Cobra MX4140V Cordless 40V Lawn Mower

Cobra RM51SP80VX MAX+ 40v Cordless Self-Propelled Rear-Roller Lawn Mower Kit (Inc 2 x 4ah Battery & Charger)

Cobra Garden Machinery

Cobra RM51SP80VX MAX+ 40v Cordless Self-Propelled Rear-Roller Lawn Mower Kit (Inc 2 x 4ah Battery & Charger)

Delivery options
By Courier (1-2 working days)
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Price Match Promise
Price Match Promise
We offer top prices, expert advice, and fast delivery. Found this machine cheaper? If it’s from an approved dealer with current prices, we’ll match it!* Call 0345 222 0231, use our live chat or our use our online form. *product must be in stock and ready for delivery, excludes bundle offers.
£649.99
RRP: £679.99 | SAVE £30
Availability: In stock
SKU
COB-RM51SP80VX
Pay in 3 interest-free payments of £216.66.
Available on purchases of £30 to £2,000
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  • Powerful twin 40V Lithium-Ion battery system
  • Generous 51cm (20") cutting width for large lawns
  • Full-width rear roller for professional striped finish
  • Self-propelled drive for effortless mowing control
  • Large 70-litre grass bag with full indicator
  • Six adjustable cutting heights from 17mm to 75mm
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RM51SP80VX MAX+ 40v Cordless Self-Propelled Rear-Roller Lawn Mower Kit (Inc 2 x 4ah Battery & Charger) by Cobra

20" Twin 40V Max+ Cordless Rear Roller Lawnmower

Experience the ultimate cordless performance and professional striped finish with the Cobra RM51SP80VX.

Maintaining a large, pristine lawn often feels like a trade-off between the heavy maintenance of petrol engines and the restrictive reach of a power cable. The Cobra RM51SP80VX eliminates these frustrations, offering a high-performance cordless solution specifically engineered for the British garden. Designed to tackle expansive areas without the fumes, noise, or mechanical complexity of traditional mowers, this machine provides the freedom to roam while ensuring your turf looks expertly manicured with every pass.

At the heart of this formidable mower is Cobra's advanced 80V brushless motor technology, powered by two 40V MAX+ Lithium-ion batteries. This twin-battery configuration delivers consistent, petrol-matching power that doesn't fade as the charge diminishes. The brushless motor not only provides high torque for tackling thicker grass but also boasts incredible efficiency and longevity compared to standard motors. By removing the need for spark plugs, oil changes, and fuel storage, the RM51SP80VX simplifies your gardening routine without sacrificing an ounce of performance.

Operator comfort is paramount when managing larger estates, and the RM51SP80VX is built with superior ergonomics in mind. The self-propelled drive system takes the physical strain out of mowing, propelling the machine forward at a steady pace so you simply need to guide it. Its lightweight, well-balanced steel chassis reduces user fatigue, while the handles feature infinite angle adjustments to suit users of any height. When the job is done, the cam-lock folding handles allow the mower to be stored compactly in your garage or shed, saving valuable floor space.

Versatility is built into the very fabric of this machine's design. Featuring a wide 51cm (20") cutting path, you can cover more ground in fewer passes, while the integrated full-width steel rear roller allows you to create those classic, sought-after lawn stripes. Beyond aesthetics, the roller provides essential stability when mowing right up to the edge of flowerbeds and borders, preventing the "scalping" often seen with four-wheeled mowers. With six cutting heights ranging from a fine 17mm finish to a robust 75mm for longer growth, you can adapt to any season or grass condition with a single lever.

Safety and convenience are seamlessly integrated to ensure a smooth mowing experience. The RM51SP80VX features a massive 70-litre grass collection bag made from high-quality fabric, which improves airflow and collection efficiency—even in damp UK conditions. An integrated grass-full indicator lets you know exactly when it’s time to empty, preventing over-clogging. For added peace of mind, the battery compartment is securely housed, and the simple push-button start means you can get to work instantly without the physical exertion of a recoil pull-start.

