Commuter Booster - <1kg Friction Drive

Discussions related to motors other than hub motors.
This includes R/C motors, botttom bracket, roller and geared drives.
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Kepler   1 GW

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Re: Commuter Booster - <1kg Friction Drive

Post by Kepler » Jan 07 2011 6:18am

I've got plenty of 40 grit I will cut you a piece :)

I have tried a simple button with a moderate ramp to full throttle. I didn't like it much. I found it worked the drive too hard when I wanted assistance going up a hill and my speed was too low. Depends on how you use the drive though so worth giving a go to see if it works for you.
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Re: Commuter Booster - <1kg Friction Drive

Post by adrian_sm » Jan 07 2011 10:01am

I just completed the remote shunt mod on my Turnigy Watt Meter. I even put a nice little switch in too. 8)

Here is what I did....

Step 1 - Remove the old shunt.
IMG_1733.JPG
IMG_1733.JPG (75.05 KiB) Viewed 6484 times
Step 2 - Wire inline with a few battery connects on the end of some 3-core cable.
IMG_1735.JPG
IMG_1735.JPG (73.01 KiB) Viewed 6488 times
Step 3 - Connect the 3-core wires to the right spots on the main PCB, adding a switch on the +ve line.
IMG_1738.JPG
IMG_1738.JPG (76.67 KiB) Viewed 6484 times
Step 4 - Shove it all back in the box. Done.
IMG_1740.JPG
IMG_1740.JPG (69.44 KiB) Viewed 6488 times
Thanks Jeremy.

- Adrian
Build #1 ~28kg ~ 700w Avanti Hardtail Crystalyte 408, 48V10Ah Headway. ~5500 kms to date. (retired)
Build #2 ~30kg ~2000w Giant AC Dually Crystalyte 408, 48V10Ah Headway + 6s10Ah LiPo = 70V. ~15000 kms to date [SOLD]
Build #3 ~13kg ~2000w Commuter Booster <1kg Friction Drive
Build #??? ~21kg ~1500w Adrian's Bafang BPM Hardtail MTB Bafang BPM code12, 15s LiPo, ~40kph, ~30kms

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Re: Commuter Booster - <1kg Friction Drive

Post by adrian_sm » Jan 08 2011 1:31am

If anyone else is thinking about doing this mod, please remember when you re-solder the shunt remotely it affects the shunt resistance, and hence reading. Therefore you you will need to recalibrate it.

Luckily the meter has a little adjustment pot just for the purpose. So all you need to do is adjust the left hand pot in this image while verifying the current with something else like a DMM or CycleAnalyst. I used my CA. It tooks heaps of turns of the little adjsutment screw but it is all good now. The voltage reading was still spot on, so no adjustment required there.

Image

So:
- left pot is for current
- right pot is for voltage.

- Adrian
Build #1 ~28kg ~ 700w Avanti Hardtail Crystalyte 408, 48V10Ah Headway. ~5500 kms to date. (retired)
Build #2 ~30kg ~2000w Giant AC Dually Crystalyte 408, 48V10Ah Headway + 6s10Ah LiPo = 70V. ~15000 kms to date [SOLD]
Build #3 ~13kg ~2000w Commuter Booster <1kg Friction Drive
Build #??? ~21kg ~1500w Adrian's Bafang BPM Hardtail MTB Bafang BPM code12, 15s LiPo, ~40kph, ~30kms

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Re: Commuter Booster - <1kg Friction Drive

Post by adrian_sm » Jan 08 2011 4:54am

Update: 63-74 motor on the road bike

Managed to fit the CBv2 with the larger 63-74 200kv motor on the road bike.
This is a bike with a large frame (i am 6'2") and there is only just enough room. I can still optimise the pivot/clamp block to give me a bit more room by getting the pivot shaft closer to the seat tube, but I suspect that most road bikes frames won't work with the bigger motor. They will end up needing something like the smaller
50-65 270kv motor I have on CBv1.

