Trek 1.2 Lightweight High-power hybrid-unlimited pedal range

[grindz145]

RE: pic posting, if your uploading them to ES server they have to be no larger than 800x800 or they
will show as they are above as a clickable link...

Best of luck with the build i hope i does everything you hope it will

KiM

Interesting, it looks like if I hold my phone vertically, the pictures will post, but horizontally no go...must be the resolution after google resizes them for me. Thanks KiM.

[gogo]

Another problem is staying within the efficiency band of the motor. If you let it bog down during hills by not pedaling like your ass is on fire, you will turn a lot of energy into heat running at 60% the unloaded speed or less.

Don't forget that grindz145 is intending to have a 10A current limit. If we assume he is addicted to WOT and assume a 2.5X current multiplier in the controller's software algorithm, the controller is going to cap the voltage at 19.2V, which will cause his effective no-load speed to be 12 MPH until he can contribute enough torque from his pedaling to keep the battery amps under 10A. Once he reaches 12 MPH, the motor can only contribute a continually decreasing amount of maximum torque. This will move the "efficiency band" considerably lower. So the "danger zone" is from 0 MPH - 7.2 MPH, there is a lesser danger plateau from 7.2 MPH - 12 MPH, and from there the danger decreases steadily between 12-18 MPH.

If grindz145 can tame his wrist, or thumb, (or a push button would work ok at these power levels), he can stay in his motor's efficiency most of the time. If you add in whatever the controller's super-low PWM ramp is, he can probably go WOT and be in the motor's efficiency band almost all of the time.

[dogman]

Nothing wrong with pedaling briskly, adding say 150 w to your wattage for awhile. But me at least, I call my sustainable for 30 miles effort to be about 100w, and even less to keep it up for 60 miles.

Any way you slice it, your goal of pedaling up some power to add to range loses it's luster the faster you go. The minimum watts needed to go fast are set in stone, unless you go recumbent or something. Meanwhile the watts you contribute get to be less and less percentage of the total. By 30 mph, you end up with nearly the same wh/mi, pedaling or not pedaling.

But the idea behind your build is still good. You'll get fantastic wh/mi by pedaling at 100w, and using 200-300w from the battery. Watching a Ca while you ride, you can really start making those batteries squeal by coasting down and pedaling hard up the grades. Some unbelievable wh/mi numbers have been done by really hypermiling it.

[GCinDC]

re images, AJ's right: max horiz OR vertical dimension is 800 pixels. (i'd always thought they were 640... so that's what i shrank them to):

IMAG0631.jpg (71.62 KiB) Viewed 2035 times

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IMAG0629.jpg (77.69 KiB) Viewed 2035 times

IMAG0628.jpg (87.69 KiB) Viewed 2035 times

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[neptronix]

Wow. That's the ultimate stealth bike...

[Gregor]

The drop bars that allow a tucked position will help alot in the speeds between 20-30mph. "Add on" aero bars that allow you to rest your weight on your forearms also help with hand fatigue. The high pressure tires sould help with the hypermiles--a range between 15 to 20 wh/mile sould be possible. I have a 58 tooth chainring that is made by Vuelta that I bought on ebay about a year ago, and that helps you still contribute your 150 watts when your in the 25mph plus range. I've used the Wilderness Energy sensorless controller with a cute motor and 14s lipo and it has a bit of trouble syncing up at 2 to 5mph, but after that it goes pretty smooth. I have mine on a 20 inch folder bike so I don't get a chance to make the motor heat up much, but seeing your build has inspired me to try a build like yours this winter. Cheers, Greg

[Warren]

http://www.jensonusa.com/store/product/ ... apter.aspx

http://www.flickr.com/photos/12887128@N00/2422551242/

http://www.ecovelo.info/2008/11/12/alfi ... drop-bars/

[grindz145]

Warren thanks for the ideas! I may have to look down that route. I like it more than my lever shifter.

It's amazing how many more people check it out when you reside the images:D

I dont have time for that ish... Thanks Greg.

