Single-speed track stealth ultralight

Great idea on the 3 button throttle! I'm also seeking a more sophisticated solution.

I was originally thinking a single button with a remote mounted thumbwheel to dial in the throttle signal value, but that sounds fiddly and would probably be a PITA on a day to day basis.

Are you going with the bullhorns for some more aero? Or ergonomics? Both?

One thing I try to explain to my flat bar riding buddies is that having the multiple positions of drop bars is so much more comfortable on the wrists than flat bars. I feel like the main improvement being in the "on the hoods" position which the bullhorns give you too.

Just the narrower grip width does wonders for aero compared to the typical mountain bike bar, all else being equal.

I'm going with the bullhorns mostly for ergonomics, but I think I may need to install a shorter stem. The reach is feeling a little too long sitting on the bike. I can say that the narrower and 90º turn in wrist position already feels better than the MTB style bars. I need to get some miles on it to be sure though.

I'll post more updates as I get the throttle made and the rest of the bars set up.

zro-1 said:

I'm planning on changing out my standard bars for some bull horn bars. In anticipation of that change, I figured out how to make a 3-button throttle today. The idea is that the three buttons would be next to each other on the bars. You press button-1 to get 30% throttle, you press button-1 + button-2 together to get 60% throttle, and you press button-1, button-2, and button-3 together to get 100% throttle.

Here's what that circuit diagram looks like to do that:
3-button_throttle_schematic.jpg

And here's what the actual wiring would be like:
3-button_throttle_wiring.jpg

I'll be using the same micro momentary buttons that Kepler is using with his friction-drive bike.
95C12A3GWRT_DSL.jpg

Since I'm using a Phaserunner controller, the "throttle" settings won't determine my top speed, instead they'll determine how many amps are going into the motor. If you ignore a few things, and all else being equal, you can almost think of this as 30% assist, 60% assist, and 100% assist, as opposed to slow, medium, and full speeds. Of course, if you used a more traditional controller then the buttons would be setting the speed limit rather than the torque limit.

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Why not go with small slider pot? Takes less space, more controllable.

multifrag said:

Why not go with small slider pot? Takes less space, more controllable.

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¯\_(ツ)_/¯ I guess because I didn't know how reliable a slider pot may be or if it was spring-loaded, and buttons on the grips are easy: squeeze to go.

I would be worried about the weatherproofness of a traditional slider pot as I am an all seasons rider. Plus they wear as they age and can result in some spotty throttle commands (or so I assume).

Been searching for an affordable linear Hall effect potentiometer in the right size.

I mentioned back in one of my first posts that I didn't have a target weight in mind other than "as light as possible". Well today I picked up a bathroom scales and I weighed the bike. It came in at 20.6 pounds.

I still have to tape the bars, run the brake cables, and make/install the 3-button throttle, but I'd be surprised if all of that came to more than 0.4 pounds combined.

Granted, I'm carrying my battery in my backpack. So if I ever put it back on the frame, that would add 3 pounds, but I'm also going to be changing over to the Xiongda YTW-06 which weighs just 2.87 pounds versus the Q100H which weighs 4.73 pounds, so that will shave off 1.76 pounds which is about half the weight of the battery pack.

With the battery mounted on the bike and the YTW-06 motor, I'd be looking at a total weight of about 21.8 pounds total. Not bad.

MonkeyWrench said:

I would be worried about the weatherproofness of a traditional slider pot as I am an all seasons rider. Plus they wear as they age and can result in some spotty throttle commands (or so I assume).

Been searching for an affordable linear Hall effect potentiometer in the right size.

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Yeah, the weather-proof-ness and longevity of a pot worries me. A linear hall might not have been bad. I think overall though my 3-button design will be the most robust and accident-proof. I plan on inserting the buttons into some non-shrunk heat-shrink then sealing the ends with liquid tape and pressing them flat. I can then use the extended flat ends to go under the bar-tape to hold the buttons in place. It'll be completely sealed from water, and won't require additional zipties or tape to hold them in place.

zro-1 said:

I'd be looking at a total weight of about 21.8 pounds total. Not bad.

