Hello all, Brian here with a project in progress. I have a adult size Stingray that I will be modding myself at home.
I have many questions and can show pics if needed. After looking over this and many other sites I have learned much, but now, I am even more puzzled about the viability of this project. A gentleman who seems quite inteligent on the Amped Bikes site states quite clearly that ebike motors are pedal assist only! He also states that kits sold with high wattage ratings are just overvolted, abused 500 watt motors. I have seen videos of 72 volt bikes hitting over 30 mph on level ground, with 500 watt motors. Well, it's time to ask the experts. My chopper has springer forks, so a front hub is a bad idea, right?
The bike weighs 45 pounds naked, I weigh 210 naked, oops, adding groceries, [on my back in a pack] batteries, lights, motor, all add up to about 400 pounds.
Next hurdle, the route will be about 20 miles with two 20 percent grades about one city block long. The last grade will be about a mile from home. Also the store isn't likely to let me recharge while I shop.
As if the water wasn't deep enough, I live in WI, so there will be days filled with snow, ice, and brutally cold -20+ temps that will bring out the wanderer in me.
Lastly, there's the dificulty of modding this bike to begin with, from the perspective of a guy with only one arm, and a bum leg. That should explain the need for power. I can't pedal the thing to begin with, but can ride it well downhill. Now, I'm not looking for speed, or brutal acceleration, but I need tourqe and range. I'm looking to get 20 mph, for 20 miles in all weather, with a 50 lb. load on my back. When you quit laughing, or shaking your heads,
I welcome your feedback. My tentative plans are for 48 volt LIFEPO4 30 AH cell in a framebag, between my knees. A 750 watt rear mount motor with disk brake setup. and a controller mounted to the back of the seat tube. My biggest issue is the rear dropout width is longer than standard. About 158.6 mm from inside of dropout to inside of dropout. A website selling replacement wheels for the bike states that the width is 177? mm from locknut to locknut. I read somewhere that this issue has been solved by at least one manufacturer. Also, I wish to keep my 4 in wide rear tire and rim involved as well. So I need to have a motor with disk brake, 12mm spokes, [ the biggest right?] and 4 inch wide rim, to fit a 20x4.25 tire. I sent an email to Crystalite earlier today asking if they would lace up a wide rim to a motor for me, but I forgot to stipulate the disk brake part.
I expect this project to take about a year to build, mainly due to limited funds.
Welcome to ES RallySTX,
My short, non-expert, answer would be to build on a bike that's more suitable for an e-conversion. You can often find a suitable steel framed MTB or Cruiser for less than a $100 (my first build started with a new $75 Walmart steel framed Road Master hard tailed MTB). You can also find some great deals on much higher quality used bikes for not much more than a hundred. You will, imo, need to go with at least a 48v lifepo4 battery of no less than 20ah/2C and a hub direct drive motor of 500-1000watts. I'd go with motor wound for good all-around torque and moderate speed (figure on a top speed of about 20mph) . You'll also need a controller that can handle at least 20-25 amps continuous (with a peak of about 30 amps). A Cycle Analyst would also be a big help in configuring the proper setup so as to meet your requirements.
Long answer would be to have an hub motor laced to your Stingray rim by an experienced e-bike shop (or mechanic). Ebike.ca, etc, should be able to "cut" a set of custom spokes for you. Excessive spoke angle could end up being your biggest problem with this "lace up" so, be sure to address this issue before you start.
Good luck and good riding!