Friction drive outrunner setup. New DJ bike.

[EVTodd]

thanks todd.

i did recently buy a mystery 60a controller because that was all i could find on ebay(i couldnt find the 80a or 100a at the time i bought it, but a day after i did buy it, i get suggestions for the 80a controller. oh well, its cheap enough that if i did destroy it, i wouldnt be too pissed.) all i needed to hear was that it was holding up. *knock on wood* im not terribly heavy (like around 120lbs.) so im hoping this will last me at least a season of riding. this time i should hook up my wattmeter instead of just thinking its doing fine

i gotta say todd, your friction drive setups always made me want to build one. now that i have one together, i regret not doing it sooner, even though it is on a standup scooter

I would add at least an extra cap the the esc. I don't know if that has helped or not but we've had one on there ever since I put her bike together.

I'm interested in hearing how long it holds up on your scooter. Since it's a smaller wheel I wonder if it takes more amps to get it going. I realize the size of the wheel doesn't change the top speed but in my mind it seems like it might change the torque required to move it. If I'm wrong I hope someone else chimes in.

Keep in mind that we're only running her on 5s lipo with a top speed of 18 to 19 mph. I wouldn't push that esc much more than that. I think I've mentioned it before but we also keep a spare 60 amp esc in my panniers just in case she smokes one. Heck, they're almost as cheap as a fuse, may as well have a spare.

Glad to hear you're enjoying friction drive. It sure is a cheap way to get into this hobby (or obsession as it were).

[EVTodd]

Wow, it's been a while since I've posted anything on this thread!

Here are a couple of new pictures and a little video I took today:






It's funny, my rim is straight as an arrow but it looks way out of true in this vid. Must be the tire.

This was a quick blast around my neighborhood. My intent was to make it 100% no pedal but I have a hard time not pedaling when I'm on a bike.

Anyway, I thought some of you other friction drivers out there might enjoy it.

[deVries]

Hey Todd,

Thanks for posting an update.

Is there any way possible just to re-post all your previous pics of this build too? I think you even had 2-3 more videos too. To save time just upload in a single post or "batch". I believe this build thread is still one of the top 3 if not #1 for an original friction drive design that has yet to be topped by further improvement.

I would like to see some 360 degree views pics/vid of this rack mount w/motor with the saddle bags removed, so one can clearly see your parts & design, attachments, etc.

Please update with more video/pics if at all possible. If you lost what you did before, then you could make a new build review video that would cover all the key steps and/or visuals to building one of these.

I'm surprised how quiet this motor seems to be. Did any of the replacement parts/bearings or something quiet this down from the original motor?

[EVTodd]

I would post a 360 view of the drive but I pretty much use this bike every day and I'd hate to take everything apart right now. It's not that bad but I would have to pull the battery pack out to get the bags off.

If you look at the pictures of my gf's kona (which you can find on my new build thread) you'll pretty much see everything. The drive is simply mounted to the rack via 2 machine bolts. I made a mount for her frame but it's exactly the same on my bike except for being mounted on a rack.

I believe I only posted one other video but I'll see what I can dig up on my old computer.

I will be posting a lot of new stuff on my Tidalforce build soon, much of which will be very similar to this setup.

As far as the noise goes. I dunno. This video does seem pretty quiet. In fact you can hear me breathing at the end but the motor is muffled. I tihink it's just the cheap keychain camera I'm using. Ya never know what it's going to pick up.

I personally think it's about the same as any other outrunner powered bike but I have nothing to compare it to. As for the bearings, believe it or not I'm still using the originals. I've changed absolutely nothing on this motor except for re-gluing the magnets and shimming the can out a bit further after it moved a bit on me. I'm shocked by how many miles I have on it (well over 2000 miles and probably getting close to 3000 at this point).

