BIKE TEST (longtermer): Cube Reaction Hybrid HPA 400

E-bikes eh? Everyone's got an opinion. But have you actually tried one, a modern one, one that you can use equally well around town and off the beaten track?

We've been putting a Cube Reaction Hybrid HPA 400 through its paces over the last few months, with a work-related trip to the Tour de France giving us even more insight into its performance on the most demanding terrain.


The Alps is the perfect testing ground for any bike, especially an e-bike.

As explained in the introduction to this longtermer series in June's London Cyclist magazine, Cube has taken advantage of a long-standing relationship with fellow German manufacturer Bosch to spec the latter's batteries and motors across its e-bike range. The teardrop-shaped CX Drive motor in the bottom bracket area and that boxy HPA battery pack mounted inside the downtube provides the most instantly identifiable silhouette of any current e-bike system. Other manufacturers use the same combination, though it's fair to say innovation in this sector is going through the roof at the moment and teasers ahead of the big industry shows are talking about little else. E-bikes — across all cycling categories — are going to be HUGE over the next few years. 

This Bosch set-up will likely be around for a good while yet though, not just because it's relatively cheap and easy to adapt into existing frame platforms, but it works — it works really well — and spares are quicker to source if something does go wrong. A few companies are working with the likes of Yamaha and Shimano on new designs, while the biggest companies are developing their own proprietary systems. But Bosch has a headstart on them all and isn't holding back on its own innovation either.  

At which point it's probably worth repeating once more that these modern e-bikes are what's known as 'pedal assist' bikes — no pedal, no go. They are NOT like mopeds or scooters where a quick twist of a throttle surges you forward. Here, like any traditional bicycle, you must pedal or you won't get anywhere — the motor just gives a bit more 'oomph' to your pedal stroke. 


The Bosch HPA Powerpack 400 battery (left) and CX Drive motor.

So how does the 'pedal assist' work in practice? How do you get that extra help when it's needed? Well it's very simple and mastered in minutes — though you'll likely spend days working out what works best for you in different situations. By clicking the +/- buttons on the left-hand changer (see bottom image), you scroll from 'off' (unassisted) through the four main modes — Eco, Tour, Sport and Turbo. Eco providing the least assistance and Turbo the most. Start pedalling as you would normally, changing gears as you would normally, but if the incline creeps up or you're feeling a bit tired you just select one of the 'assist' modes.

Whatever mode you're in is shown clearly on the handlebar-mounted computer screen, which helps you get a feel for what each level of 'assist' entails. Incidentally you can also use the 'i' button on the changer to bring up other useful info — odometer (overall mileage), trip distance, trip time, maximum speed, average speed, range or clock. We tended to leave it set on either trip distance or trip time, the most relevant for our purposes, and you can reset any mode whenever you like.


The Reaction Hybrid takes easy rocky, rooty trails (left) in its stride, as well as looser singletrack climbs.

On our mostly flat daily commutes with only one notable hill at the homeward end, we'd rarely dip into any other mode than Eco — but then we're still looking to maintain the health benefits of cycling and doing as much legwork ourselves as possible. The city-based part of our testing has been more about range and suitability and we've found that we can get a week's worth of two-way journeys, plus a few social trips, out of a solitary battery charging at the weekend.

Longer, more varied, off-road daytrips have pushed the battery close to its limits but you just need to keep any eye on the computer and be savvy about consumption. Always turn the 'assist' off when descending, use the bare minimum on the flats and you'll get dozens of additional miles in. We deliberately haven't run the battery completely down yet, even choosing routes with easier endings in case we got caught short, but we needn't have worried. It's one of a few 'what if' scenarios we'll be entertaining over the coming weeks though...


From left: the wide range cassette; chainstay-mounted sensor and spoke magnet; very tidy cable routing.

We've chalked up several hundred miles in the city now, plus a similar amount off-road on the South Downs and in the Alps, and it's given us a very rounded view of what's possible and what's not possible on this bike, what we like and dislike or might consider changing. Overall, we have to say, the spec is pretty well judged given that the Reaction Hydrid's trying to offer this 'do-it-all' capability.

The RockShox Recon fork has 100mm of travel which is enough to cope with easier rocky and rooty trails, smaller drops, steps and obstacles; the fact that the fork can be locked out for road duties is very welcome. The 69-degree head angle is fairly standard for hardtails of this ilk and certainly helps when the track points downwards, but toptube length and reach are considerably shorter than typical modern mountain bike geometry. Interestingly, there's six sizes of this model available, with the 16in and 18in having 27.5in wheels and the rest sporting bigger 29in wheels, so the relative geometry numbers bounce around a bit — check the tables carefully if you're considering buying. 

The cockpit and contact points are all solid in-house Cube items; the bar is narrower than our regular mtb riser but again it's a happy middle ground for 'town and country' adventures. The Shimano drivetrain has been faultless and the whopping 11-42t cassette more than a match for cheeky alpine gradients. And it almost goes without saying that the Shimano discs brakes have been reliable and thankfully reassuring in often slippery conditions (and you definitely need that level of confidence with the greater weight of an e-bike beneath you) — even these cheaper Deore units outshine the competition.

We do have a couple of small niggles though. Firstly, if you're pushing the bike to its off-road limits, it would be great to have a 'dropper seatpost' so that you can keep the flow going when the trail gets rougher and steeper, without having to stop and lower the current seatpost via its quick-release collar — and it's not like the extra weight of a dropper post makes any difference on an e-bike. Secondly, as the battery and motor take up so much space in the frame's main triangle there's no room for a waterbottle cage. Sure, most of the time you'll likely be wearing a backpack or hydration pack, but for shorter spins on warmer days it's nice to ride with minimum fuss; we've taken to using a trail running waistpack on such outings.


You use the +/- thumb unit to select any of the four modes from 'eco' to 'turbo', plus swap between info screens.

We've got plenty more testing ahead and this week we'll even be riding the Reaction Hybrid up a trio of alpine road climbs, ones being used the same day by the Tour de France peloton. Having ridden all these ascents before on lightweight road bikes (and remembering a couple as real stinkers), we'll be praying for mild temperatures. Did we mention that we're riding off-road to get to the bottom of these climbs too? What could possibly go wrong?

Watch out for the next full update in the Autumn issue of London Cyclist, as well as regular posts on Twitter and Facebook.

Review: John Kitchiner (editor, London Cyclist)