Main Features

  • Power System: Twin 40V (80V total) MAX+ Lithium-ion batteries with brushless motor
  • Drive Type: Self-propelled for effortless movement across uneven terrain
  • Cutting Deck: Robust 51cm / 20" high-quality steel deck for long-term durability
  • Rear Roller: Full-width steel roller for traditional stripes and easy border mowing
  • Height Adjustment: Single lever central adjustment with 6 stages (17mm - 75mm)
  • Collection: Large 70-litre fabric grass bag with hard lid and fill indicator
  • Storage: Quick-release folding handles for compact vertical storage
  • Included: 2 x 40V 4.0Ah batteries and 2 x fast chargers as standard

Main features

40V MAX+ BATTERY SYSTEM40V MAX+ BATTERY SYSTEM

40V MAX+ BATTERY SYSTEM

Built into the battery pack, this smart system recognises the specific Cobra tool in use and optimises output for peak efficiency. 40V Max+ batteries are high-performance, long-running, and fast-charging—and one battery fits all tools in the range. The Cobra RM51SP80VX uses twin 40V Max+ batteries to deliver a powerful 80V of performance, ensuring longer run times and the strength to tackle tougher mowing tasks with ease.

34cm / 13" CUTTING DECK34cm / 13" CUTTING DECK

51cm / 20" CUTTING DECK

The Cobra RM51SP80VX is equipped with a robust 20" (51cm) steel cutting deck, built for durability and high-performance mowing. This wider deck, paired with a precision-engineered blade, delivers a clean and consistent cut with every pass. Ideal for larger lawns, the 51cm width offers excellent coverage while still allowing for confident control—perfect for achieving a crisp, professional striped finish.

LIGHTWEIGHT DESIGNLIGHTWEIGHT DESIGN

BEAUTIFUL STRIPED FINISH

Equipped with a full-width rear roller, the Cobra RM51SP80VX is built to deliver a classic striped finish across larger lawn areas. The 20" (51cm) cutting width combined with the rear roller gives your garden a professional, well-defined look, while also enhancing stability when mowing along borders and edges. This allows you to mow confidently right up to flowerbeds and pathways, helping you maintain crisp, clean lawn stripes with ease.

ERGONOMIC CONTROLSERGONOMIC CONTROLS

17-75mm CUT HEIGHTS

With a fully adjustable 6-stage cutting height range from 17mm for a precise low finish, up to 75mm for tackling longer, more demanding grass, the Cobra RM43SP40VX delivers the versatility needed for various lawn conditions and cutting preferences. Adjusting the height is quick and effortless using the single height-of-cut lever, conveniently located next to the rear roller. This user-friendly design makes it easy to achieve your desired finish with confidence and control.

25-75mm CUT HEIGHTS25-75mm CUT HEIGHTS

ERGONOMIC CONTROLS

The Cobra RM51SP80VX offers smooth handling and effortless control, even across larger lawns and more challenging terrain. Its balanced design and powerful self-propelled drive system reduce operator fatigue, maintaining a consistent pace with minimal effort. The ergonomically positioned controls ensure comfortable operation, allowing you to confidently manoeuvre around borders, flower beds, and lawn edges. Designed for both performance and ease.

HANDLE ANGLE ADJUSTMENTHANDLE ANGLE ADJUSTMENT

SELF-PROPELLED DRIVE

The Cobra RM51SP80VX offers effortless control and smooth, consistent handling, even across larger lawns and more demanding terrain. Its balanced design and powerful self-propelled drive system reduce operator fatigue, helping you maintain a steady pace with minimal effort. Whether you're mowing around borders, flower beds, or lawn edges, this mower delivers the precision and stability needed to achieve a flawless finish.

