With geometry copied from the Triumph Daytona 675 and top-shelf racing suspension and brak
We rode the Enertia TTR just days after it returned to Oregon, with the same setup that put Scotsman Mark Buckley on the podium at the Isle of Man. From the tall, 34.5-inch saddle it feels indistinguishable from any other racebike with high rearsets and clip-ons mounted midway between the triple clamps. The starting procedure, however, is completely different. Flip the accessory power switch under the tail to wake up the gauges. Reset the oversized kill switches on the tank and tailsection (required by TTXGP rules), then depress the laptop-like main power button in the center of the tank. Finally, flip one more kill switch on the bar to activate the throttle. Keeping this last switch off anytime the bike is not in motion prevents you-or anyone else within arm's reach-from "whiskey-throttling" the silent machine out from underneath you.
There is no clutch or transmission; the direct-drive TTR is twist-and-go, like a scooter. Turn the throttle and the bike spirits away like a magic carpet. There is no vibration or driveline lash; a soft hum (like a ceiling fan turning on) and a bit of chain noise is the only indication that you are straddling a machine. Acceleration is brisk but hardly fierce. Theoretically, all 53 lb.-ft. of torque could be available from zero rpm, but the digital controller is programmed to deliver much less, both to save energy and to make the clutchless bike easier to launch.
A conventional twistgrip, connected by a cable to a wiper-equipped throttle mechanism, translates wrist motion into current draw. Eerily smooth throttle response recalls a rheostat, because that's essentially what it is. Acceleration is very predictable thanks to a linear throttle map that maintains a 1:1 ratio between throttle opening and power increase. "We didn't program any progressivity into the map at all," Wismann says. "We found it best to leave that up to the rider."
Given electric power's instant-on availability and the advanced processing capability of the digital controller, power delivery is almost infinitely adjustable. Tuned for the TTXGP, acceleration was decidedly soft. The TTR's battery pack holds the approximate energy equivalent of three quarters of a gallon of gasoline, which it used to propel itself around the demanding, 37.73-mile Snaefell Mountain course. Efficiency-not outright acceleration-was the goal. The bike could be reprogrammed to accelerate quicker at the cost of greatly reduced battery life. As is, we put around 40 miles on the TTR, in mixed riding conditions, before the batteries discharged completely.
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It takes an electrical engineering degree to decipher the data on this instrument screen.
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Best Buy is a major investor and the primary retail outlet for Brammo's Enertia production
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Lead engineer Aaron Bland (left) and director of product development Brian Wismann (right)
The only time we felt we needed more robust acceleration was in tight, knee-down corners, where more power would have helped pick the bike up post-apex. The TTR does not like to be flicked on its side-better to ride it like a 125cc GP bike, choosing fast, flowing lines. Corner entries can be tricky as well. There is no engine braking whatsoever, so you rely entirely on the binders to load the front end. Without any back-torque, the bike seems to speed up when you let off the brakes, which is startling the first few times. Better to have your entry speed set before you turn in.
An electric motor's power curve is the opposite of most internal-combustion engines. Max torque is available from zero rpm, and declines (eventually rapidly) as you approach the rev limit. The TTR, for example, loses almost 30 percent of its peak power by the 6000-rpm redline. As a result, the bike feels significantly more powerful from a standing start than during roll-ons. Wismann says this is a programmable variable as well. Increasing the voltage draw at the point where output begins to drop would mask the power fall-off, but would also cause a corresponding reduction in battery life. Adding a multi-speed transmission also would improve this situation, letting the rider upshift to reduce rpm-though that would be a costly and time-consuming solution.
With identical geometry and weight, the TTR handles like a well-prepped Daytona 675 racebike. Steering is neutral and lightning-fast, more akin to a 250cc GP bike than any 600. Unlike an internal-combustion motorcycle, there's no 30-pound crankshaft spinning at 15,000 rpm and creating massive gyroscopic forces that must be overcome. In fact, excepting the motor's tiny plastic rotor, there are no rotating or reciprocating parts at all. The entire powertrain is essentially dead weight that doesn't exert any dynamic force on the chassis. Line adjustments and corrections are met with little resistance and mid-corner stability is excellent, the latter aided by a compliant Elka shock and Triumph fork fitted with Traxxion Dynamics' mega-bucks AK-Gas pressurized cartridge kit. Even heavy braking-more inevitability than possibility with the overpowering Brembo Monoblocs-didn't make the chassis do anything untoward.
The TTR and its ilk won't replace internal-combustion motorcycles just yet. Racy looks aside, it's still more scooter that sportbike. It's certainly a compelling machine, though, and one that offers enormous promise once battery technology advances and fewer tuning compromises will be required for optimum performance. And there is a very real possibility that Brammo will bring a true electric sportbike to market in the near future. "A production TTR is certainly achievable," Wismann says. "The question is, at what cost? Right now, the cost would be too high relative to the performance offered. But give it a couple years, when the energy density of batteries increases and cost per unit comes down, and we will be riding something even better than this on the street."
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