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Lightest electric bikes



 
 
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  #1  
Old June 2nd 10, 04:59 AM posted to rec.bicycles.tech
spasmous2
external usenet poster
 
Posts: 2
Default Lightest electric bikes

I'm interested in getting one but don't get why they are so heavy.
I've seen some over 100 lb! When the battery runs out these things
can't be ridden.

Here's a (very) few moderate weight ones. The gocycle is light but
doesn't look like a bike and looks flimsy. The cytronex and kalkhoff
seem reasonable. Any others people know about?

32 lb
http://www.treehugger.com/files/2009...ric-assist.php

30 lb

http://www.cytronex.com/bikes.html

46 lb
http://store.kalkhoffusa.com/Product...ow=TechS pecs

Ads
  #2  
Old June 2nd 10, 05:11 AM posted to rec.bicycles.tech
Dan O
external usenet poster
 
Posts: 6,098
Default Lightest electric bikes

On Jun 1, 8:59 pm, spasmous2 wrote:
I'm interested in getting one but don't get why they are so heavy.
I've seen some over 100 lb! When the battery runs out these things
can't be ridden.

Here's a (very) few moderate weight ones. The gocycle is light but
doesn't look like a bike and looks flimsy. The cytronex and kalkhoff
seem reasonable. Any others people know about?

32 lbhttp://www.treehugger.com/files/2009/04/gocycle-electric-assist.php

30 lb


http://www.cytronex.com/bikes.html

46 lbhttp://store.kalkhoffusa.com/ProductDetails.asp?ProductCode=KA09PROC&...


Eat oatmeal. Push cranks.
  #3  
Old June 2nd 10, 05:24 AM posted to rec.bicycles.tech
AMuzi
external usenet poster
 
Posts: 13,447
Default Lightest electric bikes

spasmous2 wrote:
I'm interested in getting one but don't get why they are so heavy.
I've seen some over 100 lb! When the battery runs out these things
can't be ridden.

Here's a (very) few moderate weight ones. The gocycle is light but
doesn't look like a bike and looks flimsy. The cytronex and kalkhoff
seem reasonable. Any others people know about?

32 lb
http://www.treehugger.com/files/2009...ric-assist.php

30 lb

http://www.cytronex.com/bikes.html

46 lb
http://store.kalkhoffusa.com/Product...ow=TechS pecs


For a powered vehicle, hard to beat a Lotus Super Seven.
Quick, light, pretty too.

Otherwise, bicycles are actually enjoyable and a lot less
trouble. Mine's easily carried up a flight of stairs with no
effort at all.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971
  #4  
Old June 2nd 10, 07:39 AM posted to rec.bicycles.tech
spasmous2
external usenet poster
 
Posts: 2
Default Lightest electric bikes

On Jun 1, 9:24*pm, AMuzi wrote:
spasmous2 wrote:
I'm interested in getting one but don't get why they are so heavy.
I've seen some over 100 lb! When the battery runs out these things
can't be ridden.


Here's a (very) few moderate weight ones. The gocycle is light but
doesn't look like a bike and looks flimsy. The cytronex and kalkhoff
seem reasonable. Any others people know about?


32 lb
http://www.treehugger.com/files/2009...ric-assist.php


30 lb

http://www.cytronex.com/bikes.html


46 lb
http://store.kalkhoffusa.com/Product...Code=KA09PROC&....


For a powered vehicle, hard to beat a Lotus Super Seven.
Quick, light, pretty too.

Otherwise, bicycles are actually enjoyable and a lot less
trouble. Mine's easily carried up a flight of stairs with no
effort at all.


I rode a bike to work for a year, shivered in the AC every day, got
shingles. I love bikes, but I need to try something else for the
commute
  #5  
Old June 2nd 10, 09:05 AM posted to rec.bicycles.tech
Chalo
external usenet poster
 
Posts: 5,093
Default Lightest electric bikes

spasmous2 wrote:

I'm interested in getting one but don't get why they are so heavy.
I've seen some over 100 lb! When the battery runs out these things
can't be ridden.


Batteries have really poor energy density. So basically you have to
choose between a bike with good range, a bike with good performance,
or a lightweight bike.

Unless there is some horrible source of parasitic drag (not unheard of
in the e-bike world), it's just a really heavy bike. If you think a
60 pound 1950s balloon tire cruiser can't be ridden, well, that's your
call to make. But a dead e-bike is like that. It's maybe not a lot
of fun to ride home, but a damn sight easier than pushing the thing.

Some direct drive hub motors have an obnoxious amount of drag, to the
degree that you can pedal along with the thing, but pedaling it
unpowered is a huge chore. Others are not so bad. Geared hub motors
have one-way clutches that eliminate the drag losses of backdriving an
electric motor. So do most e-bikes with an external motor.