Here is a pic of my roadbike with the 63-74 CBv2 with 2x 5s5000mah LiPo in the frame bag, combination button/servotester throttle, and the CA on the bars. Ultimately for this DIY version I would like to replace the servotester and CA with a modified wattmeter, I just need to get my head around the AVR assembler language. There is also quite a bit of wasted space in the frame bag (rectangular pack in triangular bag), that adds visual bulk, I might try Hyena's drain pipe battery tube as I can't find a decent electronics type enclosure that I am happy with, they all have too much wasted space, but they might have allowed me to mount the ESC and batteries all in one neat package...

Anyway, I reckon it looks pretty good for a 2kw e-bike. 8)
2011_01_08 - CBv2 on roadbike.jpg
2011_01_08 - CBv2 on roadbike.jpg (88.25 KiB) Viewed 6441 times
- Adrian
Build #1 ~28kg ~ 700w Avanti Hardtail Crystalyte 408, 48V10Ah Headway. ~5500 kms to date. (retired)
Build #2 ~30kg ~2000w Giant AC Dually Crystalyte 408, 48V10Ah Headway + 6s10Ah LiPo = 70V. ~15000 kms to date [SOLD]
Build #3 ~13kg ~2000w Commuter Booster <1kg Friction Drive
Build #??? ~21kg ~1500w Adrian's Bafang BPM Hardtail MTB Bafang BPM code12, 15s LiPo, ~40kph, ~30kms

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Re: Commuter Booster - <1kg Friction Drive

Post by Solcar » Jan 08 2011 7:05am

:wink: It looks great!
LTspice free electronics simulator was helpful in my electronics hobby.

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Re: Commuter Booster - <1kg Friction Drive

Post by rearengine » Jan 08 2011 2:30pm

Very Nice & clean Adrian... Good job !! Your doing good for others on the forum also ...

It looks like you , and I are on opposite ends of the bicycle spectrum .. You up on your Road bike ,and me down on my recumbent :lol: Best part is they are running .. Bill

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Re: Commuter Booster - <1kg Friction Drive

Post by hillzofvalp » Jan 08 2011 8:16pm

How does it run?! it looks great. Do you think that the 63-74 will work on my 59cm steel frame? it looks like it would. I just ran into a speed bump because the mounts in my seat tube keep the batteries from going down. :(

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Re: Commuter Booster - <1kg Friction Drive

Post by adrian_sm » Jan 09 2011 3:58pm

Update: Weigh-in, and size comparison
- CBv2 with 5063 motor = 0.65kg
- Full bike = 12.1kg !


Okay I upgraded the old CBv1 that had the small 5063 motor, to the CBv2 design. This includes:
- single swing arm
- adjustable dead stops
- new adjustable torsion spring

This shaved some weight off.
CBv2 with 5063 motor weighs: 646 grams, or 1.4 pounds
CBv2 with 6374 motor weighs: 1239 grams, or 2.7 pounds
2011_01_09 - CBv2 - 5063 weigh-in (small).jpg
2011_01_09 - CBv2 - 5063 weigh-in (small).jpg (78.28 KiB) Viewed 6133 times
2011_01_09 - CBv2 - 6374 weigh-in (small).jpg
2011_01_09 - CBv2 - 6374 weigh-in (small).jpg (78.59 KiB) Viewed 6133 times
I also took a few photos to show the difference in size.
Here they are side by side on the bench. Bit hard to tell the difference.
2011_01_09 - CBv2 - 6473 vs 5063(small).jpg
2011_01_09 - CBv2 - 6473 vs 5063(small).jpg (96.09 KiB) Viewed 6133 times
2011_01_09 - CBv2 - size comparison (small).jpg
2011_01_09 - CBv2 - size comparison (small).jpg (91.83 KiB) Viewed 6133 times
Once you mount them on the bike it is a lot more obvious. The larger frame motor only just fits my large framed bike. As I think this style of drive suits a road bike the most, I think I am going to focus my efforts on the smaller motor for now.
2011_01_09 - CBv2 - 5063 (small).jpg
2011_01_09 - CBv2 - 5063 (small).jpg (110.31 KiB) Viewed 6133 times
2011_01_09 - CBv2 - 6374 (small).jpg
2011_01_09 - CBv2 - 6374 (small).jpg (105.67 KiB) Viewed 6133 times
I still think the most impressive thing is the overall weight of the bike, only 12.1 kg :shock: , or ~27 pounds, with CBv2 5063, and 5s10Ah of battery, and CycleAnalyst on the bars. It makes my Giant AC1 with x408, and 80v10Ah feel like a motorbike, at 32.1kg, or ~71 pounds.
2011_01_09 - Avanti Giro - CBv2 vs Giant AC1 - 408 (small).jpg
2011_01_09 - Avanti Giro - CBv2 vs Giant AC1 - 408 (small).jpg (132.65 KiB) Viewed 6133 times
Now I just wish the weather forecast would improve, so I can get some more road time on it. As I have not weather proofed anything yet, I am reluctant to use it on my commute to work yet. Maybe this is just mother nature's way of telling me I need to resolve that issue now. :)

