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[ZeroSinMA]

Any meshed gears = more friction. More friction = less mileage.

Use the inherent characteristics of the electric motor to advantage (max torque @ 0 RPM) - no gears!

How many gears did you see on a steam locomotive (max torque @ 0 RPM)? Oops - I just aged myself

Okay, youngsters - how many gears do you see on a Diesel-electric locomotive?

Trikester

Perfect analogy. Transmissions not only add weight but also increase energy loss. Zero figured this out years ago.

[protomech]

The proof is in the pudding. We cannot compare a production product that has been shipping for years to a vaporware product that does not exist except as a  prototype for racing and marketing.

I can. I just have to operate off of the admitted assumption that the specifications are correct.

I've seen the Brammo vs Zero movie over and over in the high tech industry over the past 30 years.

One company rides the technology development cost/price/margin/demand curve with wisdom and care while others reach too far, usually out of hubris, and fail.

They make fatal errors. In other words they make errors that are too expensive for investors.

They run out of money trying to recover.

Simple as that.

I think Brammo vs Zero is a long-term approach vs a short-term approach. Zero is growing incrementally, making measured improvements each year. Brammo is reaching out to a number of partners - deals with Flextronics, Polaris, SMRE, etc - that should hopefully build the foundation for rapid future growth. IF they can succeed in getting their ducks in a row, they will be in a much better position to start pumping bikes out in volume when the market grows beyond 500 units/year type numbers.

Of course, they have to deliver product in order to make good on that growth, and they've executed very poorly on getting bikes to market since the 2009 Enertia.

A six speed transmission is needed on an IC bike to invert the torque curve. It is madness to put one on an electric bike when electric motors deliver 100% torque at 0 RPM.

It is doubly foolish when the price/performance game is all about power density, to maximize the utility of expensive kilowatts.

The "100% torque at 0 RPM" mantra is a bit overblown. Zero S makes 4057 Nm at the motor, 188268 Nm at the rear wheel less drivetrain losses (4.7:1 mechanical advantage). A 250cc ICE bike with say 15 Nm at the engine will make 390 Nm at the rear wheel in 1st gear due to its higher mechanical advantage (26:1). Better yet, a clutch allows the engine to initially rev higher and deliver a sharp impulse of power to the rear wheel when moving from 0 RPM.

Give the electric bike a larger motor, or one that can rev to much higher RPM like Tesla's, and then gear it up.. and the story changes quite a bit. But 100% torque at 0 RPM alone only tells you that you probably don't need a clutch.

I think overall the IET probably is an efficiency loss, certainly if you're riding lazily and you leave the bike in the same gear from the time you get on until the time you step off the bike. However, if it's used to lower the motor to a more efficient RPM for 50+ mph travel .. then it could overcome its efficiency loss and make better use of those expensive kilowatts.

Oh, and if a motor running at high RPM is inefficient then it also generates a lot of heat (and vice versa, a hot motor is less efficient). And top speed eventually falls from 88 mph to 75 mph. A more efficient motor not only gets better range, but can hold the desired speed for longer .. or as long as 9.3 kWh will take you at speeds of 100+ mph.

I'm not knocking the Brammo engineers or questioning the integrity of the Brammo team. I fully understand how such foolish decisions are made that wreck great companies. I've seen it over and over. But sorry to say, add up all of the facts that can be independently proved and Brammo smells like failure.

We'll see once the Empulse reviews are out. If we're very lucky we'll see the Empulse TTX (likely >> $20k) at Miller on track with the Zero bikes ($14k) for a direct comparison.

I want to keep the bet friendly. What did you have in mind?

Aye, I should have said earnest rather than serious.

Let's make it more relevant - loser buys the winner 1000 miles of electric fuel. I'm 126 Wh/mile * $0.086/kWh * 1000 miles = $10.84.

I'm betting against Brammo will not "abandon the Empulse within six months AND the who[le] gig fails within 12." .. in fact, let's simplify it to whether Brammo abandons the Empulse within 12 months.

