Chalo
100 TW
vernonbain said:
Dry wax lube on a brake rotor will sodomize the brake pads just as surely as oil.
Left side drive: what's current?
- Thread starter Ham
- Start date
Dry wax lube on a brake rotor will sodomize the brake pads just as surely as oil.
Overclocker
10 kW
https://www.usarollerchain.com/35-O-Ring-Roller-Chain-p/premium-35or-chain.htm
#35 o-ring chain
#35 o-ring chain
badgineer
10 W
Hi Ham
I have a similar dream as yours
.
Unfortunately, judging by how much spare time I have, it will remain a dream for quite some time.
However I googled quite a bit for left side drive and found a few interesting things. I started searching for large diameter chainwheel, since I hope to use a large single stage reduction.
Belt Drive:
https://www.aliexpress.com/item/1005001743328202.html?spm=a2g0o.productlist.0.0.541b3ac3unwoWY&algo_pvid=72e8cdbb-73de-4f5b-9cfc-28368deaac00&algo_exp_id=72e8cdbb-73de-4f5b-9cfc-28368deaac00-0
only item that interests me from this kit is the large rear pulley. It's HTD5M, around 120-122 teeth.
They also have a version that is mounted on the spokes but I dislike the idea. Have no idea how this one is mounted, but if directly to IS disk mount, it's nice!
However I mostly gave up on belt drive, because I'm planning on using a high RPM RC motor, and for getting the reduction I need in 1 stage, I would have to go with a very small front pulley, which has 3 disadvantages:
1) Belts aren't good with small pulleys. They deform a lot around them, resulting in high wear and bad drive efficiency.
2) I plan to have regen, and when the small pulley is the driven one, belts tend to skip much more than the other way around.
3) For such small pulleys, where a small number of teeth are engaged, belts need super high tension to avoid skipping. Which is a challenge in it's own right.
All this is what I read, mostly on this forum. (so hearsay, but from pretty good sources).
If I can find a motor with higher torque that I can use at lower RPM (and thus use a bigger front pulley) I might reconsider the belt drive.
Chain drive - 25h chain
https://www.elektromoped.at/de/25h-100z-freilauf-kettenrad-escooter.html
Problem with it is it needs an adapter.
Also, 25h is very small, so I still have some reservations on reliability with 3000+ W, but for me it will probably work fine.
A problem with 25h is that the front sprockets are very small. The smallest number of teeth I found that fits on a 12mm motor axle is 12. Which is actually OK for my needs - 8:33:1 reduction.
https://www.aliexpress.com/item/4000193274588.html?spm=a2g0o.productlist.0.0.1ae774f9XmhnEG&algo_pvid=bc63f4a7-d4be-44d6-8781-2390aa65ca11&algo_exp_id=bc63f4a7-d4be-44d6-8781-2390aa65ca11-27&pdp_ext_f=%7B%22sku_id%22%3A%2210000000721390703%22%7D
For a 14mm axle, 14t is the smallest I could find (same seller on aliexpress)
Other thoughts on this type of build:
I plan on ditching the rear brake completely. Most stopping power is on the front brake anyway, and I am aiming for a direct drive configuration with regen - which I plan to use as my primary brake.
219 chains are nice and *much* stronger than 25h, there is the option of o-ring chain, you can buy "Extron" composite chainrings up to 92t which seem to get praise on this forum, .... but I could not find a single 11t sprocket that fits on a round 12mm or 14mm axle! (anybody know where to find something like that?)
What motor are you planning on using?
Please do share, if you found any off the shelf solutions for left hand drive that bolt onto IS disk brake mount.
Br,
I have a similar dream as yours
. Unfortunately, judging by how much spare time I have, it will remain a dream for quite some time.
However I googled quite a bit for left side drive and found a few interesting things. I started searching for large diameter chainwheel, since I hope to use a large single stage reduction.
Belt Drive:
https://www.aliexpress.com/item/1005001743328202.html?spm=a2g0o.productlist.0.0.541b3ac3unwoWY&algo_pvid=72e8cdbb-73de-4f5b-9cfc-28368deaac00&algo_exp_id=72e8cdbb-73de-4f5b-9cfc-28368deaac00-0
only item that interests me from this kit is the large rear pulley. It's HTD5M, around 120-122 teeth.
They also have a version that is mounted on the spokes but I dislike the idea. Have no idea how this one is mounted, but if directly to IS disk mount, it's nice!