Another possible layout for an e-bike is a normal bike with a pusher
trailer containing both batteries and motor. At high power outputs,
this kind of vehicle has troublesome handling, but at modest e-bike
power levels it seems to work OK.

The gocycle is light but
doesn't look like a bike and looks flimsy. The cytronex and kalkhoff
seem reasonable. Any others people know about?


The Giant Twist Express weighs 48 actual pounds. It's the successor
to the well-respected Giant Lafree Lite, and it's much more refined
and iterated than most other electric bikes.

Chalo
  #6  
Old June 2nd 10, 11:37 AM posted to rec.bicycles.tech
Peter Cole[_2_]
external usenet poster
 
Posts: 4,572
Default Lightest electric bikes

Chalo wrote:
spasmous2 wrote:
I'm interested in getting one but don't get why they are so heavy.
I've seen some over 100 lb! When the battery runs out these things
can't be ridden.


Batteries have really poor energy density. So basically you have to
choose between a bike with good range, a bike with good performance,
or a lightweight bike.

Unless there is some horrible source of parasitic drag (not unheard of
in the e-bike world), it's just a really heavy bike. If you think a
60 pound 1950s balloon tire cruiser can't be ridden, well, that's your
call to make. But a dead e-bike is like that. It's maybe not a lot
of fun to ride home, but a damn sight easier than pushing the thing.

Some direct drive hub motors have an obnoxious amount of drag, to the
degree that you can pedal along with the thing, but pedaling it
unpowered is a huge chore. Others are not so bad. Geared hub motors
have one-way clutches that eliminate the drag losses of backdriving an
electric motor. So do most e-bikes with an external motor.

Another possible layout for an e-bike is a normal bike with a pusher
trailer containing both batteries and motor. At high power outputs,
this kind of vehicle has troublesome handling, but at modest e-bike
power levels it seems to work OK.

The gocycle is light but
doesn't look like a bike and looks flimsy. The cytronex and kalkhoff
seem reasonable. Any others people know about?


The Giant Twist Express weighs 48 actual pounds. It's the successor
to the well-respected Giant Lafree Lite, and it's much more refined
and iterated than most other electric bikes.

Chalo


Many of the e-bikes in the $1,000-1,500 price range seem to use
relatively heavy cruiser bikes with 10-15lb extra for motor, battery and
controller. At the other end of the spectrum, you have the Gruber --
~$2,500 for the add-on, which will add only ~5lb to a possibly sub-20lb
bike.
  #7  
Old June 2nd 10, 01:34 PM posted to rec.bicycles.tech
Peter Cole[_2_]
external usenet poster
 
Posts: 4,572
Default Lightest electric bikes

Chalo wrote:

Another possible layout for an e-bike is a normal bike with a pusher
trailer containing both batteries and motor. At high power outputs,
this kind of vehicle has troublesome handling, but at modest e-bike
power levels it seems to work OK.


I built an electric powered boat trailer last summer. I used a 450W/24V
motor with a reduction gear driving one trailer wheel. It uses a 9T
sprocket on the motor driving a 32T sprocket on the freewheel. The
trailer is long (16' boat), made of wood and couples to the seatpost. I
was surprised by how well it pushed up a hill, figuring the total weight
of me, my bike, trailer, batteries, boat and boat stuff at around 600
lb. I wouldn't nail the throttle with the trailer sharply turned, but
judicious throttle in sharp turns didn't seem to be a problem. Other
than sharp turns, I didn't find (or expect to find) any handling quirks.
A lightly loaded trailer might be different, but then I don't really see
the need for lots of power in that case. A seatpost mount seems to be
more or less in line with the center of mass (slightly below), so the
thrust wouldn't seem to torque you around. The only time I had problems
was when I negatively loaded the trailer tongue, got off the saddle and
had the rear wheel go up in the air and I couldn't hold the brakes on a
slope -- that was a little dicey. Making U-turns, even on a narrow
street, even with such a long trailer, wasn't particularly tricky.

I don't find that pulling a ~350lb trailer on the flats to be
particularly difficult, but even modest hills can be show stoppers and
accelerating from stops is slow -- that's pretty much the only place I
need assist, so I geared accordingly (~150 rpm max on wheel). Right now
my only problem is throwing the chain when I go over sharp bumps under
power. I didn't think I needed a chain tensioner/guide since I laid out
a minimal chain length. I turns out that under all that torque there's
enough deflection to skew the chain line enough. The short freewheel
teeth don't help either (running a #25 chain), don't know if I can find
a deep tooth 32 sprocket with freewheel.
  #8  
Old June 2nd 10, 03:35 PM posted to rec.bicycles.tech
Jay Beattie
external usenet poster
 
Posts: 4,322
Default Lightest electric bikes

On Jun 2, 5:34*am, Peter Cole wrote:
Chalo wrote:
Another possible layout for an e-bike is a normal bike with a pusher
trailer containing both batteries and motor. *At high power outputs,
this kind of vehicle has troublesome handling, but at modest e-bike
power levels it seems to work OK.