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Specifications
Art No CORM51SP80VX
EAN 5055485039736
Brand Cobra
Power Source Cordless / Battery
Power Details MAX+ 40V Lithium-ion Battery 4Ah supplied
Engine make Cobra
Battery Voltage 40V
Transmission N/A
Starting Method Push Button Start
Design 4-Wheels
Cutter Deck Steel
Cutting Width 43 cm
Cutting Heights 17 - 75mm
Number Cutting Heights 6
Propulsion Self-Propelled
Collector 70L
Warranty Domestic Warranty: 2 years
Other Features Brushless motor, folding handles

Cobra

Cobra garden machinery has been expertly designed in the U.K to cater specifically for the changing conditions of the British garden. With a comprehensive line-up of quality and innovative products to tackle any gardening task, Cobra is the newest evolution in garden machinery. Cobra's range of lawn mowers features over 40 machines, starting with basic domestic models. Power options include electric, cordless and petrol, with own brand engines for the lower end models, right up to high end professional machines suitable for commercial use with Kawasaki, Honda and Briggs and Stratton engines. With the addition of brush cutters, hedge trimmers, chainsaws, pole pruners, tillers, blowers, multi-tools and scarifiers available there is something for just about every gardening need possible. Cobra’s philosophy is to remain true to their trusted values of innovation, quality, reliability, value and customer service. They always work hard to ensure that their products and services continue to be relevant to UK gardeners and gardening professionals.

Expertly Handled Delivery

From fast express parcels to our signature White Glove personal handover, we ensure your machinery arrives safely, quickly, and ready for work.

Standard Delivery

£9.99 (Eng/Wales) 1 - 3 Working Days
  • Reliable courier service for most items.
  • Items dispatched Mon-Fri.
  • Available to most UK Mainland addresses.
  • Next-day arrival possible in many cases.

Express Delivery

£9.99 (Eng/Wales) 1 - 2 Working Days
  • Priority dispatch for urgent orders.
  • Order before 2pm (Mon-Fri) for fastest service.
  • Available on many popular items.
  • Full email notifications for any delays.

Start 'N' Go

From £29.00 3 - 5 Working Days
  • Fully Assembled & Tested by our technicians.
  • Arrives on a secure pallet via 'Palletline'.
  • The courier will contact you to book a slot.
  • Ready to mow immediately on offloading.

Start 'N' Go +

White Glove Service 3 - 5 Working Days
  • Personal Delivery on our own transport.
  • Full Demonstration: We show you how to use it.
  • Zero Waste: We take pallets and crates back.
  • Available on select products in England & Wales.

Important Delivery Information

Working Days:
Please note that Saturday & Sunday do not count as working days. Orders placed over the weekend are processed on the following Monday (or Tuesday during Bank Holidays).
Booking Your Slot:
For Start 'N' Go orders, Palletline will contact you directly. For Start 'N' Go+, our own team will call you. Please ensure a daytime contact number is provided.
Ride-On Mowers:
Start 'N' Go rates for Ride-Ons start at £69 (Garden Riders) and £79 (Tractors). Start 'N' Go+ rates for Ride-Ons start at £99.00 (for both riders and tractors). This specialist service is currently available for Mainland England and Wales postcodes.

*Flat rates apply to Mainland England and Wales. Additional charges apply to Scottish Mainland and offshore addresses. Refer to specific models for accurate delivery guides.

Delivery Frequently Asked Questions

How much is delivery?

We charge a flat rate of £9.99 for all orders (Standard or Express) being sent to mainland England and Wales addresses. Additional charges apply to Scottish mainland addresses and offshore locations.

How long does delivery take?

Standard Delivery: Usually 1-3 working days.
Express Delivery: Usually 1-2 working days (often Next Day).
Start 'N' Go / Premium+: Usually 3-5 working days due to expert assembly.

Do you deliver on Saturdays?

Our standard delivery service operates from Monday to Friday. Saturday and Sunday do not count as working days.

What is Start 'N' Go/Premium+ and how does it affect delivery?

These services mean your machine is fully assembled, fuelled, and tested. Delivery typically takes 3-5 working days due to the assembly and specialist transport.

Will the courier call me before delivery?

For Start 'N' Go, Palletline will contact you. For Start 'N' Go+, our team will call to arrange a timed slot.

Can I track my order?

Yes. You will receive an email containing your tracking information once dispatched.

What happens if my item arrives damaged?

Please notify us immediately. If noticed upon delivery, please sign as "damaged" or refuse the delivery.

Full Delivery Details and Information

We are very sorry but please be advised that for the foreseeable future we cannot despatch orders to Northern Ireland, Republic of Ireland, the Channel Islands or any UK offshore postcodes.