[Kepler]

In my opinion the slide mount is still the most efficient method of progressive drive contact. Your video clearly shows how nicely the motor to tyre contact modulates under different loads. Its got me thinking of direct motor contact arrangement on a slide mount rather then a swing mount. Hmm, time to hit SolidWorks again

[EVTodd]

In my opinion the slide mount is still the most efficient method of progressive drive contact. Your video clearly shows how nicely the motor to tyre contact modulates under different loads. Its got me thinking of direct motor contact arrangement on a slide mount rather then a swing mount. Hmm, time to hit SolidWorks again

Lol, every time I post something someone either doesn't believe me or wants to sell the idea. Lol. That's ok I suppose. I will say that I personally think making a sliding mount is a lot easier than custom electronics but I guess it depends on what kind of background you have.

I also think you're better off with a separate roller but I know most people on here are dead set on using the can of the motor as the roller.

[spinningmagnets]

For those who have joined ES this past year, I built a friction-drive that is a copy of Todds, and I am still happy with it. It climbs well on 36V, and I suspect it will climb even better on 44V-48V. I do not recommend 22V-24V unless you live in flat terrain.

I also think you're better off with a separate roller, but I know most people on here are dead set on using the can of the motor as the roller

Todd, I agree. This is one of the things that drew me to your design. The roller diameter and motor selection are two separate choices, and also no skirt bearing is needed.

As far as the noise goes. I dunno. This video does seem pretty quiet

I found that the Exceed motor was noticeably quieter than the two Turnigy motors I tried, however the noisiest motor was still pretty quiet. When stealthily mounted under saddlebags just as you have done, the motor would be even quieter. It would be cheap and easy to box it in, and add a cooling fan to make it extra quiet if that was a worry for anyone.

Todd, I hope that my discussions in the past did not deter you from making more of these and possibly selling them to the public. I did make a similar drive head with a separate roller and motor, which I sold to ES member Rearengine. He put it on a swinging mount rather than the slider you designed, and he asked for it, I did not advertise. I can and will continue to offer aluminum rollers for sale until someone else makes them available to the public. I would prefer to buy a steel EV-Warrior roller, but used units are only available rarely on Ebay and similar venues.

It was a lot of fun making the copy of your drive, but I don't want to sell them to the public after seeing what it takes to make one, and crunching the numbers. If anyone is curious about them, all I can say is...Its a great design, and I like mine a lot.

[EVTodd]

Honestly, no, it wasn't anything here that stopped me from selling them. I seriously thought about everything and didn't really think there would be that big of a market for it. I would love to be involved with electric bikes full time but I'm not sold on friction drive being a viable product. There is so much negative attitude towards it in general that I think it would be almost impossible to overcome.

It's sad because I really believe people are missing out on something here.

I've had some interested parties including companies contact me but I don't think there have been any real offers so I'm back to just having fun with it.

[Kepler]

What I don't like about the roller set up is the need for a coupling and that the motor protrudes out the side of the drive. When I tried a set-up with the motor on the side, it really surprised me how easy it was to knock the back of my foot on the motor. Maybe it was the type of bike I was using but to me this was a safety issue and without some sort of cover over the motor, could pose a problem if building drives for sale.

When it comes to a market for friction drives, I have an inbox with enough enquires to suggest it is worthwhile pursuing however the hard part is making it user friendly enough for the general public to use hence the big focus on the electronics side.

Each to his own.

[EVTodd]

What I don't like about the roller set up is the need for a coupling and that the motor protrudes out the side of the drive. When I tried a set-up with the motor on the side, it really surprised me how easy it was to knock the back of my foot on the motor. Maybe it was the type of bike I was using but to me this was a safety issue and without some sort of cover over the motor, could pose a problem if building drives for sale.

When it comes to a market for friction drives, I have an inbox with enough enquires to suggest it is worthwhile pursuing however the hard part is making it user friendly enough for the general public to use hence the big focus on the electronics side.

Each to his own.

I agree that the motor being off to the side can be a problem as far as your foot hitting it. Usually though, if it's mounted high enough it's not an issue. I would hit my foot on my gf's setup but it's never been a problem on my bike. Coupling the motor, however, is super easy and really a non-issue (for me anyway). But, the fact is, the reason some people are having startup issues with these drives is because the roller is so big.

I'm sure there is a lot of interest in a simple lightweight drive but is there room in the market for several different kinds of friction drives? You've seen it on this forum... Once people see how easy they are to make they want to start selling them. You don't see that with Matt's drive and there's a reason. Not everyone can make one. Most people can make a friction drive if they really want to.

