Little Bill
100 µW
Long time lurker, first time posting. I have been kicking around an idea since last year, and I think I will put it in motion this year, and I need some advice from the community. (I know little about ebike issues, but hit me if you have questions about bike racing tactics / stuff - I would be happy to help)
I am a US criterium racer, and getting upgraded to Cat 2 for 2016. There is a fair amount of guys that I race against that use "motorpacing" to help develop crank / leg speed at race pace. Short simple explanation: pedaling at 270 watts (human) at 28mph in a group with a 53 tooth crank and 14 tooth cassette, creates a specific demand on the legs to accelerate that gear in the ebb/flow of cornering / racing. (Without the draft, 28mph would take 350-ish watts-human, and is not a realistic solo training pace for very long)
The speed of race pace creates a very different leg / crank acceleration than pedaling at 270 watts (human) at 7mph up a hill with a 39 tooth crank and 23 tooth cassette. So, when people motorpace, they follow a moped or motorcycle at race-type speeds. (That also teaches you about drafting more efficiently) There are many different types of motorpacing workouts that can be done, but the basic premise is working your legs at race speeds. I do not have access to a moped and willing driver during my training hours, so this has never been an option. I saw some videos about ebike speeds last year, and it got me thinking - I can use a ebike hub to supplement my pedaling power, and to mimic the power of riding in the draft of a pack at race speeds.
So, I have been reading (a lot) but my build is not something I have seen replicated. (I am 5'10", 170lbs, with a 20lb training bike w/o hub or battery) So, here are the build principles:
1. The motor is only used to supplement pedal power, where I am pedaling fairly hard (no less than 230 watts-human)
2. The motor is only used when the speed is between 20mph and 32mph (top speed can be in the low or mid 30s)
3. The motor is only used on flat ground or slight rolling hills - no hill climbing (I live in Kansas!)
4. The battery should power the build for around 60 minutes or a little more, but will likely not be used at full-throttle
5. The "donor" bike will have 700c wheels, 700x28 tires, rim brakes, STEEL front fork, and Shimano 11-speed group (this means I must use a front ebike hub)
6. The build needs to be $500 or less, because I am a poor bike racer - I will sacrifice longevity and range (otherwise I won't be able to do it)
So, I think that I need the following:
1. A geared front hub
2. With winding/gearing that will go around 400rpm
2. At 48v (maybe 36v?)
3. With 350-500 cruising watts
4. Using a 10ah battery
5. Cruise control of some sort with a dead-man switch, or switches retrofitted to existing shifters
6. I have no idea about controllers, wiring, battery management, etc
So, I am leaning towards using:
Front Hub options:
Cute Q100 - either 36v 328rpm or 24v 201 rpm - with both motors volted at 48v to get desired RPM
Bafang BPM Code 8 or Code 9, maybe 10?
Battery ideas:
48v10ah bottle battery, like: http://www.greenbikekit.com/lithium-battery/li-ion/48v-10ah-li-ion-e-bike-frame-battery.html
Other parts:
No clue (controller, display, cruise control, wiring connectors, battery management, etc)
Any feedback help from the community would be great! Thanks!
I am a US criterium racer, and getting upgraded to Cat 2 for 2016. There is a fair amount of guys that I race against that use "motorpacing" to help develop crank / leg speed at race pace. Short simple explanation: pedaling at 270 watts (human) at 28mph in a group with a 53 tooth crank and 14 tooth cassette, creates a specific demand on the legs to accelerate that gear in the ebb/flow of cornering / racing. (Without the draft, 28mph would take 350-ish watts-human, and is not a realistic solo training pace for very long)
The speed of race pace creates a very different leg / crank acceleration than pedaling at 270 watts (human) at 7mph up a hill with a 39 tooth crank and 23 tooth cassette. So, when people motorpace, they follow a moped or motorcycle at race-type speeds. (That also teaches you about drafting more efficiently) There are many different types of motorpacing workouts that can be done, but the basic premise is working your legs at race speeds. I do not have access to a moped and willing driver during my training hours, so this has never been an option. I saw some videos about ebike speeds last year, and it got me thinking - I can use a ebike hub to supplement my pedaling power, and to mimic the power of riding in the draft of a pack at race speeds.
So, I have been reading (a lot) but my build is not something I have seen replicated. (I am 5'10", 170lbs, with a 20lb training bike w/o hub or battery) So, here are the build principles:
1. The motor is only used to supplement pedal power, where I am pedaling fairly hard (no less than 230 watts-human)
2. The motor is only used when the speed is between 20mph and 32mph (top speed can be in the low or mid 30s)
3. The motor is only used on flat ground or slight rolling hills - no hill climbing (I live in Kansas!)
4. The battery should power the build for around 60 minutes or a little more, but will likely not be used at full-throttle
5. The "donor" bike will have 700c wheels, 700x28 tires, rim brakes, STEEL front fork, and Shimano 11-speed group (this means I must use a front ebike hub)
6. The build needs to be $500 or less, because I am a poor bike racer - I will sacrifice longevity and range (otherwise I won't be able to do it)
So, I think that I need the following:
1. A geared front hub
2. With winding/gearing that will go around 400rpm
2. At 48v (maybe 36v?)
3. With 350-500 cruising watts
4. Using a 10ah battery
5. Cruise control of some sort with a dead-man switch, or switches retrofitted to existing shifters
6. I have no idea about controllers, wiring, battery management, etc
So, I am leaning towards using:
Front Hub options:
Cute Q100 - either 36v 328rpm or 24v 201 rpm - with both motors volted at 48v to get desired RPM
Bafang BPM Code 8 or Code 9, maybe 10?
Battery ideas:
48v10ah bottle battery, like: http://www.greenbikekit.com/lithium-battery/li-ion/48v-10ah-li-ion-e-bike-frame-battery.html
Other parts:
No clue (controller, display, cruise control, wiring connectors, battery management, etc)
Any feedback help from the community would be great! Thanks!