I am looking to build my first electric bike and I have some questions. First, let's use the most powerful setup, batteries and motor available. So, what would be the ideal setup? I weigh 170 lbs and am looking for a system that requires virtually no human powered assistance.
Would a 700c road bike build or a 26 inch mountain bike setup be faster/longer duration? I figure to house the battery pack in a backpack. I have several of each type of bike - high end stuff, very light and strong. As a cyclist, I realize some of the speeds talked about are extremely high, are they real? sustainable? How come I do not see any road (700c) bike conversions on high end race bikes?
Thank you in advance for your help!
Mike M
My thought for that is the skinny tires are not ideal for a motorized bike. It seems to me the fatter tires give a better grip on the road. In any case most conversion kits are for 20" or 26" and not 700c, for whatever reason.
They might be.. the faster you go the more wind resistance of course that you have to overcome. But another issue is that the typical bicycle brakes and wheels are NOT designed for that high a speed. For safety to go high speed motorized you should get wheels with beefy spokes and use disc brakes. But I keep thinking a high speed motorized bicycle is a) a motorcycle, and b) in most U.S. states would legally be considered a motorcycle and fall into a different legal jurisdiction than a bicycle.
I also notice that above 20 miles/hr the typical gearing isn't sufficient so that under motor power the rider can contribute any power to the ride (and their attempts to pedal are superfluous). It may be enough to have a really tall front chainring for the highest gear range.
- David Herron, The Long Tail Pipe, davidherron.com, 7gen.com, What is Reiki
I am going to just throw out some ideas here. Depending a lot on the hill situation, you may be able to get totally away from pedaling, but it's unlikely. Even the highest power ebike hub is relatively low in comparison to a gas powered scooter. If you want raw power, I'd go with some A123 cell pack or equivalent Lithium pack, a 40A controller or more, and either a BMC 600W hub or a Crystalyte 53xx series hub. Of course, this will cost in the thousands of dollar$, but you'll get a very powerful rig...
You could go the other way and get a Wilderness BL-36 kit for under $500. It will be heavy (due to the SLA batteries) and not terribly fast, but adequate (IMO).
You can also go somewhere in-between: Get a decent hub motor, a Crystalyte 408 series or equal, a 48V Ping LifePO4 battery, and a decent controller. You'll be going mid 20's on the flats, and minimal pedaling up the hills.... Bottom line, lots of choices. What is your terrain like hillwise? How fast do you wan to go? (I am an avid cyclist too, and sustained mid-20mph's is plenty for me...bikes aren't designed to hold much faster speeds)
700C wheels are larger than 26" bikes, therefore, for each turn of the hub motor you cover more ground. Therefore you'll go faster with a 700C. BUT...you also have a larger lever arm with a 700C, so that hill will put more load on the motor than the 26". The 26 will be better for hill climbing. In general, 26" wheels have more tire choices and seem to be more robust. There are kits for either. You can even buy a bare hub motor and have it laced to whatever size wheel you want it ...
Generally, with bikes the perception is that you don't need to drop much money on a strong bike, so there's no real need to use a high-end bike for a conversion. You will be carrying a lot more weight in general, so strong is considered better over light. If you have an old road bike, I don't see why you can't convert it. I have a vintage 70's steel schwinn that I'm considering for a geared front hub conversion. I like drop bars too. You'll find that, like in riding road bikes, wind resistance is one of your biggest problems.
One other thing. Duration, or distance you can cover is generally a function of your battery's Ah rating. Estimate ~1Ah/mile traveled and you'll be ok. For a 10 mile one-way trip, for example, estimate you'll need at least a 20Ah pack.
Here is a good link to another forum that has a ton of info...g'luck! http://endless-sphere.com/forums/index.php