New build. Full carbon 29er weight weenie Super Commuter.
- Thread starter Kepler
- Start date
Kepler
10 MW
I don't worry too much about max theoretical voltage as there are other factors that will keep it below this figure anyway.
Firstly you need to decide what is the max Wattage you are prepared to throw at the motor.
Next you need decide what your target max speed is. Obviously speed and Wattage are directly related and as such you need to understand how much power is required for your target max speed.
Using a simple Bike calculator like this http://bikecalculator.com/veloMetric.html will give you a ballpark figure.
In my case, I was happy to throw 800W at the motor so around 50kph was going to be the max speed I could I could expect out of this setup.
Now that I had determined this, it was just a matter of selecting a voltage that would spin the motor up to a wheel speed that would give me 50kph.
As previously discussed, I am using the 201RPM @36V rated motor which I think is the slowest wind they have.
Running on 18S and around 72V so its now around 402RPM with my setup.
402 x 2180mm wheel circ = 876,360mm/Min or 0.88km/Min
= 52.8kph
In real life 45kph can be maintained but I can get it up to 50kph with some hard assist.
Throwing more voltage at this motor is pointless as you simply can't turn the voltage into speed due you not having the power available.
Firstly you need to decide what is the max Wattage you are prepared to throw at the motor.
Next you need decide what your target max speed is. Obviously speed and Wattage are directly related and as such you need to understand how much power is required for your target max speed.
Using a simple Bike calculator like this http://bikecalculator.com/veloMetric.html will give you a ballpark figure.
In my case, I was happy to throw 800W at the motor so around 50kph was going to be the max speed I could I could expect out of this setup.
Now that I had determined this, it was just a matter of selecting a voltage that would spin the motor up to a wheel speed that would give me 50kph.
As previously discussed, I am using the 201RPM @36V rated motor which I think is the slowest wind they have.
Running on 18S and around 72V so its now around 402RPM with my setup.
402 x 2180mm wheel circ = 876,360mm/Min or 0.88km/Min
= 52.8kph
In real life 45kph can be maintained but I can get it up to 50kph with some hard assist.
Throwing more voltage at this motor is pointless as you simply can't turn the voltage into speed due you not having the power available.
Kepler
10 MW
The Super Commuter returns to plan A. "FRICTION DRIVE". Well for a while anyway. 
Development on my friction drive has continued quietly over the past 12 months and has now reached a point whereby some serious miles need to be clocked up on it to test its durability.
So a bit of an update.
Firstly, no more RC controller being used. I have come to the conclusion they are just too expensive and too fragile for a use in a commercial drive.
Gone to a modified low cost 6 FET but use the controller case as the main frame of the drive.
Now using 36v rather than 24v to allow the drive to operate with packs other than LiPo's.
No throttle at all anymore. Gone full pedelec. Few reasons for this. Firstly my local market and Europe must be pedelec. Secondly, the 6 FET controller has really smooth ramps up and down on the pedelec output that really suits the swing action of the drive. I personally really have warmed to pedelec on low powered bikes as it creates more of a seamless interface between the rider and the drive system. A standard 6 FET LED display is used. No point in reinventing the wheel when cheap off the shelf works perfectly well. The standard 3 levels of PAS assist provided by the stock LED display work well with the drive and give a nice range of assist from around 22 kph on the low setting to 45kph on high speed.
Designed a quick release system that indexes the drive back into the same position when re fitting it to bike. This was needed so the drive could be quickly removed and re fitted without the need to set the drive up every time. Drive can be removed and re fitted in about 20 seconds.
Drive mount is much more adjustable now and fits a much wider range of bikes. I would say good for 90% of bikes on the market
In relation to rideability, I am really pleased with how the friction drive is performing. Engagement is smooth and power delivery nice and progressive. Disengagement is a little on the slow side when you stop pedaling and is a bit disconcerting at first but its nothing for the brakes to overcome the bit of run on if needed. Noise wise, I think the 6FET is actually quieter than an RC controller.