However I mostly gave up on belt drive, because I'm planning on using a high RPM RC motor, and for getting the reduction I need in 1 stage, I would have to go with a very small front pulley, which has 3 disadvantages:
1) Belts aren't good with small pulleys. They deform a lot around them, resulting in high wear and bad drive efficiency.
2) I plan to have regen, and when the small pulley is the driven one, belts tend to skip much more than the other way around.
3) For such small pulleys, where a small number of teeth are engaged, belts need super high tension to avoid skipping. Which is a challenge in it's own right.
All this is what I read, mostly on this forum. (so hearsay, but from pretty good sources).
If I can find a motor with higher torque that I can use at lower RPM (and thus use a bigger front pulley) I might reconsider the belt drive.
Chain drive - 25h chain
https://www.elektromoped.at/de/25h-100z-freilauf-kettenrad-escooter.html
Problem with it is it needs an adapter.
Also, 25h is very small, so I still have some reservations on reliability with 3000+ W, but for me it will probably work fine.
A problem with 25h is that the front sprockets are very small. The smallest number of teeth I found that fits on a 12mm motor axle is 12. Which is actually OK for my needs - 8:33:1 reduction.
https://www.aliexpress.com/item/4000193274588.html?spm=a2g0o.productlist.0.0.1ae774f9XmhnEG&algo_pvid=bc63f4a7-d4be-44d6-8781-2390aa65ca11&algo_exp_id=bc63f4a7-d4be-44d6-8781-2390aa65ca11-27&pdp_ext_f=%7B%22sku_id%22%3A%2210000000721390703%22%7D
For a 14mm axle, 14t is the smallest I could find (same seller on aliexpress)
Other thoughts on this type of build:
I plan on ditching the rear brake completely. Most stopping power is on the front brake anyway, and I am aiming for a direct drive configuration with regen - which I plan to use as my primary brake.
219 chains are nice and *much* stronger than 25h, there is the option of o-ring chain, you can buy "Extron" composite chainrings up to 92t which seem to get praise on this forum, .... but I could not find a single 11t sprocket that fits on a round 12mm or 14mm axle! (anybody know where to find something like that?)
What motor are you planning on using?
Please do share, if you found any off the shelf solutions for left hand drive that bolt onto IS disk brake mount.
Br,
badgineer
10 W
Chalo said:
Not sure if this applies to the OP, but in my case I would add another 2 practical uses for the pedals.
1) safety. I plan to have electric "assist" only once the bike is in motion, not from standstill. This seems quite a bit safer to me. On my electric kickscooter I have the same setup for the same reason.
2) legal requirement. If one plans to use it on public roads, which I do, then it must be a bike with working pedals. (and restricted power and speed, lights, <insert your local requirements here>). I'd rather live with these restrictions than go through the bureaucracy of getting it registered as a moped, and not being allowed on bike lanes.
Apologies if this is considered too far into off-topic territory...
Br,
thepronghorn
1 kW
badgineer said:
You just said you needed a small front pulley, and then later you are criticizing how small the 25h sprockets are. The smallness of the 25H sprockets is a feature!
What motor are YOU thinking of?
For me, I used a 6374 motor initially since it was cheap while I tried out my drive system. I am left wanting more power though, so I am going to a larger motor since I do not want to increase my reduction ratio. Maybe a 12070 like mxlemming but probably something smaller with 92mm or 100mm OD.
For full suspension, I have pondered numerous configurations, but dealing with changing center to center distances with idlers and spring tensioners seems quite difficult, so I think I would prefer to fix the motor to the suspension arm. If you don't want regen, the tensioner problem is easier, but then you must keep the rear brake which can also be difficult.
Hillhater
100 TW
You have not said what motors you have in mind, and i am curious which motors might have a 12 or 14 mm shaft .?
Most RC type motors will be 8 or 10 mm shafts.
Also 219 chain sprockets are made down to 10 and even 8 T but usually have a 12mm taper shaft fit with a keyway ...(check race kart suppliers )
However , for a 8.33 :1 reduction...you could easily run a 20 tooth sprocket and a 170 T driven wheel sprocket....you would just have to make one as many have before..... ( but that 8.33:1 wont be enough for bike speeds !)
It appears you are expecting to assemble this unique drive with using only existing components....with little or no fabrication .
I would suggest that is very optimistic !
Most RC type motors will be 8 or 10 mm shafts.
Also 219 chain sprockets are made down to 10 and even 8 T but usually have a 12mm taper shaft fit with a keyway ...(check race kart suppliers )
However , for a 8.33 :1 reduction...you could easily run a 20 tooth sprocket and a 170 T driven wheel sprocket....you would just have to make one as many have before..... ( but that 8.33:1 wont be enough for bike speeds !)