- Adrian
Build #1 ~28kg ~ 700w Avanti Hardtail Crystalyte 408, 48V10Ah Headway. ~5500 kms to date. (retired)
Build #2 ~30kg ~2000w Giant AC Dually Crystalyte 408, 48V10Ah Headway + 6s10Ah LiPo = 70V. ~15000 kms to date [SOLD]
Build #3 ~13kg ~2000w Commuter Booster <1kg Friction Drive
Build #??? ~21kg ~1500w Adrian's Bafang BPM Hardtail MTB Bafang BPM code12, 15s LiPo, ~40kph, ~30kms

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Re: Commuter Booster - <1kg Friction Drive

Post by deVries » Jan 09 2011 6:53pm

adrian_sm wrote:Update: Weigh-in, and size comparison
- CBv2 with 5063 motor = 0.65kg
- Full bike = 12.1kg !

Okay I upgraded the old CBv1 that had the small 5063 motor, to the CBv2 design.
Most excellent documentation, as usual. 8)

Can you make a video that shows how you adjust the motor into the ideal location/position, or explain that adjustment in detail?

Can you shoot some video of the friction drive working on the road showing it engaging & disengaging the tire?

Please, please, please. :P

Thanks! :D

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Re: Commuter Booster - <1kg Friction Drive

Post by adrian_sm » Jan 09 2011 9:28pm

Sure. I just need to finish the camera mount for the on-road shots.

As for drive adjustment, I still don't know the optimum yet. So will hold off sharing the installation instructions until I do.

- Adrian
Build #1 ~28kg ~ 700w Avanti Hardtail Crystalyte 408, 48V10Ah Headway. ~5500 kms to date. (retired)
Build #2 ~30kg ~2000w Giant AC Dually Crystalyte 408, 48V10Ah Headway + 6s10Ah LiPo = 70V. ~15000 kms to date [SOLD]
Build #3 ~13kg ~2000w Commuter Booster <1kg Friction Drive
Build #??? ~21kg ~1500w Adrian's Bafang BPM Hardtail MTB Bafang BPM code12, 15s LiPo, ~40kph, ~30kms

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Re: Commuter Booster - <1kg Friction Drive

Post by adrian_sm » Jan 10 2011 7:43am

Update: Weatherproofing & ESC mounting

Playing around with ESC mounting, and weather proofing at the moment. I was planning on using a little electronics enclosure and cutting a hole for the ESC heat sink to poke out. Then mount the enclosure to the bike somewhere. This would protect the ESC from the elements, let me hide any additional electronics and provide panel mount connection possibilities for throttle, lights, dashboard. But I might just make the enclosure the ESC came in waterproof instead, and keep wiring exposed. The 85A ESC comes with a 5 sided plastic cover, that wouldn't be too hard to seal up, leaving the heatsink exposed. Unfortunately the 100A ESC only has a 3-sided plastic cover, so this would be a bit more of a challenge.

