Wheelchair Brakes & Wheel Locks: Push-to-Lock vs Scissor Brakes

Wheel locks are a relatively small part of a manual wheelchair, but they play an important role in everyday use. Whether you're transferring in and out of your chair, getting dressed, reaching for something or simply parking on a slight incline, you need your wheel locks to hold the chair securely in place.

If you're replacing worn wheel locks or looking to upgrade, you'll generally come across two common styles on active manual wheelchairs: push-to-lock wheel locks and scissor wheel locks.

Both perform the same basic job, but there are some important differences in how they operate, how much space they take up and how easy they are to use and adjust.

There are also newer adjustable designs that address one of the longstanding limitations of conventional wheel locks, particularly for wheelchair users who regularly change between different wheels and tyres.

Wheel Locks vs Wheelchair Brakes

Although they're commonly called wheelchair brakes, the devices fitted beside the rear wheels of most manual wheelchairs are technically wheel locks or parking brakes.

They're designed to hold the wheelchair stationary once you've stopped, rather than to slow the wheelchair while you're moving.

Most self-propelled manual wheelchair users control their speed by applying pressure to the pushrims. Some wheelchairs and accessories use separate braking systems, but the familiar lever beside the rear wheel is primarily there to lock the wheel in position.

Whatever you call them, correct adjustment is important. A wheel lock should engage the tyre firmly enough to prevent the wheel from moving without requiring excessive force to operate.

Push-to-Lock Wheel Locks

Push-to-lock wheel locks are one of the most common designs found on manual wheelchairs.

As the name suggests, the lever is pushed forward to engage the lock, moving the locking arm against the tyre and holding the wheel in position. To release it, the lever is pulled back again.

One of the main advantages of this design is how straightforward it is to operate. The larger lever generally provides good leverage and can make engaging and releasing the lock easier, particularly for users with reduced hand strength, dexterity or fine motor control.

There are many versions of the same basic design, ranging from standard replacement brakes through to lighter aftermarket options. For example, the newer Bull Push-to-Lock Wheelchair Brakes use a forged aluminium construction and precision bush mechanism while retaining the familiar push-to-lock operation.

Advantages of Push-to-Lock Wheel Locks

• Simple and familiar operation
• Larger lever provides good leverage when engaging and releasing the lock
• Often easier to operate for users with reduced dexterity or hand function
• Positive and easily visible locking action
• Wide range of replacement and upgrade options

The trade-off is that the lever and mechanism remain relatively prominent around the front of the rear wheel. Depending on the wheelchair and the user's transfer technique, this can sometimes get in the way when transferring or reaching down alongside the chair.

For users who prioritise clearance around the wheelchair frame, a scissor-style lock can be a better option.

Scissor Wheel Locks

Scissor wheel locks use a folding mechanism that extends towards the tyre when engaged and retracts back alongside the seat when released.

Their main advantage is clearance. When the wheel lock is disengaged, most of the mechanism folds neatly out of the way rather than leaving a large lever beside the wheel.

This creates a cleaner area around the wheelchair frame and can reduce interference during transfers, which is one of the main reasons scissor locks are popular on active manual wheelchairs. Conventional designs such as the Eagle Scissor Wheel Locks use this compact folding arrangement while still locking directly against the tyre.

Scissor locks aren't necessarily the best option for everyone, though. Their compact mechanism generally provides less leverage than a conventional push-to-lock brake, and the folding action can require a little more hand control to operate. In particular, some users with reduced dexterity, hand strength or grip can find a scissor lock harder to retract and release.

For this reason, choosing between push-to-lock and scissor wheel locks isn't simply a matter of one design being better than the other. Clearance and ease of operation both need to be considered.

Advantages of Scissor Wheel Locks

• Fold neatly away when disengaged
• Less hardware protruding around the wheel and seat
• Can provide better clearance during transfers
• Popular on active manual wheelchairs
• Compact and streamlined appearance

The other limitation with most conventional wheel locks, whether push-to-lock or scissor style, is that their position needs to be set according to the wheel and tyre you're using.

That becomes much more noticeable when you start changing your wheel setup.