Economy wise, the friction drive is at least as good as the SWXH setup. No problems getting 15 kms from the lightweight 3ah (2.5ah usable) 10s LiPo that I am currently using.
So that's about it at the moment. Although the concept is basically the same as original, it has gone through a complete redesign. Hopefully 2 years of work will finally pay off
I know the friction drive doesn't have the stealth qualities of the small hub but it sure ticks the boxes in relation to economy and keeping the bike as light as possible. It is so nice having the high quality rear wheel back in the bike complete with a White Industries hub and 9 speed XLT shifter and cluster. Bike rolls and shifts gears like my road bike now.
Development on my friction drive has continued quietly over the past 12 months and has now reached a point whereby some serious miles need to be clocked up on it to test its durability.
So a bit of an update.
Firstly, no more RC controller being used. I have come to the conclusion they are just too expensive and too fragile for a use in a commercial drive.
Gone to a modified low cost 6 FET but use the controller case as the main frame of the drive.
Now using 36v rather than 24v to allow the drive to operate with packs other than LiPo's.
No throttle at all anymore. Gone full pedelec. Few reasons for this. Firstly my local market and Europe must be pedelec. Secondly, the 6 FET controller has really smooth ramps up and down on the pedelec output that really suits the swing action of the drive. I personally really have warmed to pedelec on low powered bikes as it creates more of a seamless interface between the rider and the drive system. A standard 6 FET LED display is used. No point in reinventing the wheel when cheap off the shelf works perfectly well. The standard 3 levels of PAS assist provided by the stock LED display work well with the drive and give a nice range of assist from around 22 kph on the low setting to 45kph on high speed.
Designed a quick release system that indexes the drive back into the same position when re fitting it to bike. This was needed so the drive could be quickly removed and re fitted without the need to set the drive up every time. Drive can be removed and re fitted in about 20 seconds.
Drive mount is much more adjustable now and fits a much wider range of bikes. I would say good for 90% of bikes on the market
In relation to rideability, I am really pleased with how the friction drive is performing. Engagement is smooth and power delivery nice and progressive. Disengagement is a little on the slow side when you stop pedaling and is a bit disconcerting at first but its nothing for the brakes to overcome the bit of run on if needed. Noise wise, I think the 6FET is actually quieter than an RC controller.
Economy wise, the friction drive is at least as good as the SWXH setup. No problems getting 15 kms from the lightweight 3ah (2.5ah usable) 10s LiPo that I am currently using.
So that's about it at the moment. Although the concept is basically the same as original, it has gone through a complete redesign. Hopefully 2 years of work will finally pay off
I know the friction drive doesn't have the stealth qualities of the small hub but it sure ticks the boxes in relation to economy and keeping the bike as light as possible. It is so nice having the high quality rear wheel back in the bike complete with a White Industries hub and 9 speed XLT shifter and cluster. Bike rolls and shifts gears like my road bike now.
Attachments
Samd
10 MW
Great to see you keep pushing your friction drive Kepler. I recently noticed another commercially available carbon bike, but using a little keyde rear hub at 150w. I don't think they could ever compete with the power to weight of your friction drives. Perfectly suited to road riders who want power assist for range and rehab.
I've often wondered about the RC controller choice. A few years back after seeing your drive on a group ride I needed to test a ku63 6fet and grabbed a nearby 50mm outrunner on my bench. It synced straight up and got me wondering about using it as a friction unit to tumble barrels of mulch in my yard. A bit like those hotdog rollers you see in shops. The soft ramp of the KU seemed like a good idea for the initial starting torque to get the heavy barrels spinning smoothly.
Not as much fun as ebikes
I've often wondered about the RC controller choice. A few years back after seeing your drive on a group ride I needed to test a ku63 6fet and grabbed a nearby 50mm outrunner on my bench. It synced straight up and got me wondering about using it as a friction unit to tumble barrels of mulch in my yard. A bit like those hotdog rollers you see in shops.
