A new internal gear reduction (no chain) mid drive announced

[ncmired]

CYC Motor has announced a new torque sensing mid drive, the Photon, for conventional bike DIY conversions that, as with the BBSHD / BBS02 / TSDZ2, keeps the gear reduction(s) internal to the motor casing.

As with the BBSHD / BBS02 / TSDZ2, various BB widths and bearing standards are accommodated - 68-120mm roughly.

The air cooling fins appear deeper and more extensive, compared to the minimalistic ones Bafang and Tongsheng provide.

Extensive motor status info is available for display - hopefully this would also mean the motor's well being is being taken care of by the software. Torque sensing is also on the plate.

Related to the chain line, it appears that the final gear reduction housing is smaller in diameter (compared to the BBSHD / BBS02 / TSDZ2, and perhaps there will be multiple chain ring spiders available to compensate for various sub frame & chain line needs. It'll be interesting to see how may gear reduction stages were implemented and what the rider cadence range turns out to be.

The motor's weight compares to the BBS02. No pricing hints at this time, nor indications on power source limitations (such as proprietary battery requirements, like for the M625 (BBSHD replacement)). CYC does have a new line of hard shell, 21700 cell based battery packs, but the power output connectors appear to be XT90 (whew).

CYC's design appears to be all new, and I'm surprised that anyone would make this investment given the trends towards motor-specific e-bike frames. Maybe there's hope and a future for us DIYers after all.

My initial guess is that this motor will slot in between the BBS02 and the BBSHD continuous power wise, with the bonus of torque sensing and a better chainline / lower front chain ring tooth count. I'd love to put one on my guest bike.

[AZguy]

Agreed - interesting

I avoid pioneering new stuff so will likely let the dust settle at least a year after they are actually available and shipping before even considering one

Many questions though... how programmable the controller is... can torque sensing be eliminated or at least tuned out... what is required for the active (while riding, for changing PAS levels) UI... etc...

Oh yeah... cost...

[ncmired]

Yeah, cost - I'll knee-jerk $1.3k for a full power (see below) Photon motor kit without battery - kit being motor, BB adaption, chain ring & spider, display & cabling. New, shiny & with at least 1/4 to 1/3 cost premium over a BBSHD, decent chain ring and display, from a reputable U.S. source.

My config bet would be that they'll let you disable the torque sensing, but not muck with much else. The power lever is set, "depending on firmware versions" - maybe this is a hint regarding profit / warranty margins / costs, as well as a "hands off" indicator - dunno.

We'll see, I guess.

[ncmired]

I snipped two pictures in particular. This first one I'll extrapolate is of a 32 tooth ring, nicely tucked close to the frame:

The lowest tooth count, decent chain line you can do on the BBSHD is 40 teeth, via the costly Lekkie. Not a big deal to me with my IGH hubs, but I suspect the 1-by MTB peeps want front chainrings at least that low, or even better, in the twenties. My pants cuffs also appreciate the built-in chain guard rings - like the high end Lekkie and Jones rings have.

Here's the display, which appears to be an 860 variant:

Nice info, but I doubt I'd be able to read anything but the speed text underway.

I'll skip the rest of CYC's dopey, dark mystery pics.

[AZguy]

Yuck! I hate those displays...

I wonder how hard the comm protocol is to hack... bafang serial is pretty easy

[73Eldo]

Ya yuck. I looks like its got a lot of pretty small text and a lot of wasted space.

[AZguy]

Probably hard to read in the sun and too bright at night

I just don't see the point of color (active LCD or OLED) displays considering how little information they are displaying and that it's pretty much all simple numerical information anyway... simpler (mono passive LCD) is far better from both a visibility (day or night) and cost standpoint...

[Retrorockit]

I was thinking CYC should have just gone to a primary belt drive for the existing design.
I've never had any trouble sensing the torque of my BBSHD.

[ncmired]

Somebody's mid drive has a belt inside - Brose maybe? Belt width may be an issue in some circumstances.

Mongo only pawn in game of e-bikes.

[73Eldo]

On one of the photos on the site you can see "38-50 CHAINRING ADAPTER" so perhaps it takes standard rings? Maybe the offset can be 'tuned' with spacers and or longer bolts? I looks like the spider is threaded so I wonder if it uses a special bolt or standard ones? The holes don't look as large as those standard ring bolt things. Also note the bullet points above the photo where you can read the 38-50 it says 34-50 chain ring options.

Anyone recognize the crank arm spline style? Is it something standard?

