This article originally appeared on BikeHub (https://www.bikehub.co.za/features/_/gear/reviews/review-specialized-s-works-turbo-levo-fsr-6fattie-r4884) and is the property of Bikehub
The Specialized Turbo Levo FSR 6Fattie is available in S-Works, Expert, and Comp specification levels. All models utilize the same M5 Premium Aluminium frame designed around Specialized’s FSR suspension with 135mm of rear travel.
When developing the Turbo Levo range of bikes, Specailized’s goal was to design a mountain bike integrating pedal assist rather than an e-bike with mountain bike components bolted on. To us it may sound obvious, but in other countries where e-bikes are fairly common, many e-mountain bikes have their roots in commuting and are not suitable mountain bikes.
The Turbo Levo FSR 6Fattie is based on the Stumpjumper FSR 6Fattie which is the 27.5 plus version of the Stumpjumper FSR – a bike that has been part of Specialized’s line up for more than a decade. The challenge for their engineers was to integrate a motor and battery into a custom frame design in a clean and functional manner. And they succeeded. Apart from the bulk around the bottom bracket, the Turbo Levo FSR 6Fattie is instantly recognisable as a Specialized and has managed to retain the stance of its siblings.
The battery pack comes in two capacity models: a 504Wh model for the S-Works and Expert bikes and a slightly lower 460Wh for the Comp specification. The Turbo Levo battery conveniently clicks into place via a cam-lock and a mini 15mm thru axle that can be loosened with a 5mm hex key. This has two benefits.
First, it makes for a rattle free design with the battery securely locked in place which, along with the quietest motor I have experienced on an e-bike, makes for a pleasant ride.
Secondly, as the battery is removable you will be able to swop it out during ultra long rides, when electricity is not available or when the battery starts to lose its charge capacity. You need not worry though, as Specialized estimates that each battery should be at 100 percent performance for roughly 700 complete charge cycles. That means if you were to completely deplete the battery every day, you would get almost two years of use before it begins to fade. A full charge is said to take only 3.5 hours using either the bike’s charge port or with the battery removed (useful when maintaining multiple batteries).
There are three pedal assist power modes to select from while riding: Eco, Trail and Turbo. Using the default setting, these offer 30%, 60% and 100% of your effort as assistance respectively. This, though, is highly customisable through the Mission Control App which I discuss in detail further below. For the bike to detect your pedalling effort, torque is measured in the motor at the crank while speed is measured by a sensor hidden in the dropout with a magnet attached directly to the brake rotor, doing away with a spoke magnet.
The 36V 250W Brose motor weighs 3.4 kgs and although it is not the most powerful model available, the output and characteristics suit the bike perfectly. Using a gear reduction of 3:1 to increase torque, the motor drives a toothed pulley on the crank with a Gates belt drive which is one reason the motor is so quiet. The motor also uses two sprag clutches – one on the crank and one on the motor. This ensures that when you pedal without the motor engaged, you are only pedaling the drivetrain without any extra drag from the motor.
The battery is chipped for use with both Bluetooth and ANT+, so connecting with a smartphone or GPS is simple. There is a built-in power meter, and the battery constantly communicates with your smartphone or Garmin head unit over ANT+ on a “fake” channel that, once paired, monitors battery life and allows you to toggle between power modes. It is reported that Garmin will be updating software to better handle e-bikes with dedicated channels.
All this technology is fitted into a tweaked Stumpjumper 6Fattie frame with clean lines and internal routing for all the hoses and outers. The frame comes with an integrated chainstay protector, as is becoming the norm these days, and a rock guard downtube protector. Compared to the standard non-assist bike, the rear stays get beefed-up main pivots and double-row bearings. Unique to the e-bike frames are bridges between the stays to help handle the extra weight of the motor and battery.
Thanks to the motor’s diminutive size and integration into the frame, Specialized could move it slightly ahead of the bottom bracket and combine it with the battery nestled in the underside of the downtube for one cohesive package. By design, it also allows for shorter chainstays than most of the competition while putting all the weight where it will least affect the bike’s feel – low and in the centre of the wheelbase.
Specialized’s designers were very specific in making this look like a regular mountain bike. As a result you won’t find a display unit or thumb control on the handlebars. Instead the three modes are easily accessible by push button on the side of the battery as well as control integration with some Garmin head units. If you really want control on the handlebar, there is a small remote available as an optional extra.
There are three buttons on the left hand side of the downtube. A power button to switch the bike on and off and and +/- buttons to switch between the three available power modes. In a very clever minimalist design there are ten LED lights that surround the mode buttons, each representing 10% battery life. They are also responsible for showing which mode you are in, with the two lights at the bottom showing that you are in ECO mode, six LEDs represent Trail mode and all ten for Turbo mode. When selecting one of the three modes the lights momentarily display which mode you are in before going back to showing battery life.
