E-bike novelty: Light-E-MTB extreme - is the Rotwild R.X 275 still an e-bike?
Christian Schleker
· 22.03.2023
The Rotwild R.X 275 is a light e-MTB with a mini battery and is almost as light as a classic mountain bike. Nevertheless, for me, classic bikes without a motor died three years ago. That was my first time on a Specialized Levo SL and knew immediately: I don't need more e-bike! Thanks to a total weight of 17 kilos, it is almost as agile as my normal enduro bike; uphill I can save enough energy for a few extra descents with the slimmed-down motor-battery concept. From then on, I never missed a bike without a motor on my mountain tours. However, even the Levo SL is often too much of an e-bike on my flat home circuit with few metres in altitude and lots of flow. I have to sprint over the 25 km/h threshold for the numerous jumps. In general, you're often pedalling beyond the assistance limit here and then even a current light e-bike feels rather sluggish. And this is exactly where the Rotwild R.X 275 comes into its own.
All topics in this article:
The facts about the Rotwild R.X 275
- Motor: TQ HPR 50 with special Rotwild software, modes limited to 200 W maximum power
- Boost button instead of remote lever: full motor power (300 watts) only for a short time at the touch of a button
- Battery: 250 Wh permanently integrated in the down tube, optional range extender with 160 Wh
- Suspension travel: 130/120 millimetres, downcountry category
- Weight: 15.6 kilos (top version in size M, EMTB measurement)
- Full carbon frame, wheel size 29 inch
- Two bottle cage holders for RE and water bottle at the same time
- Two equipment variants for 9499 and 12,499 euros
- Four frame sizes S to XL
Downcountry e-bike: birth of a new category?
For use on flat, hilly terrain I recently had a very similar AHA experience with the Scott LumenScott has lowered the e-bike's fighting weight to 15.5 kilos with consistent lightweight construction and (very expensive) high-end equipment. Declared as a sporty downcountry e-MTB, the Lumen close the gap between classic MTBs and light e-bikes. The Rotwild R.X 275 Ultra is now targeting the same niche. This very lightweight e-bike is also easy to ride with the TQ motor completely natural and is hardly distinguishable from a normal MTB in terms of handling. A bike like this is ideal for flowing trail laps with a light push, a proper Fitness required.
However, the concept is only suitable for extended adventures in alpine terrain to a very limited extent and for very few customers. The TQ motor is quite energy-hungry (click here for our extensive range test of the light motors) and in conjunction with the meagre 250 watt-hour battery, the range height is too low when utilising the full motor power. A range extender can be fitted, but then the bike weighs a kilo more. Heavier, more solid tyres would also be required for mountain tours. In addition the TQ is not really powerful and high-torque - Extreme gradients on exposed trails can only be managed with the motorbike in exceptional cases.
A niche within a niche: the concept of the Rotwild R.X 275
Scott wants to use the Lumen The R.X 275 Ultra is aimed at those switching from normal MTBs and sportier classic e-bikers who mainly ride in ECO mode. Rotwild restricts the potential clientele of the R.X 275 Ultra even further: At 250 watt hours, the battery here is another 30 per cent smaller than on the Lumen. And instead of a remote control for the individual modes on the left-hand side of the handlebars, the R.X 275 has a red rotary lever that can be used to switch between modes. Boost buttonwhich provides the maximum motor power (300 watts/50 Newton metres) for a maximum of 30 seconds. To do this, the lever must be held down. The three support levels can only be changed on the display and are set very discreetly at the factory and limited to a maximum of 200 watts. Full power is therefore only available when the lever is pressed down. The situational motor boost of the boost function is intended to give the ride a special dynamic and also prevent the small battery from being drained too quickly by continuous boost. This is also helped by the fact that the first speed level reduces the motor assistance at 20 km/h.
Longer rides are only possible if a lot of power is involved, otherwise the battery is drained very quickly. You can hardly turn the minimalism screw much further, unless you simply leave out the motor and battery completely.
Athletes who usually ride without assistance: The target group of the Rotwild R.X 275
However, the Red Deer developers firmly believe that there is an existing clientele for the niche concept: these are riders who come from classic, sporty mountain biking and still appreciate the sporting aspect. They should use the R.X 275 Use mainly like a motorless downcountry bikeThis means with very little or even no support on the fast and flat parts of their tour. The motor should only be used for short, hard climbs or for accelerating. This keeps the bike fast where you would otherwise only be able to progress at a crawling pace, or where there is simply no real pressure on the pedals due to exhaustion. What's more, long ranges are theoretically possible despite the mini battery.
The Rotwild R.X 275 Ultra is therefore aimed at a very specific target group that sporty switch from MTB. An e-bike for people who didn't want a real e-bike before. And who, even if they do have one, only want to feel and use the motor assistance very rarely, for example when that last bit of muscle power is missing on that one nasty climb. Otherwise, the e-bike should feel as if it wasn't an e-bike at all.