The soft ramp of the KU seemed like a good idea for the initial starting torque to get the heavy barrels spinning smoothly.Not as much fun as ebikes
Kepler
10 MW
Those little keyde hubs do look interesting and provide probably the best stealth ebike solution currently available. I do question the claimed performance though even in a super lightweight config. We all know what it takes to have meaningful assist and 150W is certainly not going to cut it for high speed commuting no matter how light the bike is.
As you have seen, friction drive work and have a place in the market. The hard part is going from a science project to a commercial product for the masses. Not quite there yet but getting close
As you have seen, friction drive work and have a place in the market. The hard part is going from a science project to a commercial product for the masses. Not quite there yet but getting close
pendragon8000
100 kW
Looks good.
Could Ebrakes just cut it off? So when the rider wants to stop it cuts out but when pedaling stops it tapers off.
oatnet
1 MW
Love the new friction drive Kepler, glad you made the switch from esc to 6-fet.
Hi Kepler,
Thanks again for answering my voltage question.
Wow! Love the new developments on your bike. You're work has been my inspiration for my own super commuter project.
Just came back from eurobike 2013, and I was truly impressed by the Coboc electric road bike. This is the stealthy super commuter we all want. Simple. No protruding wires. Absolute stealthiness. It's like an ebike designed by Steve Jobs or Jonathan Ive. It's a lightweight single speed machine that transforms raw power into immediate forward motion.
Their are no displays, no batteries to be seen, like the iPad, everything is in the downtube and not removable without some servicing. . The cockpit is bare, it only has two brake levers. No throttle, no switches with levels of assist to play with. You just pedal and you get pure biking exhilaration. Built with the Less is more german tradition which results into pure riding pleasure. The bike is not technically outstanding, many of us could've done it. Apart from the custom frame and controller, it's all off the shelf parts. I just love designers that know how to make the difficult choices, getting at the essence of an invention so it truly delivers according to expectations.
This bike uses the same Bafang motor that you were using. Quite surprising to know that Eurobike's Top Ebike Prize was given to an ebike using a Bafang motor.
It uses the same magnetic connector as the Specialized Turbo which is now an European standard.
Great write up here... as it won this year's Eurobike Ebike Design Gold Award
http://www.gizmag.com/coboc-ecycle-gold-award-eurobike/28876/
Thanks again for answering my voltage question.
Wow! Love the new developments on your bike. You're work has been my inspiration for my own super commuter project.
Just came back from eurobike 2013, and I was truly impressed by the Coboc electric road bike. This is the stealthy super commuter we all want. Simple. No protruding wires. Absolute stealthiness. It's like an ebike designed by Steve Jobs or Jonathan Ive. It's a lightweight single speed machine that transforms raw power into immediate forward motion.
Their are no displays, no batteries to be seen, like the iPad, everything is in the downtube and not removable without some servicing. . The cockpit is bare, it only has two brake levers. No throttle, no switches with levels of assist to play with. You just pedal and you get pure biking exhilaration. Built with the Less is more german tradition which results into pure riding pleasure. The bike is not technically outstanding, many of us could've done it. Apart from the custom frame and controller, it's all off the shelf parts. I just love designers that know how to make the difficult choices, getting at the essence of an invention so it truly delivers according to expectations.
This bike uses the same Bafang motor that you were using. Quite surprising to know that Eurobike's Top Ebike Prize was given to an ebike using a Bafang motor.
It uses the same magnetic connector as the Specialized Turbo which is now an European standard.
Great write up here... as it won this year's Eurobike Ebike Design Gold Award
http://www.gizmag.com/coboc-ecycle-gold-award-eurobike/28876/
Kepler
10 MW
Very nice bike. Love the bullhorn bars. Not cheap though and with a 25kph limit, not fast either. Unfortunately once you hit 25kph, you are on your own just when you really need the assist.