As for mounting positions, I tried a lot of different spots, but only liked two of them, and one of those would restrict the frame size the drive would suit. So then there was one.
- ESC to be screwed on to the front/centre of the clamp/pivot block in the vertical orientation.
- ESC battery wires enter from the bottom, phase wires exit out the top.
- motor phase wires now enters the bottom of the motor to add a drip loop.
IMG_1782.JPG
IMG_1782.JPG (89.69 KiB) Viewed 5125 times
Here is the bike in minimalist mode, <12kg.
- CBv2 5063
- 85A ESC
- Single 5s 5000mAh battery in the water bottle.
IMG_1784.JPG
IMG_1784.JPG (98.75 KiB) Viewed 5121 times
- Adrian
Build #1 ~28kg ~ 700w Avanti Hardtail Crystalyte 408, 48V10Ah Headway. ~5500 kms to date. (retired)
Build #2 ~30kg ~2000w Giant AC Dually Crystalyte 408, 48V10Ah Headway + 6s10Ah LiPo = 70V. ~15000 kms to date [SOLD]
Build #3 ~13kg ~2000w Commuter Booster <1kg Friction Drive
Build #??? ~21kg ~1500w Adrian's Bafang BPM Hardtail MTB Bafang BPM code12, 15s LiPo, ~40kph, ~30kms

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Re: Commuter Booster - <1kg Friction Drive

Post by hillzofvalp » Jan 10 2011 5:40pm

Do any of your kids know how to use a camera? Seriously. We need some video of you or someone on this rig

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Re: Commuter Booster - <1kg Friction Drive

Post by adrian_sm » Jan 10 2011 5:51pm

It will have to wait until the weekend. I am back at work now, and the weather is pretty dodgy. But the weekend looks good.

How is you build going?

- Adrian
Build #1 ~28kg ~ 700w Avanti Hardtail Crystalyte 408, 48V10Ah Headway. ~5500 kms to date. (retired)
Build #2 ~30kg ~2000w Giant AC Dually Crystalyte 408, 48V10Ah Headway + 6s10Ah LiPo = 70V. ~15000 kms to date [SOLD]
Build #3 ~13kg ~2000w Commuter Booster <1kg Friction Drive
Build #??? ~21kg ~1500w Adrian's Bafang BPM Hardtail MTB Bafang BPM code12, 15s LiPo, ~40kph, ~30kms

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Re: Commuter Booster - <1kg Friction Drive

Post by adrian_sm » Jan 11 2011 5:33am

Just realised something pretty good. Bikes have standardised seat tube outer diameters, for deraileur mounts etc, and variable inner diameters to shave weight, or increase strength. This means there are heaps of difference in seat post diameters, but only a few seat tube outer diameters.

- Older style road bikes 28.6mm (1 1/8")
- Newer style road bikes 31.8mm (1 1/2") <-- Size of my white CB
- Mountain bikes 34.9mm (1 3/8") <-------- Size of my black CB

Too easy. :D No need to stuff around with shims if someone wants to try out my drive on their bike. 8)

- Adrian

[EDIT] Old steel frames, really cheap bikes and BMX's may have a 25.4mm (1"). But I think the 32.8 & 34.9mm sizes cover most modern bikes this drive would suit.
Build #1 ~28kg ~ 700w Avanti Hardtail Crystalyte 408, 48V10Ah Headway. ~5500 kms to date. (retired)
Build #2 ~30kg ~2000w Giant AC Dually Crystalyte 408, 48V10Ah Headway + 6s10Ah LiPo = 70V. ~15000 kms to date [SOLD]
Build #3 ~13kg ~2000w Commuter Booster <1kg Friction Drive
Build #??? ~21kg ~1500w Adrian's Bafang BPM Hardtail MTB Bafang BPM code12, 15s LiPo, ~40kph, ~30kms

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Re: Commuter Booster - <1kg Friction Drive

Post by Hillhater » Jan 11 2011 6:38pm

Adrian,
your drive is a very attractive option , but its main limitation is (as you mentioned earlier) that most modern bikes are designed with a "compact" frame layout to minimise weight and maximise rigidity etc. That means that there is a smaller rear triangle . Only the biggest frames on road bikes have space where you fit your drive.
Checking my current collection of 6 bikes ( 2 MTB, 2 Road, 1 commuter, and one BMX) ..only one of the MTB's has space to fit even a 50mm motor in the triangle ( even then there are issues with shifter cables on the seat downtube !)
In contrast , i believe all of them could be fitted with a "Kepler" style drive.
so, not a knock at your brilliant compact design, but i suspect potential users will have to either be lucky with their current bike, or deliberately select a bike with sufficient space in order to fit your drive .
This forum owes its existence to Justin of ebikes.ca

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Re: Commuter Booster - <1kg Friction Drive

Post by adrian_sm » Jan 11 2011 7:28pm

You are absolutely right. The two biggest mounting problems are:
1) Motor Size
As Kepler just mentioned in another thread, the 50mm motors just don't have the thermal mass of the 63mm motors. So they are inherently less robust.