[grindz145]

The drop bars that allow a tucked position will help alot in the speeds between 20-30mph. "Add on" aero bars that allow you to rest your weight on your forearms also help with hand fatigue. The high pressure tires sould help with the hypermiles--a range between 15 to 20 wh/mile sould be possible. I have a 58 tooth chainring that is made by Vuelta that I bought on ebay about a year ago, and that helps you still contribute your 150 watts when your in the 25mph plus range. I've used the Wilderness Energy sensorless controller with a cute motor and 14s lipo and it has a bit of trouble syncing up at 2 to 5mph, but after that it goes pretty smooth. I have mine on a 20 inch folder bike so I don't get a chance to make the motor heat up much, but seeing your build has inspired me to try a build like yours this winter. Cheers, Greg

That's interesing Gregor, It seems like I've shifted that range from 2-5mph to 5-13mph with 20s. I might just have to try 10s to see what happens. I still suspect EMI is the issue, and I'm going to try various shielding/RF Choke solutions. Big chainring is also probably in order too:D

Again, I don't really need 30mph out of this. The main accomplishment so far is that I can pedal this for a long time without ever turning the motor on. That's an interesting and liberating prospect for me in many ways.

[grindz145]

Just weighed the beast this morning. The bike itself (without the lipo battery pack) weighs ~29 lbs. It doesn't feel nearly that heavy when riding it either.

[rhitee05]

A suggestion for your throttle. Keep the pot wired in as a normal throttle would be, then add a pushbutton switch like Adrian was referring to. I'd suggest using a momentary NC switch wired between the pot wiper and ground. When you're not pressing the button the throttle will be shorted to ground, then when you press it the motor will come on at whatever throttle the pot is set to. That gives you some adjustability but also the safety of a dead-man switch configuration. I'd think you could find a way to place the button to use it without moving your hands on the grips.

Probably wouldn't hurt to wire in the brake cutoff, too, but if you place the button correctly you could probably make it impossible to press the button and pull the brakes at the same time.

[grindz145]

Not a bad idea Rhite. I think that might be an intermediary first step anyway.

[dogman]

29 pounds is pretty pedalable. My old school road bike weighs 28. Anything under 30 pounds back then was considered racing equipment. A schwinn varsity was something like 38 pounds.

29 pounds is not bad at all really.

Like the throttle idea above a lot! Low power like that, mostly you just need on off anyway.

[etard]

I like your bike! Why not go with a triangle frame bag for controller, do away with the CA ( too big For stealth IMO) and get a RC controller like the Castle Creations HV80. I think you can current limit them. I like the push button throttle idea, I also wonder if you couldn't just use the brakes as a throttle cutoff, maybe even set up the rear brake loose so you have a point that cuts throttle but does not yet brake, kinda like neutral.

[zukster]

Just a comment on the sensorless issues people have mentioned. Not sure if any really work for large series lipo packs. I have a couple of 350W Rear Bafang, 20 Amp Keywin sensorless controller, 20 Amp Keywin hall controllers. Configured with 10S and 15S packs. The 15S gives the sensorless setup stutter problems sometime less than 5km/h. Not bad but you can feel it. No issues with any other setup. I generally prefer the hall setup now.

[zukster]

Also a question re your lean and mean build. Why didn't you go with the Cute-85 front which is only 1.6 kg? I'm thinking of doing a light-weight power assisted XC Cross Country mountain bike. I have a Rocky Mountain Element to play with. I'm considering the Cute-85 front or the Cute-100 rear. I'm biased toward rear motors but I haven't really tried a front. I'm thinking this light front motor might be simple and adequate for this application...

[BATFINK]

interesting build, i have seen a very lightweight build from a company called cytronex and they seem to be able to keep the weight of there bikes quite low, any ideas on the exact setup these guys are using http://www.cytronex.com/

[BATFINK]

here is a better picture of the kit they sell http://www.cytronex.com/kit/index.html

[motomech]

Also a question re your lean and mean build. Why didn't you go with the Cute-85 front which is only 1.6 kg? I'm thinking of doing a light-weight power assisted XC Cross Country mountain bike. I have a Rocky Mountain Element to play with. I'm considering the Cute-85 front or the Cute-100 rear. I'm biased toward rear motors but I haven't really tried a front. I'm thinking this light front motor might be simple and adequate for this application...

I think Grindz's lightweight conversion must be on hold due to the weather, but he answered that question in another thread.
The Q85 motor is only available as a front mount, something he didn't care to try with his carbon fork.

But Grindz, I have a question[or several]about the 9-speed install.
Did you have to spread the drop-outs? Spacers?
Is it the aftermarket unit w/ the 11 tooth sm. cog.
Looking forward to seeing further refinements and results.

