Wheelchairs are essential for those who suffer from mobility impairments. But have you ever noticed that the wheels often appear tilted or slanted? This design can seem strange at first glance, so why is it necessary?
In this blog post, we’ll explore why wheelchairs have slanted wheels – and how these angled wheels make a crucial difference in wheelchair users’ lives. We will look at both manual and power wheelchairs as well as different types of wheel designs.
By reading about it, you will better understand modern-day assistive technology and its continuing evolution. So, here is why do wheelchairs have slanted wheels.
Are Slanted Wheels Common?
The presence of wheels not situated at perpendicular angles to the ground is a commonplace scenario that may strike many people as surprising. Yet, it is essential to know that the degree of inclination is typically too minute to be discernible — not even to the unaided eye.
The technical term for this deviation of wheels from their axle plane is called camber. Camber is introduced deliberately into wheel assemblies to accommodate an extensive range of surfaces and traction conditions that vehicles, such as wheelchairs, must endure daily.
It is intriguing to note that camber is not a recent innovation but has been in use for centuries. Adopting camber onto the wheels increases road contact, grip and improves steering and vehicle stability. It also helps distribute loads evenly across the tire, reducing wear and enhancing tire life.
In wheelchairs, camber is crucial in enhancing maneuverability, tackling uneven terrain, and aiding in propulsion, especially for manual chairs.
Vehicle designers consider various parameters, such as the tires’ width, the vehicle’s weight, and the desired level of traction, when deciding the camber angle to be introduced.
For instance, a higher wheelchair camber angle would be required for off-road vehicles and sportscars to improve handling and performance. On the other hand, vehicles for regular commuting require a lower camber angle to prevent excessive tire wear and conserve fuel.
What is a Wheelchair Camber?
Wheelchair camber refers to the angle at which the wheels of a wheelchair are tilted outward or inward when viewed from the front or back of the wheelchair. Instead of having the wheels perpendicular to the ground, camber involves angling the top of the wheels either inward or outward while the bottom of the wheels remains vertical.
What Does a Wheelchair Camber Do?
One of the primary roles of camber is to improve stability. By tilting the wheels outward or inward, the camber widens the wheelchair’s base of support. This broader base increases stability and reduces the risk of tipping over, especially during turns or when traversing uneven surfaces.
Cambered wheels significantly enhance maneuverability. When the wheels are cambered, the wheelchair’s turning radius is reduced. This makes it easier to navigate through tight spaces, such as narrow doorways or crowded areas, by allowing the wheels to clear obstacles more effectively.
Efficiency and Propulsion
Cambered wheels improve the efficiency of wheelchair propulsion. It creates a “negative camber effect” when the user pushes the rims. This effect helps the user maintain a more ergonomic and natural pushing motion, as the hands can be positioned more comfortably without hitting the side of the wheelchair.
It also plays a role in weight distribution. It naturally distributes the weight more evenly between the two wheels. This balance prevents excessive wear on one side of the wheelchair and can contribute to a smoother and more comfortable ride.
Traction and Stability on Slopes
Camber can enhance traction and stability, particularly when going up or down slopes or ramps. The cambered wheels provide more surface contact with the ground, improving grip and reducing the risk of sliding or losing control.
Types of Camber
There are three main types of camber: positive camber, negative camber, and zero camber. Let’s explore each type in detail:
1. Positive Camber
Positive camber refers to a convex curve where the top of the object is farther apart from the baseline than the bottom. In other words, the highest point of the curve lies above the baseline. When positive camber is applied to an airfoil or a vehicle’s wheel, the top of the surface is curved outward.
This type of camber is commonly used in applications where stability and load-bearing capacity are crucial.
Positive camber provides stability to the object by creating a larger contact patch between the surface and the ground. This increased contact area helps distribute the weight evenly and enhances stability during maneuvers.
Load Bearing Capacity
It can improve the load-bearing capacity of an object by preventing excessive flexing or deformation under heavy loads.
Positive camber on vehicle wheels can enhance steering response and make the vehicle feel more responsive and predictable. It aids in maintaining control during cornering.
2. Negative Camber
Negative camber, on the other hand, refers to a concave curve where the top of the object is closer to the baseline than the bottom. In this case, the highest point of the curve lies below the baseline.
Negative camber is often used in applications where high-speed maneuverability, improved traction, and cornering performance are desired. Some key characteristics of negative camber are:
It increases the contact patch of the tire or airfoil, primarily on the outer edge. This allows for better grip and improved traction, especially during cornering or high-speed maneuvers. It counteracts the tendency of the tire or airfoil to roll or slide outward.
Negative camber reduces body roll and improves the cornering stability of vehicles by shifting the tire’s contact forces to the inner portion of the tire. This results in increased tire grip and better control during turns.
This type of camber can enhance the efficiency of airfoils, such as aircraft or race car wings, by reducing drag and improving lift-to-drag ratios. It can generate more lift while minimizing the drag produced by the object.