It appears you are expecting to assemble this unique drive with using only existing components....with little or no fabrication .
I would suggest that is very optimistic !
briangv99
1 kW
Ham said:
Boxxbike is 1.6kWh, not huge for a 12kW bike but good enough for 30-50km apparently
badgineer
10 W
Hi everybody.
Regarding 25h sprockets and size - yeah, the smallness is a feature, the 100tooth sprocket I posted is the size of a big disk rotor, so will fit most frames! But then on the other hand also a restriction for the front sprocket.
The motors I am considering:
1) 80100 (ideally an 80kV - ish version) - freerchobby / alien / (flipsky has only 130kV available). -> 12mm shaft
This is the most likely candidate because of price and space constraints for my simpler implementation target
2) 12070 80kv from freerchobby / etc - 12 mm shaft.
Super nice form factor, but the quoted no load Amps (3.5 up to 7, depending on source), make me think it will be quite inefficient and for low power applications like I plan, and super draggy when it's not powered.
3) 8057 neumotor 75kV - 14mm shaft
This is the nicest of all: .2mm laminations, super low phase to phase resistance (24 mOhm!), so excellent efficiency, but the most expensive by a large margin.
BUT: I am targeting a much lower power (2-3 kW peaks) so I can get away with a much lower RPM (~4800 RPM max)
Also, I'm planning on a 20" back wheel. This has 2 benefits: 8.33 is the equivalent of 10.8:1 on a 26" wheel, which suddenly sounds better, and i hope to be able to squeeze the 80100 in the swingarm triangle, making the motor mounting and chain tensioning easier on a full suspension frame.
Well, the least amount of fabrication I can manage. The less the better, because:
1) don't have the time to do much customization. If I embark on a project requiring a lot of customization, I am surely not finishing it before I retire...
2) I have the dexterity and handiwork skill of... well, can't find a comparison, but I'm really bad.
Well those are sort of my problems. I'd really like to avoid custom stuff. 219 taper shaft sprocket with keyway will not play nicely with the motors I posted. And regarding the 170T driven wheel sprocket, I need to custom-machine it (haven't found any ready made sprocket bigger than 100T for 25h) and I'd like to keep custom stuff at a minimum. 12:100 is already almost off the shelf available (just need an adapter for the 100T to IS disk mount, which is plausible for me to fabricate even with my skills)
Ow, and thank you all for all the feedback!
Br
thepronghorn said:
Regarding 25h sprockets and size - yeah, the smallness is a feature, the 100tooth sprocket I posted is the size of a big disk rotor, so will fit most frames! But then on the other hand also a restriction for the front sprocket.
Hillhater said:
thepronghorn said:
The motors I am considering:
1) 80100 (ideally an 80kV - ish version) - freerchobby / alien / (flipsky has only 130kV available). -> 12mm shaft
This is the most likely candidate because of price and space constraints for my simpler implementation target
2) 12070 80kv from freerchobby / etc - 12 mm shaft.
Super nice form factor, but the quoted no load Amps (3.5 up to 7, depending on source), make me think it will be quite inefficient and for low power applications like I plan, and super draggy when it's not powered.
3) 8057 neumotor 75kV - 14mm shaft
This is the nicest of all: .2mm laminations, super low phase to phase resistance (24 mOhm!), so excellent efficiency, but the most expensive by a large margin.
Well, yeah, it's not nearly enough for getting in the RPM range in which the 80100 can do the 5+kW, and the 12070 and 8057 capable of 10+ kW (don't know the exact official power, but in my case it's unimportant)Hillhater said:
BUT: I am targeting a much lower power (2-3 kW peaks) so I can get away with a much lower RPM (~4800 RPM max)
Also, I'm planning on a 20" back wheel. This has 2 benefits: 8.33 is the equivalent of 10.8:1 on a 26" wheel, which suddenly sounds better, and i hope to be able to squeeze the 80100 in the swingarm triangle, making the motor mounting and chain tensioning easier on a full suspension frame.
Hillhater said:
Well, the least amount of fabrication I can manage. The less the better, because:
1) don't have the time to do much customization. If I embark on a project requiring a lot of customization, I am surely not finishing it before I retire...
2) I have the dexterity and handiwork skill of... well, can't find a comparison, but I'm really bad.
