High power outputs aren’t normally anticipated from for-sport electric bicycles. Although these kind of e-bikes are intended to be the ideal fusion of man and machine, a 250-watt system usually does the trick. Also, it strikes the ideal balance between weight and performance, with premium motors like the TQ HPR50 providing both remarkable performance and significant weight reductions.
The lines between different mountain bike categories keep getting fuzzier, and Rotwild’s newest eMTB is a prime example of this. The R.X275 fits into the growing category of short-travel cycles with a motor that is comparable in weight to several other “bio-bikes” — dare I say, “downcountry SL e-bikes”? And no, the wheel size is not implied by the model name. Thus, the battery size must be the issue. Mistake again. What is the purpose of this compact eMTB, then?
Rotwild R.X275: Design and Appearance
The newest electric mountain bike from German e-bike expert Rotwild is an example of this. At a weight of only 15.3 kilograms, the R.X275 is the newest and allegedly lightest full-suspension electric mountain bike. In fact, Cory Benson from BikeRumor was able to test ride and weigh this lightweight motorcycle, proving that this isn’t simply a claim. It only weighted 15.86 kg in size big, which is lighter than several expensive non-electric mountain bikes.
When developing this bicycle, Rotwild didn’t hold back. Before settling on the final design, the brand developed 32 prototypes during the two years it took to develop the R.X275. A size MD frame for the R.X275 weighs 1,893g and 2,350g with all of the paint and hardware, excluding the motor. The R.X275 frames are constructed in Dieburg, Germany, from 85 pre-cut pieces of carbon.
The R.X275’s main selling points are integration and simple design. With this slim frameset, there are no geometry alterations to be discovered. The speed sensor is nearly completely concealed at the dropout, and a flat-mount rear brake that can accommodate a 180mm rotor is placed inboard of the seatstay to continue the motif. Traditional internal headtube cable openings are also present, but the handlebars have been engineered to conceal the brake lines in a deep groove and tuck into the headtube with special stem spacers.
Recently, flex-stays have become very popular among short-travel trail and cross-country trail bikes. For bikes with 140mm or less of travel, the standard dropout pivot can be removed because it barely rotates at all, saving weight. To regulate the shock rate, a single pivot located near the top of the chainring moves a rocker link resembling a clevis.
Rotwild relies on the bottom-out assistance provided by the Fox Float DPS air shock and employs a very linear leverage curve. The wires from the handlebars are kept incredibly tidy because there is no remote lockout, but there is the customary three-position compression switch to stiffen the suspension for climbing.
The reach starts at 430mm for the size SM and increases to 460, 485, and finally 510mm for the size XL. While sitting, the 75.5-degree seat tube angle gives the cockpit a longer sensation than contemporary enduro bikes with steeper angles.
I never experienced any difficulties while descending due to the stand-over height of the size medium frame I was riding or the 430mm length of the seat tube.
Rotwild R.X275: Motor and Battery
After that, let’s explore the technical specifications of this bike. It uses a revolutionary harmonic pin ring technology. It can produce 250 watts of continuous power, but Rotwild adds a little twist to the system, very literally. The R.X275 makes use of Zirbel’s electronic grip shift and converts it into a thumb switch that provides a brief, 30-second boost to the motor.
Although in charge mode, power is increased to 300 watts, enabling you bike power over challenging hills without becoming overheated. The harmonic pin ring technology used by the TQ HPR50 to deliver 50 newton-meters of torque in a silent, smooth way leaves no room for lack of torque. You may be sure that the pedal help is seamless and proportional to your input because it is coupled to a torque sensor.
The R.X275 rides smoothly and quietly, complementing its angular, elegant appearance. The bike isn’t particularly made for winch and plummet riding, as evidenced by the modest trail geometry and short travel.
Cyclists are constantly curious about how far or how long they can ride. Because to the multitude of variables, including rider weight, cadence, assist levels, gradient, tire rolling resistance, and even the type of soil you’re riding on, understanding battery consumption is a challenging topic. What I can say is that I felt no significant anxiety when exploring the Italian hillside, climbing about 500m, and only consuming half the battery in various modes.
Even in the 200% help mode at high-cadence, the startlingly quiet motor emits a low-frequency whir. Most significantly, there are no rattles or knocks on the descents, and the frame effectively prevents chain slap.
While descending, I had anticipated the 66-degree head tube angle’s agility to be the limiting factor; instead, a minor rise in center of gravity, resembling that of much heavier e-bikes, was also noticeable. This somewhat improved the bike’s ability to grip in turns and maintain control on trail sections that strained the bike to its maximum. Actually, the limitations of the frame will prevent you from moving forward before the disappointing power of the 2-piston brakes.
The 250 Wh battery is perfectly fitted into the square, angular tubing of the complete carbon frame. Rotwild was able to optimize the downtube design and route the cables internally along the triangle battery’s outside corners thanks to rearranged cell orientation. Moreover, there is enough within the front triangle for one water bottle and a 160 Wh range extender, or two water bottles. To keep the center of gravity as close to the ground as feasible, that additional energy source, weighing 1,140g, is mounted in the lower of the two positions.
Rotwild R.X275: Price and Availability
Rotwild offers the R.X275 in two very pricey variants when it comes to speccing out the bike. Shimano XT gears and Fox Performance Elite suspension components are featured on the more “cheap” model. Moreover, it has DT XC 1700 LS eMTB wheels. Sweet 9,500 Euros, or roughly $10,275 USD, was the asking price. The R.X265 Ultra, with with Fox Factory kit, a Transfer SL dropper, and a Shimano XTR groupset, will cost you 12,500 Euros, or roughly $13,520 USD, if all that technology isn’t cutting it for you.