Rotwild

The New Rotwild R.X275

The Athlete With An Intuitive Boost

Head to the bottom of this article to read our First Ride review

Neither bio-bike nor eMTB: with the R.X275, the Hessian bike manufacturer ROTWILD establishes a new category of riding a bicycle. It is not for nothing that the company confidently calls it a “trail bike with eAssist”. The focus is on the rider’s sporting ambition, the individual energy resources and the intention to use them on the trail. The R.X275 provides subtle support without imposing itself or demanding control. The rider unleashes additional power through the Boost Button, an innovative new development by the company.

With the R.X275, ROTWILD combines a unique riding experience with innovative technology and a fundamentally new riding approach. “Its linchpin is the principle of the Boost Button developed by us”, explains ROTWILD Managing Director Peter Schlitt. It is a ring that is harmoniously integrated into the newly designed cockpit, which the rider can use to release an extra portion of thrust. “The focus of the R.X275 is clearly on the rider’s own rhythm. He or she is the driving force. The motor provides constant and subtle support,” emphasizes Peter Schlitt. “For those moments on the trail when thrust and support are required, the rider releases extra energy completely intuitively via the Boost Button. Just like he operates the bike shifter and seat post.” For a maximum of 30 seconds and as long as the button is pressed, up to twice the rider’s own power is available, up to a maximum of 300 watts. “Our target group are athletes who follow an individual training plan and whose focus is on permanently increasing their own performance,” says Peter Schlitt. “That’s why we call the R.X275 “the athlete”. Our approach in the development was to create a very light trail bike with eAssist. The design with the Boost Button allows us to find just the right balance between biological power and support. We reduced everything to get the maximum riding experience out of it,” Peter Schlitt proudly emphasizes.

eAssist symbiosis with 250 watt hours and technology by TQ

The power of the R.X275 is in the Integrated Power Unit, the IPU275. It consists of the battery developed by ROTWILD itself, which effectively delivers 250 watt hours. The energy storage unit is made of state of the art type 21700 cells and is firmly integrated into the down tube. “The motor control software specially programmed by us regulates the energy management. It ensures optimal interaction of battery and drive unit,” says Johannes Matschos, product manager at ROTWILD. The motor used is TQ’s HPR50 with a maximum torque of 50 Nm. “We decided to cooperate with TQ on this concept because we see this as the optimal tool to combine our approach of lightness with efficient power assistance,” explains Johannes Matschos. The TQ motor provides support with three riding profiles. “Changing modes while riding is not the style the rider uses to move the R.X275. You do that once via the display before you start. We have integrated that into the top tube. Additional support comes via the Boost Button,” says Johannes Matschos. Users can customize the individual profiles via the TQ app.

Frame and kinematics underline the bike´s lightness

Everything in the R.X275 is trimmed for lightness. “We looked at many parts to see how we could save weight and then adapted the design accordingly,” says Johannes Matschos. In the Ultra version and size M, the bike has a total weight of 15.6 kg. One of the decisive factors for the light weight is the frame. It weighs 2,350 g in size M. It is made entirely of high-modulus carbon fiber and is handmade. The handlebar is also made of carbon fiber. In the Ultra version, the handlebars and stem are fused into a fully integrated cockpit.

This consistency in lightweight construction is continued in the rear triangle. There, flexing seatstays made of carbon are used. ROTWILD does not use any additional bearings to save weight. The Short Travel kinematics with 130 mm travel at the front and 120 mm at the rear ensure agile handling and strong grip. The 437 mm long chainstays underline the compactness of the rear triangle. In addition, the R.X275 rolls on 29″ wheels. For the first time, the manufacturer also installs a universal UDH derailleur hanger. The frame also features two bottle mounts: for water bottles or a range extender.

The R.X275 is available in Pro (9.499 EUR) and Ultra (12.499 EUR) versions and comes in four frame sizes (S, M, L and XL).

Learn more about the Rotwild R.X275 on their website here.