Dream team: Why the TQ HPR 50 is the perfect match for the Rotwild R.X 275
The minimal assist market is hotly contested. Specialized made a start three years ago with the SL 1.1. The motor was developed exclusively for the Americans by the German manufacturer Mahle. In the meantime, it is no longer up to date: too loud, too weak and only available in the Levo and Kenevo SL. Three other motors currently share the light market: the HPR 50 from TQ is in competition with the Fazua Ride 60 and the Shimano EP8 RS. Compared to the latter two, the TQ is relatively weak on the chest and also quite thirsty for power. The Trek Fuel EXe, an E-trail bike that would have passed for a true enduro bike a few years ago, is transformed by the motor into a sports bike with a wide range of applications.
Light e-bikes in the trail or enduro category can be used more widely with the Fazua or the Shimano, because their maximum support, better stability and greater range can also lift heavier and less fit bikers to the summit. In our opinion, the TQ hits the mark for E-gravel bikes and the new lightweight E-downcountry category. It is light, quiet and its power output can be perfectly adjusted. Then it works so unobtrusively and discreetly that you keep glancing at the display to make sure the motor is running. This is not a characteristic that would make fans of real e-bike power spend a single euro. And it took me a few tours before I really got to grips with this form of fun patronisation.
15.6 kilos! Dream weight due to anorexia with battery and equipment
The issue of weight plays a subordinate role with power e-bikes. At best, current models manage to weigh as much as their predecessors with increasing battery capacity. This is often around 25 kilos. In return, you get massive reach, stable parts and enormous motor power. The uphill riding fun that you can experience with a Bosch motor and a 750 Wh battery, for example, is simply not available with the slimmed-down light models. From a light perspective, the handling of the power bikes is rather sluggish, regardless of whether they have 130 millimetres of travel or 180. From this perspective, a power e-enduro bike rides in a similar way to a power e-trail bike.
If you don't like the handling of the big hulks, the only option is to use the No battery or engine power required. This is the only way for minimal assist bikes to shed their pounds. To land in the 18-kilo category, manufacturers have to virtually halve battery power and torque. This makes the issue of personal effort relevant again. Only those who are willing and able to make an effort will reach the high summit that their mate with the power bike has long since reached (and where they can relax and sip their summit beer).
However, because weight records sell well, the Scott, BMC, Thömus, Transalpes and now also Rotwild, have increased the downward spiral through additional lightweight construction of the frame and add-on parts to such an extent that the 15-kilo mark should soon fall as standard. The Rotwild does not weigh less than the Scott Lumen (although the battery is smaller), but in contrast to the significantly more expensive competitor (15,999 euros!!!), it also offers something more Tuning potentialThe DT Swiss HXC1501 wheels weigh almost 1900 grams. Weight fetishists with a fat bank account can still save over half a kilo and 14 before the decimal point reach.
The extreme lightweight construction not only has consequences for reach height and motor power: the weight-optimised add-on parts also limit the range of use of these sporty bikes with light e-assistance. The 4000 euro full carbon wheelset in the Scott Lumen is currently the most extreme example of this. Nobody wants to damage such high-end parts during heavy off-road use. Gentle riding on moderate terrain is therefore included in the price of the very light e-bikes.
Interim conclusion Rotwild R.X 275: weight record only through compromises
No manufacturer can perform miracles. The materials are so exhausted that the weight record can only be achieved by compromising on the core competences of the classic e-bike: reach height and support. The stability of the add-on parts is also severely limited - especially for heavy riders. Anyone who is only looking at the scales when making their next purchase should be aware of this.
Rotwild R.X 275 - the geometry
The geometry table of the Rotwild R.X 275 doesn't provide any surprises or extremes. The main frame is long (reach 460 in M, 485 in L), but not extreme. At 66 degrees, the head angle is rather steep by modern trail bike standards, but slack from a cross-country perspective - downcountry, in other words. At 437 millimetres, the chainstays are short by e-bike standards. The moderately steep seat angle promises a sporty riding position for long flat stages.
This is how the Rotwild R.X 275 rides - all theory is grey!
If the Rotwild R.X 275 wasn't a downcountry e-bike, it would be a good normal downcountry MTB. Visually, there is no difference to be seen: The tube dimensions are classically slim. And there's no e-bike feeling when you start rolling either. With the motor switched off, the Rotwild offers a very natural riding experience on flat terrain. It rolls very easily and reacts lively when you get out of the saddle and start sprinting. As a test, I rode a shorter trail tour (20 km/300 metres in altitude) without any assistance at all - it actually works well!
