ALLETT KENSINGTON 20B Petrol Cylinder Mower

The Allett Kensington 20B: A Precision Mower for Lawn Perfectionists

When lawn care means more than just a weekly task, you need a mower that’s a cut above the rest. The 20B Petrol Cylinder Mower is the largest model in Allett’s prestigious Kensington series, designed for people who take immense pride in their lawns. This self-propelled machine combines outstanding engineering, professional-grade features, and the finest British craftsmanship, making it the ideal choice for serious domestic gardeners.

Engineered for Power, Designed for Control

At the core of the Kensington 20B is a 127cc Briggs & Stratton XR550 petrol engine, offering reliable, smooth performance across varying conditions, and a highly trusted names in garden machinery. The engine starts via a traditional recoil system and delivers consistent power to handle large lawns with ease.

With a generous 2-litre fuel tank and 51cm (20-inch) deck, the Kensington 20B is built for longer sessions without frequent refuelling. This makes it ideal for domestic lawns up to 900m², offering supreme efficiency without compromising the quality of the cut. Its self-propelled drive system ensures steady forward motion with minimal operator effort required, allowing you to concentrate on your lines and finish. Despite its capabilities, this premium mower remains relatively quiet for a petrol machine, operating at just 96 dB(A)—a welcome feature in residential settings.

Impressive Cutting Capacity with High Precision

What truly elevates the Kensington 20B above standard mowers is its exceptional cutting performance. Fitted with a six-bladed cylinder, this machine delivers up to 79 cuts per metre, creating an elegant, even surface with every pass. The blades operate using a scissor-like action, producing a clean cut that encourages stronger, healthier grass growth over time.

This attention to detail is matched by a micro height adjustment system, giving you the flexibility to set the cutting height anywhere between 6mm and 32mm. Whether you’re maintaining a closely cropped lawn or allowing for slightly longer growth, the fine-tuned adjustment lets you adapt the finish to your personal preference or seasonal needs.

Create Lasting Stripes with Every Pass

The iconic striped lawn isn’t just about aesthetics—it reflects care, quality, and precision. The Kensington 20B delivers on all fronts thanks to a carefully engineered steel roller system. A zinc-plated front roller smooths the surface ahead of the blade, while a split rear roller with differential presses in bold, lasting stripes without tearing or dragging the turf.

This clever roller design also aids manoeuvrability. The differential allows for clean turns without scuffing the lawn, even when navigating tighter corners or curves. Paired with a spring tine comb that lifts each blade before cutting, and an adjustable front rake to lift debris and stimulate healthy growth, this system leaves nothing to chance when it comes to your lawn’s appearance.

All-Season Flexibility with the QX Cartridge System

One of the standout features of the Kensington 20B is its ability to do far more than just mow. Thanks to Allett’s Quick Exchange (QX) cartridge system, the standard six-blade cylinder can be removed and replaced with a range of optional accessories—quickly and without the need for tools.

We sell all of these cartridges, which include a scarifier, lawn brush, dethatcher, aerator, and Verticut blade, each helping you tackle different aspects of lawn health throughout the year. For those of you seeking an ultra-fine cut, a ten-bladed cassette is also available to purchase, offering professional-level refinement for formal lawns or display gardens.

Comfortable Handling with User-Friendly Design

Weighing in at 56.6kg with the grass box, this mower offers excellent stability without feeling cumbersome. Its solid frame stays composed across uneven areas, allowing for straight, steady mowing with consistent contact across the width of the machine. The 51cm (20-inch) cutting width means fewer passes are required, saving time without sacrificing quality.

The handlebar design has been carefully considered for operator comfort. With three height positions, it allows for better posture during use, reducing fatigue over longer mowing sessions. The handlebars also fold down neatly, making the mower easier to store or transport. An auxiliary wheel kit is included as standard, raising the mower when tackling slightly longer or tougher patches without losing precision.

The 70-litre grass collector provides ample capacity for clippings, making the Kensington 20B ideal for larger lawns. It’s quick to remove, simple to empty, and constructed from high-impact polypropylene for long-lasting durability, even under regular use.

A Mower Steeped in British Heritage

Allett is a highly respected British company with over 60 years’ experience designing precision walk-behind cylinder mowers. Every Kensington model is built to the highest possible standards, drawing on decades of lawn care expertise and a commitment to continuous improvement. The Kensington 20B Petrol Cylinder Mower embodies this tradition, offering a mower that’s as reliable as it is refined.

To reflect the confidence Allett has in its products, this superior lawnmower comes with a two-year warranty for domestic use, or a three-month warranty for Sports Pro environments. This ensures peace of mind for homeowners who want equipment that lasts.

Take the Next Step to the Perfect Lawn

If you’re ready to upgrade your mowing experience and invest in a machine that delivers consistently beautiful results, the Allett Kensington 20B Petrol Cylinder Mower is the clear choice. With its wide cutting capacity, advanced roller system, and unmatched cartridge versatility, this mower stands at the pinnacle of domestic lawn care. Order yours today and benefit from Allett’s superior design and expert engineering to create a lawn that truly stands out from the rest.

Take a Closer Look at the Allett Kensington Cylinder Mower Range