Both Brammo and Zero need to sell more bikes if they are to survive. Zero has done very well with the 2012 bikes relative to the earlier years, but let's optimistically assume they continue to sell 250 units / 6 months and make $4k per bike sold. $2M in revenue after component costs won't keep 60 people employed.

[Richard230]

I continue to be fascinated by the Empulse's 6-speed transmission and clutch system. In one of their promotional videos they showed a test rider revving the motor in neutral like the Harley guys do when waiting at a traffic light or to let the neighbors know that they have arrived.     I can understand the theoretical advantages of a transmission, but I am just not sure that it is worth the weight and space needed within the frame that could be used for an additional battery pack.

The other thing that comes to mind is that not a one of the electric cars that have been introduced, or announced for future production, have (or will have) a transmission.  You would think that if a transmission gives a vehicle a performance or range improvement you would see it in a automobile first. The auto manufacturers have lots of different types of off-the-shelf transmissions to choose from and yet they are not even proposing this packaging for even their vaporware concept vehicles.   Does Brammo know something that GM, Tesla, Ford, Nissan, Honda, BMW, etc., etc. don't know?

When I asked Brammo's CEO about why they were going with a transmission, instead of the direct-drive Empulse last year, he told me that it was because shifting a transmission was fun and it would be more natural for an IC rider to shift from a gas-powered bike to an electric.  I then said, that is nice, but how about making a direct-drive Empulse and sell it to us customers that don't want or need a transmission but just want to ride electric? You can always install a transmission in the next version while you penetrate the market, establish a reputation, make some cash and generate a customer base with a modern electric sportbike.  But he just laughed and said it would all be good. Just wait and see.  I still am waiting.   

[Nukie]

When I asked Brammo's CEO about why they were going with a transmission, instead of the direct-drive Empulse last year, he told me that it was because shifting a transmission was fun and it would be more natural for an IC rider to shift from a gas-powered bike to an electric. 

Yeah, it's fun to rub two sticks together to start a fire but when you have a butane lighter around, why bother? This is antiquated thinking and puts form before function.

[trikester]

If Brammo is putting six gears on an electric bike just to make traditional riders feel more at home, then that is utter stupidity! I've seen companies where marketing triumphs over engineering, and they often fail.

Fortunately, I can afford to have bought my two ZERO's (and a lot more) because in the company I retired from (as a principal owner) engineering always had the last word when marketing wanted something stupid because they liked it. Marketing and engineering have to be partners, as a team, to produce a viable product that people want to buy. Each has to keep the other in check because engineering can get carried away with technology's charm also, and load a product with expensive, little needed goodies that price it out of the market. That's when marketing has to speak up loudly.

[ZeroSinMA]

If Brammo is putting six gears on an electric bike just to make traditional riders feel more at home, then that is utter stupidity! I've seen companies where marketing triumphs over engineering, and they often fail.

Fortunately, I can afford to have bought my two ZERO's (and a lot more) because in the company I retired from (as a principal owner) engineering always had the last word when marketing wanted something stupid because they liked it. Marketing and engineering have to be partners, as a team, to produce a viable product that people want to buy. Each has to keep the other in check because engineering can get carried away with technology's charm also, and load a product with expensive, little needed goodies that price it out of the market. That's when marketing has to speak up loudly.

Bingo. You hit the nail on the head.

I spent 10 years in product management. The job is to arbitrate between the product requirements that come from the commissioned compensation world of Sales, the world of "give me this feature and Il'll sell N units" and the real world contraints of physics and engineering and cost that engineers have to live by. Theoretically engineering can deliver anything, but when and at what cost? I bet the requirement for a six gear box came from Sales and the product manager failed to pin the engineering team down on time and cost, because engineers like a stretch technology challenge but start giving them tight time and budget contraints and the enthusiasm wanes quickly. Now Brammo is publicaly committed to the six gear machine because they've made all of these arguments for it and publicized it and that's their brand and differentiation but Sales was not properly informed that meeting this requirement will take two more years and make the bike 30% more expensive than a Zero ZF9. By the time Empulse comes out, if ever, Zero will have two full iterations on its shipping product. Oops.

