Given today’s battery technology, motorcycles and light-weight vehicles are the perfect candidates for electric drivetrains. This is largely because these vehicles do not need to transport the operator in a climate-controlled safety cage. And in the case of motorcycles, this limits the pool of potential operators to motorcyclists alone. However, it wasn’t until the Brammo released the Empulse R that a serious motorcyclist would even consider an electric bike.
I owned a Brammo Enertia and at the time it was the best electric motorcycle in production. It didn’t use bicycle parts or a motorcross-inspired chassis. Despite its serious motorcycle looks, I really couldn’t call it a serious motorcycle due to its limit range, speed, handling, etc.
With the Empulse R, Brammo did something very brave. They decided that current battery technology and production cost was close enough to launch a product that was indeed a very serious motorcycle. While it is fast, it still won’t win a drag race against even a middleweight sportbike. It will, however, smoke that middleweight through the twisties. It’s a phenomenally well-handling bike and is a blast to ride.
The Empulse is a stunner. The original prototype looked great with its clip-ons and 1098 inspired (albiet flat) tail section. I think the refinements to the design really came through in the production model. I’m not a fan of the slope of the seat on the way to the pillion or of the extended light bracket. The Empulse is definitely a head turner. It really makes it hard to get through traffic unnoticed. Luckily I just get a lot of looks and not invitations for traffic light conversations.
The Enertia drew clues for its styling from several different source. Motorcross, boardtrack racers, flat-track Harley’s, and even bicycles to some degree. The Empulse’s design influences tend to lean more towards traditional motorcycle looks. Its stance resembles a modern Ducati Monster and to a lesser degree a Triumph Speed/Street Triple. The lines and body work are far more modern though, like a porous KTM RC8 where the large, angular openings reveal the technical underpinnings.
I’ve been riding a BMW R1200 GS for a while, and so I didn’t react that positively to the cockpit of the Empulse at first. I immediately thought that I’d be throwing clip-ons on there within a month. I just couldn’t seem to get my weight over the front end in the corners. I’m happy to say that I’m going to be sticking with the standard bars for quite some time. Now that I’ve adjusted my mindset a little, I find it’s trivial to get my head down and low for the corners. The seat, however, is a different story.
The seat on the Empulse is a little tight. It doesn’t give me a lot of fore and aft movement, and I when I’m low over the bike in corners, I feel like I can’t get low enough. There’s actually room to move aft, but it’s up a slope. It wasn’t until a recent evening ride that I realized that upward slope is actually pretty brilliant. You see, the front part of the seat is pretty low. It make for a wonderful low position for cruising around down, but it’s a little too low for corners. Here’s the catch; when you slide aft, it pushes your butt up just a little and actually makes for a really comfortable position in the corners. It feels a little awkward, but it seems to allow for a body position in the corners. And lastly, the firm sides of the seat give a really positive indicator when you’ve got exactly one cheek off…because the corner’s right up your crack.
The foot pegs on the Empulse are respectably high. I thought I’d want to change them our for spirited street riding, but they’re actually really good. I haven’t dragged a peg yet, and I’ve scuffed my chicken strips up a few times. The pegs will need to be replaced with rearsets for the track, but they’re working perfectly for the street. I do wish that they were a little narrower. I feel like they could each be 3mm to 8mm shorter, which would help with clearance. And lastly, they are incredibly slick when wet. I don’t like rubber, but if metal footpegs aren’t sharp and grippy, then I’ll take rubber.
One last little observation, the spring in the throttle is a little too light. It could be a little tighter, or the throttle tube could use a little friction to make it easier to hold maintenance throttle well. I find myself floating around a lot when trying to hold a constant speed. I do love the grips that they chose though.
All in all, I’m really happy with the ergonomics of the Empulse. It’s comfortable around town, allows for a good position and visibility in traffic, and is easy to move into an aggressive cornering positon. Granted, I’m only 5’7″, so it might be a struggle for a larger rider.
