Calibre is the in-house bike brand for chain retailer Go Outdoors and they have, historically speaking, a good track record with decent quality, but very keenly-priced mountain bikes, both electrically assisted ones and those relying only on pedal power too. The Calibre Shift 27 I have had for review through late Summer into Autumn is the kind of bike that satisfies the brief of a large chunk of the population, being both happy as a runaround on the commute, but most of all it’s built to handle leisure rides with confidence.
It’s worth noting that the £1,000ish end of the e-MTB market will feature a wide variety of machines and given the demands placed on any e-MTB with even semi-serious off-road pretensions it’s a hard market for manufacturers to take on and there aren’t that many truly decent machines at this end of the market. A few years ago I tried the Calibre Kinetic (still available) and was impressed. So, I was keen to try the Shift 27 which, like the Kinetic, featured a Promovec rear hub system but with a more modern looking 1 x 9 gear setup as against the Kinetic’s 3 x 9 gear setup.
It’s also worth noting my mark here has been knocked down several tenths due to a couple of mechanical issues I had with the bike. Maybe I was just unlucky and neither problem stopped me completing the test in full. There’s more detail on this further on – but I suspect the problems I encountered were more due to quality control than to any inherent design flaws and neither stopped me enjoying my time with the Shift 27.
Although I had a couple of reservations on the motor performance front, I still think the Shift 27 represents sound value and will let many on a tight e-bike budget get out and about and enjoy some fairly challenging trails.
If you are shopping for electric bikes in this price range, check in with our guide to the best electric bikes we have tested retailing at under £1,500.
£1,250 (Go Outdoors member car price) | View offer
Pros
Nice handling
Low gearing suits steeper climbs
Light weight
Good braking performance
A decent suspension fork given it is coil sprung
Cons
Motor could do with a bit more climbing power
Crude speed based power levels
Derailleur shifting was stiff and ultimately failed
Problems removing battery
Features
Promovec rear hub motor with 278Wh battery
Wide range 9 speed derailleur gearing
Lightweight – around 20kg
Proper mountain bike geometry
Specifications
Motor: Promovec 250W rear hub motor with cadence sensing
Battery: 280Wh, 2A charger
Range: Circa 20 miles depending on use conditions
Weight: 20.1kg
Brakes: Clarks M2 Hydraulic disc 160mm rear rotor, 180mm front rotor
Gears: Shimano Alivio 9 speed (the bike came with an Acera derailleur but this was replaced with Alivio – see review). 9 speed, 11- 40T rear gearing, 32T front chainwheel
Saddle: Calibre Trail
Tyres: WTB trail Boss 27.5” x 2.25”
Fork: Rockshox FS Judy CL 100mm travel
Frame material: Aluminium 6061
Calibre Shift 27 review – The value proposition
At first glance, the Calibre Shift 27 looks like a sleekly design e-MTB with conventional geometry – as noted already Go Outdoors have produced several well-received mountain bikes and e-MTBs prior to this. On my scales it weighed around 20kg – very good for any e-bike, let alone one that is budget priced and has coil sprung front suspension.
This promising start is continued the more you dig into the spec. There is a Promovec rear hub motor system and I’d had good experiences with Promovec hub motors on the Calibre Kinetic (though that was several years ago) and much more recently on the Batribike Route S. The 1 x 9 gearing features a 32 tooth front chainring and a 40 tooth bottom gear at the back – in other words a bike that should be very easy to pedal up the steepest of hills. There are also Clarks hydraulic disc brakes with an oversize 180mm disc on the front for plenty of stopping power.
The Shift 27 comes in four frame sizes and I also noticed there is a 29” wheeled option – naturally called the Shift 29 – but this gets even lower gearing at the rear sprocket cluster via a Shimano Cues derailleur that handles a lowest rear cog of 46 teeth.
There are mounting points for a mudguards, but not for a conventional rack, though there are solutions out there that would allow you to fit one. Add in some some standalone lights and you have an e-MTB that could double as an adventure bike or even a commuter.
