «whiskey-throttle.»

This classic rookie mistake can happen if you give too much throttle on a twistie and you start sliding back on your bike or ATV.

This makes your hand pull the throttle so that you accelerate even more, and you lose all control of the vehicle.

Although this makes many fun youtube videos, it can also result in severe injury.

If you give too much gas, it is easier to let off the throttle with a thumb controlled lever.

And if you lose control while doing some difficult driving, you are less likely to unintendedly jolt the throttle and pump more gas when you use a thumb throttle, with an unwanted view of the sky as a result.

Whereas this risk is usually very real when it comes to twist-throttles.

Local laws and regulations

Depending on which country you live in and whether you are riding on or off-road, there may be laws and safety regulations requiring your ATV to have a thumb-operated throttle.

Freezing throttle in the wintertime

Although not confirmed, it is believed that the possibility of a frozen twist throttle in an open position in sub-zero riding conditions is one of the reasons why manufacturers choose a thumb throttle.

But what are your options if you are one of those who doesn’t like thumb throttles?

PS! Based on the many potential disadvantages and the many stories about accidents or near-accidents involving a twist throttle on an ATV, I strongly advise caution to anyone considering trying one.

But in some cases, they may be the preferred option for some.

Because, after all, this usually boils down to the rider’s personal preference.

The major complaint riders have against the thumb throttle is fatigue, especially when riding for extended periods of time. Riders generally experience less fatigue with a twist throttle.

In driving situations where the surface is smoother, and the turns are more predictable, like in casual trail riding, street riding, and dune riding, it may be the preferred option for an experienced rider.

It is also considered to be a more precise throttle system as it allows for fine rotational control.

Buy a new ATV with a factory twist throttle.

Is this even a viable option? Not really. The major brands do indeed follow the ANSI/SVIA manufacturing standard. This originally voluntarily standard is even made mandatory in some states and countries, and it does not require a thumb-operated throttle.

But still, none of the top brands today have ATVs with stock twist throttle available.

Install an aftermarket twist throttle conversion kit

This option is mostly applicable to older ATVs without electronic fuel injection systems. If you can find one that fits your model, this is usually a straightforward bolt-on installation that won’t tip your budget.

But if you have a modern ATV, this is probably not your best option.

The «MacGyver» style conversion kit

If you want a cheap, easy to install option to test if this is something you prefer, you can try the Handy Throttle by Kolpin. This is basically just a kit with a small lever that pushes your bike’s original thumb throttle when twisting the handle.

I have not tested this option myself, but it gets an average rating at 4 out of 5 stars over at Cabelas, so it may be worth giving it a try.

Thumb throttle extension

Many manufacturers make a universal extender for thumb levers. With the extender installed, you get extra leverage, so pushing the lever takes less force, which in turn should return in less fatigue.

This option should be used with caution as it may result in unintended acceleration.

Finger throttle

Installing a finger throttle is fairly common on dirt bikes and supermoto bikes. They give the rider an option for applying throttle in different driving situations and is especially ideal for stunt riders.

Although finger throttle options for ATVs are not plentiful, one interesting concept that allows you to install a finger throttle is the DX Trigger.

It is designed to work together with your OEM thumb throttle, giving you the option to either push, pull, or even grips both levers at the same time to apply throttle. The idea is having different options gives you variation and, in turn, less fatigue.

So there you have it.

Whether you choose to keep your bike stock or to modify it will, in the end, be up to you. Just make sure you are fully aware of any potential risk involved in your decision.

Related questions

ATV thumb throttle vs. twist
A twist throttle generally allows for more precise throttle control than a thumb throttle and is less likely to cause rider fatigue. But Thumb throttles better allow the rider to maintain precise throttle control when shifting bodyweight from side to side as needed when riding ATVs.

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I'm an ATV and offroad-enthusiast, an engineer, a farmer, and an avid home-mechanic. I'm also the owner and editor of BoostATV.com. If you have any questions or suggestions regarding this article, please feel free to contact me.