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That's stellar! All up incl the lipo bricks I'm at about 28 lb. Before conversion this bike, even though CF, was over 18 lb- probably some extra beef here and there due to it's cyclocross origin.

I'll be interested to hear your experience with the little Xiongda.

I love your build MonkeyWrench. I bet you could chalk up the ~7 pound difference mostly to disk brakes and multiple gears—both of which are worth the extra weight under the right riding conditions.

Before I started changing my bars, I had taken my bike for a short run around the neighborhood to attack all of the steepest hills I knew about. I'm pleased to say that the motor held it's own, though on the steepest climb I was huffing and puffing and had the numb-thigh burn going pretty strong trying to keep my speed up for the motor.

The steepest grade according to Strava was 15.6%. Total elevation was 432 feet. Average speed was 18.9 mph and top speed was 29.8 mph (the top speed on the flats wide open is a little faster than that.

Here's the segment where the steepest climb was:


I know for some of you that bit would have been a minor hill, but here in Atlanta, that's a decent climb. It was tricky on the single-speed for sure.

I got the email notification that my YTW-06 motor has shipped, and according to the UPS tracking, it should be here Monday!

I am a big fan of button throttles on low powered setups. Having the button set a current limit is in my opinion the best way to go which is essentially what you are planning from what i can see.

I think what you are proposing will work well and will suit the bull horn bars nicely.

This is my setup on drop bars. Very stealth and comfortable to use.

Don't they provide a lightweight controller too? A phaserunner may be too much power for this little motor

cwah said:

Don't they provide a lightweight controller too? A phaserunner may be too much power for this little motor

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This motor is "rated" as 250W, but they sell it in 24V/36V/48V configurations. At 24V this motor would be running at 10.4A probably almost all the time.

The Phaserunner is completely programmable, so it'll only be too much power if I set it to be too much power. I just set what max wattage I want to go into the motor and the voltage of the battery, and the amps are computed automatically. So I could run this at 250W max (48V, 5A) all the way up to my battery max of 960W max (48V, 20A). I'll probably start at 480W max (48V, 10A) and see how it does.

I bet this motor can handle 12A (576W max) for short bursts. However, with 17:1 gearing, I probably won't even need that many amps. Even with my fast-geared Q100H I almost never use full throttle.

Kepler said:

I am a big fan of button throttles on low powered setups. Having the button set a current limit is in my opinion the best way to go which is essentially what you are planning from what i can see.

I think what you are proposing will work well and will suit the bull horn bars nicely.

This is my setup on drop bars. Very stealth and comfortable to use.

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Thanks for sharing those pics of your setup Kepler! I really like how you set the 2-buttons up. Honestly, you saying you think this will work well is a huge relief for me, because I really wasn't sure for a long time how to make it work. You sharing your wiring diagram on your for-sale thread really helped me get my head around how to wire the buttons up. If I hadn't seen that, I don't think I'd have come up with my version.

I discovered that I connected my buttons wrong, so the circuit was always closed. I'm removing the posts of the buttons to avoid someone making the same mistake I did.

One other tidbit:
Bonnie messaged me to let me know the motor had shipped, and in the message, she mentioned that they tested the motor and it was spinning at 230 RPM at 36V. That works out to 6.39 RPM/V, so at 48V, this motor should spin at 306.7 RPM. That's still dang fast in a 700c wheel with the added benefit that I'll have 17:1 gearing for loads of torque.

I can not wait to put this puppy through it's paces.

zro-1 said:

One other tidbit:
Bonnie messaged me to let me know the motor had shipped, and in the message, she mentioned that they tested the motor and it was spinning at 230 RPM at 36V. That works out to 6.39 RPM/V, so at 48V, this motor should spin at 306.7 RPM. That's still dang fast in a 700c wheel with the added benefit that I'll have 17:1 gearing for loads of torque.

I can not wait to put this puppy through it's paces.