2) Frame Space
A lot of modern road frames just don't have the space.

Add these two competing issues together and it will definitely restrict who can use the drive on their bike. Actually I might make a 2D template that can be printed to make it easy to see if it will fit a frame. Hmmm.

And finally the shifter cable problem. I hadn't mentioned that before in this thread, but some bikes do have the shifter cbales running down the back of the seat tube, rather than up from the bottom bracket. These cables are exactly where I clamp my drive. There are ways around it. But I need to have a look at a few more frames before I decide which solution I would chase.

- Adrian
Build #1 ~28kg ~ 700w Avanti Hardtail Crystalyte 408, 48V10Ah Headway. ~5500 kms to date. (retired)
Build #2 ~30kg ~2000w Giant AC Dually Crystalyte 408, 48V10Ah Headway + 6s10Ah LiPo = 70V. ~15000 kms to date [SOLD]
Build #3 ~13kg ~2000w Commuter Booster <1kg Friction Drive
Build #??? ~21kg ~1500w Adrian's Bafang BPM Hardtail MTB Bafang BPM code12, 15s LiPo, ~40kph, ~30kms

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Re: Commuter Booster - <1kg Friction Drive

Post by LI-ghtcycle » Jan 12 2011 12:26am

Good stuff! I love it when we get more improvements to design by sharing here!

I have to ask, though, what with the limited space in the placement of the CB, isn't it going to mean you have to choose to have more motor slip due to the angle at which the drive engages? If you tried to draw a straight line from the pivot, motor and rear hub, wouldn't the motor still be considerably under that line (meaning forward towards the front of the bike)?
Thank you Justin_Le for your selfless act of kindness! We all are in your debt.
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Re: Commuter Booster - <1kg Friction Drive

Post by adrian_sm » Jan 12 2011 1:38am

Not sure. I think it was Kepler that said this is the optimum engagement, to be able to draw the straight line between motor pivot, contact patch, and wheel hub. I don't quite agree and have been setting up my drives to limit the travel before that point with success.

I think I outlined my reasoning in this earlier post. But I have not totally convinced myself so take it with a grain of salt.

I can still have the same amount of engagement with the tyre but at an angle. The allowable angle is dictated by the coefficient of friction between motor and tyre. Come to think of it this will be the worst when the motor is first coming in contact with the tyre when you will have the largest angle. This could be improved by increasing the radius at whcih the motor pivots. :shock:

Damn. That is a good argument for a longer pivot arm.

:D Funnily enough now that I have a single pivot arm, I could fairly easily do this by placing my pivot point infront of the seat tube, and having a longer pivot arm. Hmmm. It would increase weight, but may help avoid slip during initial pick up. But it would also require the drive to pivot further to have the same engagement into the tyre. So it wouldn't help trying to get it on smaller framed bikes. Damn.

From my understanding of the geometry, the most critical time it will slip is during initial engagement for the pivoting designs like mine and Keplers. Once it gets over that point the geometry will only be able to apply more contact force until it is limitted by a force balance, or deadstop. If you slip at the fully engaged position you would need to adjust the drive such that you acheive more engagement, ie. lower the drive, or adjust the deadstop.

To directly answer your question. Yes the geometry of the frame does limit the travel of the CB, and could restrict engagement. But you don't need to aim to have a fully straight line between motor pivot, contact point, and rear wheel hub. You can stop short of this and have just as much tyre engagement.

