OK so I've hit 52mph - who does this for real!!!!

S

scottclarke

100 W
Joined
Apr 21, 2007
Messages
161
Location
UK Midlands
Hiya all, some will remember me from vis - I see Knoxie is around these parts:)

Long time no post - been waiting for summer to arrive /prompt me to do something good:)

The goal - a 40mph capable bike for the mostly flat but rough 13 mile route to work.

So I did something good - the product of 1 months part time labour actually - and, for the first time ever - it worked just as designed first time!

I started with a Marin full sus 'trail' frame with a sweet Fox R air shock
added some 1999 Marzochi 5 inch all air/oil forks (the best forks I have ever tried)
then some nice disc specific Mavic rims
+ a Magura Louise front caliper

then - as I have always done - made something useful out of a water bottle - a sweet ali bottle now holds the esc and the throttle assembly. With this build I opted to eliminate all the problems I have experienced with all makes of throttles tried - that is - when it pours from the sky I have seen glitching/full throttle/zero throttle. On this I have used a motorcycle grip the cable feeds into the bottle where it attaches to a spring that pulls the throttle back to zero. A linear 10K pot is securely attached to the spring/cable join and also features its own 'return to zero' spring should the joint fail. The esc also sits within and a pc fan is mounted at the base - this powered up whenever the esc's auxiliary supply is. Air inlet is via a series of holes along the length of the bottle right between the holder rails. Auxiliary input can be provided by removing the regular dust cap.

And for the first time ever - I am driving the back wheel directly. I have avoided this like the plague due to noise but this build is a work commuter so I don't care much at all. Driving it I have a 2.8KW outrunner brushless motor. Geared 9:1 makes for about 60mph at 36V 90A.

Today I finished knocking together the chain tensioner - it needs shaping so it doesn't look like a rectangle of ali - I'll do that tomorrow. I've opted for a delrin smooth 'wheel' of 50mm dia thats surface is the same width as the chain gap. I have fixed the wheel because the chain was keen to ride over the edge of it due to imperfections where I narrowed the wheel. Bonus - it's quieter!!! Anyway - that was all static - no load testing

But this evening I rode it.

One word - SCARY!!!!!

Seriously - it pulls really well all the way to the top. I did 8 5% hill starts 5-40mph full throttle to check motor heating and it got hot as expected - 74C. I checked the single front brake on the way back down each time - works really well.

But that was all in a straight line.

I went for an extended - about 150m run at which point it stopped accelerating - the wind was really rushing by - eyes were streaming. I looked down - 52mph!!!!!!!!!!!!!!!!! Then I had to turn to the left.

And thats when the brown stuff appeared!

Now seriously - who does 45+mph on an off road mtb? I can see straight line running no problem - but corners? It just felt drastically unstable - wasn't holding the line and I am sure its not down to anything set up wrong on the bike - *I* think its just the way they are????

I don't have any pics of it finished and my camera is broken after it fell off of another bike due to a pot hole. I don't have my Nikon here so you'll have to make do with a 2 week old - in progress pic...

2weeksin.jpg
 
My new hero. You've got me thinking that I want to take a lot of parts off of a lightweight motorcycle for my RC motor ebike project.

John
 
That's amazing!
Sounds like you could gear for a slightly lower speed and reduce the load on the motor.
 
holy crap, details details. what motor is that? what size chain and how many teeth on both sprockets looks like #219. what type of pack and how many volts/AH?
 
Is it april first? Look at that motor mount..

Mmmm 6000 watts:

http://www.unitedhobbies.com/UNITEDHOBBIES/store/uh_viewItem.asp?idProduct=5140
 
A couple of those 180Kv's would make for a sweet little awd off-road motorcycle.. 14Kw total and light weight. Thats where I usually see that blingin gold chain, on dirtbikes.. any case I'm waiting for an up to date pic before I decide if this is foe rills.
 
That is one insane build!

I am doing something somewhat similar... However, I am running my power through the bottom bracket, so I can make full use of the gearing. For my build, I have a 36.8:1 gear reduction planned. It will have to be a dual step down using a jackshaft. The motor pinion is 11t, going to a 80t sprocket on the jackshaft, also on the shaft is another 11t sprocket, which will go down to the BB's 42t sprocket.

