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[s44captain]

I own a Zero 2012S and have ridden the Empulse a couple times, but I have not yet ridden a 2013S. I really enjoyed the Empulse a lot and felt it handled better and was more comfortable than the Ducati Monster I test rode. I have sat on the 2013 Zero S and just couldn't get a emotional attachment to the looks which would make it difficult to buy for me (I did not fall in love with the looks of my 2012 Zero but there was nothing last year I could buy that was as fun as that Zero and ran on electricity).  Things about my 2012 Zero I liked more than the Empulse were the light weigh, belt drive, almost total silence running, ability to plug into any wall socket and smother throttle roll off. Things I liked more about the Empulse than my own Zero were the way it looks, ergos, power and the ability to plug into any of those free J17 stations all over the place out here.  If you are going to spend money on either of them I would make sure to take both out for a test ride first then listen to your own heart strings.

[BSDThw]

http://www.motorcycle.com/shoot-outs/2013-brammo-empulse-r-vs-zero-s-zf114-91574.html

[Richard230]

Thanks for the link to the shoot-out, BSDThw.  It is just about what I expected from the two bike's specifications and from previous press and rider reports.

[WindRider]

Nice Review.

I think that the Zero wins for being what an electric motorcycle can be rather than trying to pretend to be an ICE motorcycle.   I would like to own both of them but I spent my money on a Zero.

My 2 cents. 

[protomech]

Quite a good comparison. Video review is worth a look too.



In the video they claim 50 miles of abuse (186 Wh/mile @ the pack) on the Brammo and 62.5 miles (160 Wh/mile @ the pack) on the Zero. Similar riding conditions .. best range comparison to date.

Per the video:
We ran them in not the most optimal circumstances. We drag raced them, top-gear roll-ons, we were out in the canyons all day.

Assuming the ZF8.5 gets 75% of the range, that's 47 miles on the smaller Zero. Makes it a little more efficient.

“The Empulse left the Zero for dead in an acceleration contest from a complete stop, as the torque-multiplication benefits from its gearbox makes the Empulse the drag racer’s choice,” says EiC, Kevin Duke. “Yet, to declare the Brammo the clear winner in terms of power isn’t telling the whole story. A roll-on contest at 55 mph (with the Empulse in fourth gear) showed the Zero has a slight edge.”

Zero S ZF11.4 vs Empulse R is a pretty easy story to tell. Want a sportsbike and premium design? Empulse R is your bike: it goes faster and charges faster in most conditions. Want tons of range, easy operation and maintenance? Zero S is your bike.

I'm looking forward to another shootout in the future - Zero S ZF8.5 vs Empulse E1 (non-R). The bikes are a little more similar so conclusions will be a bit harder to tease out. ZF8.5 should have very close to Empulse E1 range, but also drops some weight and may pick up some acceleration. Empulse E1 drops the carbon farkles and has less sport-focused components. Both are $2000 less expensive than their big brothers; the price gap is consistent.

[baumisch]

Thank god we finally have a comparisson - still I am missing the drag-video where you see the "The Empulse left the Zero for dead in an acceleration" thing clearly ...

I drove the 11.4 Zero last weekend here in Germany and I was beaten by my friends Ninja 600 so easily at the trafficlight-sprint  I just hate the off-the-line performance of Zero, the new 2013 is a blast in any ways except the off-the-line thing ...

But anyway - I'm still on 2012 model, so I'll wait for a used 2014 bike in a few years and put more miles on my 2012-zf9 until then ...

[protomech]

Gas bikes have a pretty big advantage by dumping the clutch. Even if the Zero and the Brammo bikes didn't restrict at 0 rpm - I wonder if this is a Sevcon thing? - Gas bikes (and cars) produce > 100% torque for a second or so until the clutch locks.

If you get a chance to retest, try doing a rollon acceleration test at 10, 30, 50, 70 mph.

[BSDThw]

I wonder if this is a Sevcon thing?

In my understanding it is caused by the PM-Motor.

The motor type has a dependency between rotation and voltage => you will always start with 0V and reach your top voltage at the nominative rotation. More rotation will need field weakening (it starts at ~3500RPM)
If you start you will have 420A but ~0V(0KW) .. 5V(2.1KW) ... 10V(4.2KW) .. 15V(6.3KW) ... =>  So the 21KW at a 2012 S/DS will only be at ~3500RMP.

I make a simple picture in my head: The motor is also a generator and if propelled it produce a voltage. The voltage raise if propelled faster like your bicycle light becomes brighter as faster you ride!
The regulator has to reach this voltage and raise it (slightly) so the current will not come out of the "generator" instead it will go into the now "Motor". You can not raise the voltage more because it would produce a gigantic current.

