Rock Machine Blizz INT e90-27 Review: E-bike for Challenging Trails

Along the lines of current European trends, Rock Machine significantly beefed up its range of e-bikes. The Czech brand is well known for its vast range of bikes aimed at extreme trail conditions, so its logical that their electric-assisted models have been developed to reinforce the brand image of ragged, burly MTB rigs. The subject of our review is the Blizz e90-27 model, which not only shines on gruesome downhills, but thanks to its powerful engine, it is easy to ride up on even the steepest of slopes.

We have already published articles about the Rock Machine range of bikes on these pages, please check them out concerning the brand’s complete range of bikes!
2018: https://bikemag.hu/magazin/hirek/2018-as-rock-machine-es-superior-ujdonsagok
2019: https://bikemag.hu/magazin/hirek/2019-ben-25-eves-a-rock-machine-nezzuk-az-ujdonsagokat
In these articles we mentioned that the brand’s e-bike range is growing at a fast rate. The new e-bike models make up a significant proportion of the novelties, and they are likely to be the best-sellers for Rock Machine. This is the same strategy other bike manufacturers follow now days: since to the west of Hungary — from the Austrian border all to way to British Isles — e-bike make up nearly half the total sales for manufacturers. Rock Machine offers e-bikes tailored to their brand image: they not only match the design of the “traditional” bikes in the Czech brand’s range, but more or less every model in the RM line-up already has an e-MTB sibling.

The Blizz INT e90-27 belong to the Flash E-series in the Rock Machine range of bikes. The model name says a lot about what we can expect. The naming structure is well thought, each label has a precise meaning. Blizz denotes Rock Machine’s aggressive hardtail bicycle line, and the “INT” in the name refers to the fully integrated battery. “E” stands for electric motor assist, and the 90 is the level of equipment found on this mode: the higher the number the more advanced are the parts. The”27+” is not hard to figure out: of course it’s the wheel size, so the frame is designed around 650b wider “plus” tires.


Rock Machine designs its e-MTB bikes with virtually the same geometry as their traditional counterparts. This is the secret of the excellent handling, the e-bikes haven’t been “dumbed down” for the ease of electric conversion. So they are just as well-versed as standard versions, providing all the performance the rider expects from a Rock Machine MTB. Hence the subject of this review has a slightly different in geometry from the original Blizz, still retaining much of its downhill and climbing prowess.


Last year we reported that the biggest challenge for designing these e-bikes for Rock Machine was the creation of the bottom tube. The engineers had to come up with a design that houses the battery, without weakening the tube and the frame structure. They decided to create a five-chamber “tube” similar to the cross section of a wheel rim, which makes it strong and robust with enough internal space for the battery. Rock Machine is proud of this unique engineering solution, and told us that the “INT” frame tube in question is manufactured at the same plant which also produces parts for Apple components. So quality standard should not be a problem. The battery is covered by a strong and resistant nylon shell, which protects it from external forces.

The e-MTB version of the Blizz also features the Sharkspine EVO design, where the top tube takes a distinct bend from end of the head tube (just like the head of a shark), then continuing in an ever so slightly curved line, resulting in better vibration absorption compared to conventional frame designs. This shape has the additional benefit of providing a steeper drop in the top tube compared to older models, thereby achieving a lower frame stand over — a welcome feature for smaller individuals and those with proportionally short legs. It also allows a larger than usual frame size to be ridden, which in turn provides more room to move about over the bike. In order to use a normal length seat tube despite the low stand over height, a reinforcement was added to the frame’s seat tube to provide a longer protrusion — once again resembling the back of a shark.

The Blizz INT e90-27 is the top-of -the-range model, nevertheless it does not feature high-end components seen on race-oriented top MTB hardtails. The emphasis is on the best motor drive system available today, complemented by the trustworthy, premium midrange equipment. This component selection strategy keeps the bike functionality in tact, while offering better value. A good example is including the SR Suntour Raidon 34 suspension fork in the package, which provides virtually flawless performance, with a good range of dampening, a well-functioning lockout, and accepts Boost standard hubs for truly strong wheels.

The shifting and the drive train has been chosen from several different component groups and brands. The shift lever is Shimano SLX, the rear mech is XT, and a Shimano E8000 STePS crank set drives the 11-speed Sunrace cassette using a KMC chain. The motor drive is the excellent E8000, the left side of the handlebar has the control buttons for the StePS pedelec system.

