Karcher K7 Premium Smart Control Home High Pressure Washer

The Karcher K7 Premium Smart Control Home High Pressure Washer is the daddy of pressure washers. It's powerful, precise, adjustable and has a long hose and power cable. And in addition to cleaning your bike you can use it for getting gunk off your patio, garden fence, paving and more – which at least goes some way to justifying a price that puts it very much at the top end of the market. And then some...

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As winter comes around bikes inevitably come home caked with more and more mud. And if you don't clean it off immediately it dries on, and very soon you're carrying around extra weight, your bike's aerodynamics and clean lines are compromised, and you really don't want mud getting into your bike's sensitive parts.

So, keeping your bike clean is not just good for longevity and making sure your bike is running smoothly, it could actually make you a fraction faster too. And when a friend lent me a pressure washer a few months ago, I learnt a valuable lesson – there are two types of people in this world, those who want a pressure washer, and those who just haven't tried one yet.

So when Karcher asked me if I'd like to test one, it was a no brainer. Having spent a weekend pressure washing everything I could find with my friend's washer, I was hooked.

And then this Karcher K7 monster arrived, the 'big daddy' of the pressure washer world. It has a dedicated reduced power mode, and settings and instructions designed especially for washing bikes. I've used the little hand-held battery powered ones that Dave reviewed years ago and they're not bad – but this is a very different beast.

Disclaimer

But first, a disclaimer: you need to take care using a pressure washer. Great care. Though modern bikes and components are designed to keep out every-day mud and water, they're not designed to stop water coming sideways at high pressure. You can easily penetrate and even destroy bearing seals with a modern pressure washer, which will strip out all the lubricant, and even stainless-steel ball bearings will start to corrode when soaked.

You can also damage sensitive components such as electronics, and moving parts such as derailleurs and suspension are likely to contain bearings and lubricant, and potentially electronic controls.

Furthermore, with enough power, you could even damage the frame and any other part of your bike. Limit the power of the pressure washer accordingly, and steer clear of sensitive parts altogether.

Power

This K7 goes all the way up to 180 bars of pressure. Of course, like any ape-brained male the first thing I did was set it to 50% and point it at my slightly mossy garden fence and pull the trigger. Bye-bye moss.

Oh, and even at half power you can feel the pressure pushing back in your hands. Naturally I also had to try the boost mode, which is a super-high-pressure max that runs for a maximum of 30 seconds. It was at this point I realised I should have heeded the manual, which stated very clearly how powerful this is. The manual also advises wearing toe-capped boots, which will give you an idea...

The result was bye-bye moss, bye-bye paint coating on the fence – and bye-bye chunks of wood it tore out of the fence! I kid you not! But also – wow!

Getting a grip of myself, I decided to clean my long-suffering commuter bike first, which hadn't been cleaned for two years. Yep, sorry. But the Karcher proved excellent. You can connect it to your phone and use the Karcher app to select what you want to wash. Choose the 'bike' setting and it will choose the correct pressure, connecting to the K7 using Bluetooth.

I turned the lance head to a flat spray as recommended, pulled the trigger and the result was a precise and defined spray with clear edges. The app chose a pressure level of 2 out of 6, which was a firm pressure of water but it dissipated rapidly.

I cleaned the bike from about 60cm away, and the dirt ran off with great alacrity and I was done sooner than I thought – about 90 seconds did it thoroughly. It should be noted that the Karcher app, having reduced the power of the unit, suggests a distance of around 30cm, and to not aim the jet at 'the storage areas, chain, electrical connections and shock absorber of the bicycle'. I'll explicitly add the bearings to that too...

A couple of years of town riding had left an oily film over most of the bike. This was nowhere more visible than on the white logo of my tyres, where the words were nearly illegible. The pressure washer made short work and left them gleaming with a new-looking white in a second. In fact, pretty much everything was quickly restored to a 'newish' appearance.

