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[Richard230]

Rideapart rode a 2015 Zero SR around the Scotts Valley area for 20 miles and has published a review of the bike.  Unfortunately, the included video is not all that interesting - unless you like nice scenery.

https://rideapart.com/articles/2015-zero-sr-electric-motorcycle-review?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+HellForLeather+%28Hell+For+Leather%29

[MichaelJohn]

"It didn't feel overwhelmingly powerful" - She appears to be a small woman in the photo, I would have thought that the SR would feel like a rocket with a small person on it. I wonder what she is used to riding?

[Justin Andrews]

Unfortunately, the included video is not all that interesting - unless you like nice scenery

You know what video reviewers are going to have to learn to do as electric bikes get more popular...?

Windshield their freeking microphones...

[Richard230]

"It didn't feel overwhelmingly powerful" - She appears to be a small woman in the photo, I would have thought that the SR would feel like a rocket with a small person on it. I wonder what she is used to riding?

She claimed to be an ex-AFM motorcycle race corner worker.  Maybe that has jaded her view of street motorcycle performance.   

[protomech]

"It didn't feel overwhelmingly powerful" - She appears to be a small woman in the photo, I would have thought that the SR would feel like a rocket with a small person on it. I wonder what she is used to riding?

Even though the bike glided along these roads nicely and pulled well with all of its 106 lb-t torque, it didn’t feel overwhelmingly powerful. It can probably be compared to the power of a 600cc sport bike.

Modern "middleweight" sport bikes make about 100-120 hp peak. SR is doing pretty good if that's the "seat of the pants" comparison point with 70 ish hp.

[MichaelJohn]

"It didn't feel overwhelmingly powerful" - She appears to be a small woman in the photo, I would have thought that the SR would feel like a rocket with a small person on it. I wonder what she is used to riding?

Even though the bike glided along these roads nicely and pulled well with all of its 106 lb-t torque, it didn’t feel overwhelmingly powerful. It can probably be compared to the power of a 600cc sport bike.

Modern "middleweight" sport bikes make about 100-120 hp peak. SR is doing pretty good if that's the "seat of the pants" comparison point with 70 ish hp.

Except that it's torque that accelerates the bike and the SR has much more than almost anything out there. I personally would say that the SR's acceleration is overwhelmingly powerful, especially in the mid-range. I have friends who own supersport bikes who have ridden my Zero and they agree.

[MostlyBonkers]

This brings up something I've been pondering for a long time. There is no doubt that torque is a key factor with acceleration, but I also think power has a big part to play.

We don't ride our motorcycles in a vacuum which means that we get significant amounts of drag. It's power that determines top speed. I think there is an interplay between torque and power such that the more power available, the more is left over for acceleration once drag has been countered.

The two key equations are:

Power = force x velocity
Force = mass x acceleration

Having lots of torque gives us lots of force at the back wheel to push the bike forward. That leads to good acceleration. However as the speed increases and thus the drag, it is power that determines how much force is available for acceleration once the drag is countered. I hope that makes sense...

With the SR, you have lots of torque but not so much power. Lots of acceleration until the drag really kicks in above 60mph. I'd be very interested to learn how long it takes the SR to accelerate from 80-100mph.

I think that might have something to do with the reviewer's comments.

Also, we must not forget that gearboxes multiply the torque available at the back wheel. A high revving sports bike could reach 100mph in 2nd gear. Even though the engine might produce less torque than the SR, 2nd gear will mean more is available at the back wheel. Along with having more power than the SR and being more aerodynamically efficient, the sports bike will get to 100 quicker.

[CrashCash]

Yep, this is pretty much the argument Brammo used for their transmission. However, you don't ride an electric bike that way. Hitting 70 absolutely munches on the battery because of the V-squared drag term, so I spend my time railing around town since it's a total traffic weapon with the light weight, all the torque, and NO NEED TO SHIFT.