Luckily, this will get my rpm down to a reasonable level, and leave me with an insane amount of torque in the lower gears, and a very reasonable 40 mph top speed (which could probably be much higher if I geared it that way).

I am also not planning on putting quite as much power through my motor as you are, i'd rather try and extend my range.
 
Can you give us some more info on the motor setup?

Is there a freewheel in the system anywhere?

How did you mount the gear on the hub - I guess on the rotor holes?


What and where are the batteries?
 
I'm very surprised such tiny motor can pull so much. Specs please!!!! I'd love to replicate that. To me, from the picture, i think he used the disc brake holes to mount his custom sprocket. Definitely hardcore.
 
K all. Answers time:)

Lowell - you around? I know your bike goes silly fast - but can you corner at 50????!!!!


fechter - yeah I would love to be able to gear lower but I am having chain-swingarm clearance issues when I go bigger - last nights test proved I had some contact so I may well have to gear up slightly:(

dirty_d - motor is the same as http://www.unitedhobbies.com/UNITED...HXT_63-74_200kv_Brushless_Outrunner_(Eq:5240) Chain is the stuff used on Karts - 10mm pitch. Last nights test used an 90 tooth on the rear - like I've said I think I'm going to have to go a bit smaller. Front sprocket is a 10 tooth. Battery for the test was from my other bikes - rejigged - a 30s 11AH or so pack of nimh sub-c. In this config its good for 90A continuous but it did get quite warm.

Vanilla - no bull here:) I have dropped (pressed actaully) a doubler (a short section of very tight seat tube) in below the seat tube. Two thick sheet M6 nutserts are fixed through the seat tube and the doubler. M6 capscrews go through the 6mm ali plate - via spacers (currently washers until I have nailed clearances for good). A further nutsert is 'forward' in the main tube - this affords some adjustment of pinion pointing. And yes - I would have gone withe the 6kw baby but no clearance for it - unless I drop to a 24 inch wheel and make a super long crank or do away with pedal altogether - which I can't/don't want to.

tostino - I did a build a few years back -4 I guess very similar to yours. It worked good - but the chain wore out real quick if I was lucky - when unlucky it actually broke/fell apart - it hurts! Keep your max power below 1.5 I say! What I did was an axi into a worm - that got me 60:1 - that then drove the inner ring. A major pain in the butt tbh - having the pedals turn every time the motor runs - watch out!

Mark - I have bored the pinion to 13.9mm and pressed a drawn cup needle roller clutch in there.freezer/oven job:) For last nights test the gear was mounted on the disc brake mounts. I am putting together a cush drive for the rear wheel - until thats done its bodgy on the back end:) Batteries were taped to the frame. I am undecided what to do with them - I may frame mount them - a 'saddle' bag - as I have done before - either side of the bottle mount - running back to just in line with the shock shaft.Or I may go naked - Knoxie style and put them in a bag but I have concerns regarding disconnection in a collision................ FWIW I don't expect the clutch to last - but it may well do with a cush drive - we'll see.

Generally - this is a PITA build - all to do with clearances. I have 2mm to the front chainwheel - 2mmish to the other arm - 3mm to the tyre - 2mm to the frame - 1mm to the swingarm. That kinda fixes the rear sprocket in place if you see what I mean. I think I am going to have to gear up - I am already running the longest crank you can get.......... I am fine with 1mm clearance as long as its always more than .01 under stress - but its not - at least the chain clearance rubbed a few times.

I am going to try it on 24V then maybe 30V when I gear up. I want the V for the amps on the hills - even at low speeds......

Thats all for now -
 
OK, Who is going to be the first to mount a Hacker A200-8 to an ebike? :twisted: 8) 15,000 watts of pure evil :lol:

http://www.hackerbrushless.com/motorDetails.aspx?series=A100/200
 
Hi Scott

Great to see you online again!! I was wondering where you had been as had not seen you about for a while, looks like you have been busy with that bike! looks great! speed sounds scary fast, I now run an X5 on my bike and its plenty fast for me at 30mph, 50mph is a whole different speed though Scott!! be careful!! I must pop up and see you in the summer else bring your bike down to me and we can do another video! (Me and Scott live pretty close).

