Mini Hiryuu v2 - 1.5kw lightest.bike drive on cheap hardtail

[neptronix]

If the axles are not flattened then the axle should be the correct diameter to fit into the wheel slot. So if we remove some material, we now need rectangular shims..
Well, luckily the design is not as such

Keyde will sell you a predrilled hub with spoke counts in units of 4

I agree that i should go tubeless compatible with the rim... maybe even use that capability

Also been sleeping on this motor for a long time.. Keyde published scant details until recently.. and also they were asking ~$700 for just the motor until now. That cost is still high for a Chinese designed and produced motor but maybe they will surprise us with 0.27mm lams inside / some decent build quality, idk.

I'm willing to risk it for the brisket and buy a front p100 and do a partial / full teardown once i get the battery situation sorted. More news on this later.

 

[neptronix]

Here's another crazy thought while i'm trying to find the optimal power to weight ratio..

This 3.3lbs front wheel hub + the lightest.bike mid drive ( 4lbs ) is still lighter than my existing hub motor
.. that would provide 2100w peak power... and crazy enough, the linkdata 65P 2P battery could also handle the discharge.

Or we could have dual Keyde p100's for a hair under 7lbs... low top speed but 1000w cont, 1150w peak would make for a hell of a climber.
Hm... well, let's hold our horses until we see the build quality

 

[lnanek]

The Grin All Axle is less than $700 and only 4 kg vs. 3.3. I'd just get one of those and toss out all this multiple motor business if I wanted to be light and powerful. Get a nice carbon wheel for the non-motor one. I got a Mavic full carbon the other day for like $50 off eBay.

 

[neptronix]

Nah, carryability and good rideability with the motor off is headed in the wrong direction vs my 8lbs hub.
I do have an all axle here, but it's better on another bike.

 

[glennb]

On carryabity, since you'll be using a smallish battery, have you considered a backpack battery? Yes, you'd still technically be carrying the weight, but shifting a portion to your back would reduce the stresses involved.

 

[neptronix]

On carryabity, since you'll be using a smallish battery, have you considered a backpack battery? Yes, you'd still technically be carrying the weight, but shifting a portion to your back would reduce the stresses involved.

I've always wanted to like that idea, but what if you fall, and then a lithium battery decides to go, some seconds later. And you've got this cord to navigate around when it's not exploding. I think that would annoy me too much.

I'd like this stick battery and the controller to rest in a small, ordinary bike bag.
Paired with a small motor that could be mistaken for an overgrown light power generator.

 

[glennb]

As in, battery ignites while you're lying on the ground incapacitated? Not a great way to go, but orders of magnitude less probable than death by being flattened by a car from behind, car doored, or squashed after sliding under a truck. And if you're prepared to take those risk every time you jump on a bike ...

Completely understand though. Dangly cord I can't put a positive spin on - there's no redeeming aspects to it whatsoever.

 

[2old]

I have a 52V, 4ah battery that easily fits in a seat bag with plenty of foam encapsulation (since the bike is ridden off road). It's never been a problem for my 15 or so mile rides (BBS02), and previously used a 52V, 6ah with no problems. I don't know if this has been mentioned in the thread, and apologize if it has.

 

[neptronix]

True, it would be super rare. I just don't like the presence of another failure mode to have in the back of my head. I've taken a dive off a bike twice and, unrelated to those incidents, watched as one RC Lipo offgassed spontaneously.... magically not producing flames in the process... so maybe i have a little e-PTSD, lol.

Looks like NESE man is ready to take my order for a 2P 14S kit.

 

[neptronix]

NESE is shipped. Super exciting. I want to look it over before buying any cells.

I read on electricbikereview that the Keyde P110 has noticeable drag; i hear the Aikemas don't, so it sounds like the H128CST is the right choice.

Weighed the bike with the bafang G020, controller, accessories, and no battery. Comes out to 41lbs. Very rear heavy due to the thick rear tire, 9lbs of hub motor + torque arm, suspension seatpost, and relatively heavy seat.

I think i could get some weight off the Grin V7 torque arm with a small cutoff wheel and drill, then build the wheel with butted sapim spokes and a 20mm internal middleweight rim and lose a total of 2lbs in the rear with the H128CST.

There's also potential for a lighter seatpost. I'm also 40lbs lighter than 6 months ago, so i may be able to drop some seat weight. Maybe we get 2.3lbs total rear drop, which would be good enough.

 

[rafalg]

This discussion made me wonder why there's no good, well engineered mount for hub electric motors. They've been around so many years, and still people are using standard bicycle axles, or even thru axles now, but none of them is designed for handling the driving torque. Squared axle barely works and can easily destroy itself or the frame, thru axle can be tightened but i don't think it will handle too much torque (and can un-tighten itself easily). Almost all other bicycle parts can be standardized (or at least you get a finite number of incompatible standards) so i dont know why nothing better is offered here.
Maybe an integrated torque arm attaching to disc brake mounts in the frame could be kind of standard...

 

[99t4]

This discussion made me wonder why there's no good, well engineered mount for hub electric motors.

Lack of imagination and motivation among the producers?

 

[neptronix]

Lack of imagination and motivation among the producers?

Yep.. the usual..


I'm ready to order a motor the other day and topebikekit.com was down.

Thought about alternatives..
ebikes.ca has G310's going for $125 which are 5.5lbs, great deal but 82% peak efficiency and high speed winding ( 30mph on 52v ) are too much a downside, would require a 36v battery, and it seems to overheat easily. I wonder if the problem is high gear friction or just thicker than optimal laminations.

Keyde front P100 is 2x the cost of either and has unknown durability and rolling attributes.
topebikekit.com is back up.

NESE modules are still on the slow route.

I am exploring a new way to make 175mm cranks work on the lightest.bike mid drive, which would provide me more power than i know what to do with.

Don't think i could do better than a 1600w peak, 1000w continuous rated mid drive that weighs 4lbs.
Might even turn the power down to make the 4lbs battery work better.