Brammo Empulse R Review - about.com

[Brammofan]

An Electric Ride For Serious Riders

Well, can't say I agree with every point this guy makes, but he did enjoy his ride.

[protomech]

From the article:

hooked up to a six-speed manual gearbox with a hydraulic clutch, which is an anomaly in the electric world where automatic continuously variable transmissions usually rule

Really?

In fact, torque is so abundant it's possible to ease off the line in third gear, though you'll miss that brisk rush of acceleration from progressing through the gears.

Third gear acceleration is likely very similar to the 2010 Empulse single-speed concept - adequate, but not "brisk" by conventional motorcycle standards.

I'm convinced we will not need a six speed transmission once we have motors in the 60-80 kW range.. except *maybe* for race replicas. Race bikes, like honey badgers, do not give a single fuck about 0-60 acceleration, so they can get away with "only" 3-4s 0-60 times in exchange for placing the power curve exactly where it needs to be for a particular track.

Here's a set of hand-wavey top speed / acceleration tradeoffs, given a single speed transmission and ~400lb bike weight:
20 kW, acceleration: 6s 0-60**, 50 mph top speed (2010-2011 Zero X)
20 kW, top speed: 10s 0-60, 90 mph top speed (2012 Zero S)
40 kW, acceleration: 4s 0-60, 85 mph top speed (2013 Zero FX)
40 kW, top speed: 6s 0-60, 105 mph top speed (2013 Zero S, 105 mph gearing)
80 kW, acceleration: 3s 0-60, 100 mph top speed (600 class power, traction limited accel)
80 kW, top speed: 4s 0-60, 140 mph top speed
120 kW, acceleration: 2.5s 0-60, 140 mph top speed (1000 class power)
120 kW, top speed: 3s 0-60, 170 mph top speed (basically Lightning's race bike)

You can see there's only a small time difference in acceleration between the acceleration and the top speed gearings once you get to 80 kW.

A typical sportbike is about 3s 0-60. I think we can do a bit better than that with electrics..

By comparison, a 2013 Zero S with a claimed range of 114 miles city/63 miles highway will cost you $13,995-- cheaper, but still not chump change.

Score another victim to Zero's incomplete 2012 range specification.. very thankful Zero has improved their press communication for 2013. Btw, it might be nice to quote the 2013 range when discussing the 2013 bike.. range below are in miles, city / 70 mph highway / combined.

2012 Zero S ZF9 $13995
114 / 43.5 / 63

2013 Zero S ZF8.5 $13995
103 / 53 / 70

2013 Zero S ZF11.4 $15995
137 / 70 / 93

2013 Empulse R $18995
127 / 56 / 77

[protomech]

Also worth noting for purposes of accel vs top speed.. the heavier your bike is relative to the power level, the more you need multiple gears. Or more power If bike + rider weight increases by 50%, you need a 50% increase in wheel torque to maintain the same acceleration level. You can meet this by shorter gear ratios and a lower top speed or switching to a beefier motor/gearing combination. If your motor makes 50% more power, though, your top speed should go up significantly vs the smaller bike.

So while the Zero FX 5.7 is reportedly 3.9s 0-60, 33 kW, 85 mph top speed, 260 lbs.. the Empulse concept is probably closer to 6s 0-60, 40 kW, 100 mph, 390 lbs.

(greatly oversimplified to just discuss peak power .. power curves matter, cooling matters, etc ..)

[Brammofan]

Well, it was in about.com, so what do you expect? 

[ttxgpfan]

Just for context to Protomech's numbers, back when I was big into sportbikes and couldn't wait for my magazine's to come in the mail, 0-60 times for bikes considered "real sport bikes" (600cc +4 cylinders, 750cc+ twins) were sub 4 seconds.  I did some digging around Motorcyclusa.com's site and found Kawi's 650 twin and it's ilk are running 0-60 in just over 4 seconds, the Liter bikes high 3 seconds, and the 600s low 3 seconds.

[BasemWasef]

Well, it was in about.com, so what do you expect? 

I'm not sure where you get your information on About.com; as a contributor to a broad variety of outlets including Popular Mechanics, Wired, and Men's Journal, I can safely say that About.com allows (and in fact encourages) the most in-depth reporting of a vehicle's technical details and performance characteristics. My Empulse review for About.com ran at 1,706 words, which is considerably lengthier than most writeups you'll find online or in print (which usually run between 800 and 1,200 words.)

-Basem Wasef
http://motorcycles.about.com
http://twitter.com/aboutmotorcycle
http://twitter.com/basemwasef

[protomech]

Hi Basem,

Welcome to the forums. Sounds like you enjoyed your Empulse ride, I'm very jealous : ) Please feel free to ask questions here if you have them.

While Brammofan was snarking, there are a handful of significant factual errors in your review addressed above - most notably the snippet about the common-place automatic CVTs for electric bikes and overstating the range for the 2013 Zero S ZF8.5 (see above).

[BasemWasef]

Hi,

Thanks for the welcome.

Zero's claimed range of up to 137 miles was widely distributed in press materials, and can be found here.

As for the CVTs, my apologies: I meant to say automatic, and have fixed the article.

Basem

[protomech]

Apologies for being a pedant. An automatic transmission typically means a slush box like those found in cars or the ridiculous Boss Hoss, a CVT like most scooters and some cars, or an automated clutch multi-gear transmission like the Honda NC700 or the most recent VFR or the Aprilia Mana.

The fixed single ratio drive systems on most electrics just have a single gear front and rear sprocket and a chain or a belt between. This is both a blessing and a curse: it's inexpensive, bullet-proof, and requires nearly no maintenance.. but does not offer the ability to disconnect the motor with a clutch or select from multiple gears based upon operating speed. The Empulse's manual gearbox is the dominant characteristic of the bike.

Regarding the Zero comparison for range, you do list the range correctly early in the article. But on page 3:

By comparison, a 2013 Zero S with a claimed range of 114 miles city/63 miles highway will cost you $13,995-- cheaper, but still not chump change.

This is the city and highway commuting range for the 2012 S, equivalent to the 121 and 77 mile ranges given for the Empulse.

Did you have an opportunity to charge the Empulse on J1772?