Might get hold of a Fixie frame and do an ultra minimalistic build as my next project
Might get hold of a Fixie frame and do an ultra minimalistic build as my next project
Kepler
10 MW
pendragon8000 said:
I could do that but it just isn't necessary. The less cabling from the front of the bike the better IMO.
chas58
10 kW
wow, that is cool. It looks identical to my bike, except mine is silver, and I have to mount the battery externally. Still, 29lbs and 40km/hr speed is a nice combo for my bike. Fortunately it is flat enough around here I can get by with single speed.
The german market is just so full of those fat tired heavy things, this is like a breath of fresh air. Something that looks like (and presumably rides like) a fast urban road bike.
The german market is just so full of those fat tired heavy things, this is like a breath of fresh air. Something that looks like (and presumably rides like) a fast urban road bike.
DIY_turbo said:Just came back from eurobike 2013, and I was truly impressed by the Coboc electric road bike. This is the stealthy super commuter we all want. Simple. No protruding wires. Absolute stealthiness. It's like an ebike designed by Steve Jobs or Jonathan Ive. It's a lightweight single speed machine that transforms raw power into immediate forward motion.
Their are no displays, no batteries to be seen, like the iPad, everything is in the downtube and not removable without some servicing. . The cockpit is bare, it only has two brake levers. No throttle, no switches with levels of assist to play with. You just pedal and you get pure biking exhilaration. Built with the Less is more german tradition which results into pure riding pleasure. The bike is not technically outstanding, many of us could've done it. Apart from the custom frame and controller, it's all off the shelf parts. I just love designers that know how to make the difficult choices, getting at the essence of an invention so it truly delivers according to expectations.
This bike uses the same Bafang motor that you were using. Quite surprising to know that Eurobike's Top Ebike Prize was given to an ebike using a Bafang motor.
Great write up here... as it won this year's Eurobike Ebike Design Gold Award
http://www.gizmag.com/coboc-ecycle-gold-award-eurobike/28876/
speedmd
10 MW
Besides the hidden battery and wires, WTF. Slim pickings I guess. Totally unusable bars (way too much drop and no brakes in the main hand positions and center (brake) positions are so low that you could never put significant amount of brake force on the front without going over the bars) for most folks. Is this a fixie? Is this is a joke?
I guess the extra retro flare is what gets the gold. At least as far as the gizmo folks see it. Keplers build blows this completely out of the water in my book for commuter usability and shear quality of a daily ride. Not even a nice looking frame with relatively raw welds showing through a boring black finish. They got the saddle right. I'll stop there.
I guess the extra retro flare is what gets the gold. At least as far as the gizmo folks see it. Keplers build blows this completely out of the water in my book for commuter usability and shear quality of a daily ride. Not even a nice looking frame with relatively raw welds showing through a boring black finish. They got the saddle right. I'll stop there.
spinningmagnets
100 TW
I haven't checked this in a while, very clever making the 6-FET case into the frame of the drive! I had no preference between a properly-matched ESC or a 6-FET, but I am happy to see someone I respect as much as you showing how a conventional E-bike 6-FET can be used with an RC motor. Well done, sir.
chas58
10 kW
speedmd said:
I guess we all have different needs, but that setup works great for me for a 10mph commute. But I stand when accelerating and I assume you don’t. Flat bars work great for you, no? I need more flexibility than flat bars offer, and don’t really need drops (unless riding in the 50-120mile range – not something I do electric).
