A Road Bike with Pedal Assist?

[Masher_midge]

Hi Everyone,
I've been reading this forum over the last few days and haven't really found much information about what I would like to build.

I'm a keen (commuter) road cyclist and currently do a 25km (15 mile) journey to work each day. Wind direction dependant, I usually average about 30kph (19mph). I'm about to change jobs and my new job is going to mean a 35km (22 mile) journey to work. Now the extra distance doesn't bother me, it's the extra time it will take. I find it hard enough getting out of bed at 6am at the moment, so don't really fancy the idea of having to get up at 5:40am to cover the extra journey time. My new journey will also include a few climbs, which due to previous knee injuries, will cause me some discomfort.

What I am therefore looking into is some kind of pedal assist, to both speed up my average speed a bit and also to give me some assistance up those damn hills! Not looking for massive speed increase, maybe up to 35kph average. I'd also like to keep it as stealthy as possible due to be a Road bike.

A couple of solutions I have come across are:
1) The Vivax Assist
Love this solution, but at over £2000 for the kit, it's out of the question.

2) The Keyde SR200 kit (250W) (http://www.dhgate.com/product/keyde-electric-bicycle-conversion-kit-brushless/211917433.html#s1-2-1|3516634475)
Price, stealthy bottle battery and power (250W) seem ideal. But will this option only assist me up to 25kph and then cut out and therefore not help me get up to a slightly higher speed?
Is it possible to lace this kind of motor motor to a carbon wheel rim? My bike currently has 60mm carbon rims and would love to keep these on the bike if possible.
And finally, can the motor be used with a 10speed cassette? or is it only 7,8,9 speed etc?

Are there any other mini rear hub options available than the Keyde.

Thanks in advance for any info.

Steve

 

[Chalo]

For something lighter, stronger, cheaper, and more versatile than Vivax, consider a variation of the homegrown friction roller drives that several members here have demonstrated. The "Commuter Booster" is one example you can buy and assemble rather than making from scratch.

I have not tried this kind of system, but it does seem to fit your requirements.

http://www.commuterbooster.com/

 

[Masher_midge]

That looks great, but not sure about attaching it to a carbon frame though?

 

[cal3thousand]

I would suggest a Bafang BBS middrive.

Without a battery, it pedals and feels like a standard bike just a bit heavier. If you feel like doing the work, it won't get in your way and if you need just a light boost, the engagement is quite seamless.

 

[motomech]

Hi Everyone,
I've been reading this forum over the last few days and haven't really found much information about what I would like to build.

I'm a keen (commuter) road cyclist and currently do a 25km (15 mile) journey to work each day. Wind direction dependant, I usually average about 30kph (19mph). I'm about to change jobs and my new job is going to mean a 35km (22 mile) journey to work. Now the extra distance doesn't bother me, it's the extra time it will take. I find it hard enough getting out of bed at 6am at the moment, so don't really fancy the idea of having to get up at 5:40am to cover the extra journey time. My new journey will also include a few climbs, which due to previous knee injuries, will cause me some discomfort.

What I am therefore looking into is some kind of pedal assist, to both speed up my average speed a bit and also to give me some assistance up those damn hills! Not looking for massive speed increase, maybe up to 35kph average. I'd also like to keep it as stealthy as possible due to be a Road bike.

A couple of solutions I have come across are:
1) The Vivax Assist
Love this solution, but at over £2000 for the kit, it's out of the question.

2) The Keyde SR200 kit (250W) (http://www.dhgate.com/product/keyde-electric-bicycle-conversion-kit-brushless/211917433.html#s1-2-1|3516634475)
Price, stealthy bottle battery and power (250W) seem ideal. But will this option only assist me up to 25kph and then cut out and therefore not help me get up to a slightly higher speed?
Is it possible to lace this kind of motor motor to a carbon wheel rim? My bike currently has 60mm carbon rims and would love to keep these on the bike if possible.
And finally, can the motor be used with a 10speed cassette? or is it only 7,8,9 speed etc?

Are there any other mini rear hub options available than the Keyde.

Thanks in advance for any info.

Steve

I am not famiular with that kit(mark), but I think you are justisfied in having doubts about it.
That puny battery has neither the Voltage nor capacity to do you much good.
And I wouldn't be fooled about the warrenty being worth anything. What Would you do in the event of a problem, Ship it back to China?
There are quite a few mini rear hub motors, some that will accept a cassette(as opposed to a free wheel).
You have not provided enough info. to make a specific recommendation(where are you and what is the terrain for example), but I am not aware of any hub motors compatible with carbon wheels
. I would recommend buying another bike, with a motor, you need not have the greatest pedaling rig. If you plan to get a kit that will propel you to 25 mph or above, or if the road surface is less than perfect, think about a MTB with full suspension.
For reading up on what you might want to do, search with keywords; mini motor, Q100, Q100CST, etc.

 

[Chalo]

That looks great, but not sure about attaching it to a carbon frame though?

Seems to me that you could anchor a friction drive to the back side of the brake bridge if the seat tube doesn't offer a good mounting point.

Carbon-plastic is not a very forgiving material when used outside its intended purpose, which you should keep in mind when increasing power, speed, and weight beyond the anticipated range. It would make sense to leave your plastic bike the way it is, and use a more robust and cheaper aluminum or steel road bike as the platform for your e-assist.