The Cowboy Cruiser ST was known as the Cowboy 4 ST at the time of this review.

We previously reviewed the Cowboy 4 ST's predecessor, the Cowboy 3, and were impressed with the super smooth look. However, we felt that a number of snags made it hard to recommend in that state of design. Let's see how the latest model shapes up.

Well, for a start, the Cowboy 4 has a smaller frame and better pedals, addressing a couple of the issues we had with the 3 (although note we tested the step-through "ST" version here - the non-ST Cowboy 4 still has that same over-large frame).

It's also worth noting that Cowboy has been attracting very large amounts of venture capital recently. The Brussels-based company recently landed an additional $80m in funding to help fuel its international expansion, which means they have raised over $120m since being founded in 2017. That may well translate into more app functionality in the future which you would hope will be updateable over the air.

Would you ride a super smooth cowboy?

The ST4 retains the super, super smooth looks of its predecessor - so much so it would arguably look more at home in the minimalist display at your local Apple shop than it would in a traditional bike shop. Imagine a computer rendered e-bike image bought to life and this is it.  

But it's not just about the looks. There are performance improvements too. Both the latest Cowboy 4 models claim 50 per cent more motor torque and a new 'integrated cockpit' with Quadlock-mounting handlebar stem area that wirelessly charges your phone (if it's wireless charging-compatible) as you ride.

It's good to see Cowboy have reacted to criticisms of the predecessor model by lowering the gearing to around 72 gear inches (down from 77 gear inches). This makes for speedier starts and better hill climbing.

They have also made the frame on this ST variant considerably smaller than on the Cowboy 3, which was a whopping 59cm from bottom bracket to top of seat tube - the ST 4's equivalent measurement is 53.5cm, giving a ground to top of seat measurement of around 88cm. This is much better for a small to average riders but still not small enough for the smallest. (All Cowboy models come in a single frame size with the crossbar versions being even larger).

Lastly, the battery seems to lock extremely securely in place and, unlike last time, we didn't have any issues at all with loose battery contacts and loss of power. 

Single speeds aren't for everyone, especially those, like this one, with only a single power setting on a small hub motor. But if you are after a really, really simple-to-ride e-bike that will guide you where you want to go through the city (as long as it's not a mega-hilly city) then the Cowboy 4 ST might just fit the bill.  

Despite the elegant appearance, it's solidly built, with a through axle at the front and a rear threaded axle cleverly concealed on the inside of the frame.

A nice practical touch is the fact that once the tyre tread starts to wear out you will see a yellow band of anti-protection kevlar underneath, telling you it's time to change.

There's also a handy toolkit with the bike. It lacks an 8mm allen key required to swap out the wheels but does include a belt tensioning tool for the belt drive which is achieved by turning the offset 'eccentric' bottom bracket. 

As with any e-bike that contains any tech unique to that particular design, the side effect of getting something truly distinctive is that you are also tied to that particular company for any replacement parts.

Is it super smooth to ride?

Cowboy say the motor has had a total overhaul. Power delivery is super smooth as well as unobtrusively quiet and the torque sensing kicks in straight away, giving a gentle surge of power on the flat. 

Despite the relatively upright riding position of the new frame design, it's a lovely fast and responsive ride too, with Cowboy's own brand semi-slick tyres being reminiscent of the excellent speedy-yet-comfortable Schwalbe G-Ones.

Over the power cut-out limit, it remains fast and easy to ride on the flat. Downhill pedal power runs out at about 20mph, but the gearing could do with being a bit easier on steep hills. You can't have your cake and eat it on a single speed. Whatever your speed, stopping is buttery smooth thanks to the SunRace hydraulic disc brakes.  

Whilst the power feels very helpful up moderate hills, it certainly wilts a bit down to around 10-12mph on steeper inclines. There is still a reasonable amount of low speed torque though that even kept the bike crawling up our ultra steep 25% hill climb at around 5mph, albeit by hauling on the bars very hard. Clearly this is very far from the bike's natural habitat, but it made it up without any complaints from the motor or any weird noises, which is pretty impressive in itself.

On our less severe mile-long hill climb, it posted a well below average time, but this was to be expected given the strong headwind on a couple of the steeper sections. In more reasonable conditions it breezes up moderate hills.