Please see below for a breakdown of our various delivery services, including rates. In all instances, you will receive notification of when your order has been dispatched, and where possible tracking information will also be provided. Please regularly check your email account for any updates.

STANDARD DELIVERY

Most items will be sent out on our Standard delivery service. This service is available to most of the UK mainland*. This service is 1-3 working days (if ordered Mon-Fri, stock permitting), but is usually sooner than this. In many cases, your item could arrive next working day. Please note: Saturday & Sunday do not count as working days. Orders placed over the weekend will be processed on the following Monday (or Tuesday if a bank holiday). Some products are 3-5 working days, please refer to the specific model for a more accurate delivery guide. In some rare cases, your item might take longer than expected to arrive. If there is a delay in delivery, we will let you know via email.

We charge a flat rate of £9.99 for all orders which are being sent to mainland England and Welsh addresses, no matter the cost, weight or size. Please see below for additional charges to Scottish mainland addresses*.

EXPRESS DELIVERY

We offer an Express delivery service on many items to most of the UK mainland*. These items will be dispatched as soon as we possibly can and will usually arrive within 1-2 working days and in many cases on the next working day (stock permitting if ordered before 2 pm, Mon-Fri). Please note: Saturday & Sunday do not count as working days. Orders placed over the weekend will be processed on the following Monday (or Tuesday if a bank holiday). In some rare cases, your item might take longer than expected to arrive. If there is a delay in delivery, we will let you know via email.

We charge a flat rate of £9.99 for all orders which are being sent to mainland England and Welsh addresses, no matter the cost, weight or size. Please see below for charges to Scottish mainland addresses*.

START 'N' GO

Our Start 'N' Go service is available to most of the UK mainland*. Products that receive our Start 'N' Go service will need to be assembled and tested before being wrapped and dispatched on a pallet. Because of this, delivery is 3-5 working days (if ordered Mon-Fri, stock permitting) but during quieter times this can be much sooner. Orders placed over the weekend will be processed on the following Monday (or Tuesday if a bank holiday). You will be contacted by the Transport Company 'Palletline' to book your delivery in. Please ensure you provide a daytime contact number on your order.

Ride-On Mowers - We charge a minimum rate of £69.00 (for smaller garden riders) and £79.00 (for garden tractors) for all Start 'N' Go orders. This service is available to most mainland England and Wales postcodes. We cannot currently offer this service to any Scottish postcodes.

Everything else - We charge a minimum rate of £29.00 for all Start 'N' Go orders which are being sent to UK mainland addresses (England, Wales and some Scottish addresses*).

START 'N' GO +

Our premium Start 'N' Go+ service is available on certain products to most of England and Wales. Products that receive this service will be assembled, tested and personally delivered by one of our team on our own transport. We will also fully demonstrate the product for you. Delivery is usually 3-5 working days (if ordered Mon-Fri, stock permitting) but during quieter times this can be much sooner. Orders placed over the weekend will be processed on the following Monday (or Tuesday if a bank holiday). We will contact you to book your delivery in. Please ensure you provide a daytime contact number on your order.

Ride-On Mowers - We charge a minimum rate of £99.00 for all Start 'N' Go+ (plus) orders. This service is available to most mainland England and Wales postcodes. We cannot currently offer this service to any Scottish postcodes.

Everything else - We charge a minimum rate of £29.00 for all Start 'N' Go+ (plus) orders. This service is available to most mainland England and Wales postcodes. We cannot currently offer this service to any Scottish postcodes.

*Scottish Addresses

As of May 2024, we can no longer deliver ride-on mowers (lawn tractors, garden riders, front deck & zero-turns) to any Scottish Postcodes. Unfortunately we have been unable to source a reliable and cost efficient transport service north of the border.

If you are ordering any other product on our 'Start N Go' service additional charges will apply (in addition to our advertised standard charges).  If you wish to check if additional charges will apply to your postcode you can call us or use our Online Chat during office hours, or use the contact us page, please quote your full postcode and the make & model of the item(s) you wish to order.  You can still place your order through the website without receiving a quote and we will be in touch via email after the order has been placed to advise if there are any additional delivery costs.