I develop solar grid inverter and it is exactly the same way how to feed the PV-current into the grid.
(Grid = Generator Voltage)

If someone proves me wrong, let me know, I would really like to learn more about the e-Motor technique!

[frodus]

Here's something I found interesting..... I was Looking at the Zero DS ZF11.4....

126mi city
82mi combined
61mi highway @70mph


The gearing, controller and motor are all the same. The only real differences I see are the DS tires and different suspension. The DS is 8lbs heavier.

So the kWh/mi for the Zero DS ZF11.4 is:
10kWh/126mi = 79.4Wh/mi city
10kWh/82mi = 122Wh/mi combined
10kWh/61mi = 164Wh/mi combined

And the kWh/mi for the Zero S ZF11.4 is:
10kWh/137mi = 73Wh/mi city
10kWh/93mi = 107.5Wh/mi combined
10kWh/70mi = 142.9Wh/mi combined

And we have the Brammo Empulse R/E1:
9.3kWh/121mi = 77Wh/mi city
9.3kWh/77mi = 120.8Wh/mi combined
9.3kWh/56mi = 166Wh/mi combined

For City, Zero S to DS jumps from 73Wh/mi to 79.4Wh/mi on city, and from 142.9Wh/mi up to 164Wh/mi for highway at 70mph.

That's a bit surprising. Do dual sport tires really cause that much drag that would put the DS into the same range category as the Empulse?

Something smells a little fishy.... That's an ~9% increase in Wh/mi useage in city, and a whopping 15% increase on the highway.

[NoiseBoy]

They do differ in that the DS runs lower gearing as well as different tyre sizes. You would be surprised just how big a difference tyres make though. Have you ever ridden a drop bar road bicycle on high pressure tyres and compared it to a mountain bike?

[frodus]

Gearing is the same for S and DS on Zero's website. It shouldn't effect range that much.

[NoiseBoy]

Maybe they changed it for 2013, even then the rolling radius of the tyres will be different, so effectively the gearing is still different even if the pulleys are the same.

[frodus]

Maybe they changed it for 2013, even then the rolling radius of the tyres will be different, so effectively the gearing is still different even if the pulleys are the same.

Tire Diameters for the rear:
DS: 130/80-17 (25.189" diameter)
S: 130/70-17 (24.165" diameter)

So there's a ~1" larger diameter on the rear... that shouldn't change things that significantly.... that would really only effect acceleration .... but 9% and 15% for city/highway? That's a huge change for a different aspect ratio and some Dual Sport tires.

[protomech]

I would expect the tires to affect city riding power consumption more than highway riding.

The DS rides about 5" higher than the S. Probably is somewhat less aerodynamic - though 15% lower range seems high.

[frodus]

I would expect the tires to affect city riding power consumption more than highway riding.

The DS rides about 5" higher than the S. Probably is somewhat less aerodynamic - though 15% lower range seems high.

Discussing this on multiple forums:

Richard brought up frontal area.... and there's ~3" difference in seat height. That 3" height is almost all tires/wheels/suspension... the bulk of the bike stays the same. With that 3" height and lets say a 130mm width of the rear tire (~15") is roughly 45in^2 more frontal area. Lets kick that up to 60in^2 for good measure because if you do increase front height, you may increase the body cross sectional area a bit... but not by much.

Lets say the Zero itself is 500in^2 of frontal area... it should be close. I threw the values in my old elmoto calculation sheet with a 500 and 560 in^2 cross sectional areas, 0.8 Cd at a 70mph cruise. The drag Coefficient on these is going to be fairly bad since they're unfaired.

96.71Wh/mi for 500in^2 and
106.5Wh/mi for 560in^2

So a ~10Wh/mi change.... and it's right around 10wh/mi for other cross sectional areas I tried... like 400/460, 300/360
Looking at the Zero DS and S (166Wh/mi and 142.9Wh/mi respectively).... frontal area would account for 10wh/mi .... the actual difference is ~23wh/mi... so that other 13Wh/mi is coming from somewhere.

So yes it does effect the wattage useage some. I'd guess that less than 1/2 of that increase is due to increased frontal area.

So with 6.4Wh/mi change change for city driving between the S and DS (that's probably all to do with rolling resistance because the speed is so low)... and lets say another 10wh/mi for an increase in frontal area at 70mph... that's maybe 17Wh/mi estimated difference... but real world there's a 23wh/mi difference. Pretty close....

It's amazing what you can do with just changing the rolling resistance of the tires and your cross sectional area..... tucking sounds better doesn't it