[Richard230]

My guess is that a 6-speed transmission was chosen because the Italian company that makes it is using an off-the-shelf motorcycle transmission and then modifying it for EV use.  Motorcycle transmissions are tough things to design and manufacture. You would need to contract with a big company, like one that makes auto transmissions and pay them millions of dollars to develop and build it for you.  The big motorcycle manufacturers can do that in house, or like BMW, they can retain a company like Getrag (sorry about the spelling if it is wrong, but it is not in my dictionary) to make their gear sets.  But when a small company is looking to purchase a few hundred transmissions each year, you really have to find one that is already on the market and adapt it for your use. I think that is where the 6-speeds come from as most of the motorcycle transmissions around have 6-speeds.  But, going that route could be a problem with the kind of torque an electric motor can dump into the works.  Finding an off-the-shelf motorcycle transmission, small and light enough to fit into an EV's chassis and able to handle a lot of torque, while not costing an arm and a leg, could be tough.

[protomech]

The Volt and the Prius plug-in both make use of a planetary transmission, with the Volt's rationale being that a mechanical transmission can in some circumstances improve efficiency vs the "electric transmission" (serial hybrid). The Volt might not have needed a mechanical transmission if they had not caved on the NVH of a constant speed engine .. or if they had used an engine with a more efficient BSFC point.

Tesla initially selected a two speed automatic transmission built by Magna in order to meet their top speed and acceleration requirements. When the transmission proved to be insufficiently durable, they upgraded the motor and motor controller / inverter. While I'm not very familiar with their design considerations, it seems reasonable that the single speed transmission design was the less desired solution prior to the durability issues. Perhaps the inverter and motor upgrades were significantly more expensive than the transmission. Perhaps motor heat output was a concern for a single speed design. Regardless, it's interesting that both Tesla and Brammo selected a multi-speed transmission design for their production sport electrics, excluding the durability concerns that forced Tesla away.

A mechanical multi-speed transmission really has two main advantages:

* pick the most efficient of several operating RPMs, potentially reduce heat and power requirements
* increase wheel torque at low speeds

Coupled with a slew of disadvantages:

* possible durability concerns
* maintenance (oil changes, etc)
* mechanical inefficiencies
* added weight, cost, packaging

Yes, you theoretically would get more range by spending weight / volume / cost budgeted for a transmission on enlarging the battery pack. In practice it's not as simple as "just add a few more cells" to a design, particularly if you're using large format pouch cells.

In city riding a single speed bike's motor is generally pretty efficient. A transmission can significantly increase acceleration, but extra power in jackrabbit starts, extra weight, and the mechanical losses mean it will definitely use more power. Empulse is 77 Wh/mile UDDS, Zero S ZF9 is 69 Wh/mile UDDS.

In highway riding a single speed bike's motor can be driven to an inefficient regime, wasting battery and generating excess heat. The transmission still has significant mechanical losses, but drag becomes a much greater consideration than weight and it's possible that operating the motor at a lower RPM can reduce or overcome the mechanical losses. Empulse is 166 Wh/mile @ constant 70 mph, Zero S ZF9 is 182 Wh/mile @ constant 70 mph.


Look at this dyno plot of wheel torque vs speed for the Tesla Roadster vs a 3.6L 300 hp 6 speed Camaro:



It's easy to see with huge initial torque and relatively low weight (~2900 lbs Roadster vs ~3600 lbs Camaro) that the Roadster has much better 0-60 performance.. but especially above 80 mph or so the Roadster's power output decreases. Like the Zero, hm? Also like the Zero, the Roadster is air-cooled.. and can overheat at super-highway speeds.

My guess is that a 6-speed transmission was chosen because the Italian company that makes it is using an off-the-shelf motorcycle transmission and then modifying it for EV use.