- Adrian

P.S. One of the other reasons I don't let the drive pivot that far, is that you see a drop off in the torque required to maintain the drive in that position as you get closer to the straight line. This means the drive suddenly accelerates its rotation towards the deadstop, and hit is with a bit of a clunk. I was previously just adding a dampening material to my deadstop, but by adjusting the geometry I effectively used the compliance of the tyre to do the job instead.
Build #1 ~28kg ~ 700w Avanti Hardtail Crystalyte 408, 48V10Ah Headway. ~5500 kms to date. (retired)
Build #2 ~30kg ~2000w Giant AC Dually Crystalyte 408, 48V10Ah Headway + 6s10Ah LiPo = 70V. ~15000 kms to date [SOLD]
Build #3 ~13kg ~2000w Commuter Booster <1kg Friction Drive
Build #??? ~21kg ~1500w Adrian's Bafang BPM Hardtail MTB Bafang BPM code12, 15s LiPo, ~40kph, ~30kms

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Re: Commuter Booster - <1kg Friction Drive

Post by adrian_sm » Jan 12 2011 7:59am

Update: Installation Tempalte

For those interested if this style of drive is even close to fitting your frame, I made a very rough template you can cut out and try.

I used the "Kepler" approach of engagement (every thing in a straight line), as this appears to require more travel then my approach, so the templates should be pessimistic.

Anyway if you do try it, please let me know if it worked or not. I am beginning to suspect a lot of frame will have issues with space or cables, and that I have just been lucky with mine.

- Adrian
Attachments
Commuter Booster v2 - The “Will it fit my frame” Template - rev A.pdf
(691.14 KiB) Downloaded 499 times
Build #1 ~28kg ~ 700w Avanti Hardtail Crystalyte 408, 48V10Ah Headway. ~5500 kms to date. (retired)
Build #2 ~30kg ~2000w Giant AC Dually Crystalyte 408, 48V10Ah Headway + 6s10Ah LiPo = 70V. ~15000 kms to date [SOLD]
Build #3 ~13kg ~2000w Commuter Booster <1kg Friction Drive
Build #??? ~21kg ~1500w Adrian's Bafang BPM Hardtail MTB Bafang BPM code12, 15s LiPo, ~40kph, ~30kms

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Re: Commuter Booster - <1kg Friction Drive

Post by hillzofvalp » Jan 12 2011 1:52pm

I have been working on the battery packs more recently, but I did get four ~7/4x1/8x4"arms made which have terribly drilled holes. Even when I used the whole punch it went off a little.

The club I'm participating in is new at Purdue University, and you can check it out at electricvehicleclub.org, which was only put up couple of months ago. Many of the senior members are affliated with Purdue's evGP electric go-cart racing, so I suspect my future prototypes will come together well after having gaining access to machinery and guidance in the engineering building.

Actually, the brand new machinery rooms at purdue are very sophisticated, and they even have job openings. I plan on applying soon so I can learn to use their cnc and maybe even their water jet machines someday. Pretty cool oppurtunity, and, if I major in Mechanical Engineering, it will look really good on resume ;).

LUCKILY, my frame is pretty big at 59cm, not to mention they're 1" 1/8" tubes, also giving me extra room. I will try out the template today and get back to you, but I still haven't ordered a motor or esc yet. Waiting to see what club thinks. Btw, could/did you experiment with different tire widths?

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Re: Commuter Booster - <1kg Friction Drive

Post by adrian_sm » Jan 12 2011 3:37pm

hillzofvalp wrote: I did get four ~7/4x1/8x4"arms made which have terribly drilled holes. Even when I used the whole punch it went off a little.
Did you use a drill press, or hand drill? The motor mounts holes can be off a little, but you defintely want the pivot axle hole a very close fit for the pivot shaft, if you want to go for a single arm design.
The club I'm participating in is new at Purdue University, and you can check it out at electricvehicleclub.org, which was only put up couple of months ago. Many of the senior members are affliated with Purdue's evGP electric go-cart racing, so I suspect my future prototypes will come together well after having gaining access to machinery and guidance in the engineering building.

Actually, the brand new machinery rooms at purdue are very sophisticated, and they even have job openings. I plan on applying soon so I can learn to use their cnc and maybe even their water jet machines someday. Pretty cool oppurtunity, and, if I major in Mechanical Engineering, it will look really good on resume ;).
Defintely get as much hands on experience at Purdue as you can. It will pay off. And you can get your own jobs done :D
Before you decide on your major, think long and hard about the type of job you would ultimately like. For what I am doing now, a mechatronics degree would have been better suited, than the Mech Eng/Bach Commerce I did.

