Friction RC Commuter Build

[RayB]

Hello All,

Well, I've blundered through a few different setups over the last 2 years. A cyclone which I hated having in the chainline, noise, substandard parts. Then, I went to a Crystalyte X5 and 40x builds which made my bikes feel like tanks or like I was cycling a couch to work. I've two bikes at the moment and I would like to ditch the one I have been using as an electric on the days when I'm tired. I've got 27 km to go each way so need something reliable and that keeps my bike, well, a bike.

I've a few ideas about what I would like to try out and would love any feedback on my dopey plans.

Here is my regular commuter that I want to enable as an RC build:

From the pic there are a few quick things you will notice that limit me to certain types of builds.

- I need to keep the rear rack and fenders which eliminates keplers rear drive system
- I want to keep the disc brakes which remove any possibility of left hand side drive on the alfine hub, plus I want to freewheel as a true bicycle with no drag when the system is not in use
- keep my internal hub and dynamo eliminating any ebike hub technology plus way to much drag, i wont be going back to that
- I need it to be stealth as possible
- Retractable so I can use my bike as normal
- Rain proof as I am an all weather commuter
- LIght as possible

At the moment I've been considering 2 builds. I'll start with the RC consideration.

I'd initially thought I could adapt keplers drive to a front wheel configuration where I could get it to drop onto the wheel in front of the fender. But that would mean it would be driving the wheel from dead center top which is not ideal from what I've read on the forums. Thus, if the suggested mounting point (and please correct me if I'm wrong) is basically at the 45 degree point on any side of either front or back wheel. With that in mind, I've two possible mount points.

1) The civia comes with a kickstand plate. I thought perhaps butchering a double kickstand, mounting an rc motor between the legs which could then be sprug against the lower portion of the rear tire. I could pull the friction drive away from the tire using a drop bar mounted bar end shifter. This would hide the motor below and inback of the bottom bracket driving the rear wheel from the lower front 45 degree contact point.

2) Installing a lowrider front rack that many of which have a metal tube that crosses over the front wheel roughly at the 45 degree contact point at the upper front portion of the front tire. And, fabricate something similar to have the motor drop onto the tire from that point.

3) I know I said I only had 2, but I'd really like to get the kepler drive working on this if I could. My idea for the kepler would be to have a front rack, mount the drive to the front portion of the rack and allow the motor to drop onto the wheel from that point. But, it sounds like this one is out the window.

Finally, my other option is to use a small hub motor like a cute or tonxgin. Mount that from the kickstand plate and allow it to chain drive my inner chain ring. But, this is the last of my choices as I want to freewheel as a normal bike when I'm not using the motor.

Sorry for all the rambling but at this point I'm just trying to work out my options for a potential setup. I'm ordering my Turnigy motor at this point just so I can start fiddling with possible mounting options.

Any thoughts appreciated.

Or, should I just say heck with it, pull the fenders and rack off and use a kepler.

Thanks!

 

[adrian_sm]

If you are keen on the friction drive idea, here are some other options that place the drive in the frame, and can avoid the rear rack. You will still need to cut a hole in you fenders, but this could be minimal.

1) Commercial Option - Hidden Power
http://www.endless-sphere.com/forums/viewtopic.php?f=3&t=21186&start=30#p310442

2) Build your own option
Here is a link to my build that is similar in principal to Keplers, but different location, and bit more minimalist.
Commuter Booster <1kg Friction Drive

Good luck.

- Adrian

 

[RayB]

Thanks Adrian,

I've been watching your build and it is similar to what I would like to do, but am limited due to fenders etc. That hidden power friction drive is exactly the type of thing I'm looking for. To boot, they have a version that will drive from the sidewall as well, although, it is listed as a MTB version so not sure if that is down to rpm or issues with driving road bikes from the sidewall being risky business etc.

I can grab it from Korea which works out quite well as we've got an office there and shipping to Japan is quite reasonable. It runs around 90,000 yen so is expensive, but, soo tempting

Thanks for the links, gives me a lot to think about. I know many people are not interested in conversing in threads where there is no materialization of solutions so I appreciate your input.

