Biketest: Cairn E-Adventure 1.0

Biketest: Cairn E-Adventure 1.0

A versatile £3,000 e-gravel bike with a removable battery and motor. Richard Hallett test rode it

Ignore that huge down tube and Cairn’s E-Adventure 1.0 could pass as a regular gravel bike. It has gravel-dedicated tubeless-compatible wheels, a SRAM 1× transmission and hydraulic brakes, and the stable geometry of a machine designed for loose surfaces.

But that down tube is hard to ignore. It’s massive because it houses the e-bike’s Fazua Evation power pack. This comprises a 250Wh battery and the drive motor, which are contained in one removable cartridge. The drive pack must be removed to turn the battery on (and off) and to recharge it, so the pack’s lock and switch get plenty of usage. Those on our well-used test mule were baggy and notchy.

With the 3.3kg drive pack removed, the bike can be pedalled normally. There’s a replacement cover for the down tube available; without it the motor coupling with the bottom bracket gear box is left exposed to dirt. Most E-Adventure owners  will surely prefer to ride with assistance all the time, not least because it is very effective. Cairn quote 250W in middle ‘River’ mode, with a surge of up to 400W available in ‘Rocket’ setting. These and the lowest ‘Breeze’ assist level are selected via a pad on the down tube.

Flat battery? Feeling fit? You can ride without help

So, drive pack removed, battery turned on, pack replaced, Rocket mode selected – and away we go. Straight up a nearby 1-in-3 rocky track, which the bike handled with ease. That 400W max is entirely believable. Battery life is likely to be short at this setting and the motor was hot by the top. It whined a bit too.

The motor’s control software, which senses cadence, pedal pressure, and speed, moderates power delivery so it tails off rather than stopping abruptly. Shifting on a steep climb thus results in a gear crunch as the motor continues to drive  after pedalling ceases. There’s an app to track various parameters, and the whole thing is great fun if, perhaps, not as slick overall as the main opposition.


Powerful and sensitive removable drive system (which needs removal prior to each time it is to be used), in a competent, well-equipped gravel bike chassis.

Other options

Orbea Gain M20 £3,999

Well-equipped, lightweight, road-orientated, ebikemotion X35-powered e-bike with clearance for wider tyres. 

Boardman ADV 8.9E £2,699

Fazua-powered all-rounder with crisp styling and impressive specification for the price.

Cycle’s test promise

At Cycle, we are proudly independent. There’s no pressure to please advertisers as we’re funded by your membership. Our product reviews aren’t press releases; they’re written by experienced cyclists after thorough testing. This test featured in the August/September 2020 edition of Cycle magazine.

Tech Spec

Cairn E-Adventure 1.0 £2,989 

Sizes: S, M (tested), L, XL 

Weight: 14.5kg, no pedals

Frame & fork: 6061-T6 aluminium frame for Fazua drive, fittings for rear rack, mudguard, two cages (one double, one triple), and dropper post. All-carbon fork with 12×100 thruaxle and fittings for mudguard, two cages (triple mounts), & internal dynamo wire.

Wheels: 40-622 WTB Venture tyres, Hunt 4-Season Gravel Disc wheelset.

Transmission: Praxis Works Fazua chainset with 170mm cranks and 42t chainring, Fazua Evation bottom bracket, SRAM 11-speed chain and 10-42 cassette. SRAM Rival Hydro dual control levers, SRAM Rival 1× long cage rear mech. 11 ratios, 28-107in.

Braking: SRAM Rival Hydro hydraulic discs, 160mm rotors. 

Steering & seating: 440×31.6mm handlebar, 80mm stem, 27.2mm seatpost.

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