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Cobra Petrol Lawn Mower Review [2022-2023]

Written By: William
Last Updated on October 18, 2022

Cobra Lawn RM40SPC Mower Review

This Product May Be Currently Unavailable, 

Our recommended alternative is The Murray 2691584 EC370 37 cm Electric Corded Lawn Mower, Push, 5 Years Warranty, Black


  • Murray 2691584 EC370 37 cm Electric Corded Lawn Mower, Push, 5 Years Warranty, Black

It might just be us but there’s nothing better than seeing some nice stripes across the length of your lawn. Simply keeping grass short is certainly nicer to look at than keeping it unkempt but it’s just not the same as the impressive lines that you might see on a golf course of local bowling green.

These stripes aren’t even just form over function either, having an excess tangle in your lawn can prevent access of water and fertilizer to the roots and can prevent your grass from reaching the bright, illustrious green of healthy-looking grass.

Thankfully you don’t need to be a professional or even need to buy a horrifically expensive lawn mower to achieve a wonderful striped lawn. Since the stripes are just indicators of light bouncing off blades of grass facing in different directions, you just need a bit of time, patience and a lawn mower with a roller attached.

The snake is perhaps the best possible animal you could use to associate with garden stripes. Their whole bodies are long and straight and so it feels fitting that the lawn mower we will review today comes from a company called Cobra.

This is a British business that’s no stranger to producing all the tools you need to make your garden look the best it can. The RM40SPC is a petrol-powered self-propelled mower than can produce the perfect traditional striped finish with the use of its rear roller.

In this review, we will take a look at some of the advantages and disadvantages of this lawn mower and then ultimately tell you why we believe that it is well worth your money.


  • Surprisingly stylish looks and solid build quality with a metal deck
  • Well priced for a petrol self-powered motor with a rear roller
  • Compact, yet large capacity fabric grass collecting bag
  • Remarkably wide cutting height adjustment level with six stage


  • Customers don’t always receive the advertised free engine oil
  • At 35kg, the lawnmower is heaver than most 40cm petrol mowers

Key Features:

  • 135cc Cobra DG450 OHV
  • 40cm cutting width
  • Folding handles
  • Full width rear roller
  • Speed: 3.4km/h
  • 6 stage cutting height from 17-75mm
  • 50L grass collector volume
  • Weight: 35kg
  • 2-year warranty

Large Capacity Grass Bag

The Cobra RM40SPC is equipped with a substantial 50L grass bag which is perfect for collecting enough clippings for a medium-sized garden. The bag is made out a high-quality water-resistant fabric that allows for extensive air flow for the efficient passage of grass during use. The benefit of the collector being fabric over the normal plastic is that it can be more compact for the given volume although we do wonder at the long-term durability of the material.

Cutting height adjustment

Whether you want your grass to be a neat 17mm when you do that first cut in the spring (to remove dead ends), or a longer 75mm to provide shade in the summer then the Cobra RM40SPC has you covered.

The simple height adjustment lever has been handily positioned next to the rear roller and allows you to change between five height settings.

This lever is much more ergonomically designed than most as it is in an easy to reach position, not being hidden behind wheels like in many models.

Cobra DG450 Engine

The Cobra DG450 forms the beating heart of the RM40SPC. This overhead valve (OHV) engine is small and quiet but never feels like it’s lacking in power, it makes short work of tall grass and is rated for gardens up to 600m2.

The 135cc motor is a pull recoil starter rather than a key/button one, although that’s to be expected for this price point and the engine is still easy to start without choking or flooding.

It should be said that in some places this mower is advertised as coming with free engine oil, this doesn’t always happen however and is dependent on where you buy.

Stylish Design

This isn’t likely to be a top factor for anyone and is, of course, looks are subjective but hear me out. I believe that the Cobra RM40SPC is one of the most attractive lawn mowers you can buy. It’s not often that you get a lawnmower that has a bright red body, let alone one that with a racing stripe!

The RM40SPC is a beautiful mower with aerodynamic styling and the engine proudly mounted in full display atop the painted body. If you’re a fan of the AC Cobra and don’t have a spare £1m+ lying around then this is about the best you’re going to get.

Like its sports car counterpart, this mower has a powerful naturally aspirated engine under the bonnet that can give you plenty of thrills if gardening is your thing.

As a benefit over the car, there’s no need to wear a seatbelt or worry about accidentally speeding because, well… it’s a lawn mower. Just a nice looking one.

Full Width Rear Roller

As previously stated this lawn mower is equipped with a rear roller that extends across its whole body.  This replaces the rear wheels of normal mowers and presses grass down using the 35kg weight of the unit.

This weight is high for a mower with a 40cm cutting width and may be difficult for some people to handle, which is why it’s listed as a con but it has the benefit of allowing for a larger indentation in the grass as you move along which should produce more pronounced stripes.

You just need to line up the front wheels with the border (which it is able to get right up to the edges of) and allow the mower to do its thing.

What’s included in the box?

1 x Cobra RM40SPC Lawn Mower

1 x Grass Collector

1 x Instruction Manual


We’ve talked a lot in this review about rollers and hopefully given you a good idea why they’re important in keeping your garden looking sleek and healthy. If you’re after a roller mower in another price class, then we have you covered but for now it’s time to give a final verdict on the RM40SPC.

Cobra designed the RM40SPC to be the entry-level model in their self-propelled rotary mower range, with a full width roller in the rear to provide that classic striped effect. If you’re worried about buying an entry-level model, then don’t be, the biggest feature that’s missing is a variable speed for the motor which isn’t an issue for most people.

The 3.4km/h speed should be perfect for most people as it’s about the pace of a slow walk which is useful for giving you time to perfectly line up your mower with the edges of each stripe.

Additionally, all Cobra mowers allow for the cutting heights to be adjustable across a wider range than we usually see, this is a benefit we aren’t expecting to find that can really help with cutting sloped lawns.

The RM40SPC is a perfect mower for anyone with a small to medium-sized garden that wants to get the perfect looking garden without breaking the bank.

This Product May Be Currently Unavailable, 

Our recommended alternative is The Murray 2691584 EC370 37 cm Electric Corded Lawn Mower, Push, 5 Years Warranty, Black


  • Murray 2691584 EC370 37 cm Electric Corded Lawn Mower, Push, 5 Years Warranty, Black

About the author 

Written by William
I have always had a passion for gardening and that with a background in selling lawn mowers for the past 10 years, I have become very knowledgeable in all types of gardening tools. The site was created as a hub where I can review and write about all of the tips around gardening.
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