Available in Google’s Play Store and Apple’s iStore, the Specialized Mission Control app offers a wide range of features and allows full control over the Turbo Levo system. This is a great piece of technology and sets Specialized apart from all other e-bikes currently available on the market.
The Smart Control algorithm allows you to set your desired ride time or distance, how much battery life you would like to have left at the end of your ride and it will adjust the motor and battery output accordingly by monitoring the battery in 10-second intervals and metering its life accordingly. No need to worry whether you will make it home.
Allows you to customise your motor characteristics like acceleration response, maximum motor output or mode-setting. With its “Acceleration Response” you can set how much vigour you would like the motor to kick in with. You can also set each of the three modes’ (Eco, Trail, and Turbo) wattage assistance to your own liking, if you don’t want the default Eco at 30%, Trail at 60% and Turbo at 100%.
The app includes a comprehensive navigation (POI, search address, language coach and previous rides) in combination with an extensive and customisable on board computer
Strava integration and automatic upload opportunities to dedicated e-bike category and the ability to copy your route or ride from Strava over to the App and Smart Control will ensure your battery will last the full distance.
A comprehensive diagnosis system gives you immediate feedback and an overview of the motor, battery and system health.
Gives you a detailed overview of your fitness and ride history.
As you would expect from an S-Works model, the bike we had for the day sits at the top of the line-up. See the full specification table below.
Fork: The bike comes fitted with a RockShox Pike RCT3 with 140mm of travel. This was our first experience with a RockShox fork featuring the 110mm boost axle width having previously reviewed the 100mm width fork. As one would expect by now, the Pike delivered great composure and support through its full travel range and showed no signs of flex. With no internal changes over previous models, I would expect it to be ultra-reliable with little TLC needed to keep it performing at its best.
Shock: A Custom Fox Float does duty on the S-Works model. Befitting of the bike it is the top of the range Factory DPS with Kashima coating, boost valve and Specailzied’s Autosag function. For those not familiar with Autosag, have a look at the quick video guide here. In short, most shocks have a transfer port that balances the positive and negative air chambers inside the shock. The Autosag system works on that balance. You over-inflate the positive air chamber so the bike is totally extended, the riders sits on the bike in their riding gear with the shock fully open, then presses the Autosag valve and it bleeds out the excess air. Once the air is released, it automatically balances the positive and negative chambers to the sag-level set by Specialized (which is around 20% for an Epic and 25% for a Stumpjumper).
Drivetrain: At the heart of the Turbo Levo’s drivetrain sits SRAM’s XX1 components powered by a custom Praxis crankset running a 32T steel chainring to better cope with the torque forces. The frame is dedicated 1x and can run anything from 32 to 38 tooth chainrings. The XX1 drivetrain performed flawlessly with quick, positive shifts. I did not notice any issues when shifting under load although thanks to the power on offer in Turbo mode, chances are that you won’t be shifting under load too often.
Brakes: Complementing the SRAM drivetrain is a set of SRAM Guide RS Carbon brakes paired with a 200mm rotor in front and 180mm on the rear. The bigger rotors do an excellent job slowing the 22 kg bike. Feel, modulation and consistent performance are all very good. Lever shape is down to personal preference, but I found the carbon levers to be excellent.
Wheels: The Traverse SL Fattie 650b 148 carbon wheels are lightweight, tubeless ready rims build around a 148mm boost rear hub standard and feature a zero bead hook design. Internal width is 30mm with 24 spokes in front and 28 rear. The rear hub is a CNC machined alloy body with DT Swiss 350 internals featuring a 54T quick engagement ratchet system. Claimed weight for the complete wheelset is a very competitive 1537g with a 108kg rider weight limit. The wheels worked well on the trails with good engagement and no signs of flex.
Tyres: Specialized fit a 6Fattie Purgatory Control in front and 6Fattie Ground Control on the rear. Both are 60TPI, tubeless ready and 3.0″ wide. I found this to be a great combination for traction and speed with the tyre and rim working together to offer mountains of grip.
Seatpost: Specialized’s internally routed Command Post IRcc comes standard on all Levo models – something I’m glad to see. A nice touch is the gear lever like remote that sits on the left where a front gear shifter would be. It makes using it intuitive and natural as minimal hand movement is required to operate with your thumb. I found the return speed too fast and would prefer it to be a bit slower for health and practical use reasons.
Saddle: The 143mm wide Body Geometry Henge Expert with hollow Ti rails was very comfortable from the outset and should suit a wide range of sit bone widths.
Cockpit: A 750mm carbon bar with 8-degree backsweep, 6-degree upsweep, 10mm rise is used on the S-Works model. The sweep and rise feel good making for a steady comfortable ride. The length of the standard stem is 75mm.
