cube reaction ex625 electric mountain bike in green with gumwall tyres

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The 2020 range of Cube electric bikes offers something for everyone, and pretty well every budget from around £1600 upwards. The all-new Cube Reaction Hybrid EX 625 looks like a good value cross-country e-bike, that has some great components, like SRAM Eagle 1 x 12 groupset and the latest 4th generation Bosch CX motor with a powerful 625Wh (watt hour) battery. In this review, I will go over the components to see, if the £2599 price tag is justified.


I have always been a big fan of Cube bikes, electric or otherwise. Their 2020 range of e-bikes is massive and there really is something for everyone.

The Reaction EX 625 sits in the competitive £2500 price bracket, and when put alongside the competition, seems to offer very good value for money.

For starters, you have the latest 4th Generation Bosch Performance Line CX motor, which is lighter and more efficient than its predecessor. Then you have the Powertube 625Wh integrated battery – this is a game changer when it comes to range. If you’re not in a hurry and you only use the assist when you really need it, a range in excess of 100 miles can be easily achievable.

The bike itself looks absolutely stunning (in my opinion). The green colour scheme in particular with the gumwall tyres gives it a retro look, which I really like.

cube reaction ex625 electric mountain bike in green with gumwall tyres

As far as the components are concerned, the list is impressive, particularly the SRAM SX Eagle 1 x 12 drivetrain. This has a 38t front chainring combined with an 11-50 rear cassette – no more worrying about those steep off-road climbs!

The frame is typical Cube quality, and the large section 6061 alloy frame looks and feels tough the Suntour XCM34-Boost fork delivers accurate steering and 120mm of travel, whilst wide 29″ x 2.6″ Schwalbe tyres provide excellent grip.

Let’s have a closer look at the bike and its components.

Electric Components

As with any e-bike, electric components are a key deciding factor when making a purchase. When you are forking out a lot of money on a new electric bike, you want to be confident the electric drive system is going to stand the test of time. As with a lot of e-bikes in the Cube range, they have opted for the Bosch CX motor on the Reaction EX 625.

Bosch 4th Generation CX Motor

The latest incarnation of the Bosch CX motor has been reduced in weight to just 2.9 kg and the size has been reduced by almost 50%, making it lighter and more compact than the previous version.

The drive system accelerates smoothly and powerfully and responds to rider input without delay. The new motor features an e-MTB mode, which ensures the rider always receives the required power at just the right moment.  This brings the intuitive pedal assist to another level.

bosch performance line cx motor as fitted to the kona electric ute

This excellent motor will provide up to 75Nm of torque and provide the rider with a maximum of 340% support, which has to be experienced – riding an e-MTB with one of these motors is addictive!

Bosch Purion Display

Bosch’s Purion display has been around for a while now and it is simple and functional.  It would have been nice to see the new Kiox display on this model, but that is only available on Cube’s more expensive e-MTBs and hybrids.

bosch purion ebike display

Bosch Powertube 625 Battery

The integrated Bosch Powertube 625 battery is an absolute godsend! With this kind of energy capacity, you no longer need to worry too much about running out of e-assist too quickly into a ride.

If you’re hammering around the trails, even in higher power mode, this battery will ensure you can have a good few hours of fun before the battery is depleted.

bosch powertube 625 battery

Another great thing about this battery is the way it fits neatly into the downtube of the bike – it makes for a much cleaner look, with the added bonus of still being able to fit bottle cages.

To get a rough idea of the kind of mileage you can expect from this battery, check out the Bosch Range Assistant.

Bike Components

On an electric mountain bike at this price point, you are going to be wanting some pretty decent components, and again, Cube hasn’t been disappointing in this area – the Reaction EX 625 is well equipped with the latest SRAM 1 x 12-speed groupset, decent hydraulic brakes and middle-off-the-road front forks.

Gearing – SRAM SX Eagle 1 x 12 Gearing

With any off-road e-bike, gearing is of paramount importance, particularly where mid-drive motors are concerned. For maximum efficiency, you want to be climbing in a low gear at a fairly steady, but high cadence. Having an 11-50 12-speed rear cassette in combination with a 38t front chainring is a must for anyone tackling steep, technical trails. SRAM’s SX Eagle groupset is excellent quality and works an absolute treat!

cube reaction hybrid ex 625 rear view

Brakes – Shimano BR-MT420/MT400, Hydr. Disc Brake (203/180)

Braking is another important aspect of electric mountain biking that cannot be overlooked. Fortunately, Cube has gone for good quality Shimano BR-MT420 / MT400 hydraulic disc brakes with a large 203mm rotor upfront with a 180mm at the rear.

