"peak power" - Trek 4300 20" Magic Pie build.

[neptronix]

Can I call dibs when your done with the 20" Pie?
Maybe a partial trade for my Hx3540?

Best of luck to ya up the hill.
Then Zombiess 2nd, if he shows.

I'd actually love to get rid of the 20" pie right now. I'll include the tube and 2.3" BMX tire. It's in pristine condition for the most part. $170 plus shipping sound fair?
Not interested in the HS/HT though, sorry.. . Shouldn't be too hard selling it though.

[Brentis]

That's a fair price.
But I rescind my dibs.
Was hopin' for a trade.
Should sell to someone local/closer.
After shipping, (tax & customs maybe), it would make sense to just buy direct from Gary.
He is about an hour drive from my place, and have family minutes from him.
Good luck on the sale.

So have you decided on a dual hub setup?

[neptronix]

Lol yeah, i was thinking that. I'd be better off shipping the conUS.. you may be saving maybe $10 buying used from me, so forget it.

Pretty sure i'm gonna rock the dual setup I'd rather have a cromotor.. less weight, lower voltage etc.. but i just can't swing it ... .. and the MP is a good motor for toolin' around town after the race anyway.

[zombiess]

Neptronix, if I make the event which I am planning to do right now ill gladly lend you a motor setup in a wheel or a whole bike if I have a spare. Even if you ride a dual pie setup it would be cool to ride together so we can frock pikes peak at the same time. But we shouldn't let our motors touch. I'm starting to sound like phillistine lol.

[auraslip]

nep, I have you thought about oil cooling?
viewtopic.php?f=30&t=34369&hilit=cooled&start=45

Check this out:

Setup summary:
The hub is filled to just below the axle with 400ml ATF.
The temperature sensor is fitted in the windings at the top, not in the oil pool.
The hall sensors are sitting at the bottom, in the oil pool.
The hub is a 7 turn MXUS running at 66v, 4.5kw peak power.
Ambient temperature during testing was 8 to 10 deg C

My regular 9 mile round trip takes in some sections of 20% gradient. I rode the same route at the same speeds (stopping mid point) with identical motors, exept that only one of them was oil cooled.
This route, when ridden briskly, burns about half of my 15AH battery capacity.
In short:

Max measured winding temp No oil ----> 140 C, with oil ------> 55C
Finish point winding temp .... No oil ----> 106 C, with oil ------> 38C

That's pretty incredible. You might even be able to do the same with your mac motor and compete.

That being said, I may be in the market for a 24" magic pie.

[o00scorpion00o]

What's opti's average up the peak?

Surely the pie in a 24" can beat it? Dave have you not gone up there yet?

Come on man, get on it!!!

[neptronix]

Neptronix, if I make the event which I am planning to do right now ill gladly lend you a motor setup in a wheel or a whole bike if I have a spare. Even if you ride a dual pie setup it would be cool to ride together so we can frock pikes peak at the same time. But we shouldn't let our motors touch. I'm starting to sound like phillistine lol.

If you definitely have a motor for me to borrow, then i'll sell off the pie now and stop worrying about this build & chalk it up to experience & a demonstration of what a motor that doesn't get fair air time on here can do..

Having two 26" pies would be nice, but after the race i'd just end up riding my MAC most of the time.

Got two frames with some pretty major torque plates on em. I'm down to represent team greyborg 4 sure.

[zombiess]

I suggest not selling anything until I actually know for a fact what's going on with me attending.

[neptronix]

gotcha

[neptronix]

Oh screw it. I don't know what to do anymore. Just gonna order the 2.75" pirelli and raise the seat post for better uphill "geometry".

Been pretty indecisive lately...

[zombiess]

What is your front wheel size? If you run same size front and rear you should not have geometry problems. You could also swap to a shorter front fork. If the pedals are too low just keep them level. This isn't rocket surgery nepteonix, its a one time deal for you. Front 20 inch bmx with disc hub is awesome. A kids mtb bike like I modded also works great even stock. Ill pm u my number if u want to talk.

[auraslip]

I can build you a wheel even.

Although, I think it is funny that having a wheel built from good components comes out to around the same price as a new hub motor.

[neptronix]

Well, it is a bicycle race, so i want to be able to pedal. I have a 26" front wheel and a 20" back wheel, as you can see in earlier pics. The geometry is most definitely screwed up and i had to go to 145mm pedals to not be scraping my pedals on the ground. Double 20" rims would make the pedals excellent kickstands..

I think the reality with this frame is that the bottom bracket may be an inch lower than most. I pedal scrape on my other Trek ( same generation, slightly larger frame. ), with a stock fork height and a crank length that is only 5mm taller than what came on it stock.

I am 6ft tall with longer legs, so a BMX setup doesn't work too well.
Folding bikes seem to unstable, tried a bunch of those.
I found two people locally who can fabricate for some $, but they are not too serious about this.
The genesis v2100 bike i own with the farfle swingarm seems to also be a pedal scraper if you go 20" wheels.