[zukster]

But Grindz, I have a question[or several]about the 9-speed install.
Did you have to spread the drop-outs? Spacers?
Is it the aftermarket unit w/ the 11 tooth sm. cog.
Looking forward to seeing further refinements and results.

The Cute 100 fits on the rear fine with a 9 speed DNP freewheel. No spreading needed.
I'll get my build pics up soon. Full Suspension Rocky Mountain Element. 32 lbs wth batteries Cute 100 on the rear. BMSbattery KU63 15 amp controller. 2x6S Zippy 4000s 20C.

http://ebike.ca/store/store_motors.php

Scroll down a bit.

[motomech]

Thank for the answer. How about a ride report as well?
I have a like-new Rocky Mountain Edge[love it to bits]and although I know I would have to lose the cassette, it would be nice to be able to retain the rest of the 9-speed components.

[zukster]

The Cute 100 rear delivers as much power to the road as my Bafang SWXH rear.
I ordered the Cute 100 with the 201 rpm option for more torque for a 26" wheel - more winds.
The kit came with all sorts of junk I didn't use.

http://www.bmsbattery.com/ebike-kits/426-250w350w-q-85100sx-motor-e-bike-kit.html

The Bafang is perhaps a bit better on a hill but the Cute 100 seems to go a bit faster. More on this later. I should really start a new thread for this but here it is for now.

Rocky Mountain Element Race 1999 19" Frame
2 x 6S Zippy 4000 mAH Lipo Batteries from HobbyKing
Methods LVC cell monitor battery protection boards with breaker board power cutoff.
BMSBattery Cute 100 Rear Kit includes:
Cute 100 Rear 201 rpm for 135mm drop out
KU63 15A Sensorless or Hall Sensor Controller. Good to about 15S/63V I think.
Waterproof Connector for Hall and Motor Phase wires - too cool.

I've run the Controller at 14S okay and BMS said it was okay. Haven't tried 15S/63V yet
but I suspect the limit is the 63V capacitors in the controller.

[motomech]

Your build definately deserves it's own build thread, you already have some great pictures.
And it would showcase a Rocky Mountain on a forum where the FS category is dominated by the likes of Trek, Giant and Specialized.
To me, these late '90's/early 2000's, open triangle FS bikes make a lot of sense for an E build.
Anyhow, thanx for the info and PIC.S.
Have you done any top speed runs?

P.S. I imagine you have read the reviews here,

http://www.mtbr.com/cat/bikes/bike-full ... 95crx.aspx

[zukster]

I'm guessing about 40 km/h on a 12S / 50.4V Lipo Pack fresh off the charger on the flats. I'll be testing 15S / 63V max soon, which I'm almost sure the motor and controller will be fine with, and I'll post that when I get my new Lipo packs to test with.

I agree about the late 1900's/early 2000's bikes. I picked up the Element for 350 dollars. It was about 27 lbs. Then I added carbon handle bars, a lighter stem, Thomson elite seatpost, XTR rear derailler, maybe something else... Got the bike down to like about 25 lbs, then the hub motor, controller, and batteries, brought it to about 32 lbs (well around there). I weigh it at the bike shop later.

The 9 speed DNP freewheel did me in for weight. 600 grams or 1.3 lbs. I just bought a Suntour Microlite freewheel to try: 185 grams / 0.4 lbs.

[motomech]

Last[hi-jack]post

$350, a ganga for such a finely crafted bike. That's the beauty of these, they are dated for their original purpose[low price], but beautifully spec.'ed for Ebike.
The way I aquired mine is interesting. When the E-bug first bite, I went to a large "super store"of bicycles to ck. out possible donner-bikes. In the corner was this dusty, forlorn-looking MTB., a 2003 model. It had been lost in the warehouse for 8 years. I had them clean it up and bought it for $995.
Later, though research, I found out that Rocky Mountain had a recall on all their FS models of that period[your '99 as well], the chainstays could break at the "hanger hole". The Many were replaced by the factory, but I think mine was pulled off the floor for this reason. It still has the original, but I'm not worried as I don't plan on doing 10 ft. drops.
Have you thought about the EVFalcon bag? It's a very good fit on mine, even with the top shock mount. But my R.M is a 20.5" frame.