I recall reading somewhere that the SMRE transmission was entirely in-house. Their brief history article sounds like an in-house project.

http://www.iet-technology.com/iet-project.php

[ZeroSinMA]

Good stuff. Supports the argument for a 2 speed transmission that lets you shift the bike at around 40mph at the elbow of the torque curve... If one can be made that is cheap, light and durable. As you say if the tradeoff wasn't possible for a car  (Tesla) it's hard to imagine how it can make sense for a motorcycle.

[protomech]

Tesla's CTO published a nice writeup on Powertrain 1.5, which was the update to the BorgWarner single-speed transmission. Powertrain 1.5 was introduced in early 2008.

Tesla is (understandably) effusive in their praise for PT1.5. They mention that gearbox weight is reduced (by 8 kg), city efficiency is improved, part complexity is reduced, and motor torque is improved by about 30%. They mention that the two speed transmission had "cost challenges" that are now gone. Also that they had to upgrade to a "new generation" of IGBT (er, no mention of cost).

Powertrain 1.5 was pushed to early production customer cars and made standard in new production in late 2008.

Coincidentally, in early/mid 2008 Tesla announced that the Roadster pricing would be bumped from $92000 in 2008 to $109000 in 2009.

My speculation: "cost challenges" aside, switching from a two-speed transmission to a more powerful single-speed transmission with the same performance benchmark resulted in a significantly more expensive (and overall better) car. I'm not suggesting that the PT1.5 upgrade cost $17k, Tesla's cost estimates and projections were clearly not well-synced with production realities. (as, ahem, Brammo's were not)

Probably only Tesla knows for sure if the two-speed design was less expensive to produce than the single speed. I bet Brammo knows too, though.


When Brammo first introduced the Empulse they praised the single-speed transmission.

There's nothing between you and the road. With no clutch and no gearbox to get between your throttle command and the application of torque to the rear wheel, the Empulse provides the smoothest delivery of power you're likely to have ever experienced.

Now they rather like gearboxes and clutches.

[IET] enables the 2012 Empulse to accelerate hard from the line up to a high top speed, something that is just not possible to achieve with a single ratio electric motorcycle.

Companies spin. It's what they do. It's part of the marketing game.

But pretending that a direct drive transmission is superior in all ways to a gearbox? Well.. you've been sucked in by the marketing game.

Single-speed or multi-speed gearbox is a design decision, it has a number of tradeoffs (many of which we're not privy too in our armchairs). Brammo has picked what they feel is the best solution for their application, Zero has done the same. Chances are they're both correct.

[trikester]

When ever I'm describing my ZERO to an IC rider I have always received a very positive response when I mention that it has no transmission. They have always thought that was a plus (just as I do).

Now if you want your ZERO to get off the line faster (I don't personally know why, but to each his own) do like ":Electric Cowboy" has done and get a higher current motor controller. Remember, we are not using the maximum HP & torque available from the motor. His bike has scary acceleration   and still no multi gears!

Trikester

[protomech]

The single speed transmission is fantastic for a commuter application. It makes stop and go riding very easy, and I can even fiddle with stuff at low speeds (eg pulling my badge out of a pocket to go through the gate, while regen braking with the right hand).

Something not everyone realizes about Brammo's IET: You can do the exact same thing with it. Unlike an ICE bike which will stall below a certain point, you can start the Empulse up in a particular gear and ride it in that gear all day long and never touch the clutch. I would be willing to bet that most riders find themselves leaving the clutch alone after a certain point. A gearbox and clutch are mandatory crutches for ICE bikes. They're options for electrics.. and you can make a good bike with them or a good bike without them.

[ZeroSinMA]

Tesla's CTO published a nice writeup on Powertrain 1.5, which was the update to the BorgWarner single-speed transmission. Powertrain 1.5 was introduced in early 2008.

Tesla is (understandably) effusive in their praise for PT1.5. They mention that gearbox weight is reduced (by 8 kg), city efficiency is improved, part complexity is reduced, and motor torque is improved by about 30%. They mention that the two speed transmission had "cost challenges" that are now gone. Also that they had to upgrade to a "new generation" of IGBT (er, no mention of cost).