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This will be a great data point to have! I'll be interested to hear about the tradeoffs between the Q100 and the YTW-06. Looking forward to your results.

Good stuff on the push button throttles~

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Side Project:

After looking back over Kepler's build thread and seeing how he added the controller to a side pocket in his seat bag along with the batteries, I'm inspired to try another stab at a seat bag. IT seems like you can't get cleaner or more stealthy than having it all in a little bag with just the cable to the motor and a throttle cable. Having the Phaserunner down by the bottom bracket on my bike is clean, but since it's not getting hot, I think I can safely keep it in a bag.

Now that I've had time to get used to how this light single-speed track frame feels, I think some of my first impressions of the weight were just me not being used to the bike. I have enough loose cells to build a second 13S2P battery, but I'll need to do some cleanup on the battery ends and re-insulate them. I also need to get a 2nd BMS.

I'm not going to change anything with the battery right away. The backpack setup works well and isn't an issue. I'll build this seat bag pack separately and change stuff around when it's ready. What I'd do at that point is remove the battery cable running down the frame, and slide in the phase & hall wires to hook up to the motor cable down by the bottom bracket or chain stays.

The YTW-06 just arrived. It looks very good and matches up with the pics and descriptions online. I've added pics to the motor thread here: http://endless-sphere.com/forums/viewtopic.php?f=2&t=93087&p=1367834&sid=78f37963f901ec6e0a89c03191a7ce3d#p1367834

I don't have a ton to add right now, but I have the motor all laced/tensioned/trued into the wheel and I tested it with the Phaserunner. Everything works on the autotune setup. The halls are reading fine and it went through autotune without a hitch. If you are planning on a similar setup, you need to make sure you set the Feedback Bandwidth Tuning. I entered 2000 RADs for the Current Regulator Bandwidth and 2 RADs for the PLL Bandwidth. The help pop-up in the app for these settings say that you may need to go as high as 3 RADs for the PLL Bandwidth with small geared hub motors. Setting the Feedback Bandwidth Tuning is critical to avoid the "Phase Over Current" fault when trying to run autotune. Other than setting those the only other critical setting to get started is entering the Effective Pole Pairs for the motor (140 for the 17.5:1 geared version).

So what are my first impressions after 30 seconds of powering the motor?

1) The clutch:
The clutch is very stiff and noisy. It actually makes a sound when "freewheeling" by cranking the pedals with the wheel in the air, that almost sounds like the motor is under power. The stiff clutch seems to be the nature of this motor, as other people who have bought this have made the same comment. I'm really hoping that this goes away as the clutch wears in after a few hundred miles. A tight clutch is nice to avoid slipping, but this is a bit much right now. Its so tight, the wheel really doesn't freewheel when you spin it by hand more than a half turn or so. I'm going to commute on this for a week to see how the clutch gets, and if it stays really stiff, I may open the motor up to get a look at how the clutch is set up and see if I need to modify it with different springs or something. I don't think the clutch is locked-up, I just think it's quite stiff.
2) Motor sound level:
I am still waiting on parts to make my revised 3-button throttle. (My design is fine, but I soldered the buttons up in a short across the switch circuit, so it was like they were closed all the time). So, since I don't have a throttle to hook up at the moment, I could only listen to the motor while it was up in the air durning the auto tune setup of the Phaserunner. My first impression was that this is not very different than the Q100H that was previously on the bike. Only a ride will say for sure what the sound levels are like though.

As for the throttle, I found some nice IP67 rated waterproof buttons that will work nicely for the throttle. I'm just waiting for them to show up from mouser.

I've got all the assembly done, and my wiring completed with one exception. I'm still waiting for the parts I need to make my throttle.

Here's a few pics of the newly reassembled bike:






And just so that there is an easy reference, here's the first setup next to the revised setup:


View attachment 3

Your bike has turned out really nice that hub looks no bigger then a IGH IMO. Comparatively my 350w Mxus xfo7 looks beastly

Where did you buy the torque arm?