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Electric Bicycle Specialized

Electric Bicycles / May 31, 2021

We first got to swing a leg over the Turbo Levo last summer at its European launch. More recently, we rode the bike over a few days at the official North American launch in Moab, Utah. It was an ideal place to test such a machine; the rugged terrain really highlighted the bike's capabilities, and the area has many miles of multi-use, off highway vehicle (OHV)-legal routes. That second part is important: At this point, federal land management agencies such as the Bureau of Land Management (BLM) and the U.S. Forest Service (USFS) consider electric-assist bicycles motorized vehicles, essentially banning them from mountain bike-legal trails. I went into this launch in full agreement with this stance, not wanting to see “these things” on my trails. But after riding and better understanding what they are and what they're capable of, my opinion has become a little more accepting to this emerging technology. I also discovered that they’re incredibly fun to ride.

Since we already covered a lot of the Turbo Levo’s tech in our original piece, let's skip ahead to what this bike is—and is not. Specialized made it crystal clear that the Turbo Levo is first and foremost a high-end, performance mountain bike that has electric pedal-assist. It is designed to ride and feel like a high-end, performance mountain bike. It is classified by the federal government as a low-speed electric bicycle and as such is limited to 20 mph with a maximum electric power output of 750 watts. This bike only offers a maximum of 530 watts, and an average of 250 watts when you apply force to the pedals—in other words, it gives back what you put into it.

How much it gives back depends on what setting it is in. There are three standard settings: Eco, Trail, and Turbo. Assuming that the enthusiast cyclist produces about 200 watts, riding in Turbo mode is like the equivalent of having a ghost stoker on board providing an extra 250 watts of power. Trail and Eco modes both offer less assist and are independently adjustable with a smartphone app. Since there is no throttle, power is only applied when torque sensors in the motor perceive input, and sensors at the rear wheel detect movement. These two things are important because it really differentiates the pedal-assist bicycle from a motorcycle both in terms of function and ride characteristics out on the trail.

I have a pretty balanced perspective of motorized versus pedal-powered riding on two wheels; I am a longtime cyclist as well as motorcycle rider. Not only has an e-cargo bicycle totally changed my life, but when I'm not pedaling a bicycle, chances are I'm trail riding one of my enduro motorcycles.

When riding the Turbo Levo, right away the sensation and ride feel was way more bicycle than motorcycle. Not only is the Turbo lighter and far less powerful (more on this later) than a full-on motorcycle, but also the lack of throttle really changes things. Instead of leaning back and boosting your way up a ledge or obstacle using just the motor, you have to pedal up, which changes your body positioning and physical input. You also have to pay particular attention to your pedal position: Even though the bottom bracket is 7mm higher than Specialized’s Stumpjumper model, pedal strikes are a concern and limiting factor while climbing technical trails.

I quickly learned that pauses in pedaling to correctly time your approach to a ledge resulted in cuts in power right when you need it most. Thankfully, there is a roughly half-second lag in this shutoff where slight adjustments can be made while maintaining the electric assist. I climbed steep trails with ease and at about double my normal speed. You quickly learn that a high cadence works much better and provides more power than a grinding, slow pedal style. I have a theory that since the motor provides assist based off your sensed input through the pedals, the more frequent and higher peak torque inputs delivered via a high pedaling cadence result in pulses that are higher powered and closer together than those provided by slow, steady pedaling.

On the Turbo Levo, I could just spin up super-steep faces and rock ledges that would have stopped me in my tracks on a normal bicycle. Pedal assist makes it a real blast to ride routes that are hard and not terribly fun on a normal bike. I rode way more tough sections, and went twice as fast on the climbs, but still worked really hard doing it. Oddly, my ideal saddle height for the best power delivery was an inch or so lower than normal. This bike tricks you into pedaling your heart out because it gives back what you put into it—and last time I checked, going fast is fun. I was gassed at the end of every ride; the bike acts like a carrot on a stick, begging me to pedal harder all the time. The good thing is that you're never going dangerously fast—instead of four miles per hour, you're doing eight, and there's not enough peak combined power to cruise up a steep trail anywhere near the bike's maximum 20mph assist speed.

This bike tricks you into pedaling your heart out because it gives back what you put into it—and last time I checked, going fast is fun.

I asked Specialized for some power numbers to add some perspective, and even I was a bit shocked by it all. (We will be speaking in a lot of general terms here as far as wattage numbers go.) The average enthusiast cyclist puts out an average of 200 watts. The motor in Turbo mode adds another 250, for a combined 450 watts of total threshold power output. When you combine rider and bike weight (150 pounds and 45 pounds, respectively, for a 195-pound total), that gives you a power-to-weight ratio of 5.08 watts per kilogram. Maximum system power output or peak power by rider and motor combined is estimated at 1, 530 watts for one second. Now let’s put that into perspective. A professional mountain-bike racer (150 pounds) on a normal bike (28 pounds) puts out an average of 400 watts. Factoring in bike weight, the power-to-weight ratio is 4.95 watts per kilogram with a maximum of 1, 400 watts—that’s really, really close to what Average Joe or Jane can do on a Levo.

Perhaps even more shocking is that the average Tour de France racer puts out 430 watts, with riders like Mark Cavendish maxing out at a staggering 1, 580 watts; chances are Cav would drop you pretty quickly, even if you had the benefit of electric assist.

For all those who think the Turbo Levo is a motorcycle, consider this: A stock 2015 KTM 250cc 4-stroke motorcycle produces 43 horsepower (that’s 32, 065 watts of power). Factoring in bike weight (225 pounds) and rider weight (150 pounds, we’ll say 160 with boots and pads), the power-to-weight ratio is 188.62 watts per kilogram. That’s not just a little bit more than the Levo (which has a meager 5.08 watts per kilogram); it’s on another planet in another solar system. Make that motorcycle a more popular 450cc motorcycle and the difference gets even greater.

Source: www.bicycling.com