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[Marshm]

It was either Dirt Bike, or Dirt Rider, I forget.  They placed the power between a 250 and a 450, closer to a 450.  Had more power than a 250 4 or 2 stroke.  The range was like an mx bike with a small tank, so in the ballpark.  The rest of the bike they pretty much didn't like. Sort of strange because Zero could just copy another bikes geometry and suspension components.  Of course if the other suspension components cost more, that would add to an already very expensive bike. 

Maybe I mentioned this before, but it seems to me a smaller motor would allow more range.  If so, it might be an interesting option.  Other motorcycle makers have 250 and 450 offroad bikes, why can't electric have different motor classes? The magazine guys actually set in in eco mode and were ok with that.  Surprising since they are sort of power junkies. 

[protomech]

Maybe I mentioned this before, but it seems to me a smaller motor would allow more range.  If so, it might be an interesting option.

Generally speaking that is not true. As an example, the FX is just as efficient as the less powerful 2012 X in city riding, and more efficient at higher speeds.

A larger motor weighs more, and indeed the FX ZF2.8 does weigh 18 lbs more than the 2012 X. I don't know how much of that weight gain is the motor itself.

[trikester]

The larger motor might actually be more efficient than a smaller one, because of larger gauge copper windings having lower resistive losses.

Here is the comparing apples and oranges situation:

The power of an electric is determined by how much current, at a given voltage, you can "feed" to it by the battery limitations and the controller limitations. Those are what determine it and not the motor, up until the motor would be damaged by more current. Survival and efficiency at a given power level is a major determinant of motor size. Motor design and winding design are used to achieve desired torque and hp characteristics.

Max power with an ICE, the displacement determines how much fuel / air mixture it can explode with each firing and how often those explosions take place is determined by bore, stroke, number of cylinders, and various mechanical limitations.

When people on this forum discuss changing to a size six controller they are looking for more output power by being able to supply more current to the motor. Of course the penalty for actually using that additional power would be shorter range. There is no free lunch.  If the size six were installed but the additional power available was not used, then the range might increase a little due to lower losses, at a given current level, in the size six as compared to the size four.

Trikester

[Marshm]

What about a small RC car motor and a big 3 foot diameter motor running a rock crusher.  I think the RC car would last a long time on the Fx battery, but the rock crusher motor would run for 10 seconds.  Now you are going to tell me that the difference is just the rock crusher motor was fed a bunch of current while the RC car was not, thus it depends on current not the motor?  Is there an effect that the rock crusher motor would require more current or it would not move at all.  So perhaps larger motors always require a little more current?  Like the magazine guys, if a person was ok with the power, or thought it might be on the high side, could something be done to trade that power for range?  Eco mode is supposed to do that, and that just limits current? 

[Richard230]

There is nothing that I love more than a free lunch, but I agree those are hard to come by.   

[trikester]

I repeat, it's all about how much current a given voltage can force through the motor and how much current the motor can handle before being damaged like burning up the windings or de-magnetizing the magnets. The rock crusher motor is the size it is because it has to handle a lot of ectrical power without being damaged.

If you had zero resistance in the circuit and infinite force magnets you could provide infinite power in an infinitely small motor. Motor size has only to do with how much power it can take before damage.

That said, motor diameter, along with other things, does figure into torque and speed characteristics.

You are correct in that if you decided to never apply as much power to the motor as say the S or FX, then you could downsize the motor to save weight because it would never be pushed to the same current level as the larger motor. You might take ten lbs out of the bike that way (the Zero motor weighs 30 lbs). But if you ever increased power to the S or FX level then your motor would overheat. Not sure that's worth it.

If there's ever a big weight reduction in these bikes it will be batteries not the motor. We're getting 54 hp and 68 flbs out of 30 pounds of motor! Try that with an ICE.

Trikester

[Marshm]

Thanks for the explanation.  The savings would basically be the weight of a motor that had more capacity than what was needed.  I have a better understanding now.  If it were 10 pounds, I think that is actually quite a bit for dirt riding, but not really important for street.  Perhaps they found a pretty optimal power anyway.  From what I have read, people are pretty happy with it.  However somewhat confusing is that reviews compare it to 350 dirt bike and 600 twin street bike.  I think there is quite a bit of difference between those 2.  Maybe it is the broad range of torque with an electric motor that is what people are experiencing and thus giving comparisons like this. 

