For me, it really is that a bunch of little things add up to make the tranny not worth the effort on a motorcycle. If it were easy, didn't take up any space, and added no weight than the benefits would be worth it. I do have the transmission in my electric truck. It allows me to get reasonable performance out of a motor that is barely bigger than the one on my motorcycle with a controller that only has 50% more power. In this implementation it is an easy winner. I'm not sure how well the efficiency argument holds up in real life. Yes it allows you to draw less current which can be a way to improve efficiency, but it also adds weight, rotational mass, and drivetrain efficiency losses. I suspect that some implementations would prove more efficient while others would not. I'm fairly confident that any CVT solution would decrease range. Plus you have to figure in the fun factor :-) Once you are able to accelerate faster, are you still going to ride like you were forced to without the transmission? Ooops there went your amps :-) damon> Date: Fri, 4 Apr 2008 11:01:09 -0600> From: [EMAIL PROTECTED]> To: [email protected]> Subject: Re: [ElectricMotorcycles] CVTs vs trannys and power shifting> > My personal pursuit of a CVT or std.trans was to keep the motor rpm> up, current draw reasonable and sacrifice some speed going up a hill,> similar to the little car with a little engine, or a cyclist> conquering steep hills. Now I know electric motors have this flat> power thing going, but if we're trying to maximize our range I think> the transmission can make a difference. EVs cars trucks do use the> trans and not just because it is there, but because of the ability of> the trans to multiply the available power.> > The trans should prevent precious amps from turning into heat (waste).> If you live on the flats a single speed is probably okay. The two> times I have done 21 miles on a charge had few hills in the mix, more> like very gradual rises. Now if you could extend the wheel base (oops> I am the one doesn't like that, shoot!) move the swing arm back to> accomodate the smallest separate trans (sportster, brit bike) and use> two gears maybe the range can be stretched a little?> > Jeff> > On Thu, Apr 3, 2008 at 6:55 PM, damon henry <[EMAIL PROTECTED]> wrote:> >> >> > Once you spring for a Zilla, the point is moot. The only reason for a> > transmission is to try to get good acceleration and a high top end out of a> > moderate motor controller combo. A Zilla has plenty of overhead to> > accomplish this with a single motor... unless of course you are talking> > about Killacycle type performance. I don't think anyone on this list has a> > bike that even the lowly Z1K low voltage (156 volts) model couldn't make> > scary fast from 0 to 80+ mph. The problem is most on this list are dealing> > with 48 or 72 volt controllers in the 300 to 400 amp range and a single gear> > ratio which means you have to choose between good acceleration or a higher> > top end. Multiple gears could give you both with a much smaller cheaper> > controller.> >> > Don't get me wrong, think your solution is the correct one because it is> > the least complicated least space solution. I just don't think multiple> > motors and parallel shifting are necessary on anything short of a drag bike.> > If you really want more performance forget the transmission and buy a> > stronger controller with a motor that matches. Any of the common 6.7 inch> > series wound motors and above should be up to the task of dealing with more> > powerful controllers.> >> > damon> >> >> > ________________________________> > Date: Thu, 3 Apr 2008 20:36:30 -0400> > From: [EMAIL PROTECTED]> > To: [email protected]> > Subject: Re: [ElectricMotorcycles] CVTs vs trannys and power shifting> >> >> >> >> > I think if you look closely you'll see a sport bike transmission is so> > tightly packaged you won't have room to fit covers and seals to close it up.> > Not to mention carving away the engine side of the cases and mounting the> > resulting metal potato.> >> > How about a completely different approach - why not get the effect of a> > transmission with electronics? A Zilla controller will properly (important> > concept) shift two motors from series to parallel and back. If you have two> > motors they can each be smaller than a single motor. I'm thinking the ADC> > 5.5" series looks promising. Jim Husted might be able to dig up something> > even more suitable.> >> > There are a number of advantages with this idea. More comm area, "shifting"> > is ultra smooth because there is no change in rotational speeds, and the> > mechanical implementation is WAY easier. It is no doubt pricey (less so if> > you scrounge), but you might spend more in custom machining and reworking to> > adapt a transmission. It should be pretty easy to get a two-motor setup to> > work well first time out.> >> > One important consideration: The S-P shift can be made automatic for cars> > (senses current draw and shifts at a programmable point), but you want it to> > be manual on an EM. The shift results in a step-change in rear wheel power> > that could mess with your traction. Better to treat it like a normal two> > speed transmission that you shift, just like any other motorcycle. Except> > there are no gears.> >> > When you think about it, this achieves exactly the same thing for an EM that> > a gearbox does for an ICE. Gears on an EV are not typically the best> > solution. When we use them it's usually only because they came with the> > donor.> >> > Chris> >> > On Thu, Apr 3, 2008 at 2:25 PM, john fisher <[EMAIL PROTECTED]> wrote:> >> >> > > As to using a sport bike trans, that would be an idea. The only> > > oiling for the trans is a splash oil. The shafts run on ball> > > bearings. So if you could enclose the case, you'd be all set.> >> > yeah I was assuming enough skill to be able to close up the box to keep oil> > inside.> >> > ________________________________> > Use video conversation to talk face-to-face with Windows Live Messenger. Get> > started!> _________________________________________________________________ Use video conversation to talk face-to-face with Windows Live Messenger. http://www.windowslive.com/messenger/connect_your_way.html?ocid=TXT_TAGLM_WL_Refresh_messenger_video_042008