There were a couple of areas that stubborn dirt, scum and oil resisted, most notably where the bottom bracket shell meets the seat tube. I was able to get the nozzle almost up against the metal, avoiding the danger of any water getting into the bottom bracket itself, and I gave it a close-range blast. Again the same picture shows the metal gleaming bright a few seconds later. With a normal garden hose I'd never have been able to achieve that control and focus the water so specifically and achieve enough pressure to clean the bike.

We've all used brushes, sponges and cleaning solutions – and I've probably used several times my bodyweight in Muc-Off over the years. The Karcher produces a fine, defined jet of water that allows for great precision, so it feels like you're a surgeon wielding a big watery scalpel. The result is that I could shift the grime without using any chemical cleaning aid.

My titanium bike proved perfect for this, though I exercised more caution over the carbon components and didn't chance any close-up blasts. My disc rotors had also become slightly squeaky in recent months, and I felt that warranted a high-pressure blast. Again, because of the precise ability to direct the water and the defined edges of the spray, I could hit the disc at close range without getting anywhere near the bearings in the hub. Bingo! God, this is satisfying!

Performance

We need to be explicit about the pros and cons of the Karcher. And if you use it properly, in accordance with the suggested power cap and at the recommended distance, it really is a great tool. The precision, power, and volume throughput deliver rapid and effective cleaning. But don't abuse the tool – this machine has more than enough power on higher settings to strip the paint from your bike, blast through bearing seals and destroy components. If it rips wood apart, I imagine it could do a lot of damage to carbon fibre. So, make sure you use it responsibly.

That said, this is a phenomenal piece of kit. Is it overkill for washing a bike? Yes. Did I adore every moment using it? Yes. Would I trade it in for a less powerful model? No. Would it make any difference to my bike washing if I used a less powerful model? No.

It has a flow rate up to 550 litres per hour, so you're likely to be done in a minute or two. It's got more power than you need and is big, heavy and expensive. Its weight is three times that of the bikes I was cleaning and it's chunky too, but in spite of that it's a user-friendly design. It rolls easily on its wheels, and it has a long power line and a 10m-long high-pressure hose.

The app is a nice touch, and gives you safe usage parameters.

The lance has three different spray shapes, and there are tons of accessories. You can add a cleaning agent, for bikes – or patio stone – that just sits in the top and the machine automatically filters it in.

It is however, really expensive, and to be honest more machine than you need for cleaning your bike. You could go for any of Karcher's less expensive models from the K2 to the K7 Compact, with the K2 costing just £140, and at 3.5kg is a fraction of the weight and a third of the size of this one.

Yes or no...

If you can afford it, get this one. I can't 'recommend' that you do, and I hate myself for loving the power of the K7 – but I just do. Cleaning bikes with the K7 is the equivalent of using a sledgehammer to crack a walnut, and £550 is a hell of a lot of money to spend on a 'garden hose pressure increaser.'

But if you try it you'll be hooked too. If you need to justify the power increase, well, it'll do more jobs than the lower-pressure models. Next time the rain lets up I'll get round to doing the patio stones. I'm looking forward to that. Yes, £550 for a bike cleaner is a lot and then some, but £550 for a house and garden washer that also does bikes is perfectly reasonable.

Value

While Karcher is the brand of pressure washer I'm most familiar with, thanks to its immediately recognisable yellow branding, a quick search reveals lots of other brands make pressure washers too. Most of these are considerably cheaper too, such as the Muc-Off Pressure Washer that Dave tested back in 2019, which is only 95 quid and it did the job.

The Karcher is about five times the price of that and over twice as dear as the one I borrowed from a friend – but I'd say it's also more than twice the machine. Yes, it's expensive, but it really is so very, very good that it doesn't represent bad value.

For a much more modest £140 you could get either the portable 4-litre battery powered version that Dave reviewed, or the K2 Compact, a mains powered 110 bar unit. However much you can justify spending, whether it's the K2, K3, K4, K5 or K7, keeping your bikes clean has never been so satisfying.

Conclusion

It's a great piece of kit with a 10 out of 10 performance for cleaning both your bike or pretty much anything else you want, with care – and if you're prepared to pay the price I can't recommend it highly enough. 

Verdict

More power than you need for washing bikes, so find other uses for it to justify this addictive power!