As far as I can tell (only talked to 2 Brammo owners) I think anyone actually riding a Brammo sticks it in 2nd or 3rd and leaves it there unless they're drag racing sportbikes. So basically the transmission ends up being dead weight and a nip on efficiency.

Power-wise, my SR is not down too much at 75-80mph from my SV-650. It's definitely not a CBR-600, but if I had a little nuclear reactor feeding the motor, I wouldn't mind the expressway or the interstate.

Sure, if power is king, as in racing, you'd want a transmission. Unfortunately you have limited batteries, so you can't be squirting it all out at once.

I'm not interested in 0-100... 0-60 is where it's at with batteries, and that "insignificant difference" really colors things.

Transmissions and water-cooled motors need to wait for battery capacity to catch up.

[Richard230]

I was riding with a friend today on Skyline Boulevard in the Santa Cruz Mountains. He was riding a BMW F800GT (top speed about 120 mph) and he took off down the road and left me in the dust.  About 5 miles further I saw him pulled over at an overlook parking lot by the side of the road, with a sheriff's car behind him with its lights flashing.  The sheriff seemed to be doing a lot of writing.  As I rode by, he gave me a sheepish grin and waved.  I waved back and kept right on riding.  I bet I got home long before he did.  There is such a thing as having too much power.   

[dkw12002]

Exactly right, Richard. That's why I traded in my Gixxer 1000. I was speeding far too much and after a couple of close calls, decided I had the crazy fast acceleration and speed out of my system. I had a couple of cops look askance at me, but never got a ticket, although that was just good luck. Far as I know there is no law against accelerating too quickly, so if the speed limit is 70 mph, you could get there in 3 seconds legally, provided you weren't deemed riding recklessly. That is one way you can still have fun on a bike that has a lower top speed like the Zero. They do get you out ahead of all the traffic effortlessly.

[MostlyBonkers]

I'd just like to point out that my intention was not to demean the SR in any way at all. If I could afford one I would have one. I suppose I find it interesting that electric bikes in general have bags of instant torque, but not necessarily lots of power to go with it. I know the reasons why and also know that as battery technology improves, electric bikes will out-perform their ICE equivalents on every metric.

As another forum member said, the SR is the king of the commute.

[MichaelJohn]

I just know that I haven't lost a stoplight race yet - not that I have had that many but lately the nice weather has more bikes on the road and well...things happen. A big KTM pulled up next to me over the weekend at a red light and we nodded to each other. He was revving and when the light changed he took off so hard he wheelied but I still shot out ahead of him and continued pulling away. He gave me a big wide-eyed thumbs-up when he caught me later in traffic. The SR may not be as quick as a well-ridden superbike, and no Zero can touch a high-end bike in top speed but where can you ride 150 mph on the street? Great for the track and bench racing but wasted on the majority of riders. I took mine up to 90 yesterday on a back road and that was pretty close to as fast as I care to ride - and it got there in a hurry with very good acceleration on the high end. There may be quicker bikes out there but the incredibly easy acces to the SR's acceleration makes it tough to beat in the real world.

[oobflyer]

I'd be very interested to learn how long it takes the SR to accelerate from 80-100mph.

I opened up the throttle while already going 75 MPH, for about 2 seconds - when I glanced down at the dash I found that I was going 96 MPH.
I think Zero should follow Tesla's example and change the name of the 'Sport' mode to 'Insane'
 

[MostlyBonkers]

Well, all I can say is that you SR owners out there are lucky, lucky people! Thanks oobflyer at al. [emoji106]

[Doug S]

I opened up the throttle while already going 75 MPH, for about 2 seconds - when I glanced down at the dash I found that I was going 96 MPH.

I've managed to surprise myself a couple of times that way too. You keep thinking -- knowing -- all that torque is going to run out and you're going to run up against the flat top end, but it never seems to come. I KNOW this bike only has 67 hp, why does it seem to have such long legs? Maybe I'm just too old to be disappointed by a mediocre top speed.