So did the riding live up to the promise of the spec sheet? Yes and no…
Firstly, the cadence sensing motor system has a nice smooth, quick pickup though even the very best cadence sensing systems are never quite up there with most torque sensing systems. Although there is a bit of push from the motor for a short amount of time when you stop pedalling it still allows for quite close control on reasonably technical trails – think a few twisty tree routes and badly rutted, slippy, muddy tracks (yes it’s rainy autumn riding time again).
Disappointingly, the power levels don’t increase power as such, but increase the speed at which the motor assists you; so level one takes you up to around 6mph, whilst only the top level will assist you at the cut out limit of 15.5mph. This means I spent most of my ride time in the top power level which felt rather wasteful on the battery.
However, the 20 miles or so effective range I got from the 278Wh battery was more than I was expecting given the rather crude and rather inefficient feeling power delivery system. And whilst the ultra steep hill climb time for the Shift 27 was relatively pretty slow compared to most other hub systems I’ve run the same test on, that lovely low gearing actually mean it was an easy and relaxed ride up a very testing climb – your legs are doing quite a bit of the work, but thanks to the magic of gearing ratios it doesn’t really feel like it.
The Shift 27 will actually tackle some pretty challenging off-road climbs, if you have the technical ability to handle them too. The wide bars, grippy tyres, good weight balance and low overall weight of the bike all help in this respect. I’d still prefer a decently powerful torque sensing mid-drive with low gearing over a cadence sensing system like this any day of the week, but these usually come with quite a price premium.
In the intro, I mentioned a couple of mechanical issues. Firstly, the shifting felt rather stiff in the lower gears and (presumably due to poor adjustment of the limiting screws) and after a few hours riding the chain went over the top of the rear sprocket cluster and got jammed in the wheel causing a derailleur write off. I fitted a new Alivio derailleur (as specified on the Go Outdoors website as opposed to the Acera it actually came with) and performance was much improved.
Secondly, I could not manage to drop the battery out of the bottom of the frame despite the battery lock key turning as it should. Perhaps I missed something obvious or perhaps there was a problem somewhere, but neither the (wrong model) manual that came with the bike nor an internet search was able to solve this difficulty.
I’d imagine these aren’t issues common to every Calibre Shift 27 out there, but I’d suggest if you are interested in this bike to try and get a lengthy test ride on one and try out all the bike’s functions to make sure nothing has been missed in their quality control process, as was clearly the case for my review stint.
Despite these mechanical glitches and my carping about some aspects of the motor performance I still think this is a very capable and nicely designed off road machine for those on a budget.
If you want a model to do most of the work for you over the hardest off-road terrain this is not the bike for you, but if you have a reasonable base level of fitness you could have some quite adventurous days out on it and the motor assist is still most welcome.
Calibre Shift 27 review: The verdict
Search Amazon or similar website for ‘electric mountain bikes’ and you get a plethora of cut price designs that don’t really look like whoever designed them had actually seen a mountain bike. Really affordable electric mountain bikes that really are what they say are quite scarce on the ground but the Shift 27 is a welcome addition to the fold.
If you are game for a test ride on the Shift 27 it would also be worth trying out Caibre’s other hub motor e-MTB offerings, the Shift 29 and the Kinetic. If you have a bit more cash to splash the Ampere X-trail gives you a bit more hill climbing ability and you get plenty of additional features including a hardwired front light, air suspension at the front and even a USB charging port to keep your phone alive whilst out riding.
How about the competition?
My main consideration in comparing e-bikes against this review is that you can have mid-drive performance for not much more money than the Calibre Shift 27. Some electric bikes that offer this upgrade and that we at Cycling Electric have personally tested include:
Pinnacle Momentum
£1,250 | View offer | Our review
Pros
Very low price for the spec
Out-of-the-box practicality
Surprisingly capable off-road
Support via Evans Cycles
Cons
Noisy fork
Available power drops off below 40%
Rockrider E-CTV 100
£999 | View offer | Our review
Pros
Great overall value for money
Backed up with spares and in-store support
Sleek frame design with integrated battery
Simple app integration
Smooth motor delivery for a cadence-sensor system
Cons
Brakes feel stiff and require a firm two-finger pull.
6-speed gearing limits climbing options on steeper hills.
Relatively heavy (~23kg) to lift or manoeuvre in tight spaces