I too hope they have other display options. It seems these days like if you are going to have a standard/required display that it should be something fairly small and minimal then have an optional larger display option or some sort of phone interface for those that want a huge or more advanced display.

I would assume even with a torque sensor there is still some sort of cadence sensor in place just so the controller knows the rpm so it should be just a software option to let the user choose between torque or cadence if they wanted to.

Any photos or info on where the controller is? Doesn't look like its integral. Perhaps uses their other controller? Isn't that something people complained about that it was kinda a pain to mount?

[ncmired]

The crank arms & spindle appear to be ISIS Drive (spline) with threaded caps, and I think you use a puller similar to the square taper version - maybe even the same.

I too saw some of the chain ring labeling you mentioned, and even tried brightening the shadows with Photoshop to see better - but got mad & bored. Maybe by next summer we'll know the detailed skinny on this new kid on the block.

I agree on the display data aspects. I'd prefer a simpler, glanceable display, and want the controller to look after the motor's wellbeing (such as overheating). Lately it's been real bright sun outside and I tend to wear white t-shirts - the reflection causes the display to wash out. Maybe once or twice I'd feed the data to my Android phone (for troubleshooting and/or configuration), but I'm not comfortable with putting a delicate cellphone in/on a bar mount full time.

[ncmired]

Yikes - a preliminary CYC Photon specification list states that the top crank RPM is 190. That's even higher than the Luna V2 controller, from what I've been able to tell.

[Retrorockit]

Looking at the CYC with it's mid mounted chainring I can't see any way to get good street gearing on a 26" bike w/o some kind of IGH overdrive going on.
At that power level the short list would probably be Rohloff, Kinderany 7, or the monstrous $100 Nuvinci 171B CVT hub. Not sure if the 3 speeds are really up to it or not. Probably enough torque that 3 speeds would work if they're strong enough.

.https://electricbike.com/forum/forum...hub#post154475

[ncmired]

Hi Retro - the preliminary chain rings for the Photon mid drive are 34T, 38T, 42T, and 50T. CYC doesn't state what the chain lines are (on a 68mm BB reference), but I'm thinking they're much better ("lefter") than what can be done on the BBSHD, especially with the 34T and 38T rings.

The 34T ring would work pretty well with a 1x 11-42 derailleur drivetrain, I'd think (21-80 gear inches or so).

BTW, speaking of IGH hubs, so far my Ludicrous V2 / Alfine 8 is holding up well, shifts fine, and no skips or crunches. I've limited the controller to 2.6kw, but still.

[Retrorockit]

I guess I didn't know what the Photon was. The CYC with the outer primary chain has limited chainring options.I stopped looking at CYC due to that.
I'm glad to hear your Ludi is good with the Alfine*. my Nexus 7 wasn't even up to the TSDZ2. I swapped in a Nexus 8 but working on that takes time away from riding the BBSHD. Kind of hard to justify if the weather ts good.

[ncmired]

I swiped this CYC Photon preliminary spec sheet from a (now closed) thread over on Endless Sphere:

There's that (to me) rather alarming max crank 190 RPM / cadence number. Maybe this motor, like the BBS series, only has two stages of gear reduction - IIRC AZguy at one time speculated that more than two stages would be mechanically difficult to accomplish. Also, notice the two displays - a SW102 and the (Topology brand) DS103.

The speed sensor is listed as Bluetooth - hoping this doesn't mean a charged separately device of some sort.

Meanwhile, the weight may be slightly less than the BBS02 (I couldn't find reliable apples to apples number) - less beef but better heat shedding? Hope yous guys don't mind me speculating.

P.S. Also meanwhile, it's too bad the thread closed over on ES - I made a rather clumsy second post within the thread, and then the thread responses degenerated into a feces tossing and urine spraying show. Is this the norm over there?

[AZguy]

I don't see any easy way to get much more reduction - at least not without significantly increasing the size of things. About the only way to lower the max RPM is likely to go with a lower kv winding setup but that could reduce efficiency so I'd bet it's a balance

And yes, ES often devolves into a bunch of harsh uncivil nonsense until a thread gets locked or a mod starts handing out scoldings and bans (usually temporary)... I've seen them go way silly for the stupidest stuff mostly just a bunch of kids trying to prove they're "smarter than you" nonsense... One thing I like to tell folks that get like that is the guy that needs to be the "smartest guy in the room" is likely the loneliest guy in the room ;-}

I've been on other boards that are even worse though, know that in advance going over there, and roll up my sleeves and maybe throw a little stuff back but keeping it above the nonsense (isn't difficult) and let the dust settle where it may... can't say I've never stirred the pot on purpose either =]

OTOH I've been on boards where the most ridiculous stuff will get a mod crawling up your rear... I was on one where I know they're hyper-sensitive and was discussing bike lights that would go really dim (my present light can go down to 1 lumen).. and folks just kept persisting in asking why.. and I'd give them some explanations they didn't think were good enough and at one point said that I also didn't like attracting law enforcement at night (without giving reasons why I might want to avoid LEO contact)... and that got me a temporary ban since [as the mod scolded me] I was "promoting illegal activity" <roll eyes>

This place seems more on the civil side without being hypersensitive - which is the way I prefer things...