I’m just glad to see something light, nimble and more fun to ride than 99% of the other bikes on the German market. This is built for someone who enjoys riding bikes. I like the philosophy the kids in the video talked about too. Kudos to them for doing something different and breaking out of the German E-bike corporate mold.
speedmd
10 MW
I don't care for flat bars much at all. Just what most hybrids and mtn bikes come with. On a road bike bike, a standard road bar setup is much better for most folks having many hand positions and hand brakes where your hands are. Add the center cross style brk. levers and you have this extreme drop sudo tt track fixie setup beat big time for usability. Light is fun but not what I would call riding a full tilt fixie on a daily commute. Hell, You might spill your coffee.
speedmd
10 MW
Hi DIY_turbo
My bad, I keep calling it cross instead of CX or cyclocross. Could not stand the picture I was getting in my head of a 10 mph commute and spilling my coffee as I was needing to sip some just to stay awake due to boredom. :wink:
My bad, I keep calling it cross instead of CX or cyclocross. Could not stand the picture I was getting in my head of a 10 mph commute and spilling my coffee as I was needing to sip some just to stay awake due to boredom. :wink:
Kepler
10 MW
Ok, the Super Commuter has completed its duties as a friction drive test bed and performed admirably. Clocked up around 500km with the friction drive and gathered lots of useful data about various controllers and motor combos together with both 24V and 36V setups. I am now confident with what is the best combination to take the friction drive to the next step. Further testing will now be carried out my folder.
Started the process of converting the bike back to its pedalec hub motor configuration but with a few changes.
Firstly, the Thun has been removed from the bike. Unfortunately the plastic bearing housings have developed some slop and although still operating fine, the associated ring gear runout just is not acceptable for a high spec bike.
The Thun has been replaced by a magnetic ring style PAS in conjunction with the CA3 but set up to be cadence sensitive. Although I still believe a true torque sensor is the best option, IMO, this setup is the next best thing. In conjunction with adjustable assist settings, using cadence to to vary the amount of assist works surprising well.
Picture this. You are riding along at a comfortable speed with a comfortable cadence level. You then come up behind a bike on a bike path doing a good speed but you still want to overtake him as your cruise speed is a bit higher. So you knock it down a cog, and up the cadence level. You start to work harder but at the same time, the CA3 starts to ramp up a bit of power to match the increase in cadence. Speed increases nicely for your overtaking move and you can then settle back to your comfortable cadence level. A small tweak of the PAS assist can be then made any time to match your base assist level.
View attachment 2
Also decided to up the comfort level of the bike with a slight sacrifice to the weight weenie philosophy.
Will be fitting a pair of 2" x 700C Big Apples and some front suspension.
Bought a set of these.
And these.
Now I just need to sort out the front wheel as the forks have a 15mm axle. Hopefully White Industries have a replacement axle for the hub.
Looking forward to having my 45 kph dead silent stealth commuter back that is for sure, especially with the added comfort.. The friction drive might be nice and light but unfortunately the noise from a high revving outrunner motor isn't fooling anyone :lol:
Started the process of converting the bike back to its pedalec hub motor configuration but with a few changes.
Firstly, the Thun has been removed from the bike.
Unfortunately the plastic bearing housings have developed some slop and although still operating fine, the associated ring gear runout just is not acceptable for a high spec bike.The Thun has been replaced by a magnetic ring style PAS in conjunction with the CA3 but set up to be cadence sensitive. Although I still believe a true torque sensor is the best option, IMO, this setup is the next best thing. In conjunction with adjustable assist settings, using cadence to to vary the amount of assist works surprising well.
Picture this. You are riding along at a comfortable speed with a comfortable cadence level. You then come up behind a bike on a bike path doing a good speed but you still want to overtake him as your cruise speed is a bit higher. So you knock it down a cog, and up the cadence level. You start to work harder but at the same time, the CA3 starts to ramp up a bit of power to match the increase in cadence. Speed increases nicely for your overtaking move and you can then settle back to your comfortable cadence level. A small tweak of the PAS assist can be then made any time to match your base assist level.
View attachment 2
Also decided to up the comfort level of the bike with a slight sacrifice to the weight weenie philosophy.
Will be fitting a pair of 2" x 700C Big Apples and some front suspension.
Bought a set of these.
And these.