Powertrain 1.5 was pushed to early production customer cars and made standard in new production in late 2008.

Coincidentally, in early/mid 2008 Tesla announced that the Roadster pricing would be bumped from $92000 in 2008 to $109000 in 2009.

My speculation: "cost challenges" aside, switching from a two-speed transmission to a more powerful single-speed transmission with the same performance benchmark resulted in a significantly more expensive (and overall better) car. I'm not suggesting that the PT1.5 upgrade cost $17k, Tesla's cost estimates and projections were clearly not well-synced with production realities. (as, ahem, Brammo's were not)

Probably only Tesla knows for sure if the two-speed design was less expensive to produce than the single speed. I bet Brammo knows too, though.


When Brammo first introduced the Empulse they praised the single-speed transmission.

There's nothing between you and the road. With no clutch and no gearbox to get between your throttle command and the application of torque to the rear wheel, the Empulse provides the smoothest delivery of power you're likely to have ever experienced.

Now they rather like gearboxes and clutches.

[IET] enables the 2012 Empulse to accelerate hard from the line up to a high top speed, something that is just not possible to achieve with a single ratio electric motorcycle.

Companies spin. It's what they do. It's part of the marketing game.

But pretending that a direct drive transmission is superior in all ways to a gearbox? Well.. you've been sucked in by the marketing game.

Single-speed or multi-speed gearbox is a design decision, it has a number of tradeoffs (many of which we're not privy too in our armchairs). Brammo has picked what they feel is the best solution for their application, Zero has done the same. Chances are they're both correct.

I don't think so. Transmission or not is a "bet the company" decision at this stage of the electric motorcycle industry, if it can even be called that at this point, with a few hundred actual paying customers.

Think of the Apple Lisa and early PCs. Critical decisions have to be made that will make or break the business.

The CEO of Brammo is quoted as saying that the transmission is to make the experience more familiar to IC motocycle riders, presumably because they think the electric motorcycle buyer is an IC motorcyclist.

The IC motorcyclist thinks, "If it doesn't shift it's a scooter."

Ergo an electric motorcycle in order to be a motorcycle and not a scooter needs gears.

But what if this conception is wrong? What if the way this market develops is that a small army of consumers is waiting to buy a motorcycle if they can buy one that meets the following criteria?

- Quiet and unobtrusive
- Virtually no maintenance
- No shifting (Try buying a car in the US with a manual transmission. Good luck.)

It's a product marketing battle and in my opinion Brammo is making classic errors.

[protomech]

I don't think so. Transmission or not is a "bet the company" decision at this stage of the electric motorcycle industry, if it can even be called that at this point, with a few hundred actual paying customers.

Think of the Apple Lisa and early PCs. Critical decisions have to be made that will make or break the business.

Okay. Do you need a GUI in your OS?

Apple and Microsoft say yes. Linux says no. Which OS is right? Or can any be correct depending on the application?

But what if this conception is wrong? What if the way this market develops is that a small army of consumers is waiting to buy a motorcycle if they can buy one that meets the following criteria?

- Quiet and unobtrusive
- Virtually no maintenance
- No shifting (Try buying a car in the US with a manual transmission. Good luck.)

Sounds like the Zero bikes and the Enertia. I'm sure both Brammo and Zero would love a small army of consumers buying those bikes.

[trikester]

The single speed transmission is fantastic for a commuter application.

It is even more fantastic for dirt riding! If you are buzzing along in what would be a higher gear on an IC bike and you come into a tight, tricky, spot you don't have to take the time to kick it down to get torque after braking to a slow speed. Just hit the brake (or regen) and then the throttle to power through it and you're on your way again. Same thing if you come to a sudden steep pitch climb. Just get on the throttle. I don't know how many times I've stalled an IC bike on a steep climb because I miss-calculated the gear I needed to kick it down into (or didn't have the time to shift) at the beginning of the pitch. Not fun to be stopped part way up a steep slope. That is a thing of the past noiw with my ZERO DS.

Trikester