For all other products, depending on the postcode and size of the item(s) you are ordering, additional charges will apply.  If you wish to check if additional charges will apply to your postcode you can call us or use our Online Chat during office hours, or use the contact us page, please quote your full postcode and the make & model of the item(s) you wish to order. You can still place your order through the website without receiving a quote and we will be in touch via email after the order has been placed to advise if there are any additional delivery costs.

For more information call our sales team on 0345 222 0231

At justlawnmowers.co.uk, we are passionate about garden machinery and helping you achieve a beautiful, well-maintained garden. As a trusted online retailer specializing in lawn mowers and garden equipment, we are dedicated to providing you with the highest quality products, expert advice, and exceptional customer service.

Our Commitment to Excellence

Professionalism:

We take pride in our professionalism and deep understanding of lawnmowers and garden equipment. Our team consists of knowledgeable experts who stay up-to-date with the latest industry trends and advancements. We are committed to sharing our expertise with you, ensuring that you make informed decisions and find the perfect lawnmower for your specific needs.

Reliability:

When it comes to your gardening equipment, reliability is crucial. That's why we carefully curate our product selection, partnering with leading brands known for their quality and durability. We want you to have peace of mind knowing that the lawnmower you purchase from us will deliver outstanding performance and stand the test of time.

Exceptional Customer Service:

At justlawnmowers.co.uk, we prioritize your satisfaction above all else. Our friendly and dedicated customer service team is here to assist you every step of the way. Whether you have questions about our products, need advice on maintenance and care, or require support after your purchase, we are always ready to provide prompt and helpful assistance. Your gardening success is our ultimate goal.

Our Approach

Informative and Friendly:

We believe in providing information in a way that is both informative and friendly. Our content is designed to be easily understood, jargon-free, and engaging. We want to empower you with the knowledge you need to make confident decisions about your lawnmower and garden equipment.

Join Our Growing Community:

We invite you to join our growing community of homeowners, gardening enthusiasts, and professionals who trust justlawnmowers.co.uk for their lawnmower and garden equipment needs. Explore our wide range of products, read our informative blog articles, and engage with us on social media platforms. We are here to support you on your gardening journey, and we look forward to being a part of your success.

Thank you for choosing justlawnmowers.co.uk. Let's create a greener and more beautiful world together!

Our Pledge

We are a family business with 60 years experience in the horticultural and leisure business. We are very well qualified to offer you the consumer the best products that are available today. Our massive buying power and knowledge of these products allow us to offer you unbeatable deals. Our products are chosen for their quality, reliability and price. We are deeply committed to give you the best possible service at all times.

Why Buy From Us?

  • Fast, affordable delivery to your door (usually next working day, if ordered before 2pm - excludes some Scottish and offshore postcodes)
  • We are authorised agents/dealers for most leading garden machinery brands
  • Our friendly sales staff have extensive knowledge of all the products we sell
  • We dispatch many orders from our own extensive warehouse facility here in North Norfolk
  • Direct access to over £20 million of stock via our main dealer accounts with manufacturers
  • Having been around since 1965, we know a thing or two about garden machinery!

Help and Advice

If you need some advice about which product is best for your needs, just call our friendly and helpful sales team on 0345 222 0231 (Mon-Friday 8.30am - 5.00pm, excluding Christmas & bank holidays) or use our chat facility at bootom of your screen. You can also contact us using our online form.  With a wealth of experience and expert knowledge about all the products we sell, they can answer your questions quickly, accurately and reliably. You should then have a much clearer picture about which product is right for your specific needs.

No Hidden Costs

When you buy from us, there are no hidden costs; all our prices include VAT and even better, we offer fast delivery with a fixed delivery price, no matter the size or weight *. Plus, by selling online we keep our overheads low, so we always have discounted prices; 365 days a year.

Buy Online With Confidence

Perhaps you are still a little concerned about buying online? Don't be; we use Braintree 128 bit encryption technology and PayPal to ensure that buying from us is always safe, secure and reliable.

Support

Our online support can handle all your after sales needs including consumables, spare parts, servicing, and more. Visit Support.

*excluding Start 'N' Go products

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