[Retrorockit]

Yes ES has turned into a POS. I had a thread locked after I was insulted but not allowed to reply. It would have been epic! A couple months off and now I can post in peace there. This was the zip tie mod. It gets 20 hits per day there. Almost up to 2500. They did finally toss the troll. IDK what the rest of it's like now. maybe they cleaned it up?

[AZguy]

It's always been a s^!tshow over there... A local guy bought the site about seven or eight years ago with every good intention, put it on a better server, worked on an android app, etc.... but after months of just getting bashed he gave up... I met him a couple years ago - super nice guy

The trolls usually just get temporary bans so don't hold your breath they won't be back... they're pretty easy to ignore over there and for the most part it's what I'll do... but then again I don't feel inspired to contribute much either

[73Eldo]

Interesting.

Integral controller should be a good thing, one less thing to have to mount.

Kinda seems like all the chain ring options will have the same offset. That's good and bad I guess. Good would be unlike the BBS's going small doesn't give you a 10mm ish penalty in chain line. Bad would be doesn't give you options for the best fit/line.

I'm not real up on cadence numbers. What can the BBS's do? I don't even know my own numbers but I would expect I'm in the 70's and maybe spun out by 90-100, probably much lower if I'm not riding clipless. If I'm running throttle only I try to select a gear that I can barely or not even keep up with but I have no idea what speed that is... 120? So if my guesses are in the ballpark 190 is stupid fast and does make you wonder if it has to be that fast to really generate torque? Does this mean the BBSHD is your v8 that hits its torque peak at 2500 and this new thing is your 4 banger that doesn't hit its peak till you are well out of its usable range? Does this mean its more of a throttle system and pedals are just for show? But then why bother with the torque sensing?

[ncmired]

Good point on chain line / spacing options. I'd guess it's a lot easier / less expensive to space outwards though (as we know all too well with the BBS motors). The only build I've needed a wide chain line on is with the Rohloff (58mm), on which I'm using the Jones 34 tooth chainring - 34T front to a 19T rear, on 27.5 wheel.

[ncmired]

Thanks guys (in general) ...

73Eldo, on cadence Bafang lists 140 and 150 rpm for the BBS02 and BBSHD respectively - numbers critiqued for years as too damned high on BBS redesign wish lists.

My V2 controller'ed BBSHD motors, AFAIK, spin 185 rpm.

I've always been a relatively low cadence, "stomper". 85-90 cadence / RPM used to be my limit, where I felt "bouncy", awkward, clumsy, and unstable. There are riders than can push past 200 cadence (on rollers usually), but I've no idea what kind of power they can manage up there.

We keep reading, "keep the motor spinning fast for best efficiency", but I've yet to see any sort of percentage numbers. Does "motor spinning fast" mean, say, with 80-100% of the unloaded speed, or 50-100% or, well, what?

• 80% of the stock BBSHD 150 rpm is 120 cadence - some can keep up with that, which is good
• 80% of the stock BBS02 140 rpm is 112 cadence - attainable by many, and perhaps why some prefer the BBS02 "ride quality"

But ...

• 80% of the V2's 185 rpm is 148 cadence
• 80% of the Photon's 190 rpm is 152 cadence

Well out of my cadence range, anyway.

I'm probably doing it wrong, but I gear my go-to distance bike so that the motor is maxing out RPM in the "20 mph-ish" gear ratio I usually ride in - 8th, said to be the most efficient gear on the Rohloff 14-speed. "Air" pedaling just keeps the motor on, at a cadence I can't possibly manage to contribute effort to - but said to still aid one's health. (34t to 19t, 27.5 wheel)

My other go-to grocery errand bike is geared a little higher (Alfine 8, no choice), so that the trip to the store is in 3rd, a slightly less efficient hub gear (but still 20 mph-ish), and the go home gear is a fast, keep the frozen food frozen 6th gear. (40t to 24t, 27.5 wheel)

If "motor spinning fast" meant 50% of the motor max, hey I'd have a chance! I've read that people can out pedal the Bosch motors, so I'd guess that might mean they have a lot of gear reduction.

