Le Toy II electric street bike

johnrobholmes said:
It also takes longer to lean from one direction to another. (seems odd since the center of mass should be similar to old position, maybe even more centralized)
It is harder to park at racks, since it is topheavy.
With the reduced front weight it wheelies a bit too easy now.
Click to expand...

If you go back to Endless Sphere I had posted a lot on a very involved thread about how center of mass effects handling. The mistake most people make is thinking that the axis of rotation is a constant at all speeds, but in fact the axis angle changes. The faster you go the more rotation occurs along the horizontal axis, while the slower you go the rotation occurs on an axis that goes from about the top of the front wheel (typically) to the contact patch of the rear wheel.

Anyway... we all kind of know intuitively that rear rack mounted battery ebikes are going to handle badly... but just how badly it really is can come as a shock. (no doubt)

You probably remember it:

http://endless-sphere.com/forums/viewtopic.php?f=3&t=5891&start=465&hilit=center+of+mass

file.php
 
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AussieJester said:
Cheers for the info on the tires/rims...i shall checkout the site you mention and also hit up some moped/scooter sites also...They definitely look the part MUST have hehee...OH..spokes...you would of had to drill out the stock bicycle hub holes to suit larger gauge spokes? This doesn't make the hub too much 'weaker' does it? like, there is still adequate "meat" on the hub so the spokes wont 'pul' out and break the hub?


Thanks again mate ;-)

KiM
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I chose my hubs specifically for drilling out. High flange downhill or street type hubs. The front is a marzocchi qr20 type. The rear I don't recall offhand, it is a cheaper one.

I did have to size up the holes a few, from 14ga to 10ga.

safe said:
If you go back to Endless Sphere I had posted a lot on a very involved thread about how center of mass effects handling. The mistake most people make is thinking that the axis of rotation is a constant at all speeds, but in fact the axis angle changes. The faster you go the more rotation occurs along the horizontal axis, while the slower you go the rotation occurs on an axis that goes from about the top of the front wheel (typically) to the contact path of the rear wheel.

Anyway... we all kind of know intuitively that rear rack mounted battery ebikes are going to handle badly... but just how badly it really is can come as a shock. (no doubt)

You probably remember it:

http://endless-sphere.com/forums/viewtopic.php?f=3&t=5891&start=465&hilit=center+of+mass
Click to expand...

I certainly do remember that long *** thread, and the handling changes significantly with speed. At higher speeds I didn't notice much difference, but at lower speeds I could feel the weight jacking the rear around. I typically use front brake only, unless entering a turn. Every time I hit the brakes I could perceive that weight behind my *** acting up.

For slow putting around the low slung weight would be great, for really fast corning higher weight would probably be best. For the way I ride my bike I need the weight centralized in the bike, otherwise I can't yank the bike around fast. I want to at least hop curbs at speed again.
 
As I recall the "saddlebag" location works pretty well for touring. Just getting the weight lower in the rear will help. However, a lot of the tricks that you do on a mountain bike require the balance to be just about perfectly in the middle.

There was a guy using the name "Tiberius" at Endless Sphere that mounted his batteries really high and forward and then entered a race in England and blew away the competition. He said he was really pleased with the way it handles at higher speed even though at slow speed it tended to fall over.

Higher weight locations will tend to rotate more easily in the front, but it will rotate less easily in the back. It really all comes back to those orthographic vector diagrams I had posted. In order to rotate a mass you need leverage from traction, but if the center of mass is offline of the natural rotation axis then the mass has to rotate itself in a semi circle which is the root of all the weird feeling behavior. It's a complicated topic that's for sure...
 
I am putting this particular build on hold for a while. I sold off the hub to a friend so he could get his ebike up and running. It will allow me to focus on other builds in the mean time, and put a fire to get them done. In the mean time I am riding around a 50cc gasser that gets 90mph. Sad but true, the gasser is less expensive to operate over the long term since I use Lipo batteries on my builds, and the initial cost of vehicle was rather low at $600 built.
 
LiPo and LiFePO4 are great performers, but expensive.

You might think about doing something like I did with NiCads and solderless tubes. The NiCads last a long time, are idiot proof, and the solderless tubes allow you to easily repair cells that go bad. (which they always do) The SubC size allows for 10C discharge rates, so that's an added plus, but I tend to use more like 3C at most.

Gasoline is better on the "bottom line" than electric.

It will take at least $4 gasoline before that changes...
 
I forgot...

Geez... when a guy that sells batteries decides to switch to gasoline then you know that the economic argument for "Going Green" is in the toilet. ("Going Obama?")

The Lipo and LiFe batteries are great as far as performance, but they are still expensive compared to NiCads. However, even when it comes to the NiCads the "special deal" that used to exist at All Battery has gotten more expensive.

What used to be:

100 NiCd Sub C 2200mAh Batteries for PowerTools No Tabs - $109

is now:

100 NiCd Sub C 2200mAh Batteries for PowerTools No Tabs - $160

...the price is going up not down.
 
safe said:
Geez... when a guy that sells batteries decides to switch to gasoline then you know that the economic argument for "Going Green" is in the toilet. ("Going Obama?")
Click to expand...


Nothing we didn't already know though Safe ...has always been the case, Electric is a hard sell simply due to the cost before you even get to the
complexities and range issues.. BUT...not everyone does it for the 'green' factor granted the majority do but there is a select few that
get a kick out of the performance...i believe you refer to them as "outlaws" :p I would have a watercooled 10hp 47cc pocket bike motor in a bike in a heart beat if i knew i could get away with it here, i can't i would be nabbed soon as i left the hills.

KiM
 
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Your reality "makes sense".

Given your ability to get the "free pass" with the "mobility scooter" it allows you to go infinite on the power side... as long as it's electric. Try to switch to gasoline and you lose your "free pass".

It still leaves the rest of us scratching our heads about the meaning of all this... I don't think that the expensive batteries are worth it for me, at least not now. Everyone keeps hoping that some breakthrough will occur where batteries suddenly become competitive with gasoline, but it just never happens.

Sport seems the only angle worth bothering with... so my "EBRR" concept is (though heavily ridiculed) actually the "most realistic" avenue to look into. The Go Kart guys are now getting pretty good at electric, so maybe Go Karts and EBRR machines can all race on the same tracks.

You saw this right?

Imagine that motor on your next machine!!!

http://www.greenmotorsport.com//products_and_services/3,1,388,17,12958.html

...they even say that the motor is for:

"Personal mobility vehicles"

...so you could use it. (36 hp for only about 36 lbs)
 
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The tradeoff is right at $4 per gallon for a lipo to break even on cost vs gas. LiFe generally does better than gas because of the much longer cycle life, but it depends on which cells you pick.

With the energy it takes to produce a battery, ship a battery, plus the charging energy, I can't say that I feel it is more "green" than an efficient guzzler. Would be an interesting study if you are into carbon footprints.



I am already started on another project. Actually two of them. One is converting my santa cruz Bullit to electric, and the other is making a series-parallel hybrid with a 50cc engine.
 
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