How Center of Gravity Affects Your Wheelchair's Performance (And Why Most People Get It Wrong)

Daryl Bullard·July 24, 2026

If you've ever sat in two wheelchairs that looked nearly identical on paper but felt completely different to push, center of gravity is almost certainly why. It's one of the most consequential settings on a manual wheelchair, and it's also one of the most misunderstood — sometimes even by the clinicians prescribing the chair.

Let me break down what's actually happening, why it matters, and how to think about it when you're specifying a chair.

What Is Center of Gravity, Exactly?

Every wheelchair has a combined center of gravity — the point where the combined weight of the chair and the user is effectively balanced. For practical purposes, what really matters is the horizontal position of the rear axle relative to your body's center of mass (roughly your shoulder line when seated).

When people in the wheelchair world talk about "setting the center of gravity," they're almost always talking about moving the rear axle forward or backward relative to the seat.

Rear axle moved forward (toward your front) = weight shifts rearward = "anti-tip" stability decreases, but rolling efficiency increases
Rear axle moved backward (away from your front) = weight shifts forward onto the casters = more stable, harder to tip, but significantly more work to push

Most rigid ultralight chairs offer axle positions adjustable somewhere in a range of about 1–3 inches forward or back from a default position. That's a small measurement with an enormous effect.

The Real-World Difference This Makes

Here's a concrete example. Take a 150-pound user in a 20-pound rigid chair. With the axle in a rearward position, a significant percentage of that combined weight sits on the front casters. Casters create rolling resistance — they pivot, they shimmy, they're inefficient. Every inch of weight you can shift off those casters and onto the rear wheels makes propulsion meaningfully easier.

Studies on wheelchair propulsion consistently show that a more rearward center of gravity (axle forward) reduces the number of pushstrokes needed to cover a given distance, lowers peak force per stroke, and reduces the cumulative strain on the shoulder joint. For someone pushing themselves around for eight or more hours a day, that's not a minor detail. That's the difference between healthy shoulders at 55 and rotator cuff surgery at 42.

But — and this is important — the same setting that makes the chair easier to push also makes it easier to tip over backward. You can't have one without the other. This is the central tradeoff of center of gravity adjustment, and anyone who tells you otherwise is selling something.

The Anti-Tip Myth

A lot of people — including some rehab professionals — default to a conservative (rearward axle) setting because they're worried about falls. That's understandable, but it has real costs that often go unacknowledged.

When you push the axle back, you:

Increase rolling resistance substantially
Force harder, less efficient pushstrokes
Increase long-term shoulder wear
Make it harder to pop the front casters over thresholds and uneven surfaces (counterintuitively, a more rearward CG makes maneuvering harder in many practical situations)

A properly set center of gravity for an experienced manual wheelchair user who has the trunk control to manage a more responsive chair is almost always going to be more forward than the factory default. The factory default is typically set conservatively because manufacturers don't know who's buying the chair.

The right answer isn't "safe" or "efficient" — it's wherever your specific skills, trunk control, and daily environment intersect.

Trunk Control Is the Variable That Changes Everything

The reason center of gravity can't be prescribed the same way for everyone is trunk control.

A paraplegic user with a T6 injury and full trunk stability can handle — and will benefit greatly from — a more rearward center of gravity (axle well forward). They have the core stability to correct a rearward tilt, they can wheelie intentionally to navigate obstacles, and they'll pay a real price in shoulder health if their chair is set too conservatively.

A user with a higher injury level, multiple sclerosis affecting trunk stability, or significant muscular weakness may genuinely need a more forward axle position — and that's not a failure. That's appropriate fitting.

This is why good seating clinics will watch you actually move in the chair during a trial, not just measure you on a table and look up a setting in a guide.

Seat Height Changes Everything Too

Center of gravity isn't just about axle position. Seat height relative to the axle matters just as much.

Lowering your seat drops your center of mass and shifts more weight rearward — effectively the same directional effect as moving the axle forward. Many ultralight chairs allow you to set both, and they interact.

A common configuration for an experienced full-time manual user: axle as far forward as their balance allows, seat height low enough that their elbow is at roughly 100–120 degrees of flexion when their hand rests on the top of the rear wheel. That elbow angle is the classic marker for efficient push mechanics, and it's almost impossible to achieve if the seat is set too high.

Get the seat too high, and even a well-positioned axle won't save you — you'll be pushing from a mechanically disadvantaged position regardless.

How to Actually Figure Out Your Setting

Here's my practical advice:

1. Start more forward than you think you should. Most people are prescribed too conservative a setting. If you haven't tried a more forward axle position in a controlled environment, you don't know what you're missing.

2. Trial on your actual terrain. A center of gravity that works great in a clinical hallway may feel nervous on the sloped sidewalks around your house. The only way to know is to try.

3. Build skills alongside adjustment. If you're new to a more rearward CG setting, balance training — learning to hold a controlled wheelie, to catch a tip — makes a genuinely more forward axle position accessible to more people. Ask your ATP or PT about this specifically.

4. Revisit after 6–12 months. Your skills, strength, and daily life change. A setting that was right when you first got injured may be wrong two years later. Most adjustable chairs let you change this at home with a wrench — take advantage of that.

5. Don't let "it's set in the middle" be the answer. Middle is a default, not a prescription. If no one has explicitly assessed where your axle should be relative to your body and your life, that work hasn't been done yet.

The Bottom Line

Center of gravity is arguably the single most performance-relevant setting on a manual wheelchair. It affects how hard you work to move, how your shoulders hold up over years, how the chair handles on real surfaces, and how safe you are from tipping. It's not a one-size-fits-all number, and the factory default almost certainly isn't right for you.

The good news: on most quality ultralight rigid frames, this is adjustable. The less good news: you have to actually know to ask about it, and you need someone specifying your chair who understands the tradeoffs well enough to have an honest conversation with you about them.

Ready for a Chair That Actually Fits?

Center of gravity is just one of a dozen settings that need to be dialed in to your body, your injury level, and your daily life — getting it right from the start saves your shoulders and makes every single push easier.

I work directly with clients to specify and order custom ultra-lightweight wheelchairs — no middlemen, no upsells, just the chair that fits your life.

Get started at wheelchair.direct — answer a few questions and I'll reach out personally.