Cairn Adventure 1.0 | E-adventure, E-gravel, E-commute?

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Hannah gets her first taste of an e-gravel bike, with the Cairn Adventure 1.0. Is it for disappearing into the hills, or just riding to work?

You’re probably aware of the team behind the Cairn – The Rider Firm also produces Hunt wheels, which have acquired a reputation for good value and good customer service. They produce products that they want to use, and the Cairn is a product of that: it’s a bike to replace a car, go to work the long way round, and throw in a bit of weekend adventure.

Cairn Adventure
Caught on a rare day out in the sun. Note the slop: the sun was brief.

Of course, the Rider Firm Folks are all down south, so their training grounds are the South Downs. Coastal byways, hedge lined back roads… at least that’s how I imagine it all being. Sunshine and occasional sea mists. How would the Cairn fare in the nothern grit of the Pennines?

The Bike

The Cairn Adventure 1.0 comes in Small, Medium, Large and Extra Large. I tested a Medium, and was provided with both a single Fazua battery and the battery replacement storage box/frame cover., which is an optional extra at £69. This is part of the aim of the Cairn: to make an e-bike that can be ridden without the battery, if desired. If for whatever reason you want to go ‘acoustic’ you remove the battery and replace it with the cover – which then gives you a handy storage area should you want to carry a foot long sub sandwich on your travels.

Up front there’s a carbon fork which has been designed by Cairn and is now available as an aftermarket fork for anyone else wanting a carbon fork with anything cage mounts and dynamo routing for adventure riding – they felt there wasn’t anything on the market already that did everything they wanted. The bike has 12x100mm front/12x142mm rear spacing, and you can fit up to 700Cx45C tyres or 650Bx2.25in sized wheels and tyres. This is helpfully noted on the frame. Of course, I didn’t read the instructions carefully, and having fitted a 29×2.25in up front I got to the rear to discover that it was only in 27.5 guise that you can go that wide. Doh. For the record, no, 29×2.25 doesn’t quite fit at the back. It really doesn’t. Luckily the Hunt wheels this bike comes with are the easiest I’ve ever encountered to get tubeless tyres on, off and seated. Thumbs alone could do the job, even with the WTB Venture tyres – I’ve previously had WTB tyre/wheel combos where they’ve been so tight that I’ve been afraid to venture out alone for fear of getting a puncture and not being able to do the fix myself.

The frame is alloy, with Anything Cage mounts on the down tube, bottle cage mounts on the seat and top tube, and full mudguard mounts front and rear. Aside from the downtube, the only sign that this is an e-bike is the small battery display and mode shift on the bars. There are four settings: off (if that counts as a setting), green (light assist, officially termed ‘Breeze Mode’), blue (a bit more assist, ‘River Mode’), and pink (turbo zoom, ‘Rocket Mode’). Since my bike was made, Fazua has released a new ‘Touch Remote’ which will be integrated into the downtube and on models ordered now. Personally, I like the dropper-post-like ease of access of a bar mounted assist shifter, so while I can see the benefit of having more space on your handlebars (for a dropper post trigger perhaps, even?) I’m not sure that I’d prefer the new frame-mounted assist adjust, especially for quick shifts on on rougher sections. The ‘older’ bar mount option will still work with the new bikes and could be sourced by Cairn or customer if wanted.

The brakes are a fairly standard SRAM Rival Hydro and the drive train is a mix of SRAM derailleur and cassette, however there’s the addition of a Praxis alloy crank designed and made specifically for the Fazua motor on the Cairn, which varies in length between bike sizes. As with the fork, it was felt that there wasn’t anything on the market that did what they needed (light and strong for gravel riding) so they had their own made. This was a weight saving effort, part of the aim of making the bike feel natural, even without e-assist. On weight, my medium weighed 15kg/33lbs with the battery, and 12.16kg with the baguette carrier.

Spec, covered. Time to take the Cairn Adventure 1.0 on the trail and see what it all adds up to.

The Ride

If you’ve not ridden a Fazua motor before, the sensation may come as something of a surprise. In green mode it’s easy to think that it’s not really doing anything – but switch it off and you’ll realise that no, your legs aren’t as amazing you thought. I found I used this green mode almost all the time  – it’s just enough to take the sting out of a headwind, counteract the weight of the bike, and keep your speed up on a gentle climb. It’s gentle enough that you don’t really notice it’s there – which means you don’t really notice too much when you hit the 15.5mph cut off for UK assist and have to provide all your own propulsion.