Hillhater said:
Well those are sort of my problems. I'd really like to avoid custom stuff. 219 taper shaft sprocket with keyway will not play nicely with the motors I posted. And regarding the 170T driven wheel sprocket, I need to custom-machine it (haven't found any ready made sprocket bigger than 100T for 25h) and I'd like to keep custom stuff at a minimum. 12:100 is already almost off the shelf available (just need an adapter for the 100T to IS disk mount, which is plausible for me to fabricate even with my skills)
Ow, and thank you all for all the feedback!
Br
badgineer
10 W
Hillhater said:
Regarding the reduction ratio, some details:
I did a super rough estimation of the values for 80100 80kv, just super rough, so I can simulate the system (don't read anything in the efficiency please
, it's just for the gearing ). With 12T-100T Transmission, 20 inch wheel, on a 16S lipo at nominal voltage, the bike would be geared for ~48 kph at ~4200 RPM for the motor. 80100 performs best in 6000-8000 RPM, so 4200 is LOW, but i hope I can get away with this low RPM if I need only 1100W continuous and 3000W peak, which is less than half comparing to what 80100 can do at ~7000RPM.
https://ebikes.ca/tools/simulator.html?motor=cust_80_0.1_0.08_7_0.05_0.0005_0&mid=true&eff=100&gear=1&tf=12&tr=100&wheel=20i&batt=cust_59_0.02_8&cont=cust_50_100_0.02_A
Ow, and before I forget - that low RPM is actually also a feature - it keeps Eddy current losses lower, so I still have hopefully decent efficiency at low power low speed, when using the hypothetical dream bike safely on public roads
Br,
I have 178T pulley with 20T motor pulley on 6374 motor (the cheapest kind). Regen capability before belt starts skipping is indeed pretty limited, but it is enough for me (about 15nm I think)
Max speed combined with 24v (8s lifepo) is 50kmh and torque on 45 phase amps (can be higher, but I don't wanna waste efficiency) gets me almost there using motor power only, about 52kmh with vigorous application of human power.
Acceleration given considerable system weight (there are pros and cons of building your own frame) is ponderous, so I'm also adding a similarly powered crankdrive, but with double reduction.
Max speed combined with 24v (8s lifepo) is 50kmh and torque on 45 phase amps (can be higher, but I don't wanna waste efficiency) gets me almost there using motor power only, about 52kmh with vigorous application of human power.
Acceleration given considerable system weight (there are pros and cons of building your own frame) is ponderous, so I'm also adding a similarly powered crankdrive, but with double reduction.
badgineer
10 W
My respect for that frame! And the amount of work and care that has gone into it!BalorNG said:
My approach is sort of the opposite though. Trying to minimize the time I need to invest, by investing more $ to buy more off the shelf parts.
mxlemming
100 kW
- Joined
- Jul 17, 2020
- Messages
- 1,122
Ham said:Skaiwerd said:
I may well end up having to make my own adaptors at this rate
How about mounting the disc rotor on your motor shaft? All the braking force would go through your belt/chain that way so that would have to be pretty robust but htd8m/chain should cope fine.
mxlemming said:Ham said:Skaiwerd said:
I may well end up having to make my own adaptors at this rate
How about mounting the disc rotor on your motor shaft? All the braking force would go through your belt/chain that way so that would have to be pretty robust but htd8m/chain should cope fine.
Well, rear brake is a 'backup brake' anyway, I think simply relying on regen for 99% of speed scrubbing and front brakes for the rest 1% and emergency stops is fine. Just make sure you have good ones on the front... if you are going custom, there are two-disk forks and hubs in 20mm axle
TorontoBuilder
100 W
JackFlorey said:
I second this...
I'm using left side belt drive, using gates carbon drive components because they'll work for me with minimal custom machining required. I'm mounting rear sprocket to the disk break mounting holes via custom offset adapter.
TorontoBuilder
100 W
badgineer said:
That belt drive system is cheap, but poor choice due to the tooth profile
I'm using a gates carbon drive 22 tooth cog that will attach to my custom motor spindle using the Bosch Gen 2 spline going to a 55 tooth cog attached to an adapter mounted on the disk brake mount. The rear 55 tooth cog has the same 190 mm diameter as the cheap system from aliexpress while the drive cog is ~80 mm versus the 39 mm of the aliexpress system. The gates drive belts are far superior and cogs are available up to 243.2 mm in diameter.
Pair that drive system with an alien power 30KV 2800 watt APS 6374S motor and you've got a sound ratio to deliver a lot of torque and do about 50 mph using 29" wheel. If you want more power then there is the 50KV 4000 watt APS 6384.