3. Zero Camber
Zero camber is a flat shape or a curve where the top of the object aligns precisely with the baseline. In this case, there is no curvature present. Zero camber is often used when a neutral or balanced performance is desired without emphasizing stability or maneuverability characteristics.
Its benefits are as follows:
Zero camber provides a neutral or balanced handling characteristic to the object. It compromises stability and maneuverability, making it suitable for various applications requiring well-rounded performance.
It is often used in applications where the object needs to perform well under different conditions or varying load distributions. It offers versatility by not favoring specific performance attributes.
Zero camber often implies that the object has symmetric characteristics. This symmetry can simplify manufacturing processes and maintenance, as the object can be used interchangeably in different orientations.
General Camber Angles In Wheelchairs
The camber is termed negative when the angle between the wheels is such that their tops are closer together. Conversely, if the distance between the wheels at the base is smaller, it’s called positive camber.
However, standard wheelchairs usually possess zero or negative camber for enhanced stability and ease of maneuvering in most environments.
The curvature of the wheels, known as camber, has a considerable impact on the functionality and performance of a wheelchair. While a low camber angle of 3 degrees is suitable for everyday use, such as in households, higher camber angles of up to 15 degrees are best suited for performance-oriented applications.
Furthermore, chairs with high camber angles improve stability and maneuverability while keeping the weight distribution optimum. The user can better travel over uneven terrains, and they have improved traction and turning control on steep inclines.
Benefits and Drawbacks of Increasing Camber in Wheelchairs
It is essential to learn the pros and cons of raising the wheelchair’s camber before making any adjustments.
Accessibility is improved due to wheelchairs’ cambered wheel shape. This is due to the fact that the shoulder joint of the user is positioned above the wheels while being used for movement. Adjusting the mobility aid to this position relieves stress from the shoulders. These extended chairs are great for kids since the push rims are right where you need them.
Individuals with disabilities who wish to lead an active and fulfilling daily life may find a wheelchair with tilted wheels highly beneficial.
This specific design of a wheelchair is most commonly employed by athletes participating in a range of sporting events, as it provides both increased speed and greater maneuverability during intense physical activity.
By utilizing a wheelchair with tilted wheels, disabled individuals can engage in a wide range of activities that might have been otherwise challenging or inaccessible, fostering greater independence and a sense of personal achievement.
As such, wheelchair designs with tilted wheels represent a pioneering new advancement in assistive technology, enabling individuals with a range of disabilities to lead active, fulfilling lives and achieve their full potential.
Safety for the User
Avoiding hand and elbow injuries when relocating a chair is a top priority. Wheelchairs with cambered frames are angled slightly to aid with maneuverability. Your fingers and palms do not go past the bottom of the wheels at a right angle. As a result, you may ride comfortably in confined areas without your hands rubbing against any obstacles.
Cambering the wheelchair’s base makes it more stable and allows for more precise turns, both beneficial for athletes. This decreases the likelihood that the chair may tip over, protecting the user from potential harm.
The user may go about their day without feeling any jarring effects because of the broader base, which deflects stress away from them.
Improving stability by altering the camber might lead to unwanted wheel contact with the armrest side rails. This might be unpleasant for the wheelchair rider and could ruin the upholstery.
Wider Space for Wheelchairs
Due to its extended design, wheelchair wheels increase the overall breadth of the device. Therefore, if you’re not accustomed to using a wide chair, you may have trouble moving around inside and finding a suitable parking spot.
Tires Deteriorate Unevenly Over Time
If you’ve used a traditional wheelchair before, you may have noticed that the tires wear out quickly. The main reason for this is the angle of inclination of the wheels to the ground surface.
Unlike car tires, which have offset tread patterns that help distribute weight evenly and prevent wear, wheelchair tires have tread centered in the middle of the tire. This causes the tire to wear out quickly, primarily when the wheelchair is used on uneven or angled surfaces.
To combat this problem, many wheelchair manufacturers now offer cambered wheels. These wheels are specially designed with an offset tread that accommodates the degree of cambering (or the angle at which the wheels are tilted).
Cambered wheels help distribute weight evenly and reduce wear, making them an ideal option for anyone who spends a lot of time in their wheelchair.
To achieve the required tilt angle, producers of wheelchairs employ wheelchair axle plates and camber tubes. In addition to their portability, these wheelchairs’ durability is a must. As a result of these high production costs, companies have to raise the retail price for the products. A wheelchair like this may set you back a couple of dollars.
Cambering a wheelchair can be beneficial in certain scenarios and detrimental in others. If you are an athlete who needs more stability or maneuverability from your chair, then a cambered wheelchair may be appropriate. However, if you’re looking for a lightweight and portable option, then a standard wheelchair should suffice.
The decision depends on your individual needs and budget. Ultimately, it’s important to remember that the user should be comfortable in their wheelchair and that each individual will have unique requirements depending on their lifestyle.