After working out the ergonomics, I was finally able to get to really get down to business with this machine. The Empulse R is all about the cornering. This bike’s geometry is so dialed, and I haven’t even setup the tire pressure and suspension. For my review, I purposely decided to leave everything as it came from the factory.
Despite the fact that the Empulse R is heavier than similarly sized ICE bikes, it uses that weight as a benefit when it comes to handling. But really, there are three factors that work together in perfect harmony to provide a stellar ride:
- Low center of gravity
- Low rotational mass
- Low vibration
With the exceptionally low center of gravity, I find that I cannot get this bike to drift once set into a corner. It’s hard for me to carry enough speed on the street to even get the bike to hold me up when hanging off, and so I find myself with too much pressure on the inside peg. I know this will be rectified once I get the suspension set up, because the firm suspension is working against me in the bumpy corners that I encounter on the the street around here.
I never put much thought into rotation mass, because I’ve never been the kind of guy that would fork over gobs of cash for magnesium wheels. Granted, light-weight wheels are a big advantage because they lighten up your unsprung weight helping your suspension track better. They also help reduce the gyroscopic effects when flipping the bike from one side to the other. Well, the Empulse lightens up the rotation mass where it matters, the engine. So often, engines are left out when considering gyroscopic forces. When you consider that some inline four cylinder engines rev to 17.5k rpms, then start to realize that there is a considerable amount of rotation mass in the engine. The Empulse reduces that engine mass to one little motor, and the effect is a very flickable bike. It also means that it’s easy to make mid-corner adjustments even without using the throttle. I’m still trying to decide if I like this, because it works against that comfort that you get on an ICE of knowing that you’ve set it in a corner and that it’s going to finish that corner on the exact same arc unless you give some throttle input. I do know that I really like the following: with the low rotation mass, there is not the strong gyroscopic penalty of going through corners at 90 mph+. You feel like you have just as much control as you would going 60 mph, and that is a very confidence-inspring attribute.
I usually ride v-twins, and so this last point about the Empulse’s handling is perhaps the most significant for me. The Empulse’s low vibration allows the rider to get very intimate with the road surface. You get amazing feedback from the road, and consequently I don’t think I’ll ever push the front end on this bike. The downside of this, is that you feel every bump and that can make you feel a little nervous. I’m going to see if I can mute that feedback a little when I setup the suspension.
For me, handling is all about the corners. Any bike with standard bars will handle fine in a parking lot or in traffic, but the real test is when you’re flopped over and wringing out the throttle to finish a corner. Any review will be incomplete without some track time, and so I promise a follow-up after my first track day on the Empulse.
When I finally measured the sag, I realized that there was way to much sag in the rear. I added some preload to the front and a lot of preload to the rear and it completely transformed the bike. The harshness in the rear has been replaced with firm but compliant travel. Now the bike feels even more planted once it’s set on its line. Heck, even the seat feels comfortable now.
Two Bikes in One
When I wrapped up my break-in period and was finally able to use Sport mode, I was amazed. Sport mode transforms the bike into a completely separate machine. The two settings provide two different power curves and two different regenerative braking maps. A similar thing is done with fuel-injected sportbikes nowadays, but it’s a pretty complicated affair and they don’t have the same amount of precise control as you can get with software and an electric drivetrain. Sure ICE bikes can even provide dynamic engine braking as found in the Buell 1190 and the EBR 1190rs, but it can’t be nearly as adjustable as an electric drivetrain.
When it comes to tuning, electric drivetrains may just be a sea change for software-controlled vehicle dynamics. I’m certainly not the first to be awed by the possibility. Chris Harris has similarly amazed when reviewing Mercedes new electric SLS. I could almost the light bulb going off in his head.
Power and Performance
The Empulse R has really deceptive power in the form of really good torque and a broad powerband. After spending several months away from my ICE bike, I was shocked at how often I needed to shift. In all actuality, I shift just as often on my Empulse. The key difference is that an ICE has a very steep torque. Forgive me if the following line of reasoning is non-Science… If torque helps you to accelerate, then the slope of the torque curve defines the jerk or change in acceleration. The Empulse accelerates just fine but when you’re running in sport mode, you tend to stay in the flat part of the torque curve most of the time (above 5k) and you just don’t get that same jerk. A really nice side effect of this is that the chassis is way more stable during acceleration.