Looking at the ride data recorded by the app confirmed this is far from the most powerful motor out there with peak power of around 350W. I've tried legal hub motor systems that peak at over 800W. (Note the 250W legal stipulation is a 'continuous' rating which allows for such high short-term peaks.)

Over our hilly range test course, in very windy conditions, the bike used around 14Wh per mile, suggesting a 25 mile plus range from the 360Wh battery in these challenging conditions. 30 miles plus seems entirely feasible on flatter terrain in calmer weather. Having a lower power level would have been a nice option on flatter sections, where you just want minimal assistance which would of course increase range. Fortunately, a 3 amp charger means speedier charging than normal if you do run out of juice and have to refuel en route. 

The fairly small cockpit area felt comfortable, though the saddle could do with a bit more padding for my particular body build. The new 'tactile grip' pedals proved very grippy and the Quadlock fixing for my smartphone felt nice and secure. 

Mudguards come as standard but the clearance on the front one was very minimal and prone to occasionally trapping bits of road debris between it and the tyre, which rattled around. (The mudguards are removable but only have minimal adjustment).

As on earlier models, lights are beautifully integrated into the frame, though a rear light on the rear mudguard would make more sense as it would not be prone to being obscured by luggage as the current frame mounted one is. 

Speaking of luggage, there is an option to get a pannier rack and also an optional kickstand, making it an almost complete city bike. Sadly it lacks a chainguard, though the belt drive is an excellent low maintenance feature. 

Full marks to the app

I couldn't experience the full benefits of the new smartphone optimised system as my phone doesn't allow wireless charging. If your phone does have it then Cowboy say it should work with this bike. Once mounted, compatible phones will pick up induced charge from the coils hidden inside that oversize handlebar stem. It would have been great to see how effectively it worked compared to the probably-more-efficient method of a cable. Without being able to charge on the go the bluetooth connectivity certainly drained my phone quickly. 

The bluetooth and the app itself is superb though. There's the choice of a simple speedo screen with a power meter showing the motor response as a fluctuating red bar around the edge of it, or a navigation screen that uses a single style of clear mapping. 

Keying in a ride with my local bookshop as a destination I discovered that the suggested route took me the way I usually go: a slightly longer route than on main roads along a Sustrans route and then through a supermarket car park and under an arch between buildings to arrive at the shop's doorstep. That's a staggeringly impressive level of detail. 

The app is programmed to use the cleanest air route (quite likely to be pretty scenic too) - this is admirable, not to mention clever, but if you simply want the quickest route and are prepared to ride down busy main roads the app doesn't cater to you. Cowboy say more routing options may be added in future. There are over the air updates to the bike's firmware via the app, so you would hope such options would arrive automatically.

Does it match the competition?

The obvious Cowboy competitor is the Dutch designed Van Moof. At £1,998 this is almost £500 cheaper, has a similar smartphone app-heavy approach and sleek physical looks. It also has four gears that shift automatically, a larger 504Wh motor plus several power levels to choose from. On the downside, it has a front hub motor which can be prone to wheelspin and can make the bike feel rather front heavy. On paper, the bike itself is also a couple of kilograms heavier than this model of Cowboy. Our tester felt the Van Moof was the benchmark for a fully integrated, GPS and smartphone enabled e-bike. 

A couple of other urban single speeds cover similar ground but without most of the 'smart' aspects of the Cowboy and Van Moof. The recently reviewed Tenways CGO600 and Volt London both have more hill climbing power, the Tenways having a smaller battery and the Volt a larger one. In terms of value the Tenways is hard to beat if you don't mind their rather meagre app, while the Volt is a great hill climber, despite its heft. 

Note that both Theft Insurance and Cowboy Care - AA style callout services - are available on a monthly subscription basis. The former comes with theft alerts to your phone should the bike be moved whilst you are away from it. It's a pity that the only way to take advantage of the Cowboy's integrated remote tracking system appears to be to subscribe to this.

At £2,490 this bike looks decent value for all the tech and high quality of manufacture you get - until you consider the value Van Moof  brings in direct competition to it. Still, I can easily forgive the Cowboy 4 ST this (and that questionable front mudguard clearance) given the wonderful functionality of the power delivery, belt drive and navigation app. I'm already imagining myself rolling around Paris or London, typing in my desired sightseeing destination and just letting the voice commands get me there whilst I enjoy a simple, silky smooth ride, admiring my surroundings - which is what my kind of biking is all about.