semi-serious 20inch racing build

bzhwindtalker

bzhwindtalker

100 kW
Joined
Dec 1, 2008
Messages
1,807
Location
Lyon, France
Hello all, not even done on my 1250 miles road trip on a homemade velomobile, i started thinking about my next ebike. I wanted full susp, good torque and at least 25-30 mph on flat, good handling too. I had a 80-85 around for some time now, but i could not find a controller. This time i decided to try a hobbyking ss series 190 amps on 6s a123 (got a pair just in case!), I don't mind really high power, as I'm only 60kg but i would like at least 2000w. if this does not work, I will go with a sensored controller or another motor...
so here's the bike!REside.JPG I still need a freewheel on the back, some cranks, a pulley for the motor, make a battery mount, figure a way to control the rc controller from a hall effect half twist. I will try to get a real disk brake on the front, the road bike caliper does not have a lot of braking power! I plan on putting a fan on the controller to keep it cool, and ill probably make an arduino interface to make it pedal first.
I hope the controller will give some fun before giving up :)
This is my preparation for some ebike racing :p
 
Now that looks like FUN! I would do it through gears, but that's just me. I like the way you stretched it, it looks natural on the bike. The forks are cool too and give you a bit more wheelbase it looks like, cool....!
 
That looks super cool. I'm intrigued with that front fork. Never seen one before. Looks simple enough to reproduce. 8)
 
Wooo woo! Got the servo tester working! Thank you for pointing out this tutorial, would not have guessed it would have been this easy. The esc has no BEC, so I used an old sony ericsson phone charger as DC/DC ;) I also put an overvolted computer fan on the ESC for good measure, it would probably help a bit with low speed heat... The driveline work, but I still need a freewheel to screw onto the rear wheel and secure the belt pulley. Im going single stage with poly-v belt, I really like them!
Still a lot of work but the build is coming along!
 
First test today! this seems to have some peeps, and the sync isn't that bad above 5 kph! I still need a lot of work to be done, this was just a quick throwaway to test it :roll: the controller was not even warm, but the front pulley was slipping quite a bit, because i just used the prop adapter with some tape to make it haha! Now i have a lot of time until I get back to school in September when ill be able to machine some aluminum pulleys, I will use this time to refine everything else on the bike, and getting it ready to kick ass in september :mrgreen:
 
I like everything about your ride. It's way cool

The v belt has the added benefit of limiting torque by slipping. If you added an adjustable belt tensioner you could dial in you torque limit so to speak, and save the esc from over current. How stable this would be with belt stretch and wear however, i got no idea...

Good luck with the rest of it :)

D
 
Thanks for the support guis! I did some more testing tonigth, the controller seems to hold some power, as I did some acceleration tests, and it did not heat up that much, probably less than 40 c°.
I also cleaned up the wiring and secured the controller and servo tester interface to the frame rigth next to the motor. I cant find a damm bmx freewheel in any bike shop, something is wrong in this town...
 
You need a left hand freewheel, or what?

Chalo
 
just a standard BMX low tooth count freewheel! Like the ones used on 99% of single speed bikes, but i've been trough a lot of shops without success...
 
Firstly, let me qualify my following concerns by stating that I have bad eyesight and I've never worked with a rear suspension like that. But, don't the upper stays need a pivot down where they meet the swingarm? And wouldn't you need about twice the spring rate on your shock because you now have about twice the leverage on it?
 
My pictures does not detail the rear suspension a lot, but there is actually a pivot just before the part I welded, so the suspension can actually work. The shock was way too stiff with the original configuration, now the suspension is a bit more useful but I don't bottom out even jumping it quite hard, so I should be okay if the pivots can takes the increased forces due of the longer swing arm !
 
I just have to ask. Are the down tubes on that front suspension, reversed ?? It seems to me , that the brakes should be on the inside of the forks, so the bolts that hold the brake mechanism is not overstressed when applied ?? Also, the drop outs are on the inside of the forks, so, does that not change the rake ??

If those tubes were swapped around, it would look much better to me ??

I haven't messed with Bicycles for many years, and, I want to build up a good solid frame, with suspension, and, want to do it right ???
 