In contrast, I almost never used the blue, medium setting, finding that it gave a slightly uneven or surge-like sensation around that cut off point. On a steady climb it was useful, but for flatter riding I preferred the ‘ooh my legs feel great’ sensation of the green. The pink turbo zoom setting is nowhere near as powerful as you’ll find on other motors, but it’s still very effective at seeing you up a steep climb. I tended to use the pink for steep but not technical climbs, and the blue for steeper, rougher climbs. The pink does quite noticeably drain the battery though, whereas on green you’ll get a good many miles in. 30 hilly miles will still have you with plenty – 2 or 3 bars (out of 10) – left in the tank if you resist the urge to use the pink setting, but go into the pink and those bars will likely have disappeared. At least that has been my experience. As is the case with the fuel meter on my car, I did find that the battery life display didn’t seem to run down evenly. The maximum bar seemed to empty almost immediately, then you seem to spend for ever in the middle few bars, and then the last two bars get gobbled up rather rapidly. Not a problem once you’re in tune with that curve – I just ended a couple of commutes in the early days with an empty tank. Of course, the new Touch Remote display looks different, so the battery life display may also have its own characteristics.

Cairn Adventure
Fazua specific cranks, sized to the bike

Pedalling is more frictionless than any e-bike I’ve experienced. In the green setting it’s easy to wonder if it’s on or not, and I think it’s the weight of the bike rather than friction that you notice when you turn it off. Back pedalling gives a ratchet sound, but otherwise it’s very ‘normal’ in drive train action.

The size medium felt right to me at 175cm tall, though some I loaned the bike to found it a little short. I think this is partly the product of the ride position – it’s on the racier side of gravel, rather than a more relaxed touring option, and the bars are quite compact compared to some of the wider flared bars you find on many gravel bikes these days. This set up will likely suit those who are doing a mixed surface commute rather than MTB-lite, but those in less of a hurry – or perhaps looking to carry more luggage – may appreciate a more relaxed spec. Personally I like a relaxed old school touring style position so I can sit up and enjoy the scenery, and I like wider bars to go with my fatter tyres so I can take any trail I like in search of that scenery.

Cairn Adventure
Bars could be more flared

I think a good future development for the Cairn Adventure 1.0 would be to offer it in two build specs. Something like ‘town and country commuter’ and ‘adventure spec’. The current build fits the ‘Town and Country’ option well. I can see that this could make a very sensible alternative to doing daily battle with railway commutes. With a bit of commitment, a commute of up to 30 miles on a mix of road and canal would certainly be a feasible option. Depending on how many hills there were, or how much time you spent out of the green zone, I think you might want to invest in an extra charger (£149) so you could charge up at work before heading home.

Cairn Adventure
Splooshy commute?

While the bike can be ridden without a battery, I’m not really sure why you’d want to. Since you have to take the battery out and put a cover on to remove the weight, wherever you end up you’re going to be without battery. If you were riding from home and back again, you’re effectively riding a bike that offers the ride qualities of an entry level gravel bike, but at an e-bike price. It’s much handier to be able to ride the bike relatively comfortably with the battery switched off, and that has been achieved, although hit the hills – or try and keep up with a road bike on the flat – and you will notice the weight. The ‘battery off’ experience could perhaps be improved even more with a smaller, lighter battery for those with shorter journeys – only really using the assist for hills.

Cairn Adventure
On the flat, the battery takes the sting out of drag from the trail surface, or headwinds.

This battery weight issue applies to assist-restricted UK and EU riders, where the assist limiter kicks in at 15.5mph/25km/h. This is right about the speed that a regular rider is likely able to quite comfortably ride on the flat on a smoothish surface on these sorts of tyres. The benefit of the assist is greater for hilly or rougher routes, or for riders who can’t maintain that level of effort – maybe those carrying a bit of luggage who don’t want to get to work in a froth and lather. It’s also very handy for taking the sting out those days when you’d really rather grab the car – headwinds are much less of an issue with the motor to help you out. If you live somewhere without these assist restrictions, you’ll feel the benefit of the battery power in a much broader range of journeys. The limiting factor of the e-assist restriction is I think the biggest downside of this bike – it really limits the usefulness of the bike to much more specific circumstances than would otherwise be the case.

