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

[Brentis]

...

Checked out a 20in. wheel for the front today, BIG problem - i only get about 1 inch of pedal clearance of dropping that low - but the bike's geometry is correct! With a 20in. wheel, i can use one of the pedals as a kickstand,

So anyway, i'm thinking of going from 165mm to 150mm cranks to get me 1/2 inch more pedal clearance, ...

No, don't do it. Wear your pedal strike as a badge of nuttiness.
Free kickstand , keeps unskilled newbs off, etc.
Ala "Ghetto" http://www.endless-sphere.com/forums/viewtopic.php?f=6&t=32831
Works fine on the street/light off-road..

On a side note.

When you get a chance, can you grab me overall axle length?
I'll be using Dogman clamping dropouts. So no nuts or torque arms to worry about.
But I still need 190mm ish to make it work on "Strong".

Thanks.

[veloman]

That clearance is dangerous. I already hit my pedals occasionally if I try pedaling on even normal corners. I guess the full suspension rides lower and these newer pedals are wider. I once hit a curb on my right while turning right from a stoplight. That woke me up real good.

[neptronix]

scorpion; as promised:



70deg. motor temp at the beginning, 80deg. motor temp at the end, used 120% setting for the majority of the ride, and the pie was cooled off after about 15 min. This thing sheds heat well

Yeah, a recumbent would be nice, a 3 wheeler KMX for example. But in reality, there are no bike lanes out here, and i live upstairs.. a recumbent would be great for the race, but would be impractical outside of the race.. maybe later on when we get settled and buy a house.. that is if this country doesn't fall to crap .. until then i'd like to make the 2 wheeler work.

Brentie: axle length is about 8 inches. It's a little shorter than most ebike hub axles. I'm thinking the pinch will work for you, as long as you have standard 135mm dropout spacing.

veloman: It is dangerous indeed. But remember that i won't be pedaling too much - prolly just gonna hit the throttle on the curves and pedal on the straights.

I think not having suspension keeps the pedal strike predictable. After my geometry corrections, i should lose about 1/2 an in. of ground clearance, which is liveable

[Brentis]

Great vid.
Beautiful country you gots there
No snow or ice.
Whats the top speed in video?

[neptronix]

Great vid.
Beautiful country you gots there
No snow or ice.
Whats the top speed in video?

Actually there is a wee bit of ice hangin' out still. But for the middle of winter, not bad..
Usually it is much greener here.

Top speed is 34mph ( 120% speed setting ), 27-30mph average though up the hill.

[veloman]

That's right, you don't have suspension, which will help a lot.

How big was this climb? grade? its hard to tell on video.

[StudEbiker]

Impressive ride vid! Looks like fun for sure.

[valsislav]

I can see why you live there - what a lovely country...
Now - if Ron Paul is elected president, I am applying for citizenship.

[o00scorpion00o]

Why is everything brown and not green ? does it not rain ?

Thanks for the vid!

Do you by any chance have a android or Iphone? if you do why not download the everytrail app and it will record the grades and the speed.that would be very interesting!

I would like to test that 20" up the 16% I took mine up! I bet it would fly!

What amps were you running ?

[chroot]

Thanks for the vids, Beautiful scenic!

[zombiess]

That's exactly why I went with the frame I did. Having full suspension allowed me to adjust the bike geometry through a longer rear shock, then a longer front fork and eventually through extending the rear swing arm 8".

Check out the phases.



You would look like a circus bear on a bicycle on this but it worked great!


The swing arm mods




Finally where I'm at today


After seeing that ride I want to come visit you and go for a ride.

If you want to tame the twitchy throttle at low speed lower your phase amps. It has the biggest effect on take off torque on the EB3xx controlers and doesn't effect my top speed at all, just how fast I get to top speed if I set it too low.

[neptronix]

Veloman: it is a 2-3% grade constant for a few miles, nothing too hardcore, but longer than the 8% grade 1/2 mile sprints we have out here.

scorpion: I don't have a smartphone and never will.. but i like http://toporoute.com to figure out things like that.
I don't know my amps yet since i haven't got the CA set up, or a precharge unit set up either.. been too cold and windy most of the time to solder, with occasional breaks of 50F-60F

It gets very green and lightly rainy up here in the spring - summer. Colorado is what you get when you mix a forest with a desert, and add insane mountains and unique geographic features ( like the rock formations at the Garden of the gods ). Definitely some eye popping, breath taking scenery in some areas, kinda boring and dusty in others.

zombiess: i would totally look like a circus bear on one of those, lol. 6 ft. with long legs makes even ordinary bike fitment difficult at some times. I normally ride a 21" frame, and always have to fit longer cranks. If i had the space to weld ( live in an apartment right now ), i'd totally do what you're doing though. The Trek hardtails are awesome though - excellent triangle space, rear rack bolts in no prob, beautiful flat dropouts, i love em.

[neptronix]

OK, some updates...

1) I ordered a RST Gila for the MAC bike, and will be transferring the shorter fork ( about 1.25in shorter ) on the MAC bike to the this bike, this will help the geometry. Will keep the 26" wheel.
2) cell_man shipped me out a 18FET 4115 infineon controller per my special request ( thanks Paul!! ), i should have that in about a week, the tests at 30S ( just for kicks ) will commence shortly after
3) Will be grinding at the frame tonight, cutting off the rear vBrake post holders, and the front derailleur doohickey off the seat tube so that the controller can be mounted between the wheel and seat tube..

Afterwards i should be able to fit a 2.75" tire in the back, and 12 lipo packs in the center triangle with the controller out of the falconEV bag.

[The Mighty Volt]

OK, some updates...