You can easily find a cnc shop to machine you a hub to mount a drive cog to one of the bike standards, but I'd turn up an entirely new motor shaft with a 43 mm hub on the end, threaded to the Bosch Gen 2 specs then mill the splines to mount the 22 tooth cog. Fewer failure points.
The spider to connect 6 hole disc brake to the "front" 5 hole sprocket can be easily custom cut by any waterjet shop. The spider legs may need to be bend to offset the cog depending on your bike's configuration.
I'm actually constructing my own motor for this with the cranks passing thru the motor's hollow spindle... I can't use torque sensor with my design, but I can use 24 magnet PAS sensor.
My right side drive will be the opposite, 55 tooth to 22 tooth on the rear internally geared hub.
Chalo
100 TW
TorontoBuilder said:
Torrington needle roller clutch, or something else?
TorontoBuilder
100 W
Chalo said:
One way roller bearings yes, that was the general idea...
Chalo
100 TW
TorontoBuilder said:
That's how I'd do it. Make sure you use enough width, because you don't have a lot of diameter to carry the torque.
A waxed chain (provided you have a good concoction) is better when it comes to efficiency and nearly as maintenance free, but is noisy. I'll try ordering laser cut cog 'cores' and overmolding them with rigid (it still works as a damper) TPU. Will not work for very high powers obviously, but using a slightly 'oversized' (TF8/219 chain instead of 25 chain) for relatively low-power setup should work... after all, belt uses 'all rubber teeth' basically! Of course, it is much wider than chain internal diameter. If only silent chains were less esoteric...
TorontoBuilder
100 W
Chalo said:
Yes I plan to fill the available space with as many bearings as will fit. Since everything will be custom built I wont have any artificial constraints to adhere to
Chalo
100 TW
TorontoBuilder said:
I'd use clutch-bearings on the outside, and clutch only in the middle.
TorontoBuilder
100 W
Chalo said:
I'm unsure what you mean by "clutch only" in the middle... have you an example product or design?
Chalo
100 TW
TorontoBuilder said:
A Torrington roller clutch-bearing has three rows of elements-- roller bearings on the outer edges and a roller clutch in the middle.
A roller clutch is only that, without the supporting bearings to operate independently.
The clutch-only unit can withstand more torque, because its entire width is dedicated to clutching elements. So once you have bearings on the outer ends, the middle can be occupied with full width clutches.
There are specs for hardness and thickness of the shaft and housing, for the clutches to deliver their full torque rating.
TorontoBuilder
100 W
I see what you mean now... It's merely a matter of the terminology differences.
I've never distinguished between roller bearings units with separate bearing and cam rollers and bearings with only cam rollers.
Then again, I also call bearings units with external ball races and internal sprag cams one way bearings rather than clutches.
I've never distinguished between roller bearings units with separate bearing and cam rollers and bearings with only cam rollers.
Then again, I also call bearings units with external ball races and internal sprag cams one way bearings rather than clutches.
badgineer
10 W
Hi TorontoBuilder
The belt drive you are describing has a gearing ratio of about 1:2.4...
I think that at this low reduction, the 6374s will not be spinning nearly fast enough to produce the 2.8 kW it's supposed to. (You have to spin a motor it in its optimum RPM range to get the nominal power, regardless of kV.) I am aiming for gear ratio in the vicinity of 1:8 for a 20 inch driven wheel (or ~1:10 for a 26 inch wheel, but this is utopia). 1:2.4 is far far too low to get decent power from small motors.
But yeah, your tooth profile point is valid though, no objection there. It will be a much better overall belt drive than the aliexpress one, especially for regen braking. But then I'd need another reduction stage.
....
Still hoping somebody will prove I'm a total idiot who can't google by posting a link to a 219 sprocket for axle mounting on a 12mm or 14mm axle.
Br,
TorontoBuilder said:
The belt drive you are describing has a gearing ratio of about 1:2.4...
I think that at this low reduction, the 6374s will not be spinning nearly fast enough to produce the 2.8 kW it's supposed to. (You have to spin a motor it in its optimum RPM range to get the nominal power, regardless of kV.) I am aiming for gear ratio in the vicinity of 1:8 for a 20 inch driven wheel (or ~1:10 for a 26 inch wheel, but this is utopia). 1:2.4 is far far too low to get decent power from small motors.
But yeah, your tooth profile point is valid though, no objection there. It will be a much better overall belt drive than the aliexpress one, especially for regen braking. But then I'd need another reduction stage.
....
Still hoping somebody will prove I'm a total idiot who can't google by posting a link to a 219 sprocket for axle mounting on a 12mm or 14mm axle
. Br,