Now I just need to sort out the front wheel as the forks have a 15mm axle. Hopefully White Industries have a replacement axle for the hub.
Looking forward to having my 45 kph dead silent stealth commuter back that is for sure, especially with the added comfort.. The friction drive might be nice and light but unfortunately the noise from a high revving outrunner motor isn't fooling anyone :lol:
adrian_sm
1 MW
Kepler said:The Thun has been replaced by a magnetic ring style PAS
What PAS ring is that? How is is attached?
Kepler
10 MW
Its one of the new ones available from BMS Battery. Its not a bad quality PAS for the price.
To fit the PAS ring to the crank set was a bit of a job. I removed the granny gear and hand filed a recess for the PAS ring to drop into. I then machined the centre out of the PAS ring and epoxied it into the crank set.
To fit the PAS ring to the crank set was a bit of a job. I removed the granny gear and hand filed a recess for the PAS ring to drop into. I then machined the centre out of the PAS ring and epoxied it into the crank set.
zukster
1 kW
Kepler said:
I don't know where you're at with the above. I could not find any info on a Bafang CST Mini based on the SWXH, other than what someone posted on the new ES wiki.
You can get Dura-Ace level shifting with a new XTR derailleur (I use a RD-M972 carbon) and if you build your own freewheel based on an old Dura-Ace MF-7400 7 speed freewheel. I start with an MF-7400 12-13...21 or whatever you can find. You only need the body and the 12,13 cogs. Take it apart and add cogs from the new SIS MF-HG37 or MF-HGxx 6 or 7 speed. Now you have a Dura-Ace 12-28 freewheel
You retain the first two cogs from the Dura-Ace which are Shimano UG SIS UniGlide, but they are small and you don't notice that they are not Shimano HG SIS HyperGlide. 7 and 8 speed SIS freewheel/cog SIS spacing is almost exactly the same, so you use the spacers from the 7 speed newer freewheel, which are lighter. Than you can use 7 speed Deore XT Thumb shifters or 8 speed legendary Deore XT SL-M739 rapidfire shifters (or XTR equivalent). The XT M739 pod shifters are actually smaller and lighter however. Get the Dura_Ace or XTR 8 Speed chain. It works for the 7 speed freewheel you just built and also works in the 9 speed M972 derailleur. (A 10 speed derailleur would probably not work). For a crank, for trail, the Shimano Deore XT FC-M770 44/32/22, or for street, Shimano Deore XT FC-M771 48/36/26. These are very light or an XTR 9 speed triple will be lighter. You won't find a 48 top cog 9 speed XTR unfortunate. I like to use and old FD-M900 or FD-901 for the front derailleur. Front shifting is better with this setup with an older 8 speed front derailleur. The M900/M901 is bottom swing, is as light as they get, and will shift almost any 6-8 speed drivetrain. Prob okay with 9 speed too but I have not tried that... Well I digress. You get the idea. You can swap in road parts instead of the same grade to achieve the above.I've built two of the above setups and shifting is Ace
I run the rear Cute 100's from BMS battery and Grins torque arms. BMSbattery KU63 controllers are super light and tiny and work good enough for me.
full-throttle
1 MW
pendragon8000
100 kW
Kepler, regarding your big apple, its different tread to my 2.35" 29er
Also you may be interested in the vee rubber speedster:
I had to contact an eBay seller in USA to get it but its really choice as a front tyre for on/off road. Leans well in dewy grass and sandy dirt.
Also you may be interested in the vee rubber speedster:
I had to contact an eBay seller in USA to get it but its really choice as a front tyre for on/off road. Leans well in dewy grass and sandy dirt.
Kepler
10 MW
Ooh, I like that last one especially. looks like a great crossover tire.
Kepler
10 MW
full-throttle said:
Cheers mate. Picking one up from Grand Prix Cycles tomorrow. $69.00 so not too bad. Glad I found one local rather then having to wait for one from an online vendor.
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