1) I ordered a RST Gila for the MAC bike, and will be transferring the shorter fork ( about 1.25in shorter ) on the MAC bike to the this bike, this will help the geometry. Will keep the 26" wheel.
2) cell_man shipped me out a 18FET 4115 infineon controller per my special request ( thanks Paul!! ), i should have that in about a week, the tests at 30S ( just for kicks ) will commence shortly after
3) Will be grinding at the frame tonight, cutting off the rear vBrake post holders, and the front derailleur doohickey off the seat tube so that the controller can be mounted between the wheel and seat tube..

Afterwards i should be able to fit a 2.75" tire in the back, and 12 lipo packs in the center triangle with the controller out of the falconEV bag.

OH! Tell us more

[neptronix]

Hehe yeah, i can't wait to get the 18FET..



Group shot of the lipo.. that's 2.5kWh.. I love how half of it fits into a topeak rear bag.



So yeah, 2.30" wide tire limit begone.. vbrakes FTL anyways on a build with this kind of power.



Left a little meat on for structural stability. Might not be necessary, but i'm not taking chances.

I can't find a 2.75-2.80" tire, so i'm gonna see if a 3.0" tire will fit. Should actually gain some speed on the flats from a tire upgrade like that.. lol

[gensem]

My front 3.0 24" bicycle tire actually measures 2.6" wide using a 45mm rim.
My back 2.75 17" moped tire measures 3.0" wide in a 45mm rim.
You would be better of having a caliper at hand.

[o00scorpion00o]

Dave you are crazy, 30S will take you to 50 mph ? that's what, 124 volts hot?

Mad man, maybe time for some body armour ?

That's about 5kw you will be pumping into the pie at 40 amps, I'm doing that with just 60 volts and 80 amps LOL!

Or 6.2 kw if you use all 60 amps that controller is capable of, Beef it up and I'm sure 10kw wouldn't be impossible, that would be some serious power with the large diameter of the pie!

You will surely race up Pikes Peak now!

[cell_man]

Cool Video David You got some nice scenery round there, certainly beats the views around here....

Stay safe when you up the voltage, looks like you are motoring pretty good as it is

[The Mighty Volt]

I see you guys are running rear and front suspension, I am chopping some BMX frames to convert them, I recently bought two Manitou Metel-R's as they were going cheap. My problem now is with the spring rate, I figure with a heavy X5 in the rear and 16Ah 72v of A123, I am going to be running an above average weight. Does anyone here have any idea what sort of spring rate I should be looking at? Personally, I am tempted to go the highest possible, at around 800lbs. Nukeproof or Manitou were what I had in mind. Thanks.

[zombiess]

I see you guys are running rear and front suspension, I am chopping some BMX frames to convert them, I recently bought two Manitou Metel-R's as they were going cheap. My problem now is with the spring rate, I figure with a heavy X5 in the rear and 16Ah 72v of A123, I am going to be running an above average weight. Does anyone here have any idea what sort of spring rate I should be looking at? Personally, I am tempted to go the highest possible, at around 800lbs. Nukeproof or Manitou were what I had in mind. Thanks.

To calculate your spring rate you at least need to know what your leverage ratio is and the loaded weight. I know on my bike I'm 1:4 on the shock as in 1 unit of shock movement = 4 units of swing arm movement so with 1" of shock travel I have 4" of rear suspension travel. If I went 1:5 I'd need a higher spring rate and 1:3 lower spring rate. A lot of this depends on where and how the shock is mounted.

[The Mighty Volt]

I see you guys are running rear and front suspension, I am chopping some BMX frames to convert them, I recently bought two Manitou Metel-R's as they were going cheap. My problem now is with the spring rate, I figure with a heavy X5 in the rear and 16Ah 72v of A123, I am going to be running an above average weight. Does anyone here have any idea what sort of spring rate I should be looking at? Personally, I am tempted to go the highest possible, at around 800lbs. Nukeproof or Manitou were what I had in mind. Thanks.

To calculate your spring rate you at least need to know what your leverage ratio is and the loaded weight. I know on my bike I'm 1:4 on the shock as in 1 unit of shock movement = 4 units of swing arm movement so with 1" of shock travel I have 4" of rear suspension travel. If I went 1:5 I'd need a higher spring rate and 1:3 lower spring rate. A lot of this depends on where and how the shock is mounted.

Thanks, I think I will just order the heaviest rated spring and see how it goes.

What mm travel did you finally settle on for the front susp forks? I find that some 700c forks offer around 67mm travel and do not excessively raise the front profile of the bike. It seems that less travel on the forks means less geometry issues, is that generally accurate?

Thanks again.

[zombiess]

I have around 3.5" of front and rear travel when accounting for sag/angle. Front shock is for a 26" wheel and is spec'd at 100mm travel.

[veloman]

I see you guys are running rear and front suspension, I am chopping some BMX frames to convert them, I recently bought two Manitou Metel-R's as they were going cheap. My problem now is with the spring rate, I figure with a heavy X5 in the rear and 16Ah 72v of A123, I am going to be running an above average weight. Does anyone here have any idea what sort of spring rate I should be looking at? Personally, I am tempted to go the highest possible, at around 800lbs. Nukeproof or Manitou were what I had in mind. Thanks.

I swapped my spring out on my bike (thread in signature) for a lower weight one, simply because I wanted it to be more active on small bumps, and I don't do drop offs more than about 6 inches. Nice ride quality in comparison.

[neptronix]

Scorpion: 30S will be more like a speed / power handling test for the magic pie, rather than something i run permanently.

2.75-3.0" wide 20in. tires seem impossible to find, other than some stupid looking chopper tires that look really weak.
Have wasted many hours in bike shops so far :/

Anyone got some suggestions?

[gensem]

16" moped tires shoulda fit without issue on a 20" inch bicycle wheel.