I built an electric powered boat trailer last summer. I used a 450W/24V
motor with a reduction gear driving one trailer wheel. It uses a 9T
sprocket on the motor driving a 32T sprocket on the freewheel. The
trailer is long (16' boat), made of wood and couples to the seatpost. I
was surprised by how well it pushed up a hill, figuring the total weight
of me, my bike, trailer, batteries, boat and boat stuff at around 600
lb. I wouldn't nail the throttle with the trailer sharply turned, but
judicious throttle in sharp turns didn't seem to be a problem. Other
than sharp turns, I didn't find (or expect to find) any handling quirks.
A lightly loaded trailer might be different, but then I don't really see
the need for lots of power in that case. A seatpost mount seems to be
more or less in line with the center of mass (slightly below), so the
thrust wouldn't seem to torque you around. The only time I had problems
was when I negatively loaded the trailer tongue, got off the saddle and
had the rear wheel go up in the air and I couldn't hold the brakes on a
slope -- that was a little dicey. Making U-turns, even on a narrow
street, even with such a long trailer, wasn't particularly tricky.

I don't find that pulling a ~350lb trailer on the flats to be
particularly difficult, but even modest hills can be show stoppers and
accelerating from stops is slow -- that's pretty much the only place I
need assist, so I geared accordingly (~150 rpm max on wheel). Right now
my only problem is throwing the chain when I go over sharp bumps under
power. I didn't think I needed a chain tensioner/guide since I laid out
a minimal chain length. I turns out that under all that torque there's
enough deflection to skew the chain line enough. The short freewheel
teeth don't help either (running a #25 chain), don't know if I can find
a deep tooth 32 sprocket with freewheel.


These bikes are popping up around PDX, although the article does not
really tell how the motor is set up. I was looking at one the other
day operated by Portland Roasting Company, and it looked pretty cool
-- probably hauling 600lbs of stuff. http://b-linepdx.com/press/bikeportland-2009-04/
-- Jay Beattie.
  #9  
Old June 2nd 10, 06:57 PM posted to rec.bicycles.tech
(PeteCresswell)
external usenet poster
 
Posts: 2,790
Default Lightest electric bikes

Per spasmous2:
I'm interested in getting one but don't get why they are so heavy.
I've seen some over 100 lb! When the battery runs out these things
can't be ridden.

Here's a (very) few moderate weight ones. The gocycle is light but
doesn't look like a bike and looks flimsy. The cytronex and kalkhoff
seem reasonable. Any others people know about?

32 lb
http://www.treehugger.com/files/2009...ric-assist.php

30 lb

http://www.cytronex.com/bikes.html

46 lb
http://store.kalkhoffusa.com/Product...ow=TechS pecs



Gocycle looks pretty slick to me, but I didn't even look at the
price....

You can convert a beater bike using a FWD motor.

I do that during the winter with my Surly 1x1 in order to avoid
mouth breathing-induced bronchitis. I use the electric assist
only on hills to avoid mouth breathing.

Main problem with ebikes is the battery weight. I hear that
better days are coming - something about batteries that use
atmospheric air as part of the process and weigh about 1/7th what
Lithium batteries weigh today.

Since I use so little battery, I get along with a couple of
DeWalt 36v power tool packs. IIRC, I get away with about 36 lbs.

The conversion route isn't that hard, but there is definitely are
a few things one has to know beforehand.
--
PeteCresswell
  #10  
Old June 2nd 10, 08:41 PM posted to rec.bicycles.tech
AMuzi
external usenet poster
 
Posts: 13,447
Default Lightest electric bikes

spasmous2 wrote:
On Jun 1, 9:24 pm, AMuzi wrote:
spasmous2 wrote:
I'm interested in getting one but don't get why they are so heavy.
I've seen some over 100 lb! When the battery runs out these things
can't be ridden.
Here's a (very) few moderate weight ones. The gocycle is light but
doesn't look like a bike and looks flimsy. The cytronex and kalkhoff
seem reasonable. Any others people know about?
32 lb
http://www.treehugger.com/files/2009...ric-assist.php
30 lb
http://www.cytronex.com/bikes.html
46 lb
http://store.kalkhoffusa.com/Product...Code=KA09PROC&...

For a powered vehicle, hard to beat a Lotus Super Seven.
Quick, light, pretty too.

Otherwise, bicycles are actually enjoyable and a lot less
trouble. Mine's easily carried up a flight of stairs with no
effort at all.


I rode a bike to work for a year, shivered in the AC every day, got
shingles. I love bikes, but I need to try something else for the
commute


Ouch.

Someone of my acquaintance reports that's now quite
manageable with modern antivirals.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971
 




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