I am thinking that commercial option is very attractive also given throttle and controller issues should be resolved.

Cheers,

 

[jbond]

I know you're thinking about RC drive but you should consider a geared hub. Something like the baby Bafang QWSH/K or Cute-85. Get a 20" (high rpm) version of the motor and lace it into a 700c rim. Run it at 36v or 48v. There is a tiny bit of drag in these hubs, but it's really not as much as you probably think. If you didn't know the motor was there, I doubt you could feel it when pedalling with no power. A rear hub will be a little heavier, but it's very stealth as you can't really see the small motors behind the gearset and disk. Put a Ping battery in a bag on the rack, hide the controller and the only giveaway will be the handlebar controls.

 

[RayB]

@jbond,

I do understand the thinking of where your going. But as I've already been down the hub path it is not really something I can put a lot of faith in. The only thing I am considering for a cute85 or similar at the moment would be to drive a crank or disc mounted sprocket. There are 2 issues I have with using hub motors. One which you touched on is the resistance, which granted on these smaller hub motors may be next to nil. My main opposition is to reliability and quality of build. My round trip commute is 60km. Maybe it is my mind set but I just can not see a $66 dollar hub motor like the cute 85 being reliable beyond a few months at most. I already had a crystalyte fail in a short time span under similar distances and I just dont want any kind of motor failure to affect the fact that I can continue my trip as expected. Hence keeping my bike a bike.

With that being said, I am considering having a cute 85 drive the rear sprocket mounted on the disc brake. Perhaps use the rear version of the cute85 with a shimano free wheel on it. I'd like to go the RC route to be honest

 

[RayB]

Slowly moving forward.

I've decided on going with the commercial option kindly pointed out by Adrian. I've ordered up a sample of the Hidden Power system which I now eagerly await. I really was torn on weather to go with kepler's system but with the distances I need to go I really wanted something as an entire kit. i.e. LiPo battery solution combined with everything in place, i.e. controller, throttle etc. I don't mind messing around with things but at the moment this was the cleanest option for myself.

Once I receive the kit in a few days (hopefully) I'll be posting loads of pics and opinions.

 

[AussieJester]

- I want to keep the disc brakes which remove any possibility of left hand side drive on the alfine hub, plus I want to freewheel as a true bicycle with no drag when the system is not in use

You can buy disk brake freewheel sprocket adapters allows mounting of sprocket on left side while also keeping disk brakes...just an FYI....you would still have drag from the freewheel on the other end.

KiM

 

[adrian_sm]

I've ordered up a sample of the Hidden Power system which I now eagerly await. ................

Once I receive the kit in a few days (hopefully) I'll be posting loads of pics and opinions.

Awesome. I can't wait to see what hear how it performs. How much did you end up paying for it?
Hope it suits your needs, as it appears on paper to be a great little lower power assist kit.

- Adrian

 

[RayB]

You can buy disk brake freewheel sprocket adapters allows mounting of sprocket on left side while also keeping disk brakes...just an FYI....you would still have drag from the freewheel on the other end.

KiM

Hi Kim,

That was the way I wanted to go but the way this frame mounts the disc and my BB7s there is not enough room between the disc caliper and spokes to squeeze in another sprocket. Plus Kings Sales and Service don't seem to like to respond to customer requests for their products.

@Adrian,

Ya, I'm quite eager now to get my hands on it. After flogging all of my other ebike stuff I've ended up only 300USD out of pocket which isn't too bad. Don't want to say outright what I've paid for it at this point as I might help him bring these into Japan if it turns out to be what it is on paper as you say.

 

[adrian_sm]

:wink: Say no more.

I got a similar email by the sounds of it. I asked for a bit of info, prices, availability etc, and promptly got an email back with some "trade prices", sample prices etc, asking if I wanted to be a distrubutor.

