Fliess 3 - "Einmal DirectDrive - Immer DirectDrive!"

if it is, its a really long one with a posted limit of 30 mph that i regularly break testing boards, much to the piqued interest of a local officer who camps at the stop sign and thinks i’m nuts but wants one of my boards. Every time i see him with another customer’s board he’s like “wtf are you riding now? Can i catch that in my cruiser?” or something equally friendly.

I’m going to ask him if i can get video of him lit up chasing me down the street. I doubt he’ll go for it but it might be fun.

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@longhairedboy, you have intrigued me with your “worst street ever” and how your boards handle it. Appreciate some photos of a street. Really, not for fun, rather to compare with my conditions and to know if I stress my direct drive enough while testing.

Thanks @PartyPoison. I am using sk3 6372. Yes, I used only my mini lathe. Kegels are nice but only 80mm in diameter, so may be good for testing but not for the real usage :slight_smile:

If I manage to eventually bend 12mm axle, then there is a plan B to use 14mm. I am only 75kg, sometimes jumping while switching sides, bumping hard against the curbstones and the axle is still straight. Need much heavier rider to test it better :smiley:

these are what my roads look like…

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its hard to capture the depth of the asphault wear between the aggregate stones on camera but imagine 80 grit sandpaper scaled up to street size, then touch it up with bad pothole patching, unpatched potholes, sudden inexplicable sections of entirely different asphault from another era, these not-quite a pot-hole holes that are just the right size to grab a wheel and throw you into the emergency room and are really deep for some reason like somebody stabbed the street with a pole, and random patches of gravel that seem to congregate from nowhere because the street sweeper truck is out there three times a week. Unless you’re on superflies even a solid silicone board would rattle.

I’ll try to get some pics if i can.

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@cryo, Purple Kegels are 83a, while Flywheels I use have 75a. There is a huge difference in softness when you go bumpy roards. Another really noticeable difference is how fast you can ride “asphaltless” road not losing a traction, especially when you suddenly switch from the asphalt on a speed. And riding over metro railways, if you have such in your area :smiley:

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what kV are your motors? seems the lowest SK3 offers with the 63’s is 149. is a lower kV not a design consideration for non-in-wheel direct drives?

He stated that already. 149 kv with one motor and he rewound the other to 110kv

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that’s slightly worse than my street. If you removed the web of cracks that’s what mine would look like. And add some holes.

add a couple trees growing out of the middle of the road and youve got my street. ill take a pic when I get home

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Thanks @fliess, we are same in weight, i already have a trucks with axle of 14mm (lathe, unfinished project),

Motor is 148 kv right? Better start with motor and deal with the direct drive later on.

Btw what battery you are using for that motor?

Hi, I don’t know if you followed the direct drive vs geared efficiency discussion: on the paper a geared system should be more efficient than a hub motor.

BUT there is still no empirical evidence about that: @trampa suggests that the only (scientifically) FAIR comparison must be done using the SAME motor (same stator and amount of copper). Your awesome direct drive would be perfect to try both configurations. Do you have the possibility to try your SK3s geared 1:2.5 (with idler) and record your ride through ackmaniac’s app?

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@GrecoMan, honestly I expected to see something worse on your picture :wink: Not kidding. Yes, it’s definitely not comfortable to ride, but should not be fatal for the motors even if you ride there daily. Okay, on the night ride without lights it could be if you aim a couple of really deep holes :smile:

@longhairedboy, best description ever :smile:

@mikenyc, one is 149kv switched to star (which gives ~0,7*149kv). Another was 168kv, but I rewound it entirely to something < 100kv.

@jrpwit, you’ve been “almost” correct :smile:

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@PartyPoison, both motors <100kv, check my previous reply. Battery is still from the 1st build, 10s5p R25. Not the best, but gives very confident 29km of range if you ride it hard. Okay, “riding hard” is very subjective, but in my area and with my modest skills I usually end up with something like this:

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@fedestanco, no I didn’t follow. Thanks for the suggestion to make an experiment, but, dude, really I don’t have enough motivation to do it right now. Moreover, I suspect what approximate results I will get - belt driven is gonna be slightly more efficient. I like that feeling of sudden acceleration very much (luckily it is still very good with direct drive) and of course belt driven system is more efficient in such a case. But, if you are going perfect straight with a constant speed and motors KV perfectly fits a speed, then I believe direct drive is more efficient. Anyway, it would be even difficult to practically prove.

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That was the exact idea I proposed that none of the belt guys would accept lol.

[quote=“BigBoyToys, post:32, topic:35056”] under low-med load cruising situations( at motor rpms within the efficincy range for its KV), where heat isnt much of a concern, the hubs should be more efficient [/quote

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@BigBoyToys, ah these old-fashioned “belt guys” :smile:

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I ride in SF every two weeks and Tony, who has a Raptor 2, goes to every ride. We are both using the exact same battery (10s4p 30Q) and I always end the ride with more battery than him.

We’re going the same speed doing the exact same route with the same incline (typically not much incline on our routes).

You may say direct drive is more efficient, and that may be true for long stretches of trail, but for the stop & go riding style of urban and city riding, I think belt drives still retain better efficiency.

I’ll take a picture comparing the two boards on our next group ride :slight_smile:

@BigBoyToys

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