As you may know, most ATVs and quads are designed for only one person, and in most places, it is illegal to ride more than one person on a single-person ATV.

So why do they make them so large if not to bring a passenger? Let’s take a look at the reasons why ATV seats are designed the way they are.

ATV seats must be large to allow the rider to shift weight for vehicle stability and control in active riding.

Utilizing the rider’s body weight is important to maintain the vehicle’s stability and avoid flipping when riding either up or down steep hills, sideways on slopes, or when doing high-speed turns.

The seat needs to be big enough for the rider to be seated comfortably and securely in all the different seating positions the different riding situations require.

Variations Between Different ATV Brands & Models

While an ATV seat, by definition, is a seat designed to be straddled by the rider, there is no industry standard for seat size and placement. There is no correlation between engine size/power and how big they make the seats.

On average, an ATV seat on a bike designed to be used by only one person is about 24 to 30 inches (60 to 75 cm), but it can be even shorter or longer. Polaris brand ATVs generally have the longest seats, while Artic-Cat has the shortest.

You will find that seats on ATVs intended for sport or racing typically are about 2-3 inches longer than on machines intended for utility use. Seats on racing bikes are also generally not as wide in the rear end of the seat as they are on utility-style bikes.

This is likely because racing requires an even more active riding style and therefore requires the rider to shift to even further extremes to maintain the bike’s balance.

On a utility and recreational ATV, ride comfort is more important than on race quads, especially for longer trail rides. Added padding and comfort is why the rear part of the seat on non-racing ATVs is a bit wider and softer.

The Need for Free Movement

On an ATV, shifting your body weight is basically the only way you can affect the bike’s balance. The bike will lean the same way the terrain leans because of the four-wheel setup, so you must counteract by moving your body in the opposite direction.

You cannot lean the machine itself like you are on a motorcycle, so the ability to move around is extra important on an ATV.

Especially when you are doing active riding, you need to move around a lot and shift your body weight from side to side and back to front. This shifts your combined center of gravity and the bike in the direction you are moving.

Going up Steep Hills

When going up a steep hill, you must lean forward towards the handlebar with your arms bent. Except when climbing very steep hills, there is usually no need to shift the whole body forward on the seat. This will shift the combined center of gravity forward and further in front of the rear tires, making a backward rollover less likely.

On really steep inclines, you may even need to stand up and lean your body forward as close to the handlebars as possible to move the center of gravity further to the front. This is why the seat is more narrow in the front so you can stand comfortably.

Going Down Steep Hills

On the other hand, when going down a steep hill, you move your bottom back on the seat while fully extending your arms. This will keep the combined center of gravity backward and further behind the front tires, which, in turn, will make a front rollover less likely.

Rising Slopes & High-Speed Cornering

If you are riding on a slope, you need to shift your body weight to the bike’s upper side.

Or when you are driving fast while turning, you need to shift your body weight to the inside of the turn.

So the seat cannot be wider than what allows this type of leaning. The narrow front part of the seat will allow you to lean further to the opposite side.

What Benefits Would a Small Seat Have on an ATV?

If shifting body weight were not crucial to safely operating an ATV, the manufacturers would most likely make the seats much smaller.

Just look at UTVs, typically bigger and wider vehicles with a lower center of gravity than ATVs. UTVs do not rely on body placement for vehicle stability. Therefore, they can be equipped with bucket seats and seat belts, allowing minimal free movement of the rider or passenger.

A smaller seat would likely make it less appealing to bring a passenger.

Reducing the seat’s size would also increase the distance between the seat and the handlebar, making age-inappropriate use of the machine less likely.

Why Never Bring a Passenger on a Single-Person ATV

It is important to understand that ATVs are not equipped with large seats to carry more people.

There is a very good reason why bringing a passenger is not a good idea, especially when doing active riding in difficult terrain.

A passenger will greatly restrict your mobility, so you won’t be able to shift the center of gravity as you need to.

If you, for example, put a child in front of you, you won’t be able to lean forward on inclines.

Or if you put a passenger behind you will prevent you from moving back on declines. They will also limit the free movement of your arms, so you can’t turn the handlebar properly.

Both of these scenarios will increase the risk of a rollover.

A passenger will also add weight, creating a higher center of gravity, making your whole equipment more top-heavy, making it harder to control, and more prone to tipping over.

As the passenger will have limited ways to hold on to the bike, they are prone to be thrown off the bike from acceleration, jumps, tipping, etc.

About one-third of victims in fatal ATV accidents are drivers with passengers or passengers themselves.

How to Bring a Passenger on an ATV?

Choose an ATV Designed as a Two-up Machine

Because of the risks involved in riding with a passenger on a one-person ATV, it is highly recommended that you get a bike that has been specifically designed to accommodate two people if you intend to bring passengers on your rides.

These ATVs are commonly named two-ups or touring models and come fitted with a special passenger seat from the factory.

Usually, these types of machines are also equipped with a longer wheelbase (about 8 inches) and a stronger rear suspension to handle the passenger’s added weight.

These types of machines are now becoming widely available by most manufacturers. The price is usually slightly higher than on a one-up model, but not by much.

However, this ATV type has disadvantages over machines specifically made for one person.

The stronger suspension combined with the longer wheelbase will make it less nimble when going off-road. The extra seat may also be in your way when you move around a lot.

It would be best if you looked for a model with an easily removable rear seat for when you want to ride alone.

If maneuverability and off-road abilities are most important for you, and you do not plan to bring a passenger, choosing a bike intended for just one person would be the best option.

On the other hand, if you plan to bring your spouse or kid along on your adventures, I recommend you accept the relatively small disadvantages and get a purpose-made bike for 2 persons. Remember that a kid under the age of 8 should, in any case, not be put in the rear seat.

Install a Passenger Seat Kit

For most ATVs that were originally designed for only one person, you can find a wide variety of extra seat kits that can be attached to the rear racks of the machine. This will extend your current seat to the back so a passenger can comfortably sit.

One model that riders seem to recommend is the WES deluxe seat.

However, before choosing to go down this route, you should be aware of the potential risks involved.

In most places, mounting a kit like this will still not make bringing a passenger on your ride legal when your bike was originally designed for only one person. To legally bring a passenger, the bike must be designed from the factory for this purpose.

Some people understandably think this is quite strange.

If the rear rack is rated for 180 pounds, why shouldn’t you be allowed to bring a 165-pound human?

While we can agree that the placement of the extra seat and the passenger will be less than ideal, where it sits on top of or even behind the rear axle. The same would be true for any ordinary cargo, wouldn’t it?

I’m no lawyer, but I would not risk these arguments holding water in court.

While this is purely speculation on my part, an explanation as to why you are allowed to bring cargo but not to bring a human passenger may be the fact that a “dead” cargo, when properly strapped down, will not move around as much as a live human.

With a moving person, there is a risk of altering the center of gravity or the passenger getting in the way of the driver.

The extra seat is also a modification to the bike that has not been tested and certified together with the current ATV model and therefore is not approved to transport humans.

These seats are usually marketed as “storage boxes” or “rest seats,” and any serious manufacturer will inform you that they are not approved for passenger use.

But if you decide to accept these risks and mount one anyway, you should be aware that you may risk being fined, or worse; you may be in for some serious liability issues if the passenger becomes injured or dies in an accident.

The Ideal ATV Seat on a One-up Vehicle

The ideal seat should be no larger than what you need to move freely and comfortably in active riding.

It should go as far back as about just above the rear axle and not extend toward the handlebars beyond what is needed to comfortably shift the center of gravity forward when going up steep hills.

This is why ATVs have Large Seats (Hint: Not for Passengers)