GT i-drive 2.0 Build

[etard]

Whoa, traffic circle... That wasn't Dupont Circle was it? Nice stop, next time I want to see some fishtailing though! :lol:

 

[GCinDC]

so did you finally beat dbaker when you forgot set mode 1 switch?

i'm pretty sure my bike couldn't have been on SW 1 - that's only ~15mph top speed, and we were going faster than that. it could have been SW 2, which allows an anemic 25mph, so yeah, we'll have to give it another go...

am i doing something wrong here, or would it really be this close (at full speed)?


while i'm at it, here's a comparison of current setup (hs3540) vs prior (2807):

Whoa, traffic circle... That wasn't Dupont Circle was it?

no, that's sheridan circle, just beyond dupont. i was a bit surprised the rear tire bumped/shuddered/whatever, rather than skid/fishtail. i'm not sure why that is/was. i've noticed it since adding the disc/hs3540. sometimes instead of skidding it bumps up and down!?

 

[Lenk42602]

Personal experience now with smaller diameter wheels tells me that indeed it could be. Smaller diameter wheels + high volts appear to acheive two separate things.

Even going from 26" @ 74v with 40 amps to 21" @ 80v with 40 amps yeilds the same top speed for me.

len

 

[dbaker]

Lenk,

How would you desribe the torque difference for the 2 wheel sizes?

 

[deecanio]

Strange how ppl have different experiences, when running the puma motor originally it was in a 20" wheel, just swapping the rim for a 24" with the exact same setup i can honestly say i didn't notice any difference at all?
not working till midnight G, on nights - rear disks rule.

D

 

[Lenk42602]

Lenk,

How would you desribe the torque difference for the 2 wheel sizes?

it is significant, however my 20" set up is on a significantly heavier (50 pounds) chassis. it is definitely quicker to speed, but would be even more so if i had this on a light bicycle chassis like the lts -5 . as it is now, my most notebale acceleration is in the 25-32 mph range - literally jerks you forward when you hog on the throttle at these speeds...

Strange how ppl have different experiences, when running the puma motor originally it was in a 20" wheel, just swapping the rim for a 24" with the exact same setup i can honestly say i didn't notice any difference at all?
not working till midnight G, on nights - rear disks rule.

D

The other thing to note is that the 5 series wheelie machines on the forum are usually lightweight setups, 20" wheels, and conrollers drawing at least 100 amps - I have been trying my machine at various controller amp settings. At 80 amps the bike is a hoot, will jerk the front wheel off the ground, but I KNOW it will fry the wiring if were to actually take a sustained run with it @ WOT. Instead I have the controller dialed back for efficiency @ 45 amps. Max amps through the CA at this setting is around 55. Anyhting past that is just wasted energy in the form of heat (although increased the acceleration from 0 is fun...)

daily driving baby.

 

[GCinDC]

Smaller diameter wheels + high volts appear to acheive two separate things.

2 things like mean higher torque, lower top speed?

from fooling w/ simulator with a 100V100A setup (which i don't have), another thing that changes dramatically with smaller wheel is the 'overheat in' value...

 

[Ypedal]

I just finished re-lacing my 100v 50amp norco in a 24" wheel, am going back to a 20" !

 

[GCinDC]

I just finished re-lacing my 100v 50amp norco in a 24" wheel, am going back to a 20" !

why? for torque?

 

[Lenk42602]

efficiency, and better gearing. motor out put is a function of power in. rpms are the next phase of understanding the optimal config for a hub motor.

smaller diameter wheel reaches motor's optimum rpm faster, and is able to stay in a more optimum rpm range longer. often times, the speed limiting factor for small wheel set ups is power into the motor, then gearing. if your motor is not operating at or near the optimum rpm, you get inefficiency in the form of wasted energy (heat).

if power into the motor is done via high voltage, sufficiently so that back emf generated by the hub motor spinning at a very high rpm (beyond optimum) is not an issue, then gearing (wheel diameter) becomes the limiting factor.

for my set up, given my power into the motor - 80 volts/45 amps, it makes no difference how many more amps I throw at the motor, as voltage is my limiting factor. whether I run 35-120 amps, at 80 volts my max speed only changes 4-5 mph.

