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From: Zebee Johnstone on 22 Jul 2010 01:31
In aus.motorcycles on Wed, 21 Jul 2010 22:28:19 -0700 (PDT)
ross_w <rwonderley(a)gmail.com> wrote:
>
> I think these are still toys for now, but they'll suit someone with
> modest needs who might otherwise consider a 125, but then such people
> will have a budget of around $10,000 less.

On the other hand... a one make race series, say 5 laps, would be
hellish close racing.

Zebee
From: theo on 22 Jul 2010 05:18
On Jul 22, 1:28 pm, ross_w <rwonder...(a)gmail.com> wrote:
> On Jul 22, 1:25 pm, VTR250 <goo...(a)m-streeter.demon.co.uk> wrote:

> > Good point - I am concerned that the top speed is too close to the
> > limit.  One question I will be asking is if this is the advertised top
> > speed, what will its top speed be after a year?  My idea of a
> > nightmare is grinding along at 90 kph when all the other traffic wants
> > to do 100+.  I will need to have a look at one; it's not a petrol
> > engine so I'm led to believe performance at the top end is totally
> > unlike what you would expect from a petrol engine i.e. the time to
> > accelerate from 90 to 100 is quite short (?)  I think it can get the
> > front wheel off the ground at 70??  The torque does not reduce
> > significantly with speed - something to do with the internal workings
> > - this may be completely wrong. If that's the case the 105kph limit
> > might be due to the OBC.
>
> > I will put something in the forum if it's anything to write home
> > about.
>
> Actually the maximum torque of an electric motor is at zero rpm.
> That's why they don't need a gearbox, and the peak kW output is not
> directly comparable with a petrol engine. An electric motor that seems
> modest on paper will still give good acceleration from standstill.

That very much depends on the type of electric motor. E.g. a series
wound AC/DC motor does have max torque at zero revs but they are very
power inefficient, OTOH you could hold the shaft of a 3hp induction
motor (with a pair of multigrips, not your hand) and you'll find it
has damn-all torque at zero revs. Those are very efficient at speed
and have heaps of torque at near full revs. I have no idea what sort
of motor they put in electric vehicles.

Theo

From: F Murtz on 22 Jul 2010 11:21
Fraser Johnston wrote:
> "VTR250"<google(a)m-streeter.demon.co.uk> wrote in message
> news:5f31f2e1-889e-48ea-8a8c-939de933560a(a)n19g2000prf.googlegroups.com...
>
>
> I rejected Zero last time I looked at them (in 2009) but the 2010
> range has moved on a bit and I'm starting to wonder now. The main
> drawback of owning one is having to hire a Duke for the weekend to
> make it to Unagural or PI.
>
> I do about 70km per day and 17,000 km per year, all weather. Out of
> each 34 km commute, nearly 30 km is at 100kph which is basically the
> top speed and most of the rest is at 80kph. On paper, it can deliver
> exactly what I need. The question I have is: how long will this thing
> last? Part of me says 'go for it' and part of me is thinking 'don't
> buy one of the first 50,000 units'.
>
> ++++++++++++++++++++++++++++++++++++++++++++++++++++
>
> Personally I would go for a safety margin of at least 20% more than the top
> speed zone I was going to ride in. My VTR 250 was about the minimum I would
> ride now. Sometimes being able to keep the dickheads behind you is the safest
> way to ride.
>
> Fraser
>
>
I would be inclined to be more worried about distance between charges
and allow a large margin as my experience of most battery operated
things is they are at their optimum for a while then drop markedly.
From: VTR250 on 22 Jul 2010 18:49
On Jul 22, 3:28 pm, ross_w <rwonder...(a)gmail.com> wrote:
> <snip>
>
> There is another reason why the margin between top speed and your
> required speed is important. You don't think they worked out that 80km
> maximum range at top speed in a headwind with the lights on do you? If

Yes. It will also have to do the same old run when it is dark at 4pm,
with heavy sheets of rain being driven by powerful 70+ kph gusts of
wind.

> your commute is 70km a day, running at maximum part of the way means
> you might not get home unless you've got somewhere to plug it in at
> work.
>
> Then of course after a couple of years when the battery is no longer
> fresh...
>
> I think these are still toys for now, but they'll suit someone with
> modest needs who might otherwise consider a 125, but then such people
> will have a budget of around $10,000 less.

I'm inclined to agree it cannot meet my demands. Next year's model,
however...

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