The bike is, according to Cairn, for those who want to get away on a long distance adventure on a weekend without relying on a car. It’s also being pitched as an ideal option for those with long commutes.
The addition of e-assistance means that longer distances, perhaps into more remote and challenging terrain, can be tackled, which is a deeply appealing idea.
Some might pipe up concerned that this sort of bike will encourage riders to go further than they could otherwise manage and get into a sticky situation. This may be true, but remember, that’s a fault of the rider, not the bike.
The Fazua motor and battery is totally removableJack Luke / Immediate Media
The bike is built around a Fazua motor that can deliver up to 400 watts of assistance. This isn’t quite as much as some other systems, but other testers on BikeRadar have found it to provide ample assistance without totally overwhelming your own input.
The motor and battery unit weighs in at 4.7kgJack Luke / Immediate Media
Uniquely, the system is also totally removable, with the battery and motor housed inside a single quick-release unit weighing 4.7kg.
I’ll never get tired of seeing that handsome little drive shaftJack Luke / Immediate Media
This means that should you wish to run the e-adventure sans-assistance, the weight of the bike will be closer to that of a regular bike.
On that subject, Cairn is also considering shipping — or at least offering as an accessory — the bike with a blanking box, similar to Specialized’s SWAT compartment that could live in the place of the motor and battery unit.
It was noted that the capacity of this box is pleasingly similar to the size of two large cans of beer.
What about battery life?
Battery life is, of course, a concern with any e-bike, particularly one that is designed for back-of-beyond adventuring.
It’s nigh on impossible to quote an accurate figure for range because there are too many variables, but Cairn reckons that in good conditions, you should expect to get 90km out of one battery.
Cairn Cycles is developing external batteries for the bikeJack Luke / Immediate Media
For longer rides, Cairn is also planning on offering additional batteries that can be mounted externally onto both the seat tube and the forks, massively increasing the assisted range of the bike up to a theoretical 200km.
Cairn Cycles e-adventure bike highlights
I had a chance to ride a prototype modelJack Luke / Immediate Media
It’s worth stressing that the bike I rode is a prototype, so details will change before it reaches production, but the overall DNA of the bike will remain the same.
The paint, by Fat Creations, highlights the topography local to Hunt and what changes are expected to be made on the production modelJack Luke / Immediate Media
The alloy frame has been designed by Richard Shaw, a well-regarded designer who’s worked on highly rated bikes from a number of brands.
Geometry wise, the bike doesn’t present anything particularly radical, with a 71-degree head angle, a 73-degree seat angle and a 1,030mm wheelbase on a size large.
One of the coolest features of the bike — and the production bikes will also feature this — is the dropper post that is actuated by a modified left-hand SRAM shifter. We’ve seen this system on a number of gravel bikes and it’s something I wholly expect to see more of in the future.
The bike is fitted with super-wide Ritchey handlebarsJack Luke / Immediate Media
Final build spec is still TBD, but my test bike came outfitted with a SRAM Force 1x groupset, MasonxHunt 650b Adventure Sport wheels fitted with 650×1.5in Panaracer GravelKing SK tyres and super-wide Ritchey VentureMax WCS handlebars. In this guise, the bike weighed 16kg.
The bike is built around a 1x SRAM Rival drivetrainJack Luke / Immediate Media
The bike is designed to work with either 650b or 700c wheels, with Cairn hoping to offer the bike in both flavours when it goes to production.
Pricing is expected to be around £3,000 with initial availability some time around spring 2019. International shipping will be available.
Cairn Cycles e-adventure bike first ride impressions
There are next to no photos of me on the bike because I was too busy razzing about being an idiotOllie Gray / The Rider Firm
Cairn Cycles came to BikeRadar’s home town of Bristol to show off the new bike, and our test loop took in a familiar mix of gravel roads, singletrack and sketchy off-piste mountain bike trails.
To start, we took in a few of Bristol’s more vertiginous locales en route to the trails and hoofing up these while taking advantage of the Fazua system’s Rocket mode was great fun, with enough assistance to move comfortably through traffic.
It’s been said a million times, but getting to the top of this climb I was just as puffed out as I would have been on a normal bike, but I’d got up it in about half the time it would normally take me.
Off road, the bike is an absolute hoot.
Having the motor placed so low on the frame gives the bike a super planted feel over rough terrain. The effect is most pronounced on rough and steep climbs, with the assistance allowing you to power easily through choppy terrain.
On corners, the front end feels super stable. The wide Ritchey bars contribute to this, but the low centre of gravity also helps.
The additional weight of the motor does make it a little harder to flick the bike about compared to a non-assisted bike, but the effect is a little less noticeable than something like the Orbea Gain — with its hub-based motor — that I rode last year.
I think these tyres are a perfect match for a bike like this. The extra heft of fat rubber isn’t a concern on an e-bike and the extra control and comfort they afford is invaluable.
We (accidentally) took in some fairly sketchy off-piste mountain bike descents on our loop. While a gravel bike will never be the perfect ride for such escapades, the sure-footed handling of the bike here left me impressed.
The dropper post undoubtedly helped and I can absolutely see these becoming standard issue on gravel bikes in a few years time.
Our ride was only 30km long, but I finished very impressed by the Fazua system. The power delivery is very smooth and the motor reacts to changes in cadence in a more natural way than competing systems.
I found the difference between the Breeze (eco) and River (tour) modes a little vague for my liking, but Cairn was keen to stress that the ride characteristics of these modes can be tuned to a degree by the end user, with further remote modification by Cairn and Fazua themselves possible.
With that said, I spent the vast majority of my time in Breeze mode and found the additional oomph it provided to be more than enough to boost me about at a truly reckless speed.
175mm cranks caused a few pedal strikesJack Luke / Immediate Media
175mm cranks wouldn’t normally pose a problem on a gravel bike, even on one with a particularly low bottom bracket, but as you have so much more power on tap with an e-bike, you’re much less likely to have to ratchet your way up awkward climbs.
This means you tend to pedal right through the stroke, even on the gnarliest terrain, and I found myself striking the cranks on a number of occasions.
Come production, so long as it doesn’t adversely affect your pedalling, I’d hope to see 170mm cranks, or possibly even shorter, specced on the bike.
It’s worth noting that this is relatively common issue when we review e-MTBs and we’ve found dropping down a crank size or two has next to no effect on pedalling performance.
Cairn e-adventure bike early verdict
I was pretty surprised when I heard that The Rider Firm was spreading its wings into the e-bike market — the company has not been afraid to try new things, but an e-bike is in a whole different league compared to its other ventures.
However, I finished my short time on the Cairn Cycles e-adventure grinning ear to ear and very impressed by the whole package.
The handling of the bike is superb, the build is almost perfect for the intended use and the Fazua system might just be the best I’ve used so far.
My time on the bike was too limited to draw any final conclusions and details will undoubtedly change before it reaches production, but overall, I think Cairn Cycles is on to a winner and this is definitely one to watch in the future.
Jack has been riding and fettling bikes for his whole life. Always in search of the hippest new niche in cycling, Jack is a self-confessed gravel dork, fixie-botherer, tandem-evangelist, hill-climbing try hard, and thinks nothing of taking on a daft challenge for the BikeRadar YouTube channel. With a near encyclopaedic knowledge of cycling tech — from the most esoteric niche nonsense to the most cutting edge modern kit — Jack takes pride in his ability to seek out tech and stories that would otherwise go unreported. Jack has been a Senior Staff Writer at BikeRadar for three years now and is currently testing an All-City Mr Pink as his long term test bike.