semi-serious 20inch racing build

[The Apprentice]

http://www.framebuilding.com/index.htm advertises online frame building kit. I haven't used them but just come across the site when considering projects. If you just want a scrap frame to cut up I've got a broken Merlin alloy frame that you're welcome to in Plymouth.

[AussieJester]

Re:Girvin Fork....the only parts i'm wanting are the tops, I don't need the actual fork legs I would make my own to the length required matey, all the moving parts to of the forks and the shock is what i'm chasing if you would be willing to let them go I would definitely be interested..i'm in Perth Western Australia post code/zip code 6076... Appreciate it mate, I would love a set on my 2speed cruiser to give it even more "unique" look lol..

With your fabrication skillz...I would cast my vote for the monocoque composite frame buddy, you could rip that shit up piece of Piss, thus getting EXACTLY the frame your after, and yeeees, make a while lot more ES members jealous Hahahaha..

Best of luck mate, no hurry on checking into postage etc etc whenever you get the time my friend, thanks again

KiM

[bzhwindtalker]

Hey all! Small update on this, i found a way to make the bike frame work for a while before i really take the pluge and make my own frame. I cut some forged alloy cranks, that I will use as supports for the shock. They will be epoxied in place and hold the forces with carbon strands warped around. It will work, because it already does using old 250kg kite lines and no resin (even jumping pretty hard) .

Sorry Kim I did not have time to check shipping for the grivin, will do that next week!

[Whiplash]

HUH, I would never have tried that, but some epoxy is VERY strong so I don't doubt it will hold for a while, but I would be leery of using it long term as it might stress crack over time...

[AussieJester]

Possibly, the carbon fiber stands wrapped wrapped around in the epoxy is going to make out pretty hard to break though...

KiM

[liveforphysics]

A good lashing pattern and layout can be amazingly strong. Way stronger than you would think by looking. A good slathering with epoxy into the fibers would make a pretty damn strong connection IMHO.

[bzhwindtalker]

I used dyneema kitesurf lines, each strand is good for 250kg and made a pure boyscout lashing pattern hope it hold in the long (at least one hour) term ! A failure would not be that dangerous so i'm not worried about that!
I got the bike into ridable state again, but the A123's are probably out of order, sagging a full 25% under load (down to 15v from 19.6, under 150A) I built the pack with some pretty thick copper bus bars, but a lot of this sag may be due to the 12awg wires I used between it and the controller I think I will upgrade wires to 8 awg and get 800wh of 6s lipo for some more voltage and less sag. But then the controller will likely be the weak link, even if i'm pretty sure it could handle more than what i'm curently putting througth it! Ride and learn. I crashed pretty badly on the last ride
I will try to get better pics later!




thats 180mm bottomed out. I felt from 1.5m rigth on the from wheel, with zero horisontal speed.



The last pic don't do it justice, I crashed quite hard!

[bzhwindtalker]

Showing off a little of what the bike can do, trialwise

Check it out!
I would love 0rpm torque and +10kph top speed, more than 45 would just be too dangerous on those trails

Adam

[GCinDC]

great stuff. that's awesome.

[nieles]

very nice bike!

could you show some pictures of your rear wheel set-up, specifically how the gears are mounted to the hub

thanks

[bzhwindtalker]

I remade the wiring and doubled up the power wires, and upgraded the plugs to 8mm bullets, but those mods actually made sync WORSE!! peaked at 3200w but I can't go WOT too fast otherwhise it will bog... I found a hall sensor mount on an old Koll, and have a 72v 50A controller

[Byte]

Hehe awesome! Cool vid

[bzhwindtalker]

Just an update saying all is going well on this bike, the ESC has proven to be really relyable even with 220+ A peaks. I did a new wiring that removed a lot of the battery sag, but the a123's are old and showing their âge. The bike is totaly rocking offroad, and helped me a lot to improve my riding skills. But now I need more power and most of all low end torque ! That's why I got 16 headways, and I'm getting 16 more next month, to make a 32s pack for my next build, based on a heavy pit bike frame, and 24' dirt jumping bike wheels, runing a big hubbie as jackshaft and using rear gering for max efficiency offroad. Firsts tests with 16s and 20' wheels soon, I have a week off I am aware headways are WRONG, but I live at my parents in a just built wooden house, with no safe place to charge and store my bikes. Draft and pictures of the actual frame later today I'm now thinking E-Motorcross rather than ebike, but the current bike is totally un-pedalable anyway... I'm shooting for 5k+ watts and less than 40 kilos with 1kwh onboard.