For my longer home tour (45 km/900 m elevation gain), after some back and forth, I programmed the level 1 mode specially configured for Rotwild so that it supports climbs and starts with a gentle but noticeable push at a maximum of 200 watts of power. At 20 km/h, it then fades out early and imperceptibly. The Rotwild rides like a classic MTB on coke: the handling is super agile and the acceleration is really dynamic without ever feeling like an e-bike boost. Thanks to the short rear triangle (436 millimetres) and the lightweight battery in the down tube, the Rotwild is also very responsive on the rear wheel. However, you have to be active on steep climbs and put weight on the front wheel so that the steering doesn't become too light. The subjective riding experience was very close to that of a classic trail bike the whole time. I haven't had so much fun bunny-hopping over fallen tree trunks for a long time. When pushing off roots, the Rotwild pops high and is very manoeuvrable in the air.
I only used the boost button developed by Rotwild very briefly for a few steep stabs on the entire ride. This keeps the speed high and suits the lively character of the bike perfectly. The maximum boost doesn't have an impressive amount of power, but it helps enough. A high cadence of at least 70 is a prerequisite. Because if you crank too slowly, it chokes off the TQ's thrust. Nasty climbs should not be too long, otherwise you will have to release the lever briefly after 30 seconds (three-second pause!) and restart the boost time window by pressing it again. In between, the motor does not switch off, but goes back to the currently set continuous mode. In my case, however, this was sometimes just not enough to be able to continue on a steep gradient. Nevertheless, the boost button is somehow a cool feature that gives the Rotwild an interesting unique selling point. The lever should just be a little longer to make it even easier to reach. Being able to configure the time window yourself would be ideal. I managed the 40-kilometre trail lap well with the 250 battery. At the end, I still had 20% juice left, even though I was able to maintain an average speed of 19 kilometres per hour. But I also only weigh 70 kilos and like to burn off energy.
Rotwild R.X 275: Conclusion of the EMTB editorial team
Rotwild's latest e-bike range is pure niche! Only light, fit riders can enjoy the gentle tailwind. An e-MTB has never been so close to a classic mountain bike without a motor. Thanks to its low weight, it rides very naturally and extremely agile even without motor assistance. The time-limited turbo boost in combination with otherwise minimised assistance allows reasonable ranges on moderate trail tours - despite the mini battery. If you embrace the concept, the R.X 275 is a very agile, manoeuvrable and lively e-bike without the e-feeling. The boost function with time limit is a feature that makes the concept unique. But it is a special concept that should not make every e-biker happy and certainly does not. Core competence: The Rotwild R.X 275 filters the hard peaks out of the tour, takes the fear out of a few short horror climbs and makes you want to ride more often. However, you have to have the necessary spare change for this subtle portion of motor boost. - Christian Schleker, EMTB tester
Test summary by Peter Nilges, BIKE test manager
I rode the slightly cheaper Pro version: 9500 euros, 16.5 kilos. That's one kilo more than a race-ready, super-robust enduro bike. A non-motorised trail bike in this price range weighs a whopping four kilos less. So in terms of weight, the Rotwild is still a long way from a normal mountain bike, despite a few tricks. Nevertheless, the concept works. Even the lowest level of assistance, at 50 watts, pushes so powerfully that you can ride faster than on a lightweight bike without a motor. The extremely good rolling Wicked Will tyres also play their part in this.
I really like the smooth transition of the TQ motor. You can hardly feel how it starts and stops. In some situations, I found myself squinting at the display to check whether the HPR 50 was pushing or not. I was also pleasantly surprised by the low energy consumption. With the discreet assistance, longer rides are definitely possible. The bike handles well downhill. Due to the slightly higher weight, it is even slightly better on rough terrain than comparable bikes without a motor. However, it is also not quite as light-footed. However, I didn't warm to the boost button at all. In situations where you want the extra power, it's awkward to hold. Technical uphills require full control, which is lost when I have to fish for the lever with my thumb. Nevertheless, even with the 200 extra watts of the normal modes, you can ride uphill sections that would not be possible without them.
Would I buy a bike like this? A clear no. Because a lightweight trail bike is lively and powerful even without an e-drive. And the extra weight of the motor and battery simply cannot be ignored. On the rare occasions when I get on an e-bike, I want to feel the real e-bike bang, otherwise I prefer to ride non-motorised. The Rotwild concept works really well to compensate for differences in performance. The power is easily sufficient for this, and touring bikers don't have to struggle with a super-heavy e-bike. However, the price is steep.
The 50 watts of the Eco mode sounds meagre. In practice, however, this is easily enough to climb faster with the 16-kilo bike than with a 12-kilo bike without a motor. So the concept works. But for me personally, it doesn't offer enough added value compared to a non-motorised bike. If you want to keep up with fitter bikers, you can benefit. - Peter Nilges. BIKE test manager
