Have you ever wondered why ATVs come with thumb throttles like the ones you find on snowmobiles and on 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 worlds first all-terrain vehicle by today’s ANSI definition of an ATV.
The snowmobiles at the time 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 than of a bike.
The primary way of turning a bike is by using a technique called 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 leaning of the bike 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.
When riding an ATV on the other hand, you are not able to 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 a more active use of the full range of motion of the handlebar, and the shifting body position affects the angle between the arm and the bars to a greater extent.
A hard right turn is especially 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 at the same time.
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 body of the rider 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 just to hold on to the bar, not to speak if you also needed to maintain a precise control of a twist throttle.
Safe and relative precise operation of the thumb throttle is not so dependent on you 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.
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.
Manufacturers 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 a lot of 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 to 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 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 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 for 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 riders 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, for an experienced rider it may be the preferred option.
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 on your bikes 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.
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.
ATV thumb throttle vs twist
A twist throttle does generally allow 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.