I haven’t done any head-to-head comparisons through the twisties with a comparable bike (Monster 696 or Street Triple), but I do feel like the Empulse will own them. That is until you hit about 90 mph. The Empulse really stalls out when accelerating towards the top of it’s speed range of 105 mph. Again, sorry for my pseudo-Science but it’s almost like the motor is using all of its energy to make horsepower to punch through the wind.
There are plenty of thrills to be had in the corners with the Empulse R. You’re not going to get any excitement drag racing it to the next stop light. If that’s exclusively what you’re into then buy a literbike, slap an exhaust on, remap it, slam it, and throw on a new swingarm.
The addition of a transmission to the Empulse has been a lightning rod for criticism. Firstly, there are the Internet nerds (myself included) who realize that there’s enough torque in an electric motor to not need a transmission. So why bother? Heck, even seasoned motorcycle journalists say a one or two speed transmission is all you need. I’m going to make an argument that the use of a 6-speed transmission makes this a true and complete sportbike.
- Regenerative braking on a motorcycle is hard when you’re thinking of using the levers as inputs. Most braking is on the front wheel which would require a front hub motor. Most riders don’t have very fine control over the rear brake and that makes using the rear brake as a controller for the main motor a tricky affair. However, if the rider controls the regenerative braking in the exact same way that he controls traditional engine braking, then this is a no brainer.
- Rear braking is crucial for corner entry to keep the rear end settled and the front compliant for trailbraking. The Empulse’s regenerative engine braking is perfectly up to the task of providing that rear braking for corner entry especially since so many mortal riders and racers can’t use the rear brake to save their life without breaking the rear end loose. But if a rider is going to rely on the Empulse’s engine braking, then you sure as hell have to give him more than two or three “settings”. In fact, you really should give him all six engine braking “settings”.
I think any agressive rider will pick up on this. It’s just a hard thing to get your head around, because most of us are accustomed to thinking that we need the transmission solely for accelerating on an ICE bike with a narrow powerband. And in the far off future, maybe 2-speed transmission coupled with really advanced regenerative braking software will do the trick. I’m an embedded software engineer by trade and I just don’t believe it’ll happen for a long while.
And as for convincing my nerdy brethren that a transmission is needed…that one’s beyond me. You really have to get into a corner hot and drop three gears before tipping it in to really understand. Who knows…maybe Zero will own everyone in the TTX class this year. Maybe shifting gears is a waste of time. If that’s the case, then I will definitely need to issue a public apology…and maybe dedicate some time to an open source motor controller project.
One thing that is beyond argument, is that the transmission is an important tool for any motorcycle rider. It gives the rider 6 options for how they want to bike to accelerate and 6 options for how they want to bike to decelerate; just like an ICE motorcycle. Controlling engine braking is a very important component of motorcycling. With the new Zero DS, they have provided an iPhone application that lets you set the regen. It’s not very practical in the sense that you really can’t make a change as you’re heading into a corner. The Mercedes Electric SLS and the Cadillac ELR use their paddle shifters to engage regen without using the car’s brake pedal. I know that the ELR’s switches are just on/off. I hope that Mercedes use the paddles to climb up and down through regen settings as a way of simulating downshifting as you go into a corner. Regardless, Brammo’s decision to put in a transmission makes a lot of sense in this context.
I’m sure it must have been a difficult engineering task to develop the power maps and the regen maps for each gear and for both modes, but I think the transmission was a huge win. The folks over at BrammoForum.com posted a poll to figure out people’s preferred shifting habits in the city. I’m one of those guys that shifts all the time just like an ICE. The beautiful thing is that the Empulse accommodates the rider that just want to stick it on one gear and go…like me when I’m carrying a cup of coffee on my way into office.