I expect that you have seen recumpences thread with his outrunner motor then? seems quite a few folks are going this way for rides, I like the idea a lot! I have a little folding commuter bike that would be ideal for a set-up like this, the bike has 12 inch wheels! so there is not too much room, it would be cool to rig one of these up I only want low speed high torque to overcome the fixed gear of the bike helping me up some of the steeper hills making the bike more useable around my hilly town, else I may go for the same set-up as the cyclone a bike which is a nice little rig for a small bike, driving the wheel direct off a freewheel sprocket..

Keep the pictures coming (and video) if you can.

Knoxie
 
Little Thought!

For a small bike, like the little folder, would it be possible to attach a prop to the motor and mount it in a cage off the back of the bike? it would look hilarious I know! but is it feasible? I doubt it is very efficient but it would be kind of unique? I remember years ago a fella in the papers had a strimmer motor and a huge fan on his back on a racing bike, that worked very well, the cops pulled him for safety reasons.

But if all you wanted was a little push up the hills and max running time of say 10 mins, I wonder what size prop etc would push you average bike and rider along? I reckon you would need a bigger motor than this one though, interesting thought though! chocks away!!! ha ha.

Knoxie
 
knoxie said:
Little Thought!

For a small bike, like the little folder, would it be possible to attach a prop to the motor and mount it in a cage off the back of the bike? it would look hilarious I know! but is it feasible? I doubt it is very efficient but it would be kind of unique? I remember years ago a fella in the papers had a strimmer motor and a huge fan on his back on a racing bike, that worked very well, the cops pulled him for safety reasons.

But if all you wanted was a little push up the hills and max running time of say 10 mins, I wonder what size prop etc would push you average bike and rider along? I reckon you would need a bigger motor than this one though, interesting thought though! chocks away!!! ha ha.

Knoxie
Click to expand...

That would be really dangerous. even small plastic propellers can cause serious damage, you would have to stay far away from people and be very mindful of where you move your own body.
 
Knoxie, yeah 50+ is tbh silly fast - at least round corners. Maybe a tire change will fix that - I dunno.

One thing I did find in 5 minutes of riding - at these speeds you really do need a full face coverage helmet. I don't think I can slow it down at all - well I know I can't so running at 40mph or so will be the sweet spot in terms of noise and motor heating. Its what I wanted I suppose but I would much prefer a lower top speed I think. If only there was room to gear it down a bit:(

Scott

PS the trike is on hold - nothing technical - more a lack of a market and for a winter or two I'm quite happy to don waterproofs and a full face and do the work run on 2 wheels - as long as the journey time is <20 minutes.
 
That United Hobbies outrunner is only $65! Gotta be a misprint!!!!!
otherDoc
 
My bike definitely corners well at 50+, but these days the original NiMH cells don't put out the power like they used to.

Do you have any pics of the bike in completed trim? Videos?
 
Try some monster 2.5 or 2.7 inch downhill tires to get more bite.

What kind of controller did you find to run that motor? Was it hard to get a sprocket to fit the shaft? wasn't that motor designed for model airplanes? I am surprised it can move weight like a person on a bike at those speeds without burning up in 5 minutes.
 
10mm chain? are you sure, google turned up nothing, go carts use #219 #35 and #40, where did you buy the sprockets and chain? im curious about the needle roller clutch, ive seen some on mcmaster.com but im not sure how they are secured to the motor shaft, also whats a cush drive?

actually i saw them on sdp-si.com, these? https://sdp-si.com/eStore/Direct.asp?GroupID=388. the metric bore sizes confuse me too, 10H8, 10H6, whats the difference?

how long is the shaft on that motor also?
 
Oh well, run number 2 involved 10% hills

bad idea - REALLY NEEDED TO SORT THE WIRING FIRST!!!!!!!!!!!!!

had a wee fire on my back - have some pack reworking to do! Turns out I definately need some really beasty wire - I'll pick some up in a bit!

Scott
 
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