Cairn Adventure
You need some hills to get the benefit of the e-assist with UK restrictions

Taking the bike further afield, further off road and into ‘adventure spec’, I’d want to see chunkier tyres, maybe even a swap to 27.5in ones, with some wider bars for a more comfortable ride. 40C tyres – as my bike came with – are quite hard work on rocks rather than gravel, although it’s said there is room to go up to 45C. I’d recommend a tyre insert too – I found that the rocky trails of Calderdale had me choosing between clonking the rims at lower pressures, or rattling my eyeballs at higher ones. More important than my eyeballs perhaps were my hands – on my standard test loop, with a long, rough packhorse descent, I struggled with tingling and numb fingers. This might be down to the stiffness of the fork, it could be the fairly slim and stiff bars, the alloy frame, or a combination of all three. In discussion with Cairn, they agreed that taking it to similar – arguably quite extreme for a gravel bike – conditions, away from their South Downs development roots, they’d found things a little stiff. Future iterations of the bike will have the bridge at the rear of the bike removed to reduce stiffness, and Cairn said that my hope for a couple of build specs was already on their radar.

Since Cairn makes its bikes in small orders and doesn’t stick to model years, it has the scope to evolve the bike fairly rapidly in response to feedback. In the near future, look out for a battery carrier to fit the Anything Cage mounts – handy for taking the Cairn further afield, loaded up and into the real wilderness. Extra batteries can be bought for £399.

Cairn Adventure
If only all commutes could look like this?

If you want this bike to replace your car, I suspect you’d be looking to add racks for easier hauling. This is currently something of a limiting factor, since the weight saving carbon forks are not pannier rack compatible – though there is the Anything Cage option.

Longevity Notes

I have ridden this in probably some of the filthiest conditions any gravel bike – or e-gravel bike – will ever experience. I have ridden it through huge puddles that have had my toes dipping in the water as a I pedal, along gritty sloppy canal paths, and down rocky bridleways. Save for a collection of sandy grit getting into the bottom of the frame and stopping the battery slipping in and out neatly, I’ve not had any issues with any of the gubbins associated with it being an e-bike. Apart from dropping the battery on my foot, repeatedly. Butter fingers.

The only thing that really seems to me to be suffering the effects of wear is the brakes – perhaps to be expected when you’ve got road brakes holding back a heavy bike in what is effectively mountain biking conditions. In an ideal world I’d like to see something with a little more power, but if you’re riding in conditions like I have (and if you commute every day, you will), then you’ll probably get through brake pads a little quicker than you’re used to.


I enjoyed riding this bike, even though in its present spec it isn’t especially well suited to the rough and steep trails of Calderdale. It made the bike an easier choice to make on days when it felt hard. For someone looking to make their commute more fun but keep their average speed up, it would be a good choice. It would also be a brilliant addition to a hire fleet anywhere that there is a network of minor roads and bridleways, or for the back of your camper van – being able to explore as much of the countryside around you on holiday as possible could be an awful lot of fun. Unlike an e-MTB, the Cairn isn’t a boring slog to ride on sections between fun trails, so makes for happy exploring. If you fail to get back in time for tea (or before the battery runs out) it’s not the end of the world, either.

Cairn Adventure
South Downs contour map

This has been my first venture into e-gravel, and while it’s a well specced and strong performing bike, I think that this will best suit some quite specific riders. Whether we’re about to see a surge in numbers of cross country riding long distance commuters may depend considerably on the state of the rail network, and the cost of owning a car. If you’re one of those people already looking for a (mostly) pedal powered alternative, I haven’t seen anything else in the market that quite ticks all the same rough-off-road faring boxes, so if that is what you’re looking for, you’ve probably found your bike.

Cairn Adventure 1.0 Specification As Tested

  • Frame: Frame: 6061-T6 Alloy, Anything Cage Mount on down tube, bottle cage mounts on seat tube and top tube, full mudguard mounts front and rear, full internal dropper post routing option.
  • Fork: Full carbon Cairn Adventure Fork
  • Motor: FAZUA Evation 1.0 Motor, 250W battery
  • Headset: FSA
  • Stem: Ritchey Comp 4-Axis, ±6°, 80mm
  • Handlebar: Ritchey Comp Butano, Drop 118 mm, Reach 73 mm, Sweep 4°, Flare 12°, 44cm wide
  • Bartape: Fabric Knurl
  • Saddle: Fabric Scoop Elite Shallow
  • Brakes: SRAM Rival Hydro, 160mm rotors
  • Wheelset: HUNT 4 Season Gravel Disc, Thru-Axles, 12×100 mm Front, 12×142 mm Rear
  • Tyres: WTB Nano 700x40C
  • Chainset: Praxis Works FAZUA-specific, alloy 42T, 170mm
  • Rear mech: SRAM Rival 1x Long Cage
  • Shifter: SRAM Rival Hydro 1x
  • Cassette: SRAM PG-1150, 10-42T
  • Sizes: S / M / L / XL
  • Price: £2,989