Harold,
google up "Girvin forks" they are nice but getting hard to find....& i suspect even more rare in 20" wheel models
(i picked up a decent set at the swap meet in tocson) & yes the dropouts are arainged that way to keep the trail (caster) in the designers range. looks funky but the worked for John Britton. :D

research "Girder forks" for more info. (i have been playing with the design for awile....time to build myself some)

http://www.google.com/imgres?imgurl=http://66.147.244.179/~vintagm8/sites/default/files/images/killerv900.jpg&imgrefurl=http://66.147.244.179/~vintagm8/node/37&h=581&w=1000&sz=452&tbnid=_lI6PKgAVmI7DM:&tbnh=69&tbnw=118&prev=/search%3Fq%3DGirvin%2Bforks%26tbm%3Disch%26tbo%3Du&zoom=1&q=Girvin+forks&docid=oc5vkpMOQWgdOM&hl=en&sa=X&ei=ushCTpCbOOv9sQK4yvzsCQ&ved=0CFUQ9QEwBg
 
Harold, I'm positive that's the way those forks should be used, as seen on ES > http://endless-sphere.com/forums/viewtopic.php?f=9&t=27806 What you are looking for is a girder fork, like that
1220647_f520.jpg
Those are the simplest way to make a front suspension, and are still quite effective. They require less maintenance too because they don't need fancy shocks with seals and oil. I'm sure they have a lot of drawbacks too, because otherwise they would be on every mountain bike!
I did some progress on the build, but the freewheel i finally found was too wide and the wrong tread anyway (smaller bmx rear wheel tread...) I got some cranks, some pedals and chain.


Just saw Thud's post, actually those are 26' forks, without disk brake tabs, so I'm having some problems finding decent brakes to fit, and I don't really want to weld them or trust some rivets...
 
Have you thought about using a modern V-belt, like a Powertwist? http://shop.ebay.com/i.html?_nkw=powertwist&_sacat=0&_odkw=polytwist&_osacat=0&_trksid=p3286.c0.m270.l1313 They are ment to have alot more grip along with no stretch characteristics and extremely long lasting. They have the added benifit that they can be made any length :mrgreen:

Does anyone have any suggestions for a primary V-belt pulley with a center bore of 10mm or less and a overall diameter of 2"or less? Otherwise i might need to beg you to make one extra when you go back to school :oops:
 
OK. Thanks guys. After studying forks on the ES, this set just LOOKS backwards. :roll: :roll: :roll:

While in Fl recently, I bought springs and freeze plugs, to build a "Springer forks", from plans on the 'net. Also, studied AJ's build of springer forks.

I have a cheaper bike here, with 26" wheels. I going to mount a Motorcycle wheel in the rear, with swingarm suspension, and, adapt a drive system. It's a front wheel from a 250 Ninja.

Yeah, it's going to be a heavy bike, but, I need strong for the 2 of us to ride. :roll: :shock: :lol: :lol:
 
I think I better not try two riders on this bike haha! By the way I got it working, with pedals, a disc brake on the front wheel, no slipping, it accelerates quite fast but the belt pops out sometimes... top speed around 45kph but the battery was dying!
I need to put my cycle analyst somewhere on it just to monitor peak power, guessing above 3kw, and the system seems to hold that well, no overheating of the controller yet :roll:
 
Cool
 
Very nice. I think you have more belt slippage than you realize. That is a VERY small motor pulley.
 
I know I have a lot of slippage, and I think I should go with a chain drive+torque limiter for reliability, as I have some alignement (woobling) issues with the current setup, especially when jumping! The belt stays on, but the belt tension isn't constant over its revolution...
[youtube]QmnohV-oug8[/youtube]
 
I ordered a Extron 92tooth in 219#, a 219# 11t front sprocket, 228 links of chain. I will machine an adapter for the sprocket on the back, and a torque limiter/clutch at the motor shaft to ease the load on the controller. This set-up is expensive, but I hope it will hold all the power I would ever like to put on a bike frame. This set-up will give the same reduction as the current belt drive, that tops out at 45kph on 20v. I will soon order 500wh of 6s lipo to rise the voltage a bit ! The bike wont be ready again until mid September when I'll get back to school, hopefully cleaner and more powerful ;)

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 ;)

I'm soon starting to build a new velomobile too, and I'm seriously thinking to build a dual 65mm motor+ 2 of those controllers on 22v, this could be really really fast with the velomobile aerodynamics!
 
You must log in or register to reply here.

Similar threads

N
Newbie NEEDS Help/Suggestions for new build
Replies
12
Views
313
MxusMick
M
A
Nucular 24F with Display
Replies
1
Views
498
Amperry417
A
T
    • Like
My first scratch build: 30kw full suspension tandem velomobile.
2
Replies
27
Views
4,146
amberwolf
amberwolf
RustyKipper
    • Like
    • Cheers
I'm in the 40,000 mile club!
Replies
8
Views
1,860
RustyKipper
RustyKipper
TommyCat
Using an On/Off-Momentary Push Button Switch that’s normally open to replace a hall throttle.
Replies
5
Views
2,869
E-HP
E-HP
Back
Top