[trikester]

Comparing an electric powered bike to an ICE powered bike is never going to be very accurate because of the big difference in torque / hp vs RPM curves. The electric is not changing gears to achieve the desired performance and the ICE bike is changing gears.

I understand the desire to put electric drive in terms people are more familiar with since there is a lot more experience riding ICE powered bikes than electric. But the comparisons will always be very generalized and not well defined. It's the nature of the thing.

Maybe it is like comparing dogs and cats, some similarities but a lot of differences.

Trikester

[NoiseBoy]

Good point Trikester and a point I always make when discussing the acceleration of the Zero's is how repeatable it is.  On the 1/4 mile sprint (with a sweeping bend in it, not a drag) the 2012 bike was running time after time within 1/10th of a second.  The ICE bikes with experienced riders varied by 2 or more seconds on alot of the runs.

The 2013 S does 0-60 in about 5 seconds?  People tell me their R1 does it in 2.8 seconds but that is total nonsense, maybe on a drag strip with hot tyres and a top fuel level rider.   If someone on an R1 could get everything right with the clutch, throttle body position etc. to get to 60mph faster than the Zero 3 times in a row from the lights i would be very impressed.   On a Zero you just open the throttle and get perfect acceleration every time.   That has to be beneficial in racing too, especially motocross.  Not to mention how often you see enduro and MX riders stall their bikes in ruts etc.  Not with electric!

[trikester]

What I love in electric bike dirt trail riding is when I come upon a sudden steep pitch I don't need to think about whether I down shifted to a low enough gear to make it to the top without stalling. On the electric, I just twist the throttle more and go to the top. If I don't make it, it is because of tire traction, not torque (the reason I put bigger, more aggressive, tires on my Zeros).

Trikester

[dkw12002]

Exactly right about those claimed times on an ice bike. For someone to actually get an R1 to 60 mph in 2.8 seconds, it wouldn't be pretty...reving like crazy, popping the clutch and winding it up to 60 all in 1st gear at redline. If they did shift to 2nd, it would have to be flawless. I will go a step further cause I own a Gixxer 1000. I'm a fairly experienced rider and I am FASTER on the Zero 0-60 mph than I am on the Gixxer race bike. Top end is something else but you would likely NEVER have anyone beat you off the line in town on a Zero S. Part of that is they have no idea you are about to unleash 68 ft. lbs of torque cause there is no noise and by the time they know that you're way out ahead. Heck, it's one of my favorite things about the Zero S. It is FAST off the line, every time. Just twist the wrist.   

[emotofreak]

We drag raced an FX vs a new honda CRF 250 with a 1/2 dozen riders of various skill levels on both bikes. Regardless of rider skill level, the FX won EVERY time. Some of the good riders on the ICE bike could keep it sort of close. But a significant amount of time on the CRF people would get poor starts, stall the bike, or wheely too much. It was at that exact moment when I saw a total noobie smoking a pro on a CRF that I new I was watching the beginning of the end for ICE bikes.

"ProTip" Giving a bit of throttle and holding the brakes before launch, and then just releasing the brakes to launch buys you maybe a couple tenths...

[Doctorbass]

"ProTip" Giving a bit of throttle and holding the brakes before launch, and then just releasing the brakes to launch buys you maybe a couple tenths...

Yeah i also do that on my 2012. This avoid the delay between  the throttle signal and the controller output power. Engaging the throttle a little bit activate the controller wich no more have delay as long as throttle is engaged a bit!

[trikester]

It's going to be interesting to see how well my trike gets off the line. Even though it will be heavier than an FX and has one more wheel to push, it does have a lot of rear rubber contact and the front end should stay down. I hope my motor mounts can take the torque. 

One thing i know for sure, it's going to be a hot rod compared to the 200 cc ICE it used to be. I'll have to get used to that, but it is a good thing to get used to. 

Trikester