Cairn E-Adventure 1.0 review

Electric bike builder Cairn is part of The Rider Firm, the British upstart that boasts an ever-expanding stable including celebrated wheel maker Hunt, Privateer mountain bikes and Dissent 133 gloves. The collective’s team design and refine its products, but it’s not just in-house suggestions that influence the build of its bikes.

Take version two of the E-Adventure 1.0 electric gravel bike on test here. Extensive feedback from cyclists who brought the first iteration led to a refinement of the 2018 original, resulting in some choice changes and upgrades to the already well-appointed aluminium frame.

The rear seatstays have been shortened and more slope has been added to the top tube. This creates a greater standover height, which allows you to easily shift your weight around and manoeuvre the 1.0 through tight, technical trails.

The shortened seatstays also produce a lower seat clamp, which allows more of the quality carbon seatpost to be exposed and unsupported. This ensures more flex from the post and greater comfort when the going gets rough. Cairn has also removed the bridge on the seatstays to allow for more flex in the frame.

A bolt under the fork crown means you can run a proper mounted mudguard.

The final key upgrade comes in the Fazua Evation drive system. Earlier versions used a bulky bar-mounted remote control for the motor, whereas this new model neatly mounts the controller into the top tube.

Cairn E-Adventure 1.0 motor and battery

The Evation system offers three default levels of assistance. The first is ‘Breeze’, providing 100 watts of constant power; ‘River’ is a sporty mode that puts in 210W; and ‘Rocket’ mode takes things up to 250W.

There’s also an Eco mode that drops the power to 70W, 140W or 200W to extend the range, and a Performance mode that increases the levels to 120W in Breeze, 260W in River and finally a short boost of 300W in Rocket. Charge levels are indicated by five LED lights.

The Fazua is a clever system that closely matches your own efforts. In Breeze mode, it’s so unobtrusive that I hardly noticed its effect until the road started to rise. The beauty of the system is the absolute lack of drag, so I did end up riding quite a lot with the system on ‘off’.

The River mode packs more effort alongside your own and Rocket does have a bit of punch.

Fazua claims a class-leading 60 newton-metre (Nm) of power from the motor, but for me it simply doesn’t have the same oomph as Cannondale’s Topstone Neo with its Bosch power or Specialized’s Turbo Creo.

This isn’t a criticism of the Evation power because it’s a more subtle form of e-assistance than other mid-mounted motor systems, more akin to the likes of ebikemotion or FSA’s new HM 1.0 system.

Range wise, it’s a case of weighing up variables, such as rider weight, weather and terrain. Cairn claims around 80km on a charge for the 1.0, but I achieved 107.4km with 1,050m of elevation gain, so the time when I was riding with the system turned off has been factored in.

With Fazua, you can remove the battery and most of the motor and then ride the bike unassisted, reducing overall weight by 3.3kg.

A downside to Fazua’s system is the need to unhinge the battery to locate the switch on the battery itself: a clumsy solution to what’s an otherwise smart system.

I also had a few issues with Cairn’s Bluetooth signal to the app dropping out but, as I’ve used Fazua’s system on various bikes without issue, I’ve put that down to Cairn’s much-used demo bike probably being in need of a good service/update.

Cairn E-Adventure 1.0 wheel size and clearance

The bike comes in the 700c-equipped model you see here and an off-road-biased version with 650b (27.5-inch) wheels and a dropper seatpost in place of the carbon post.

Tyre clearance is very generous on both wheel options, up to a 45c in 700c and a massive 57mm for the 650b model.

Cairn E-Adventure 1.0 geometry

The geometry is well thought out. The relaxed 71-degree head angle isn’t so slack as to make the bike feel lazy on tarmac sections between tracks, while the road-bike-steep 73-degree seat angle gives a natural pedalling position that allows you to put down the power on fast, flat sections and climb with the best.

The relaxed head angle and 48mm fork offset give a 63.5mm trail (this figure is derived from a combination of head-tube angle and the fork offset; a small measure of trail makes for a fast-handling bike while more trail slows down the steering response). With its longer trail, this bike is stable handling personified.

It’s impressive how true and straight the bike rolls when you’re travelling through seriously rough and rocky gravel sections. If this was combined with a standard cockpit from a road bike, then the long stem would slow the steering further (think of the large steering wheel of a bus compared to a Formula 1 car).

Cairn has been clever, using a short Ritchey stem of 80mm on my test machine. The Ritchey Butano gravel bar also has a noticeable backsweep to its shape, further reducing the steering length and speeding up the handling response.

Cairn E-Adventure 1.0 ride impressions

What’s most apparent with the E-Adventure 1.0 is just how well it rides off-road: assuredly, feeling both stable at speed and nimble enough to cut its way through technical singletrack.

The Shimano GRX shifting is superb and the 42, 11-42 gearing offers plenty of range. The clutch-equipped rear mech, combined with the tooth pattern on the Praxis chainring, kept the chain in check, even on the roughest terrain.

The equipment is all smartly chosen and crafted. The Hunt X Cairn aluminium wheelset impresses with the wide rims shaping the tyres well and the tubeless setup maintaining pressure throughout testing.

My only criticism is with the Vittoria Terreno tyres. I think the Terreno tyres are superb and the graphene-infused compound is wonderfully supple, it’s just in this Dry weather spec they’re somewhat hopeless when the ground is less than optimum.

Cairn E-Adventure 1.0 bottom line

The Cairn is a truly excellent gravel bike first and foremost, one that’s been enhanced with e-power rather than an ebike that’s been adapted to go gravel. Bravo, Cairn: the updated E-Adventure 1.0 should make an even bigger splash than the original.