 

[Ypedal]

Absolutely, it added weight, lowered efficiency, lost acceleration, and gets hot if i play in the trails...

only bonus was higher top speed but it does not outweigh the losses..

Currently have my 409 laced in a 24, not taking it apart... but going with a 408 in a 20 to make up for the speed.!

 

[Lenk42602]

get Luke over here! he loves this conversation!

 

[Ypedal]

I"m no engineer, i fully admit that but give me a bike to ride for a few days and let me look at the numbers, i know what i like even if science says i got it wrong lol..

 

[Lenk42602]

y,

after three years I see the light! I see the light!

the band! The BAND!

[youtube]lX5tfRdkoY0[/youtube]

[youtube]P1KZKZs-2YM[/youtube]
len

 

[chroot]

Hell yeah bring Luke over here!


@Lenk- Thanks for explain and I am looking forward mount ilia's 5403 in 20" wheel with the motorcycle tires Pirelli ML75 2.5 for front and 2.75 for rear. I assume you also build new Farfie's genesis v2100 bike? I saw your comment in sale section. :lol: 8)

 

[Lenk42602]

Hell yeah bring Luke over here!


@Lenk- Thanks for explain and I am looking forward mount ilia's 5403 in 20" wheel with the motorcycle tires Pirelli ML75 2.5 for front and 2.75 for rear. I assume you also build new Farfie's genesis v2100 bike? I saw your comment in sale section. :lol: 8)

nah, dude. i am done building for a while. have my own machine to ride

 

[Hyena]

from fooling w/ simulator with a 100V100A setup (which i don't have), another thing that changes dramatically with smaller wheel is the 'overheat in' value...

Uh oh, you're starting to graph things, ES history dictates this is a dangerous road you're going down my friend... :lol:

Glad you're finally enjoying the HS. I found my 9C bike is snappier off the line and because it accelerates so fast anyway it tends to feel faster overall, but the HS definitely has more midrange pull which I love. The lack of low end can be compensated for with moar amps
Effeciency smishency :lol:

A word of caution - is that torque arm you posted only on one side ?
I had my HT motor rip itself from the drop outs on a short ride on the weekend. Admittedly my torque arms were inadequate and largely only thrown on for testing (amped bikes style on one side and front wheel ebikes.ca style on the back) but the torque rounded both of them. The amped bikes one snapped the hose clamp that held it to the chain stay as the axle turned - the ebikes.ca one ended up rounded but the bolt kept the wheel on the bike (wheel ended up skewed and the tire jammed against the chain stay) Luckily I was only going slow but I'd hate to see something similar happen to you at the speeds you're doing on the road.

As for the rear tire doing funny things under braking, I find mine just skids, because the big front brakes stop so hard they lift all the weight of the back off the bike and it hardly has any traction (ie getting towards endoing if you braked any harder)

 

[kfong]

Greg any luck with a new bike frame yet? If I were to build a commuter to ride the streets like you do. I would be looking at this motor http://endless-sphere.com/forums/viewtopic.php?f=2&t=33831 on a 24 or 26 inch wheel on a solid DH frame. I'm actually excited by it. This one shows serious potential and will put your bike into a small motorcycle territory.

 

[GCinDC]

Greg any luck with a new bike frame yet?

Yeah, I've got most of it welded up, but I'm gonna wait till it's finished and perfect before posting closeup photos and groundbreaking videos... just kidding. dontcha hate that! :lol:

no new bike frame yet. i'm still all over the map on what to get. it's maddening. i want it all - quiet,fast,light,high torque,etc... the cromotor looks fast but probably unwilling to get hucked off stupid drops... might well be two bikes for me, blah, blah, blah till i bore you to tears... one tough commuter, and one light noisy huckster w/ 3" nobbies that stays off the precious park trails cause it's making it own in there...

is that torque arm you posted only on one side ?

