Well, anything that could be removed in an hour and didn't require permanent modifications to my bike would be acceptable.Do you mean removed *quickly*? There are tons of add-on motor kits out there, but most of them require at least 30 minutes and significant tools to install/remove.
Here ya go...
I regularly remove it in under 5 minutes with a hex key and a screwdriver. Three screws and a hose clamp for the motor and mount. Pull three electrical connections and un-velcro the battery bag. I leave the chain ring and throttle.
Cost me $400. Adds 5 1/2 Lb total. Up to 450 watts. It really gives a nice assist up Northern California hills, and is imperceptible on the downhills.
View attachment 1247936
Of course it is DIY...
All parts are off the shelf except the motor bracket. Does require wiring (soldering). In 10 years, if anything fails, all parts are generic. (I'm curious to see what happens in 10 years when a Levo PCB frys...)
The bike works very well! If you are seriously interested in building something like this, then I would suggest that you skim the build thread on Endless Sphere, and ask questions there. It would also be worthwhile to follow the recipe (there are Very Good Reasons!) and Make No Substitutions on critical (most) components. That way you get to take advantage of some actual engineering and development. At least read the Bill of Materials post on page 4.This is exactly (well almost exactly) what I was wishing for too.
Turnigy D2836/8 1100KV Brushless Outrunner Motor $15.02, up to 336W
Turnigy Plush 30amp Speed Controller $14.18
Vktech Gold-plated Bullet Connector (3.5 mm 40pcs) $8.99
What battery? Does it have to be 12V to fall within the 7.4 - 14.85 V motor volt range? Or can it be compatible with a more normal Li+ 24V 250W battery?
You think an LBS that works on e-bikes would even attempt to do this for someone? I guess I can get my stepson to do it for a few $$, he has a soldering kit and builds his own computers so this shouldn't be hard for him.
The bike works very well! If you are seriously interested in building something like this, then I would suggest that you skim the build thread on Endless Sphere, and ask questions there. It would also be worthwhile to follow the recipe (there are Very Good Reasons!) and Make No Substitutions on critical (most) components. That way you get to take advantage of some actual engineering and development. At least read the Bill of Materials post on page 4.
I'm sure your stepson could solder everything together and set up the speed controller. He would need a cheap heavy soldering iron to do the power connections. The motor mount would be the tricky part, as all bikes are different. I could post up some drawings over on ES, and i'm sure you could find a small machine shop that could finesse the details and attach the motor to your bike.
If you have the ability to replace a chain, replace front chain rings, and tune a derailleur, you could do the rest. Otherwise, an E-Bike shop might come in handy.
Just FYI - The motor you selected will spin the PEDALS at 500 RPM, but with no power at all...
Some criticisms if this:
Seriously, no one in their right mind should be interested in this; perfect for ES, not a good topic for MTBR. An abomination, and I'd advise that any posting that advocates unprotected LiPo on an e-bike is out of bounds. Bikes, not bombs.
- an unprotected and unmanaged LiPo pack lacking required protective structure, yet being evangelized to the naive, terrible, unsafe
- less than 100 Wh, grossly inadequate for many riders, easy to be light weight when there's no battery
- lack of PAS, along with advocacy for removing the throttle in favor of an on/off button! is that a joke?
- no means of locating the chain in the proper plane, along with use of a chain not designed to tolerate it
- no chain tensioner
- lack of freewheel meaning the motor creates drag while pedaling, mitigated by how small and ineffectual the motor is
- 9T cog wears like cheese, as evidenced in the ES thread already
Thanks for the compliment! I already have sufficient patents, and don't want to hassle with it.... $10K to 30K and 1-3 years... Sounds like work...FZ, you should try to patent something like this, it has way more potential than you even realize. If you or someone else can get it to the point where the chain / motor / battery can be removed within 1-2 minutes, it would be a great alternative to a mid-drive because you remove those three components and you have a perfectly normal bike that just has a large chainring on the other side. And then riders, instead of having to shuttle with two trucks, can simply ride back up faster after they are done with a long downhill session. They ride down without the components and then slap them on at the bottom. These would sell like hotcakes because they are light, cheap, and easy to take off and put in a pack.
What I'd personally like to do (and even sell on Amazon, etc.) if I had more mechanical skills:
1. Chain guard on large chainring
2. Remote wireless throttle or push button on/off for watts, no wires from the handlebar, only from/to the battery
3. Chain that's easy to remove, with a user-friendly missing link that you push in and quickly break & put in pack
4. Cassette-based 0.5 lb LiPo battery, plugged in securely to some type of housing attached to one of the tubes. I'm calculating about 2.5 miles worth of battery uphill at 250W, is that in the ballpark? The kit could come with maybe 5-6 of these batteries that you simply plug in to the housing (kind of like printer ink) and then connect the battery wire to the motor in seconds
5. Kit bag with all components, extra batteries, motor, chain, any screwdrivers, etc. for attaching at the bottom of the mountain
If someone could make a kit like that for around $250 that weighed under 10 lbs with the extra batteries...