The reason I ended up building my own, rather than going for something like this, was price and the thought I could do better, cheaper. :lol: But for what you get I must say it is a pretty reasonable price, once you take all hidden costs into account.

Keep us updated.

 

[RayB]

:wink: Say no more.

I got a similar email by the sounds of it. I asked for a bit of info, prices, availability etc, and promptly got an email back with some "trade prices", sample prices etc, asking if I wanted to be a distrubutor.

The reason I ended up building my own, rather than going for something like this, was price and the thought I could do better, cheaper. :lol: But for what you get I must say it is a pretty reasonable price, once you take all hidden costs into account.

Keep us updated.

Ya its an interesting offering. The thing that has me confused, maybe a battery person can enlighten me. But some have thought this is like an RC motor. But, there is an option for Lifepo4 battery instead of the LiPo. I was under the impression with RC style motors that the C rating was nowhere near usable with RC type motors. He also mentioned that it is nowhere near as loud as an RC. Guess I'll find out soon enough. It also says that they are custom build in Korea so don't think it is that HC inrunner that some are saying.

 

[adrian_sm]

Ya its an interesting offering. The thing that has me confused, maybe a battery person can enlighten me. But some have thought this is like an RC motor. But, there is an option for Lifepo4 battery instead of the LiPo. I was under the impression with RC style motors that the C rating was nowhere near usable with RC type motors.

Well it depends which ratings you believe on their spec sheet.
They quote:
BLDC Motor, 300W Nominal, 600W peak
Controller: 80A controller, PAS
Battery: LiPo 14.8V 18Ah or LiFePo4 13.2V 15Ah

At 600W That is only 2.25-2.7C. Well within LiFePo4's capabilities.
At 80 Amps that is 4.5-5.4C. This would mean you need decent LiFePo4, but since you are not pushing it like this all the time probably still all right.

He also mentioned that it is nowhere near as loud as an RC. Guess I'll find out soon enough. It also says that they are custom build in Korea so don't think it is that HC inrunner that some are saying.

My friction drive definitely has that RC scream thing happening. Will be interesting to see how this little in-runner sounds, being a lower power unit will help too. As when I go easy the sound levels are much better.

- Adrian

[EDIT: Fixed type]

 

[adrian_sm]

Oh one other thing. I found some fenders you might be interested in, that don't extend forward of the seat stays.
See the post on my thread for more details, but here is the teaser pic. Available at Amazon.

- Adrian

 

[AussieJester]

You can buy disk brake freewheel sprocket adapters allows mounting of sprocket on left side while also keeping disk brakes...just an FYI....you would still have drag from the freewheel on the other end.

KiM

Hi Kim,

That was the way I wanted to go but the way this frame mounts the disc and my BB7s there is not enough room between the disc caliper and spokes to squeeze in another sprocket. Plus Kings Sales and Service don't seem to like to respond to customer requests for their products.

Yes i imagine a common issue with alt of frames...Another FYI: ES member Recumpence sells nice CNCed disk brake sprocket adapters also and is very punctual answering PMs .

KiM

 

[RayB]

Yes i imagine a common issue with alt of frames...Another FYI: ES member Recumpence sells nice CNCed disk brake sprocket adapters also and is very punctual answering PMs .

KiM

I did speak to him about his adapter which would of been an option. Only issue I had with his solution was minimum chainring was 40 tooth. As I was going to use a hub motor (cute) as the drive the rpm was quite low so only needed a 2/3 ratio and needed something a little smaller.

Funny thing is I had already ordered the Cute setup from BMS Battery and it was here in 4 days!!! from all the forum posts I was expecting 6 weeks on that thing. But they did ship me the wrong version, meh, I asked for the disk mount version and I got the reg one. But, that will now go on my wife's soon to have brompton so no worries I guess.

 

[RayB]

Oh one other thing. I found some fenders you might be interested in, that don't extend forward of the seat stays.
See the post on my thread for more details, but here is the teaser pic. Available at Amazon.