[Whiplash]

I think you should seriously consider using LiPo, the new Nano- Techs are amazing, the energy density is FAR superior to the headways, and that is the BIGGEST component on a performance oriented e-machine ...

[bzhwindtalker]

Yeah i'm aware of the loss of energy and power density compared to lipo, but if I have 1kwh, the cells won't be stressed much with 5c peaks, they should do fine. Also, its my personnal liking to work with round cells. I can't wait to get my hand on NMC cells, but until that Crapway may be my best option. Also I like bigger cells, makes the pack easyer to manage. I'm not looking for insane power levels, But I knew rigth when I ordered those that I was probably making an error. Still, my dad does not want me to charge a kilowatthour of RC lipo In my bike laying against the wooden walls. Understandable I guess...

[bzhwindtalker]

Here some pics :








Thats what I'm talking about:
storage/charging place


I'm not sure how to build tha swingarm, the carboon one is nice but not really adapted to the frame, a 8kg piece of chineeze steel
the hub has to go the other way, and will be pedal driven on the left side. The freewheel wil be either keyed or hard loc-tited in place to keep it from unscewing.
The drive side has a 15t track cog with a lock ring and plenty of steel thread to screw on.
This will be an heavy pig, but hopefully multispeed and hubbie will be a good match
Stay tuned I'm geting started real soon

[Whiplash]

VERY COOL! what frame is that? I would love to build one! Could be the next poor man's Stealth! What does the frame weigh?? Is it a standard head tube size that will fit a MTB fork?

I hope you don't mind if I try this as well! I really like the look! I will crunch some RPM numbers but I bet a slow wind 9C would make a MONSTER climber throught the gears! and by the looks of it, you could get 30AH of 44.4V LIPO in there EASY with an 18 FET under the main tube!

[Chambers]

Awesome build(s) man, I love watching the progression
How much heavier do you think the new bike will be with the solid pit frame and big hub?
Gonna look awesome no matter what I reckon!

[bzhwindtalker]

If you look closer at it, you will find that the motoped frame is a modded crf 50 or 70 frame, with a custom swing arm. This frame is a crf50 copy frame, its really heavy at 8+kg. I'm shooting for a total weigth of 45kg max, or 110kg for the bike plus me on it, as I think more than that would be pushing the limits of bike components... The head tube is not at bicycles standards, but integrated beaings can be made to fit quite easy I think with some adapter rings or some epoxy+aluminium powder. The hardest part will be to sort cleerances around pedal input and the motor, as I will either need to offest it rigth to clear the frame, or get the chain trougth it. Tigth!

[AussieJester]

WELL You did say it was "semi serious" definitely "semi" with a frock and headwwys..REALLY?? my man...
heading the wrong way IMHO...but as always wish you well...you haz the skillz

KiM

[Whiplash]

A build like this really needs the new Astro I just saw Rec. is working on, now THAT would be Wicked!

That being said, 17lbs is not THAT heavy, I am sure the stealth is every bit of that, and this frame has some metal that can be shaved off for our applications for sure! I guess you could just slice the head tube in half and weld in a new one fairly easily to keep the geometry good no? I really want to try this for my own personal build, I think this could be a really fun bike with the right combo of motor and gearing/reduction. I think it could be fairly cost effective to build too! I mean a hub like that can be had for less than 200 bucks and I know my Conhismotor could take an easy 3000+ watts to it and it would be dead silent still! HMM really got me thinking! I'm off to check Craigslist for a cheap pit bike! LOL!

