Currently a hub user. Which way should I go?

D

drewdiller

100 W
Joined
Nov 5, 2009
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172
I ride on a single speed Cute 128 rear hub with an Infineon controller. It tops out at 16 mph and I worry about driving it hard up hills (and, I wish it had more torque for more serious hill climbing ability).

I want to build another e-bike. This will be a snow e-bike, I want it trail worthy in November. Here is the bike I plan on buying, a TommiSea Terrain Destroyer. It's like a less expensive, less complicated version of a Surly Pugsley:

http://forums.mtbr.com/showpost.php?p=7054694&postcount=10 (I hope you are able to see it, I am logged in at the mtbr forums.)

Look at that huge space in between the rear tire, chain stays, and seat tube.

WHAT TO DO WITH ALL THAT WASTED SPACE**?
** sarcasm

Things that have occurred to me (keeping in mind that this is already a heavy bike, there is a lot of rim and rubber going on there, I believe 35 lbs as a single speed):

A) Run a cyclone kit through a NuVinci N360 hub.
  • Pro: Power through gear ratios.
  • Con: Noisy, I think. Haven't heard one in person.
  • Con: Heavy (5.5 lb hub, 6 lb motor, plus battery).
B) Reuse my Cute 128 hub in a two-chain drive located in the aforementioned empty space, again mated to a NuVinci N360.
  • Pro: Power through gear ratios.
  • Pro: Conservation-minded.
  • Pro: Not silent, but acceptably quiet, can't be heard 20 feet away.
  • Con: Heavy, same as (A).
  • Con: Uncharted territory, would have to make a custom mount.
  • Con: How the heck to solve problem of driving two chains? Can get a freewheeling crank, but wouldn't a fixed cog just unscrew itself under load?
C) Screw all the notions of gearing and use the space to mount a Grinhill ripoff build.
  • Pro: Light!
  • Con: Uncharted territory, never done RC before.
  • Con: Noisy? Haven't heard it.
D) Something else?

Thoughts?
 
Drew, couldn't see the pictures, but, if I had what you have to work with I would go with your middle option. i.e., use the Cute motor as a mid drive with a multi-speed hub. I wouldn't bother with two chains, just lengthen your original chain to go up around a sprockett on the motor. probably need to add an idler between the motor and your chainring, probably work that out when you design your motor bracket. Might not need a tensioner if the idler is adjustable to take up the slack.

The Stoke Monkey guys say you don't need a freewheel on your chainring, but I tried without it and didn't like it. Much happier with the freewheel. As far as I know the Cute has a built in freewheel, so no issue there.

You are right, the "track" cog you screw onto the motor will unscrew when the motor runs. Use a lockring (from an old bottom bracket) along with some locktite. I understand some guys convert bikes to fixees using this method, and the lockring has to resist their braking forces when they push back on the pedals. Also might be able to drill a set screw into the track cog.

Whatever you decide to do, good luck. :D
 
This image should work (credit to this guy's blog):

Dscf0179.jpg
 
Recupence reduction drive would slot in that space in front of the rear wheel nicely...
RC setup is more difficult than the other options but you will be blown away
by how light and powerful the end product is, still amazes me the power these
rc motors have for their size, its ridiculous something smaller than a coke can
puts out 8hp.

Best of luck...

KiM
 
how many volts? What is the wattage of your controller?

I've played with a cute128 front motor with a 44v lipo pack and a 500 watt controller and got pretty good performance. it had a top speed of about 26 mph and could climb a pretty steep hill (slowly). I think 16 mph is a little low-- but the cute 128 rear motors are rated for 350watts instead of the 500 watt for the front versions.

Honestly, i don't like the cute motor for power applications because the phase wires are too thin-- in my opinion. For serious hill climbing, go with a brushless, gearless hub with a high voltage (at least 48v) controller. Plan on consuming at least 35 amps.
 
jondoh said:
how many volts? What is the wattage of your controller?
Click to expand...
36V Headway pack, 22A controller, so about 800W peak.

At its top speed - 16mph / flat ground / no wind - it consumes 200 to 250W.
 
The little cutie isn't going to have enough power to get you thru the snow, except at near walking speeds, which may not be a bad idea in the snow and ice.

Love the bike. I need to do something similar with nice fat tires.
 
John in CR said:
The little cutie isn't going to have enough power to get you thru the snow, except at near walking speeds, which may not be a bad idea in the snow and ice.
Click to expand...
Right. I wish I had two throttle modes. One "normal" and one "tractor". There are some modes of ice that are dangerous even with studded tires. This is usually in the spring, when the ice thaws in the day, pools again, and freezes again at night. This ice is both wet and untextured. I'd love to put a foot down, have the throttle be a lot less sensitive, and just motor through as a tripod. But I'd also love to able to switch back, and just over accelerate up a long snowy incline with the rear end fishtailing all over the place... because it'd be fun. :D
 
what did that bike in the picture run over something? looks a bit like a fetal pig or feral pig not sure!!!!

I would get a nine c. cooling wont be a problem with all the snow on the motor casing. big hills big ev grin!!!!
 
Nice frame!

Great place to put battery packs, motors and controllers in the front and rear triangles. The very long frame should give more stability at higher speeds and better front braking power.

I've always loved the Surly Pugsley but wanted front suspension. Now that "29er" forks are made with 140mm travel and wider with 120mm x 20mm axles, I wonder if one of those wider forks on the wider 120mm hub would clear the very tall and wide 26x3.7" Endomorph tires? Found a place online that uses "tandem rated" suspension fork of the dual crown style that should squeeze in the tire. My Rock Shox J4 fork juuuuust clears a 26x3.0 knobby tire with a 100mm wide hub, I think a 120mm wide axle being 0.8 inches wider should clear the less knobby 3.7" Endomorph.

You can find the dual crown, tandem rated "29er" forks at this site http://www.mtbtandems.com/Forks.html#anchor34938
I like the Risse with 6" (152mm) of travel and 120x20mm axle.
 
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