Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Electric Bikes Here's a place to discuss ebikes, from home grown to high-tech.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 12-17-09, 02:38 PM   #1
jawnn
Senior Member
Thread Starter
 
jawnn's Avatar
 
Join Date: Aug 2004
Bikes:
Posts: 410
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Question Ecospeed with NuVinci gears?

I am trying to find out if a 500watt motor connected to the drive chain like the Ecospeed motors will move 450 lbs up a 16% grade when using a NuVinci continuously variable gear hub. With out over powering the motorÖthat is I donít see how the motor can run fast enough to keep from over heating. 2 or 3 mph will be enough for a trike but no less than 3mph for a bike with trailer.

I climb these hills with 400lbs less than 2mph, by leg power alone. I tried using Sheldon Browns gear calculator but it did donít explain what the number are.


This is what I do with my legs and gears that I have.

18 front / 34 rear sprockets = 1 to .53 ratio .............
60 rpmís at the crank x (.53) = 31.76wheel rpm's..............
62.8Ē circumference x 31.76 rpm's = 1994.82 ipm ..............
Divided by 12 = 166.235 fpm ..........
166.235 x 60 minutes = 9974.117 fph ............
Divided by 5280 = 1.889 mph.........

my blog is called 'commuter cycling technology' if any wants to see where I'm coming from.
jawnn is offline   Reply With Quote
Old 12-17-09, 03:08 PM   #2
Allen
Senior Member
 
Join Date: Sep 2005
Bikes:
Posts: 4,749
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I don't have a grade that steep but I've pulled 400 + on my Giant Twist (inline motor) and a NuVinci.
The Giant has a 350 watt motor and it does not overheat.
Allen is offline   Reply With Quote
Old 12-17-09, 07:54 PM   #3
misslexi
Senior Member
 
misslexi's Avatar
 
Join Date: Aug 2008
Bikes:
Posts: 218
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I guess it depends on how you couple the motor to the load. You want the motor running at it's most efficient speed, if you are at a point where the motor is running too fast, it's time to gear down. If by doing that you aren't moving at the right speed then the coupling gears aren't right. Not to state the obvious but the Ecospeed system's motor does not directly drive the bike's gears.
misslexi is offline   Reply With Quote
Old 12-28-09, 01:14 PM   #4
jawnn
Senior Member
Thread Starter
 
jawnn's Avatar
 
Join Date: Aug 2004
Bikes:
Posts: 410
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
what grade?

what grade do you think it may be? you could messure it with a level and a ruller. My hill is 3.2 " rise over a 20 " span.


Quote:
Originally Posted by AllenG View Post
I don't have a grade that steep but I've pulled 400 + on my Giant Twist (inline motor) and a NuVinci.
The Giant has a 350 watt motor and it does not overheat.
jawnn is offline   Reply With Quote
Old 12-30-09, 03:10 PM   #5
crackerdog
Senior Member
 
Join Date: Mar 2008
Location: Port Townsend, WA
Bikes: xtracycle, electric recumbent, downtube folder and more
Posts: 982
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Jawnn, that small bike you tried a year ago or so was a 500 watt motor. Since it was driving the gears, I would imagine it would be in the same ballpark.
crackerdog is offline   Reply With Quote
Old 02-13-10, 01:35 PM   #6
jawnn
Senior Member
Thread Starter
 
jawnn's Avatar
 
Join Date: Aug 2004
Bikes:
Posts: 410
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
The Nuvinci gear-hubs for bicycles are worse than useless, they can't handle more than 26 gear-inches of torque with human legs meaning that any motor will make them slip. :shout:

The maximum torque before it starts slipping is 130Nm or 96 LbFT . One wheel revolution to one crank revolution is the lowest gear possible.


Some one told me they saw a video of some guy jumping on the pedals, and thought that it showed how strong the thing is. All it really shows is that it takes much more leverage to move in higher gear. And it shows how strong the chain is; I have torn chain links just climbing hills in low gear.

However there is an application that my be useful; let the motor do the job of bringing the bike up to a speed that you can pedal in high gear. the motor will have to be connected to the other side of the wheel.
jawnn is offline   Reply With Quote
Old 02-13-10, 02:27 PM   #7
Allen
Senior Member
 
Join Date: Sep 2005
Bikes:
Posts: 4,749
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Not my experience with them.
Mine has never slipped and I have an inline motor.

Where are you getting your information?
Allen is offline   Reply With Quote
Old 02-13-10, 02:27 PM   #8
Allen
Senior Member
 
Join Date: Sep 2005
Bikes:
Posts: 4,749
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Not my experience with them.
Mine has never slipped and I have an inline motor.

Where are you getting your information?
Allen is offline   Reply With Quote
Old 02-24-10, 01:45 PM   #9
jawnn
Senior Member
Thread Starter
 
jawnn's Avatar
 
Join Date: Aug 2004
Bikes:
Posts: 410
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Exclamation info? where?

I am not getting enough info....from any where.....I can't find photos of the nuvicni set up for steep hills because every one concentrates on speed not hills.

Even the manufacturer will not give me what I need.
jawnn is offline   Reply With Quote
Old 02-24-10, 03:28 PM   #10
Llamero
Senior Member
 
Join Date: Oct 2009
Bikes:
Posts: 179
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I can't remember where, but I found a trike manufacturer that sells gas/electric trikes with Nuvinci and Rholoff transmissions. However, the manufacturer puts both of these hubs into the drive train rather than the rear wheel, most likely to keep the torque within reasonable specs on the transmissions themselves.
Llamero is offline   Reply With Quote
Old 02-24-10, 03:31 PM   #11
Llamero
Senior Member
 
Join Date: Oct 2009
Bikes:
Posts: 179
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Here's the link to the NuVinci gas powered trike: http://www.utahtrikes.com/RECENTTRIK..._Gas_Quad.html The electric/Rholoff variants are just elsewhere on the site.
Llamero is offline   Reply With Quote
Old 02-24-10, 04:56 PM   #12
Allen
Senior Member
 
Join Date: Sep 2005
Bikes:
Posts: 4,749
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
http://www.bikeforums.net/showthread...i-gearless-hub
You got several in depth answers to your cross posting of this thread in the Utility section.
Allen is offline   Reply With Quote
Old 02-24-10, 06:15 PM   #13
CowtownPeddler
Senior Member
 
CowtownPeddler's Avatar
 
Join Date: Feb 2010
Location: Calgary
Bikes: Old Norco frame in conversion process
Posts: 110
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
An idea for measureing grade would be to use a piece of string. Make a big loop and secure two points on the hill with some weight, make a triangle of the string and then it's a matter of geometry. If you use a plumb bob for the downhill side and line its line with the string "triangle", it should be easy to mark the anchor points and the angle on the downhill side. Once there, A^2 + B^2 = the length along the ground, then use trig to get the angle of the slope.

Attached Images
File Type: jpg measure.JPG (10.2 KB, 2 views)
CowtownPeddler is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 06:51 AM.