Still living in an apartment, but have dreams of owning a house with a garage where i can work with metal, weld and such; put together these awesome custom frames that everyone is making here on the forums.
Until then i am a bit limited on what is possible.
So 26" sounds good, but an extra half inch of raise in the rear should help quite a bit.


Next week i go to Utah to visit salt lake city. There is a KMX dealer out there. I'm taking my big car out there with the lady, in case i fall in love with one, scrap this build, and put a pie on the back.. till then, this build is definitely in flux!!

All i know is that i'm not too happy with the stability/handling of this bike.

[neptronix]

Also, thanks for the offer auraslip. Real hard to find a 24" with disc brakes. We'll see how things go with the fat rear tire, if i get enough clearance to pull a front 24 off.

[auraslip]

Building wheels requires one tool: a spoke wrench.

Cutting down pedals and re-tapping them requires a hack saw, a drill, and pedal taps.


It seems to me you're hitting a wall that you keep trying to go around but you can't! Eventually you're going to need to get some tools and get your hands dirty.

[neptronix]

I'd love to get my hands dirty, dude. But i live upstairs in an old victorian below cranky folks. I will probably be a nomadic apartment dweller for some time. Me and the lady are still hunting for the right place to put roots down. We know it is west of California and east of Kansas. That's about as far as we got it nailed down

You should see how extensively i've utilized my kitchen. I'm maxed out on what a man can do in an apartment seriously.. bike parts, lipo, electronics, hardware strewn everywhere. It's like an episode of those TV shows about out hoarders.

More experimenting needs to be done. But a 26" or 24" rear wheel motor would help greatly, but everyone keeps telling me to forget it.

The idea of running the 5kW golden motor 'car motor' keeps coming to mind. Heavy as hell, but a fitting end to all my power wants/needs, lol. no probs with a 26" wheel and proper geometry.. or cooling when only running it at 3kW constant..

[auraslip]

how the hell are you going to rig up a non-frock hub motor when you can't even lace up a bicycle wheel?

[neptronix]

Hardware store, drillin', grindin', and angle grinder when the downstairs folk are at work

I surely could put together a wheel. I guess i just don't have the interest to invest the time into learning how.

[toolman2]

havent got those photos of the 4 computer fan, vented cover pie up yet, but incase it helps, the pie was good for 31NM constant without any ventilation and about 41NM constant with drilled out covers and fans on and all in still air.

so using justins sim for 100kg? it says about 2100w in, and 36kph up a 12% grade, this is the max (continuous) you can climb with a 20" wheel.

[neptronix]

Toolman, been waiting for your update
I am 240lbs, so that 100kg figure is a little low, lol. But the grade is going to be more like 7-10% continuous..

If you're right, after cooling and all that stuff, then i'm gonna blow this motor, period.

p.s. the golden motor '500w' in justin's simulator is not the magic pie, so what motor did you select?

[toolman2]

100kg is 220lbs , and i was using justins sim backwards as i knew the motor can do 41NM so it didnt matter what motor i selected, the end result is that you would be well clear of overheating as long as the grade of your climb stays below 12% and even then, you are doing 36kph.

so on a 10% grade you could prolly do 45ish kph forever without overheating it, reckon most 6kg hubs might struggle against that.

thats without adjusting for altitude though, it would be hard to get my lathe/dyno setup up the top for testing this.

[neptronix]

Well, the whole rig, 30 pounds of batteries, 240lb rider should be about 150kg.
Will also need a bigger tire.. so i am going to be running more like a 21".
Max speed on 83v nominal ( 22S lipo ) is going to be 32-34mph, which is a bit on the high side :/

I think i need a bigger motor, dudes.

Two 26" pies is appealing, but 32lb of motor is kinda burdensome, lol.
Maybe i'll start selling off all my crap ( including the beloved MAC motor.. weep ), take out a little loan and just get a cromotor.
I think it'll do the job of 25-30mph constant on a 24" wheel..

[neptronix]

Just realized a cromotor problem.
single speed gear. That means 16t on the rear. I have a 60T front chainring, but that only means for a ~23mph pedaling speed on a 26" wheel.

My ideology of it being a bicycle means you have to be able to pedal. Sorry - i'm fixed on that idea.
This is verging on hilarious.

KMX kart with either the magic pie, or a 5kW golden motor rig continues to look more and more appealing by the day. I have a big aerodynamic advantage with the KMX. Probably enough to prevent overheating.... and the 5kW motor could be much more easily mounted.

[chroot]

Whoopi come to bay area and root here so until would see me and bunch of ebikers include Edward Lyen, Eric (green machine) and etc but let me warn you that here living cost is a ridiculous!

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[chroot]

Err.. Whoo. Not Whoopi. ES app won't let me fix this error and save the post.

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