no sir. i have two on the other side. won't be winning any beauty contests tho. i do tighten the hell out of the nuts. do you? sounds gruesome. did the wires survive?

after three years I see the light! I see the light!

oh yeah, nothing special next recent highlights, but a couple scenes the last couple grey daze:
[youtube]6Bn6m4mA1M0[/youtube]

 

[kfong]

Greg, looks like you will end up in the same sink hole. I'm up to 6 ebikes now. They all serve different purposes to me. My BMC- Motobecane will always be my preferred trail ride since it's so nimble and goes around tight corners. My Cyclone-GT is my utility beater bike for groceries and errands. My Kona DJ will be my RC huckster, light, balanced and powerful. My 9C Tidal Force is setup for long road trips, with a focus on reliability and luggage. My mongoose is my loaner/experimental bike and finally my latest build the Versus DH, a backup bike for trails but nowhere nears as nimble. It will allow me to get into the high speed arena, but unfortunately I don't care to be on the road with an ebike. I've owned a motorcycle before and never felt all that safe riding them. I trust my abilities just not others, but being on the road occasionally has some advantages worth doing if the bike can keep up with traffic. Hal's hub motor or a magic pie would be my choice on the DH build, but currently I already have a spare BMC for it. Might have to make so it's easy to swap out motors.

 

[newb]

hey greg, thought id share the project I mentioned to u earlier this yr since it has a few similarities to ur ideas. didnt get it completed but was together enough to go for a few spins b4 I had to leave it behind. its a 2005 cannondale gemini 900 frame w/ a 2805 n a 20” wheel (21.5” with this tire) & @ 48v the top speed was 33mph. even n the few rides I can say it was a gr8 choice in frames, very smooth & solid w/ none of that tail whip iv experienced w/ most FS frames. next time im back stateside ill make a battery box to mount below the downtube so it will have a low COG w/ the added bonus of acting as a mud guard. with the extra clearance of the 20” wheel ill have space for upto 18s 4p which should put me at > 45mph.

 

[Hyena]

i do tighten the hell out of the nuts. do you? sounds gruesome. did the wires survive?

Yeah I tighten them, the amped bikes torque arm let go first, breaking the hose clamp that holds it.
With the arm still tight against the main nut I was able to use it like a spanner (err, wrench for you US folk ) - by gripping and turning the long part of the torque arm it re-tightened the nut back up and I was able to ride a bit of the way back. That was until the other side gave out. Luckily the wires survived, which is a miracle in itself for an early HT model that chopped it's wires up just taking it out of the box The torque arm held it tight enough that the motor only dropped down about 10mm, just working its way out of the drop outs but rounding them nicely in the process (and the threads of the axle ended up nicely 'tapped' into the flats of the torque arm.

Out with the angle grinder this weekend to make something proper!

EDIT: I spoke too soon, I fabbed up a thick torque arm this arvo, tested it on just the one side before making a second one for the other and it seemed to work OK, then I gunned it hard and it ripped the motor from the drops again, this time breaking the hall wires. Bastard!

 

[GCinDC]

I fabbed up a thick torque arm this arvo...seemed to work OK, then I gunned it hard and it ripped the motor from the drops again, this time breaking the hall wires. Bastard!

huge bummer, hyena! gotta pic?

thanks for sharing newb! that is a fun looking rig. are those extra short cranks?

20” wheel (21.5” with this tire)

this line confused me, as i'd always thought 20/24/26" referred to the rim size, but i just learned those are nominal OD sizes.

 

[GCinDC]

My Kona DJ will be my RC huckster, light, balanced and powerful.

got any pics? what are your plans? i love the sound of this one..

 

[newb]

sorry for the confusion. they are 20" bicycle rims w/ 16" motorcycle tires which are much taller hence the 21.5" statement and the cranks are 170mm.

thanks for sharing newb! that is a fun looking rig. are those extra short cranks?

20” wheel (21.5” with this tire)

this line confused me, as i'd always thought 20/24/26" referred to the rim size, but i just learned those are nominal OD sizes.