[bzhwindtalker]

I'm changing my plans.
I put the frame, forks and motor on a scale and it already reads 13.6kg; no way i'm using that on a trail. But I still want to experiment with gears, so its time for a new build, custom frame this time. I Just saw a super cool vid about a japaneeze man building crazy custom gazzers, and now that I sold my moped I don't have something fun to carve with... my offroad is not really good on road, the high seating position makes it crap to lean too much, and 20's are not helping either! I also want something classy to cruize around, with some nice range and doing 50km/hour. I'm thinking 72v10ah headway, 3-4kw, 7-8 gears and somewhat pedalable. Relyable. Hardtail for simplicity, and some sort of grider forks in front. Discs F&R, probably hydros, as I found some really nice shimano sets for a fair price! This will be fun :p

Anyway, I also have my velomobile build going on, plus a FPV set up with a diy quadcopter to get runing... I Know from experiance that having too many projects at the same time is a bad thing


On the offroad side of things, the present bike rocks. It lacks low end torque but i can live with that. The problem is that its absolutely not pedalable, and the a123's are getting old to be pushed like that.I'm amazed the controller survives the brusts! I have a new (old) frame coming from the bay, that will hopefully be good to get the thing going a little better with pedal input. I have another ss 190-200 on hand if this one blows, but so far so good, I have about 15 hours on it without a problem runing 3k peaks and 1500w continuous! Not bad for 32$...

[farmkid4]

Some very neat build(s) looking forward to watching this one.

What motor do you think you will use?

[GITech]

I think that the hobbyking SS-190/200 is worth something in our applications, it handle some serious power nicely! Quite cheap too, 25euros delivered. The drawback is that you have to stick with low voltage, but that makes gearing and battery balancing easy! I only have 1hour of run time on it, so i may be a little optimistic

Is this the type of ESC your using?

http://www.hobbyking.com/hobbyking/store/uh_viewitem.asp?idproduct=14500

Im wondering (should I go RC on my next motor buy) would one of these work with an Turnigy 80-100-B 130Kv Brushless Outrunner?

Regards
Tom

For me I burnt out an HV sentillion 100A and a HV super brain 110A at 22.2v on the 80-100-130 outrunner.

Then I decided that since I was going to retire that bike build altogether, I would get few more (careful) rides out of it by taking my super simple 90-100Amp version out of my custom E-maxx. I got some of those cheap $3.00 self-reseting circuit breakers from my local auto parts store to limit the current to the controller, as I really didn't want to fry it and I intended to put it back into my E-maxx.

So I started with just one 20A circuit breaker, it would pop open easily. Too easily, so I added another one in parallel for a 40A limit, better, but still popped open too often, so I replaced one of the 20A breakers with a 40A, still popped open if I held WOT long enough just to get to top speed, I thought good, but this little 100A super simple ESC still didn't seemed stressed, so after trying two 40A breakers for 80A total and them almost not popping at all, I took the breakers out altogether and no longer had to think about how much current was being pushed through it.

BUT, then the ESC shut off on me after WOT for ~1/4 mile at 35mph+! Without any breakers in the system anymore I thought "well, this ESC finally bit the bullet". But no smoke! Hmmmm, it was super HOT, so hot the shrink wrap was splitting off of it...then, all of a sudden I hear "beep beep beep be-deep" and I was back on the road!

I went back home and replaced the stock heatsink with a PC CPU heatsink and never had a problem with it no matter how hard I tried...for the few more times I took it out before Finlay retiring the bike. It was the frame I was truly worried about breaking at the wrong time.

It also lost sync with the motor MUCH LESS than either of the more expensive HV ESC's!

Moral of the story: The little 90-100Amp Super Simple ESC survived all that abuse!

CRAZY IMO!

Just thought I'd share,
Jay

[sn0wchyld]

cant believe i've only just found this thread!! nice nice work mate, and good to hear how much abuse the SS controllers take. Whats the diamiter of the hub your using there? A mac with the flanges removed may be a better option?