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  1. superdave

    Non Suspension Bike Conversion

    Desired range, speed, and type of riding are the three things that shape donor selection for an ebike. Speed is the main factor in determining whether suspension is needed. Up to 20 MPH on-road is no problem on a non-suspension frame/fork. Faster than that, or lots of off-road use and suspension...
  2. superdave

    Your Creation's Before & After Pics

    I finally finished my second build and have been enjoying commuting with it for a couple weeks now. The goal was a short-distance commuter with good handling, and a clean look. If anyone is interested in details, let me know and I'll post a detailed write-up on the build. Unfortunately, I...
  3. superdave

    Do you need a e-brake?

    Nope, they're NO (normally open). Otherwise you couldn't run most controllers without an e-brake switch (or a jumper) connected.
  4. superdave

    The joy of wheelbuilding............

    Though I have the utmost respect for the late great Sheldon Brown, I found Steve Litt's webpage on wheelbuilding much easier to follow/comprehend: http://www.troubleshooters.com/bicycles/wheelbuilding/index.htm On the subject of interlacing Steve Litt writes "Interlacing makes the wheel stiffer...
  5. superdave

    What length spokes for a 9c motor and 29er rim

    I've heard good things about the Rhyno Lite rims, but never used one myself. That 612 ERD number (effective rim diameter) is what you'll need to calculate spoke length. The Ebikes.ca Spoke Length calculator (http://ebikes.ca/SpokeCalc.shtml) will do the rest. The only other thing you'll need to...
  6. superdave

    Magic Pie 1500W motor : Do I face the risk of radiation ?

    The media wants very badly to convince people that they're all going to die from non-ionizing radiation (i.e. EM fields). It's this type of radiation that has the OP concerned. What the OP needs to understand is the huge difference between the DC EM fields associated with an e-bike motor, ELF EM...
  7. superdave

    A new build, the same questions.

    An e-roadbike is possible, but keep in mind that steel framed pre '90s road bikes are about as stiff as overcooked pasta. That flexibility is one of their charms (helps absorb a lot of road vibration), but it will be problematic when motorized. If you're a strong rider, you can probably already...
  8. superdave

    steel vs alum ?Schwinn Transit -power this bike can handle?

    I wouldn't run a front hub motor on any typical consumer fork without torque arms. The steel forks won't get fatigue cracks in the drop-outs the way Al forks do, but that doesn't mean they won't spread and destroy themselves (and your motor's axle) if the nuts loosen. And thats assuming a 90's...
  9. superdave

    Magic Pie 1500W motor : Do I face the risk of radiation ?

    Step one to living a healthier, happier life: stop taking health and happiness advice from the mainstream media :) The stress of worrying about EM fields is doing far more damage to your health than would sleeping with 10 charging cell phones under your pillow. For what it's worth, much of that...
  10. superdave

    KU123 + 3 Speed Switch

    Maybe a silly question, but you do have a throttle connected, right? The speed switch works in conjunction with the throttle. The speed switch alone won't run the motor.
  11. superdave

    where can i find a v-break compatible 29" suspension fork ?

    I think you're getting some questionable fitting advice. First off, any LBS that says 2.5 cm makes no difference in sizing is either clueless or lying and you should avoid any future interaction with them. Second, raising the seat to get a more upright position doesn't make much sense. Lowering...
  12. superdave

    Stuck seat post driving me crazy!

    To understand why there are so few good mechanical solutions to the stuck seatpost problem, you need to look at the math. Let's say I can put a constant 100 lbs of force on the end of my 36" pipe wrench for a total of 300 ft lbs of torque. At the seat tube/post interface that's a force of about...
  13. superdave

    inexpensive motorized bicycle work stand

    Nice find. I've been looking for something like this -- never thought to check Walmart.
  14. superdave

    Stuck seat post driving me crazy!

    Amberwolf, if it's steel-in-steel, heat + penetrating oil is your best bet. Since the tube and post have the same coefficient of thermal expansion, the tube will expand slight more than the post. Not enough to make it loose, but enough to let the oil work in between where it can work its magic...
  15. superdave

    Stuck seat post driving me crazy!

    Four hacksaw blades and a very sore shoulder later ... Victory! Cutting out a section along the full length of the post did the trick. Though even with the section removed, it took the 36" pipe wrench to get enough torque to break it loose. Once I got movement, I was able to use penetrating...
  16. superdave

    Stuck seat post driving me crazy!

    Grease is better than nothing unless you have a CF setpost or frame. Oils often cause laminates to swell -- creating a problem instead of preventing it. When I finally get the old seatpost out, I'll be using Permatex anti-seize compound on the new one: That stuff is amazing for protecting...
  17. superdave

    Stuck seat post driving me crazy!

    I recently picked up an old cromoly frame mountain bike (an '87 Mongoose Altus) to use for my next ebike project. I figured the strong frame and big triangle (nice horizontal top tube) would make it an ideal donor, and I like the fact that it's a bit of a classic (Mongoose was a pretty respected...
  18. superdave

    Aluminum fork w/ front hub

    When it comes to fork failure, you need to look at torque, not power. A 500W geared hub is typically going to put a higher strain on a fork than a 500W DD hub. And of course with DD hubs, wind, size, etc. all affect how much torque your forks will see. I ran a 9c at 22A peak in a base level...
  19. superdave

    BMSBattery/ECityPower Experience

    I guess I lucked out. I ordered a Bafang BPM and KU controller from BMSBattery a few weeks back, picked the cheapest shipping option (FedEx CN) and it arrived in just a little over a week with no drama whatsoever. Shipping was crazy high, but item prices were crazy low so it was pretty obvious...
  20. superdave

    Anyone done a carbon fibre ebike ?

    Ti is actually a far better frame material (from a failure standpoint) than heat treated Al. Ti's properties (especially when it comes to fatigue) are similar to steel but with a higher tensile strength and lower density.
  21. superdave

    36V vs 48V

    I was lumping PWM limitations in as a form of controller current limiting. You're right that winding inductance also plays a role in determining impedance, but it doesn't change the conclusion that most motors at stall will sink way more current than the controller/battery can/will provide. So...
  22. superdave

    36V vs 48V

    I'll probably regret jumping in here, but ... The problem with steady-state formulas that gets everyone wrapped around the axle (pun intended :) ) is the incorrect notion that current (and therefore torque) is a constant during acceleration. While it's completely true that torque is only a...
  23. superdave

    New Build, New Builder, Noob questions.

    For on-road use at < 25 MPH, don't underestimate how nice a good steel road bike rides. On the street, my steel road bike rides much better than my aluminum hard-tail hybrid with a mid-grade front suspension fork. The things that would push me to want suspension are an Al frame, speeds > 25 MPH...
  24. superdave

    Is regen safe for Ebikekit 36V 9AH?

    Thanks for the suggestions. The Ebikekit support is very responsive, but their FAQ already says regen is not supported so I wouldn't expect an email response to say anything different. But having run my own business, I know that "not supported" doesn't necessarily mean "not possible" :) As time...
  25. superdave

    Is regen safe for Ebikekit 36V 9AH?

    I'm running a stock Ebikekit 9C setup with the 9AH LiFePO4 battery. This weekend I tried soldering the regen jumper in the controller and in a brief test it appears to work -- at least to the extent that the motor is providing a pretty strong braking force. I've seen some posts that indicate...
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