Wheels and Tyres

The front and rear wheels use Shimano MT-400 Hubs with Boost Thru-Axle and Centre Lock disc rotors, the rims are good quality Cube EX30 discs, which are tubeless ready. Tyres are excellent Schwalbe Smart Sam Active 29″ x 2.6″, which are decent all-terrain tyres, with plenty of grip for off-road riding.

Front Suspension

The Suntour XCM34 forks have 120mm of travel. These forks are okay on an electric mountain bike at this price, but they do have their limits, so I wouldn’t recommend any heroics like big jumps etc.

cube reaction hybrid ex 625 front view

Finishing Kit

The handlebars, stem, seatpost etc, are all Cube-branded components that are high quality as you would expect from Cube. There is also the provision for a dropper seatpost if required, which is quite useful.


As always, Cube doesn’t disappoint in the frame department. The Cube Reaction Hybrid EX looks gorgeous. The alloy frame not only looks great but is incredibly tough.

Full Specification

  • FRAME: Aluminium Superlite, Gravity Casting, Agile Ride Geometry, 1.5 Headtube, Boost 148, Internal Cable Routing, Full Integrated Battery, Kickstand/Fender/Carrier Mounting Points
  • SIZE: 15″, 17″, 19″, 21″, 23″, Trapeze: 15″, 17″, 19″
  • FORK: SR Suntour XCM34 Coil, Tapered, 15x110mm, 120mm, Lockout
  • HEADSET: FSA Orbit Z 1.5B ZS, Top Zero-Stack 1 1/2″ (OD 56mm), Bottom Zero-Stack 1 1/2″ (OD 56mm)
  • STEMCUBE: Performance Stem, 31.8mm
  • HANDLEBAR: CUBE Rise Trail Bar, 700mm
  • GRIPS: CUBE Race Grip 31mm, 1-Clamp
  • REAR DERAILLEUR: Sram SX Eagle™, 12-Speed
  • SHIFTERS: Sram SX Eagle™ Trigger, Single Click
  • BRAKE SYSTEM: Shimano BR-MT420/MT400, Hydr. Disc Brake (203/180)
  • CRANKSETACID: E-Crank, 38T, 175mm
  • CHAIN: Sram SX Eagle™
  • COLOUR: Black´n´blue / Green ‘n’ Orange
  • CASSETTE: Sram PG-1210 Eagle™, 11-50T
  • FRONT HUB: Shimano HB-MT400-B, 15mm, Boost, Centerlock
  • REAR HUB: Shimano FH-MT400-B, 12mm, Boost, Centerlock
  • RIMS: CUBE EX30, 32H, Disc, Tubeless Ready
  • TYRES: Schwalbe Smart Sam, Active, 2.60
  • SADDLE: Natural Fit Sequence
  • SEAT POST: CUBE Performance Post, 30.9mm
  • SEAT CLAMP: CUBE Varioclose, 34.9mm
  • BATTERY: Bosch PowerTube 625
  • DRIVE UNIT: Bosch Drive Unit Performance CX Generation 4 (75Nm) Cruise (250Watt)
  • DISPLAY: Bosch Purion
  • CUBE integrated battery design, Bosch e-power and Sram Eagle 12 speed: a new standard in e-MTBs
  • CHARGER: Bosch 2A
  • WEIGHT: 23,8 kg
  • PART. NO: 334252

Is the Cube Reaction Hybrid right for me?

That depends on what you are looking for in an e-bike. For a beginner to intermediate XC mountain biker, I would say the Reaction EX would be just the job. It’s capable enough to handle some of the rougher stuff, but also pleasing to ride on the road.

If your daily commute involved canal paths and pot-holed back lanes, then the Cube would make a lot of sense.

As far as battery range is concerned, you won’t get much better than the 625Wh battery for this price. Go easy on the power and you will easily see 100+ miles out of a single charge. Even if you wanted to spend an afternoon hacking around your local trails, you wouldn’t have to worry too much about running out of power.


As I have said before, I like Cube e-bikes. I have ridden various models in their 2020 line-up, from the entry-level Acid Hybrid One 400 to the Kathmandu Touring hybrid bike. The Reaction EX 625 was my favourite of the bunch for off-road riding. The Kathmandu was best for long-distance road riding, and the Acid was the cheapest, offering a good compromise between value and quality.

cube reaction hybrid ex 625 review

I think for the £2599 price tag, the Reaction is competitively priced and should give the competition a good run for its money. I’ve checked out the specifications on similarly priced Trek, Giant and Specialized e-MTB and the Reaction EX looks to be the best in this price range.

The Bosch motor and battery are excellent, all the components are top quality and on top of all that, I love the look and feel of the bike.

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