FIRST RIDE

THE NEW Rotwild R.X275

First Ride by Robert Johnston | Photos by Mountain Bike Connection Winter – Rupert Fowler

Rotwild was showcasing their brand new R.X275 bike at the Bike Connection Agency Mountain Bike Connection Winter 2023 event in Massa Marittima, Italy. This allowed me to learn all about the new bike from their Marketing and PR manager, Jonathan Zimmermann, and about the TQ drive system from the friendly faces at TQ, then get some trail time on board. Conditions combined with the “fast” tire spec on the bike to limit the amount I was able to push things to really deduce its capability limits, but it’s safe to say it was a fun ride. The look of the R.X275 is impressively slim, with only a slightly larger volume around the bottom bracket to give its “E” away. As a rider who spends the majority of their time on enduro bikes, the similar weight of the Rotwild doesn’t give much away either. Very impressive indeed. 

Out of the gate, the standout feature of the Rotwild bike was the natural feeling that the custom tuned TQ HPR50 provided. So natural in fact, that aside from the slightest of mechanical whirrs that the drive system produces when giving assistance, I was hard pressed to say for sure whether it was giving assistance or not at times. This was quickly proven when I misunderstood the controls of the dashboard initially, and managed to set it to the no-assistance mode for a period of time on a mellow climb. Clearly, the bike itself is a competent enough climber without the assistance, as it wasn’t until the terrain pitched up a few percent that I figured out that the motor wasn’t actually helping me. Of course, the motor does give you a legitimate helping hand when you turn it on, as my speed increased by a couple mph for the same input effort in the lowest assistance setting. This can then be boosted with that bar remote to give a punchier hit of assistance, but even with the full power of the motor at your disposal it still feels like a proportional response to your input power, with excellent sensitivity to your pedaling force. This makes it easier to get going from a stand still without looping out or losing traction, but does give the sensation of a less powerful motor than the more artificial feeling of other systems. Jonathan at Rotwild described the mindset of the R.X275’s TQ assistance to be “your own power, but on a really good day”, and that proved to be the sensation out on the trail too.

The test climbing trail at the Italian trail area of Monti Arsenti, named Spaghetti for obvious reasons, is a seriously fun way to gain gradient on an eBike or a sportier analogue machine, with seemingly never ending switchbacks that let you deduce the climbing capabilities of a bike very quickly. Given that the Rotwild R.X275 is effectively an eBike and sporty analogue bike combined, it may come as little surprise that it made for a fun time on the way up the hill. Climbing position is very typical of the modern downcountry to trail crop, with enough of a centered seated position to keep your body in a commanding position without feeling totally upright, and fairly low bar height thanks to the minimal rise of the integrated cockpit to give you a more forward pitch. The pedaling support in the rear end is healthy without being totally jarring over the rough stuff, negating the need to use the climb switch on the shock. This means that you can ascend the Rotwild with as little fuss as possible, maintaining good cadence and even negating the need to change gear as often thanks to the Boost button. Battery life seemed to be fairly good, with two full climbs of the 340m hill (including an “all boost” second climb on an old fireroad that pointed straight up the hill) with varying assistance levels leaving me with just under 50% battery remaining.

The initial descent in Massa Marittima didn’t tell me much other than just how slippery the rock and mud were following heavy rain overnight with the Nobby Nic/Wicked Will tire spec. Thankfully, I was able to squeeze in a second lap on a slightly drier trail, which let me open up the taps on the R.X275 and get a clearer picture about its feel on the descents. Rotwild has created a real singletrack ripper in their e-trail machine, with a sporty feel that rewards working the terrain. It’s not one of the lightweight enduro crowd, with more feedback and a less surefooted feel when you hit hard compressions than some, but it still supports some fairly aggressive riding for its genre. It’s hard to feel the weight penalty of the TQ system, with the mass concentrated low and centrally and only really coming into play in the most dynamic moments when you’re lifting the bike. 

Overall the Rotwild R.X275 was a serious amount of fun, and a really promising look into another emerging category in the assisted mountain bike world. I can’t comment on durability nor quite suggest the full limits of this lightweight trail eMTB, but it feels to be a pretty good example of the concept, so if you want to feel fresh every time you hit the trails then it might just be the bike for you.