The Tektro brakes may seem an unusual choice – I have never used the HD-M745 brakes before riding this bike — but I was pleasantly surprised by the sheer braking force they provide even with 180mm size discs. They did a good job managing the speed, even on challenging terrain.

The wheels perfectly fit into the overall design of the Blizz INT e90-27, the WTB Scraper i35 rims are laced to a Shimano 6010 hub set, complemented by WTB Vigilante 27.5 × 2.65 “TCS LHG tires. This combination provides good traction and grip in the majority of circumstances.

The handlebar, stem and seat tube — with the exception of their own branded saddle — is sourced from Race Face. The Aeffect 125mm dropper post does a good job at allowing the rider to shift the center of gravity on technical slopes, it is controlled from the handlebar, hence there is no need to get off the bike to adjust saddle height.

After so much talk, I guess the reader is wondering what kind of ride this bike dressed in the colors of dawn offers! In a nutshell, it is incredibly fast on the flats, riding uphill requires minimal effort, and the descents are even faster…

Before the ride, the STePS system has to be turned on using the button on the down tube. The battery charge level can be monitored on the handlebar-mounted display unit or alternatively on the down tube. If you are heading out on a long journey, it is a good idea to charge up the battery fully, then you will not have any surprises on the mountain. Stepping on the pedals, a mere 4-5 turns are needed to reach 25 km/h. The bike can sustain this speed even on steep uphills provided we are strong enough to supply the rest of the power. Alternatively the rider can change the support setting: BOOST-mode for example is quite powerful, letting you ease off even when climbing steep gradients. The ECO is generally enough on the flats, we were able to reach the 25 km/h assistance limit during the test in ECO alone. Crossing the cut-off speed caused the motor support to be switched on and off. Of course, this e-MTB beast was not designed for riding flat terrain: it feels at home when ridden on hard uphills and gruesome descents.

We have no reason to worry when climbing with Blizz INT e90-27+. I could tackle steep uphills which I wasn’t able to ride on a conventional MTB. When the BOOST assist mode is selected, the Blizz literally pulls you up the harshest gradients. Without motor assistance, the handling is a bit sluggish when going uphill, but in reality this is never experienced, as the powerful electric motor gives enough momentum to overcome the distinctly shallow head angle. On the hand, the added stability provided by the laid back frame geometry is a blessing on the descends. It would be difficult to criticize anything else: we are able to overcome anything the terrain may be throw at us, the motor assistance solves basically anything, and even hobby riders can dictate the tempo only the pros were capable of previously.

The Shimano E8000 drive system is one of the best on the pedelec market, both on the software and the hardware side. Shimano designed and built the STePS motor drive to perfection: it is very good at sensing power coming from the pedals, and it gives matching support. For example, if you press hard on the pedals, the system instantly gives you more power, on steep uphills, it can even make you do wheely! Soon you learn not to make such mistakes, and you’ll certainly appreciate the lack of lag in the power support. Unlike with some of the competing pedelec systems, you do not have to wait a quarter or a half turn in the pedals for the motor to step in. This is one of the the great advantages of the STePS system, it always in perfect harmony with the rider.

On the descents, the Blizz acts like an indestructible tank. The wide tires, the stable geometry all help to provide unparalleled downhill capabilities for this bike. Even the rather portly weight of the bike comes handy on the descents, further enhancing its steady character. On the other hand, the 23kg weight is noticeable when taking corners, it slows the bike down, but it’s something you get used to quite quickly. You can certainly do jumps with the Blizz INT e90-27+, it’s stable in the air, but you should pay attention to the difference in the center of gravity when you’re attempting such feats for the first time!

During my rides with the Blizz INT e90-27+, I often wondered what I would do differently if it was mine. For example, I would probably not use a chairlift in the bike parks provided the starting point was not very high. When we were riding in the Kalnica park, one of the Rock Machine managers did just that: he choose not to stand in line for the lift, and rode up the ski slope to the hilltop. He was there a few minutes before we arrived!

To sum up my experience, the Rock Machine Blizz INT e90-27+ is recommend to those who would like to get maximum enjoyment out of mountain biking, and are ready to dive into the e-MTB experience. If for any reason you are slow on the uphills, or have trouble tackling the steep sections, this bike will provide an immense benefit. It will help you get to the top of the hardest mountains you can imagine, then let’s you bomb down on the other side with confidence.

Detailed specifications, geometry and lot more information can be found on the Rock Machine website.
English language website for this model:

Recommended retail price: 1,299,900 HUF.
Available at dozens of bike shops nationwide:


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