I'm sure with the right marketing someone could have a decent go at selling them but like you said, they have to be user friendly and there are SOOOO many issues with lipo, mounting the drive, etc... And that's not even getting into the subject of product liability.

[spinningmagnets]

Kep, I believe that your drive is the absolute lightest and most compact an E-assist can be, and because of that, it is very appropriate for it to be promoted on light road bikes (though of course its good with any frame styles that it fits). Road bikes seem to have the shortest possible chainstays with the front of the rear wheel very close to seat-post.

Beach cruiser style frames, and also the recent crop of feet-forward frames would leave plenty of space between a riders heel and the protruding motor. However, If you set your mind to it, we could design a sliding housing to hold a motor-shell drive!

I was drawn to Todds design for several performance reasons since your amp-limiter was not available and I couldn't make one myself, but the thing that spurred me to actually make the drive was the ability of a seat-post mount to be popped off and carried up to the third floor where my apartment was (for the last year), while the bike remained chained outside.

I would only recommend planning on using less-than 2-HP/1500W peak with a friction drive, since at these mid-power levels, tire wear is not a concern. I had to really try hard to get 1500W to register, and that was where I was getting significant slippage and tire wear.

Todd posted that he drew 40W peak and 10W continuous, and my CC-ESC logged the same result, so...to maintain cruise on level ground at 20-MPH the system was drawing 25V X 10A = 250W, and normal acceleration drew 25V X 40A = 1000W. My drive climbed much better @ 37V, but my 37V Hobbywing ESC doesnt have data-logging.

[EVTodd]

I was just working on my bike this morning getting everything tuned up for spring if it ever gets here. I thought I would do a little reading on the 'ol sphere since I haven't been here in a long time.

I can't believe how long ago I started this thread, almost 4 years ago!

Quick update if anyone cares. I'm still on the same motor with it's stock bearings. I had an issue with the motor's can starting to pull itself over to one side but I put red lock tight in the groove and pressed it back together, been fine ever since. Actually, looking back at the thread, that little issue was quite some time ago too.

I'm also still using the original batteries, and steel roller with very little sign of any wear on the knurls at all.

During warm months (when it's not raining) this has become my main form of transportation since I only have about an 8 mile round trip for work every day (with one very large hill coming home).

Fun stuff, looking forward to another season with it.

[def215]

its good to see you back here todd!

good to see the bike is still running too! is the "ghetto" friction drive still together and running if i may ask?

[spinningmagnets]

Glad to see you posting Todd. Hope things are going well...

edit: I recently moved to a job much farther from my home. I stopped E-bike commuting when winter first set in, so I probably won't be riding much on workdays. Just wanted to say that during the 8 months or so that I ran the friction drive, I had no problems with it. Your design is excellent in every respect, and having the motor and roller as separate elements is a definite advantage. I wouldn't lose traction till somewhere above 1,000W, which was rare, because one of the main benefits to me was the excellent miles-per-WH, so...I was always taking it easy so a very small pack would get me there.

[EVTodd]

its good to see you back here todd!

good to see the bike is still running too! is the "ghetto" friction drive still together and running if i may ask?

Thanks! I kinda missed it here. I've been busy starting a new business and dealing with family stuff. Hopefully I'll have more time for some of my hobbies again.

But yup, still the original drive, motor, bearings, batteries, esc, everything. I lost track of how many miles I have on it because of my cheap chinese speedometers going bad but it's racked up quite a few at this point.

The gf's Tidalforce "ghetto" drive bike is still going strong too. She doesn't ride quite as much as I do but her original mystery controller is still working. I'm actually shocked it hasn't blown yet (knock on wood) but she's pretty easy on it.

I really couldn't be happier with the drives. I really never thought they would last as long as they have. I was talked into building a couple of copies of it last year for some other local e-bikers. They're still going strong too and we get together every couple of weeks during the summer for a ghetto drive ride. lol

My biggest problem is that it's still snowing here in the Midwest even though it's officially spring.