Why Wheel and Tyre Changes Affect Your Wheel Locks

Wheel locks work by pressing against the tyre, which means their effectiveness depends on the relationship between the tyre and the locking mechanism.

Change that relationship and the wheel lock may need to be adjusted.

This can happen when changing:

• Wheel diameter
• Tyre width
• Tyre profile
• Tyre pressure
• Rear wheel position
• Between everyday and off-road wheel setups

A relatively small change can make a noticeable difference.

If the wheel lock sits too far away from the tyre, it may not apply enough pressure to hold the chair securely. If it's positioned too close, it can become unnecessarily difficult to engage.

Traditionally, correcting this means loosening the wheel lock or its mounting clamp, repositioning it on the wheelchair frame and tightening everything again.

That's manageable if you rarely change your setup. It's considerably less convenient if you regularly swap between two different sets of wheels.

Adjustable Scissor Wheel Locks: A Different Approach

A newer approach is to build the adjustment into the wheel lock itself rather than relying entirely on repositioning the lock along the wheelchair frame.

The SHIVLCK-AX Adjustable Scissor Wheel Locks are one example of this design. They use a conventional low-profile scissor mechanism but add an adjustable section that allows the effective brake position and tension to be fine-tuned without having to reposition the entire wheel lock assembly.

The SHIVLCK-AX provides up to 16mm of length adjustment, controlled using an adjustment knob on the clamp.

For a wheelchair that stays on exactly the same wheels and tyres all year, this simply provides an easier way to fine-tune the setup. Where it becomes particularly useful is on wheelchairs that regularly use more than one wheel or tyre combination.

Switching Between Everyday and Off-Road Wheels

A good example is an active wheelchair user who has one set of everyday wheels and another set fitted with wider off-road tyres.

Off-road tyres can have a slightly different width and overall profile from everyday wheelchair tyres. Depending on the setup, this can change where the wheel lock needs to contact the tyre.

With a conventional fixed-position wheel lock, changing between these setups may require the wheel lock position to be altered to maintain appropriate engagement.

An adjustable wheel lock allows that difference to be compensated for at the brake itself. With the SHIVLCK-AX, the adjustment can also be fine-tuned while seated in the wheelchair without removing the rear wheel or reinstalling the lock.

For users who regularly swap between everyday, sports or off-road wheel setups, this can remove much of the trial and error normally involved in resetting wheel locks each time.

When Should Wheel Locks Be Replaced?

Wheel locks don't necessarily need to be replaced simply because they're old. A well-made set can last for years.

Replacement or upgrading may be worth considering if:

• The locks no longer hold the tyres securely despite correct adjustment
• The mechanism has developed excessive play
• Levers or locking surfaces are damaged or heavily worn
• The locks have become difficult to engage or release
• You're changing wheel or tyre setups and your existing locks don't offer enough adjustment
• Your current wheel locks interfere with transfers
• You want a lighter or lower-profile setup
• Your current lock style is difficult for you to operate comfortably

Before replacing a wheel lock, it's also worth checking your tyre pressure. On pneumatic tyres, a significant drop in pressure changes how firmly the lock can engage the tyre.

If a wheel lock suddenly stops holding properly, the wheel lock itself isn't always the problem.

Push-to-Lock or Scissor: Which Is Better?

There isn't one wheel lock style that's best for everyone.

Push-to-lock wheel locks are simple, provide good leverage and are generally easier to push on and pull off. For users with reduced dexterity or hand strength, that can make them the more practical choice.

Scissor wheel locks provide a much cleaner and lower-profile setup when disengaged, which can be especially useful for active wheelchair users who want more clearance around the frame during transfers. The trade-off is that their compact folding action can be slightly more difficult to operate for some users.

Adjustable scissor wheel locks retain those clearance benefits while adding another level of adjustment. They're particularly worth considering when different wheels or tyres are regularly used on the same wheelchair.

The right choice ultimately depends on your wheelchair, hand function, transfer technique, wheel and tyre setup and personal preference.

If you're unsure which style will suit your wheelchair, get in touch with Wheelchair Outfitters and we can help you check the options and compatibility.