700c Road Bike / Commuter Project

I don't understand why adding a torque arm into the design would cause electrocution.
It must be a flawed design then, if it can rotate in the dropouts and can cause electrocution of the rider. Glad I ride a 2x gas engine.
 
heavy duty track bike 700c $189

http://www.jensonusa.com/store/product/BI276L02-Se+Bikes+Draft+Lite+Fixed+Gear+Bike+09.aspx

bi276l02.jpg


You could put a Grubee on this! 26# with heavy duty 36hole wheels and high flange hubs.

Keep in mind the narrower frame spacing though. you might need a 36 tooth to clear the frame.

Either way, I bet this thing would be scary fast.

If you have machining experience, I bet you could bolt or weld a 36 tooth grubee chainring to a track cog.

Or you could rebuild with a HD type wheel if the frame will clear it. Its hi tensile steel, so you could probably bend it out a little.

You can use track tensioners on this frame! Oh wouldn't that be a joy vs axle creep?
 
Happy. the original bike was designed for human power and the addition of 500 to 1000 (or more)watts has to go somewhere and the poor frame dropouts just can't take the torque, therefore you add the reinforement with a torque arm to prevent the dropouts from spreading out and allowing the wheel to spin in the dropouts. If the motor did spin in the dropouts the wires for power and throttle would get tangled up and MAY cause a direct short that could be felt by the rider. (OUCH !!)
 
Tanaka, ok, we are getting our signals crossed. I support the addition of or inclusion of a torque arm in the design. I thought you were saying somehow that using the torque arm could cause dropout failure.

I understand what could happen if one is not used. Do most Ebike hubs have or not have a torque arm?

I suppose if yours doesn't, you could flat the axle BMX style and make a corresponding filed-wide hole in a flat stock piece that you whittle down for the purpose, and secure with hose clamps or those electrical conduit clamps that are popular for making idler braces.

If you have access to a welder or a generous friend with the same, it wouldn't be hard to replace the conventional dropouts on most frames with a piece of thicker steel. Plus you could convert to vertical dropouts or track forks at the same time.
 
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most kits, dont have a torque arm when you purchase the kit, you get a torque washer which fits the wheels axle and that in turn slips into the dropouts on the bike. I have built and owned a few e bikes before i went gas, always had a torque arm never got electri- fried !!!!! Adding a torque arm does not increase your chances of getting fried , loose wiring in the motor that comes into contact with the steel frame might make it happen....

Torgue arms are a valuable addition to any electric kit, last thing you want to see is your wheel spinning off or ripping from your dropouts, the wheel in turn will rip your wires apart (FACEPLANT ANYBODY !!!!) and ruin your kit.

I have had kits on alumi bikes too, so long as your careful and dont blast the throttle from a standstill ,they work just as fine as steel forks.

The reason for more 26 inch kits.... easy answer... more 26 inch bikes and universal parts, 700c ( road bikes racers mostly) more specialized size and you have to hit the bike store for specfic parts.

I am about to build another bike for a friend in a week or so, 36 volt kit with a nice ping lipo4 20ah battery, just waiting for the parts to come in and then find a good donor on craigs list....should be a sweet ride at a sweet price, man i could build my dream cruiser for the cost !!!!

DUI cost him his license for another 2 years so realibilty is what i am aiming for.
 
MODERATION and proper parts choice is the key for a road type bike.
I have a Jamis Nova 21" >steel< cyclocross frame,
with 700c Sun dual wall 36 spoke stainless steel eyelet aluminum rims, shimano disc brake front hub
(modified Xt series)with 160mm avid bb7 rotors and calipers.
I run 42/52 tooth chain rings, hollow tech bottom bracket and hollow tech splined crank arms and a 7 speed cassette with shram 7 speed twist grip shifter.
This was pretty much a standard heavy duty cyclocross rigid (no front or rear suspension) bike set up.
I purchased a 1000w rear hub motor with a 48 v 20 ah battery, a 50 amp controller "motor cut out" brake levers and a stand alone(separate) BMS battery charging system. (Sans rear rim and tire)
I laced the electro hub to the heavy duty rear rim and I used a dab of blue loctite on each spoke nipple as I built up the wheels, after careful measurement and dishing(and a bit of cussing) I've only had to true them once a season.
The skinny 700c tires were a problem at first, but I found a set of very thick thorn proof inner tubes that seem to stabilize the carcass of the tire.
Careful throttle control helps, knowing when to "get on it" and when to exercise throttle restraint is always a good idea.
When conditions allow this thing fly's and has decent range.
Top speed with my 200lb weight, and my 12 to 15 lbs of gear is a measured 35 to 40 to mph if I peddle.
At 50 pounds fully loaded its no light weight.
Its doable and worth while.
I'd be happy to answer any questions.
good luck.
BBB
 
That sounds pretty reasonable. My beach cruiser mo-bike weighs 70-75 lb, and only has one gear. The motor chain broke once, and I had to pedal for a while. I was glad I selected a low gear.

Surly makes heavy duty cyclocross frames and forks, including one wide steel fork with v brake bosses. That might work for E-bike use.
 
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