Descendence bikes open-source electric bike frame

I fitted my seat onto the bike and just got back from a bit of a burn around, and the difference was crazy... you really have to lean over the front wheel to get traction on the front, and having the seat on it forces you to sit higher and you can't slide forward on the seat like you could a moto.
When you accelerate on a straight, it shifts the COG right back (as in trying to do a wheelie) which has the effect of taking traction off the front tire, which feels freaky. It didn't really do that without the seat there, i presume because my body weight was about 150mm lower on the frame. There isn't really a way of countering it when the seat is on.
Definitely need to make a low padded moto style seat for the battery box.
 
so i made a few mods tonight, seeing as the missus is at her folks tonight for a lil chrissy do that i got a hall pass from...

20151224_000653 - Copy.jpg

i cut the battery box in half and hinged it so i could access the CA wires without having to unbolt the entire seat assembly, and sealed the gap up with a layer of 3mm rubber under the hinged joint/gap.

i also made a super dodgy bobber seat out of 3mm staino plate, some foam, and (betraying a rather dodgy past) some nice red leather held on my eyelets and leather strap.

gotta love midnight modifications!
 
Nice work. Could you make a few more shots of the seat, preferable in side view also?
 
macribs said:
Nice work. Could you make a few more shots of the seat, preferable in side view also?
Click to expand...

here you go mate-

20151224_152401 - Copy.jpg

its really quite rubbish, but it does the trick and is actually quite comfortable (and it was a 9pm-1am, half carton effort, after all). its pretty much impossible to pedal from because its so low, but that's not really the point of it, of course.

on other matters, one thing i'm noticing about the hub motor is it has a strong gyroscopic effect when you get up in speed. i dont notice it when i'm riding my back yard track cause i cant really go that fast, but when you fang down the road or a dirt track it really can get a good wobble up. quite disconcerting when you're going 70km/hr on a 1m wide gravel track thru trees.

of course iv heard this about hub motors, just never had the chance to test it for myself. i wonder if it'd be worth using the hub as a mid-drive unit? not sure if it'd be worth the effort tho.
 
wobble? does it run true?

Mid drive? I don't recommend high power for through bicycle chain drive, pain to up keep to be honest now that I am experiencing it first hand. With your fab skills something powering the disc brake side would be insane for off road though.

I am interested in your heat over the rides you have been doing... Have you been monitoring your motor and even more so your battery? Just a hand test is sufficient to see if you are killing them, Guy I was riding with recently had no idea how hot is batteries were getting until I felt them.
 
Yeah the rear is straight and true, it's a real gyro wobble, no other way to describe it. If I actually try to shake it, it starts.
The battery gets quite hot, but not too much to touch. The phase wires have got hot enough to kinda melt the paint onto the wire insulation tho, which is a bit of a worry. The motor itself gets really hot, but it's solid ali so that's not that surprising.
I was thinking if I were to do it, I would just run dual bmx chains. It'd be cool to be able to gear it down for more torque.
Why is a mid drive more work to maintain? I've no experience whatsoever so everything is new to me here. ..
 
More moving parts = more complexity for failure.

Typically the cheaper Chinese mid drive models also had inherent design flaws and/or made with weak or shitty parts, leading to premature failure.
 
Yeah I've heard the cng/hurricane jobbies had a habit of breaking. To be honest I do not trust that many free hubs and ratchet pawls- only one fails and pedals are spinning into your shins.
I was planning on just doing a direct drive and pissing off the cranks completely. Maybe. I love the idea of a high rpm tiny little RC motor as a mid drive, but like you say so many moving parts...Just a single direct drive motor geared down enough with one chain, seems a simple solution.
 
Have a look at tangentdave's design. $$$ but uses a quality motor and well made kit to go with it.

https://endless-sphere.com/forums/viewtopic.php?f=28&t=70099#p1057394
 
madm3chanic said:
The battery gets quite hot, but not too much to touch. The phase wires have got hot enough to kinda melt the paint onto the wire insulation tho, which is a bit of a worry. The motor itself gets really hot, but it's solid ali so that's not that surprising.

Why is a mid drive more work to maintain? I've no experience whatsoever so everything is new to me here. ..
Click to expand...

As I suspected, you are pulling too many amps.
Don't want to sound like a broken record or your parent, but just want to make sure that you know that if your battery is warming up it means you are damaging it. Also in case you don't know, when you finish a full pack and it's warmed up, you should wait for them to cool down before you recharge them.

It also sounds like your wiring is too thin if they are hot.

As for mid drive, the more, shafts, pulleys, bolts, brackets, chains, nuts, springs, tensioiners, sprockets, etc all have their limits and the same goes for bicycle components especially the rear hub / body / rachet / bearings / pawls which were not designed for more than 1kw etc......

The right approach is to avoid all that and yes no peadals would solve a lot especially if you have your own property you ride on, or the disc brake with no connection to the pedals.

Those small RC motors are going burn up too.... few have tried but more have failed. The LMX concept would be a good starting point to shoot off from in my opinion.

Anyways enjoy your holidays mate :D
 
madm3chanic said:
That's a thought, anyone know whether the CA still limits current draw etc with the throttle wire pulled out? Cause I can mess with its settings but it's hard to know if it's actually doing anything.
Click to expand...

pretty sure it will, I used to use it with the throttle wire out too.

Best way to check is set the amps to really low like 5 amps which you will hit very fast and you will see it start limiting.... takes a minute to check
The problem is though the oscillations that you will experience will be so annoying and potentially dangerous to controlling the bike, that's where having full throttle ramping customisation comes in to smoothe that out.....
 
Nice going! Welcome to the addiction :)
 
made a rather shite little vid of us stuffing about on the charge on some DH trails we spent the week making down in Balingup in WA. i wish i had taken more footage (we spent hours shredding berms, doing drops and trying to convince ourselves to make gaps (mostly landing short and axing ourselves)) but only took a few vids.

http://www.pinkbike.com/video/434269/

i also managed to get the machines out and made a rather epic back yard track out of those massive jumps that were out in my back paddock when i moved in (i turned all the monster gaps into individual tabletops), so ill get a bit of footage of that track up sometime soon.

well thats about it for this forum i suppose- i will be shortening the chainstay length of the swingarm to 450mm (500mm is too long for cornering; as i ride it more im realising doing or not doing wheelies are about controlling power delivery and body position, but correct geometry for handling/freeriding is paramount, so shorter it will go) and fitting a new seat at the correct height for cornering with my arse on, but other than that i suppose its finished. as soon as i have the seat thing completely sorted, ill put this frame set up on my website and start pushing them a bit, as i'm totally happy with the durability and suspension.

now we're moving onto a mid-mount using a fan-cooled astro 3220 and lipo bricks; this bike was a great stepping stone, now its time to make a proper monster machine! expect that one to take around the same amount of time as this one, but im already buying bits for it :) ill start a new thread for it, as i would REALLY appreciate input for this new one, as you guys have most awesomely done for my last build. Kudos!
 
here's raw footage of a POV run around of my backyard track

https://www.youtube.com/watch?v=E-_W8sKyTi4&feature=youtu.be

now i just gotta get the stones to send that creek gap in the middle at about 0:58s! its only about 5 or 6 meters but kinda scary cause its over a fairly deep hole. i also quite like how i flat-landed the spine from about 2m high at 0:30 haha
 
Epic thread. Read. Learned. Enjoyed. Thank you. ...off to try and find the mid drive frame build. ..
 
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