- Adrian

Spot on Adrian, This was the only caveat to the hidden power setup. There is no way I'm gonna slice up my honjos . I was going to take my winter fenders from my 2nd bike and cut'em in half. But these seem a far better solution. I had also thought of mounting the hidden thing under the BB and have it pushing the rear wheel from just under the rear wheel fender. But that may be very wishful thinking as I think product design and physics will have something to say about that..

 

[RayB]

The Hidden Power drive showed up today. It looks great, compact, well fabricated. Going to have to get it on this weekend and try it out. Here is a teaser pic, at work so I can't spend to much time playing with ebike parts

 

[Kepler]

Man, you must do a detailed review on this drive for us. Cant wait see how well it works. How much did it end up costing you?

 

[adrian_sm]

And how does the drive pulley attach to the output shaft. I can't see how the torque is transferred?

One way clutch bearing?

How do the installation instructions say the drive should be attached, tuned, setup?

Now I wish I did buy one just to play with it.

- Adrian

 

[vancblue]

How do the installation instructions say the drive should be attached, tuned, setup?
- Adrian

Installation instructions for both the rim (RB) and side of tire (MX) motors. (More detail is shown on the MX download) at http://www.pedalix.com/downloads/manual/

 

[RayB]

Well,

I've had some time today to get the kit installed onto my commuter.




My initial impressions of the system are quite favorable.

Even with the controller, battery and motor on the frame it does not stick out too much. Eventually I'll be moving everything into a touring bag to make it more stealthy. I will post a video as well. The noise level is obviously more than a hub motor but in this small room it is bearable. I think once I get it on the street it shouldn't stand out to much. But, I will have to wait until I get it on the road.

Speed wise with no load, i.e. lardass sitting on it, Its getting about 36km/h. So I am hoping for 30 once I use it as I do peddle quite a bit, this whole thing is for tired/windy/can't be arsed days. To answer someones question above, yes it appears to have a clutch bearing in the roller/pully.

Things I do not like so far. Cables being to short to move anything into bags. No apparent on/off switch except for the throttle and I can't charge the battery while its hooked up but this may be a LiPo thing? I'm used to Lifepo4 where I have been told its fine to charge while hooked up to the controller. So not big issues to start with. Lets see how it rides. Here are some more pics. But, my main goal of keeping my bike, a bike, I think given the weight of this solution at 2.6 kg all in. I've met that goal.

Planned Modifications

Thus far, things that I've noticed that I'd like to change a little for my own use:
- The system appears to be designed to always be engaged with the tire. Unless I've setup the spring incorrectly and its supposed to jump back off the tire. I'm awaiting confirmation from the manufacturer on this point as I can't find any videos yet of the system to see how its supposed to perform
- If it is always supposed to be engaged then I will be running a cable from a left side bar end shifter to pull it off the wheel whenever I know I won't be using it.
- Get some longer RC cables so I can move the battery and controller into a touring saddlebag. The system comes with very short cables and it appears is to only be installed as the maker intended. i.e. everything close together as in the above picture.
- Fenders. I've already begun hacking up my metal fenders. I'll get them back on soon.

If anyone wants a pic or thought on any specific aspect of it let me know.

Controller




Motor













Throttle

 

[jbond]

There's an end stop for when it's under power. Where's the end stop for when it's off? It looks like you could just raise it a few mm and it would no longer touch the tyre when off.

 

[adrian_sm]

How does the throttle work?

 

[RayB]

The throttle is a roller dial. Basically mount it under your bar and roll if with your index finger. First one I've come across that I can use easily on the drop bars.

@jbond, there is no end stop for when its off. Basically there is a spring that wraps around the end of the motor to the mount that you can adjust to keep it from bouncing off. I've tried a few adjustments but when there seems to be no happy medium where the motor will bounce off, and when re-engaged cleanly hit the wheel again. Going to see what they say.

 

[Kepler]

The adjustment seems to be an end stop when under power and I think you adjust the drive postion so its in contact with the wheel all the time even when not under power. I think the idea is to keep the contact light and have the one way bearing free wheel when not under power. Thats what it looks like to me anyway