For leisurely long distance rides I've fussed and fussed with ride position and comfort, so 73Eldo's patented Ass Hours calculation works out ok. For these rides I want range, and am doing pretty well with the 30AH battery bike, giving me the luxury of higher speed on the way back if I get bored. I'm adapting the other wannabee bike to 42AH, via dual 21AH batteries and AZguy's patented high reliability power crossover design.

[AZguy]

FWIW the efficiency vs. rpm needs to take into account the torque (or power) too so it's not just a simple two dimensional relationship (it's 3d)

Having said that I tend to put ~100-175W from my leg(s) so I'm only going to go so fast, usually in the 70's for continuous with short bursts >100rpm... I suspect the efficiency improvement at higher rpm's would be more than offset by the drop in my contribution so if purely looking for practical range I'm likely better off keeping it in my optimal range

If I were just running throttle (I so almost never do this) then my gears are plenty low to max the motor rpm... my [admittedly dim] recollection with a fresh 52V battery at low loads (i.e. going <<20mph in a low gear) it would max out close to 180rpm (I've got a sensor) but that more heavily loaded and battery not so fresh closer to 160rpm... but that's just my dim recollection... I should go out and measure it again since it logs...

[ncmired]

I'd like to know what the measured unloaded / lightly loaded stock BBSHD numbers are, if you don't mind sharing them. I'll jam them into a local copy I have of Sheldon Brown's gear calculator, on which I've enlarged the cadence / RPM table up to 200 (from the 120 they stopped at).

[AZguy]

I should do it next time I've got a fresh battery on, easy enough

FWIW, I've got an excel spreadsheet gear/rpm/speed calculator I'll share too - it's nice since you can compare a ton of stuff side by side and for all the gears, etc.

[73Eldo]

My belief that spinning a BBS at the upper limit of ones comfortable pedaling speed or higher is most efficient is just based on observing the power meter on my display. If I notice I'm in the red on the power meter I will shift to an easier gear which then usually drops the power into the yellow or green range but I maintain the same ground speed.

[Retrorockit]

I do my fastest running with the BBSHD at the end of my ride because I know how much battery I have left to get home. The 24Ah battery is almost always up to it, but after a 30+ mile ride I don't feel like spinning so much.

[73Eldo]

Pretty much the same thing for me plus its up hill from most directions when I get close to home.

[Retrorockit]

For me it's usually strong headwinds on the way into town that use up some range. Sometimes on the way back too. I never know how much battery I will have left until I get there. 24Ah is much better than 17Ah. Usually there is enough for a full throttle run over 30mph, but not always.

[ncmired]

Thread update, now that there are two more videos out on this motor that show real motor mechanical tidbits and install details. Also, the with chainring and display U.S. motor (no battery) pricing is $950.

The first is from Electrify Bike, showing among things, weight and no-load sound comparisons with the BBS motors:

The next one is from Golden Motor showing the installation and a brief ride:

It looks like CYC still has that black text on a light background display which concerns me, and I don't see what keeps this motor from spinning around on the BB.

[ncmired]

From what I can read, the ISIS standard spline that CYC uses doesn't have the issues that the Bafang spline (whatever standard, if any) has, if the crank material is good - not unlike the Bafang square taper "cheese" crank arm woes. And on displays, CYC has several displays similar to the Bafang ones, such as the 500C and 750C. What they don't display, AFAIK, is the motor temperature data.

[Retrorockit]

Electrifybike thinks a TSDZ2 is a good motor.
My BBSHD doesn't sound at all like that. if fact it doesn't sound at all
I think we need a tractor pull to sort this out..

[Retrorockit]

It's missing about 500W. It looks like a nice upgrade from the TSDZ2 (what isn't?). Sound like it too.
They will see my tail light too.

[ncmired]

My guess is the Photon will be no contest to the BBSHD - both initially and over a long hill pull. Bolt on Luna's V2 BBSHD controller and you have a quiet beast of a mid motor.

For the Photon versus the BBS02 - dunno, but at least the Photon would try and save itself.

Retro's got it with his Tongsheng thought: weight, chain line with a smallish chain ring, better heat dissipation, overtemp management, VESC software base, and maybe more.

It's nice to have another choice for us DIYers - I was beginning to wonder if what we had was it, being that Bafang doesn't seem that interested in further refining the BBS motors (in useful to DIYers ways), and the Tongsheng requires major fixes before use.