Although the standard assist settings are good out the box, those looking to get the most out of a Turbo bike should install, pair and setup the Mission Control app which only takes a couple of minutes. Each bike can only be paired to one app to ensure no one fiddles with your settings.
Once the bike is set up – just turn on the power, choose a mode, and start pedaling. The pedal-assist will kick in when it senses torque on the pedals and detects forward motion via the speed sensor.
From the first “assist” it was clear that the Mission Control plays a big part in separating the Turbo Levo from the crowd. With the “Acceleration Response” setting I was able to reduce the unsettling kick-in on the first few pedal strokes that many e-bikes suffer from giving it a smoother feel more like a traditional pedal bike. When climbing fire roads, the kick-in experienced on other e-bikes does not seem to be a big issue. But when the trail gets narrow and you have to navigate tight turns, you will need to be careful with pedal strokes as the awakening motor can catch you off guard. This is not a problem on the Specialized. Power delivery is smooth and assistance gradually picks up – a major plus. Not only does it make for a safer and more enjoyable ride, but it adds to the regular mountain bike feel of the Turbo Levo, allowing the rider to focus on what they are there to do, ride their bike.
Those who have spent a day riding in the Jonkershoek valley will know what the climbs there do to the legs. Using the full assistance mode makes light work of the steepest climbs and gets you to the trailhead fresher and faster. After the first few ascents, I dialled it back to the Trail or Eco mode to get a reasonable workout with some assistance to take the edge off. It was such a joy popping out at the bottom of Neverending Story and thinking “let me do that again”, turn around and head back up without any concern of blowing up on the climb.
The motor really is frictionless with no signs of drag when free wheeling or pedaling unassisted. When the Euro speed limit of 25km/h kicks in the motor simply switches off making the drivetrain feel like any non-assisted bike. Other e-bikes I’ve tried have a form of retarder build in that will slow you down once you go above 25 km/h. The Turbo Levo, however, will allow you to pick up speed at will with zero interference with your ride.
The pedal assist does not have to remain on at all times for the bike to be fun. Going down single track with the motor off, you realise just how good a mountain bike the Turbo Levo 6Fattie is. The suspension soaks up everything in your path while the extra volume of the tyres allows for very rough line choices without the feeling of being shaken off the bike. Even with the longer rear (compared to its non-motorized sibling) the bike never felt cumbersome through tighter sections and, as long as you are willing to move your weight around, the bike turns with razor sharp accuracy. There is very little indication (even with the motor off) from the feel of the ride that you are piloting a 22 kg bike.
Climbing is good with the shock’s tune combating any sign of bob. When the climbing gets rough, the 6Fattie will out climb the best in its class thanks to the extra grip and traction on offer with the bike only showing signs of its meaty tyres on faster, open climbs.
On single track the 3.0″ plus tyres let the rider carry extra speed through rough sections, around berms and corners. This helps to maintain momentum and speed meaning less yo-yo effect of slowing down and speeding up again.
Specialized delivers three knock-out blows with the Turbo Levo FSR 6Fattie.
The first one comes in the form of the 6Fattie platform. As a mountain bike the S-Works Turbo Levo FSR 6Fattie is an excellent trail machine. Pardon the pun. It will rail, jump and huck like it is nobody’s business without any signs of the extra weight at speed. The geometry is close on perfect and puts the rider in the bike rather than on it. After riding the bike I cannot help but think that the plus tyres make the perfect platform to build an e-bike on. The drawbacks of the fatter tyres are negated by the additional power while offering extra traction for control. The wider tyres also enable the rider to carry speed making for a smooth enjoyable ride.
The second “left hook” is the well executed e-bike integration that sits inside the 6Fattie skeleton. The way power is delivered and shuts off is seamless taking nothing away from the natural riding experience. The quiet motor does not disturb a peaceful morning on the trails.
The third and final sucker punch is delivered by the Mission Control app. It takes many of the e-bike concerns out of the equation by offering customization of your ride and ride history which elevates the Turbo Levo range a notch above the rest. I cannot overstate how great it is being able to set the acceleration response and level of assistance. You can even tell it how long you expect to be riding for to make sure you have juice left when you get home.
In the Levo, Specialized have not only built an e-bike. They have taken their time to re-think and develop the platform to deliver a product that takes full advantage of available technology. With the advent of apps and the smartphone computer in your pocket, it makes complete sense to go the full monty, instead of simply strapping a motor to a bike.
As things stand, if you are looking for a pedal assist e-bike that is a proper trail bike with the latest and greatest technology, the Specialized Turbo Levo FSR 6Fattie is the one to get. Mountain biking has just been catapulted into the digital age.
Visit the Specialized website for local model availability and pricing of the Turbo range.