LUCKILY, my frame is pretty big at 59cm, not to mention they're 1" 1/8" tubes, also giving me extra room. I will try out the template today and get back to you, but I still haven't ordered a motor or esc yet. Waiting to see what club thinks. Btw, could/did you experiment with different tire widths?
As for the motor, the 6374 seems like a good cheap option. If you go smaller you will be restricting the power that it can reliably handle. So I would recommend the large 63mm motor, in as lwoer a kv as you can get, with the best bearings, and preferably a skirt bearing to internally support the motor can.

Tires. No other that switching between my mountain bike, and road bike. Both have worked. Thye both have a pretty smooth centre section for contact. I don't think I am getting close to enough torque to shear the rubber so a narrow road tyre doesn't appear to limit things too much.

- Adrian
Build #1 ~28kg ~ 700w Avanti Hardtail Crystalyte 408, 48V10Ah Headway. ~5500 kms to date. (retired)
Build #2 ~30kg ~2000w Giant AC Dually Crystalyte 408, 48V10Ah Headway + 6s10Ah LiPo = 70V. ~15000 kms to date [SOLD]
Build #3 ~13kg ~2000w Commuter Booster <1kg Friction Drive
Build #??? ~21kg ~1500w Adrian's Bafang BPM Hardtail MTB Bafang BPM code12, 15s LiPo, ~40kph, ~30kms

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hillzofvalp   1 MW

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Re: Commuter Booster - <1kg Friction Drive

Post by hillzofvalp » Jan 12 2011 4:11pm

Ugh, I hate dealing with hobbyking. I wish I could get a cheap 63-74 in the US.

My question about tires is more along the lines of: Will a 28mm, wider tire, work better? Maybe ideal tires or tire pressures could be investigated. how much surface area contact is ideal?

I've got 20mm on my bike now (hehe a little small) but I've got some 23s as well.

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adrian_sm   10 MW

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Re: Commuter Booster - <1kg Friction Drive

Post by adrian_sm » Jan 12 2011 4:34pm

I have 23s on my bike. Worked fine.

As for ideal. I haven't spent much thought on it. I would prefer it to work on whatever is one the bike already.

One thing to note is that a wider tire is usually taller, which will restrict space for the drive.

- Adrian
Build #1 ~28kg ~ 700w Avanti Hardtail Crystalyte 408, 48V10Ah Headway. ~5500 kms to date. (retired)
Build #2 ~30kg ~2000w Giant AC Dually Crystalyte 408, 48V10Ah Headway + 6s10Ah LiPo = 70V. ~15000 kms to date [SOLD]
Build #3 ~13kg ~2000w Commuter Booster <1kg Friction Drive
Build #??? ~21kg ~1500w Adrian's Bafang BPM Hardtail MTB Bafang BPM code12, 15s LiPo, ~40kph, ~30kms

Hillhater   100 GW

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Re: Commuter Booster - <1kg Friction Drive

Post by Hillhater » Jan 12 2011 4:45pm

hillzofvalp wrote: My question about tires is more along the lines of: Will a 28mm, wider tire, work better? Maybe ideal tires or tire pressures could be investigated. how much surface area contact is ideal? .
I think that is referred to as... "sweating on the details" ... whilst ignoring the real issues. ! :lol:

build the drive onto a bike first ..then refine the details like tire size etc once you have a working test bed.
Unless you plan on a multi kW drive, friction onto the tire wont be one of your biggest problems.
This forum owes its existence to Justin of ebikes.ca

kevo   100 W

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Re: Commuter Booster - <1kg Friction Drive

Post by kevo » Jan 12 2011 4:49pm

Adrian,
Love your bike build and writeup! Do you have a link for the triangular bag on your white road bike?
Thanks Justin of http://ebikes.ca for your amazing talents, dedication and contributions to ES!
Post licensed under "Open Source" http://creativecommons.org/licenses/by-nc-nd/3.0/

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