StudEbiker's E-Bike-E build- ride vid pg. 7.

[StudEbiker]

Good tips Gordo, thanks. What about using dry ice? A local store here sells it. Would that be too cold? How long should I put it on the dry ice before trying to put it through the bearing?

[Gordo]

Dry ice is not such a good idea as -100C can do unwanted (unknown by me) things to steel. Over kill too. Bush ape rule of thumb, you only need 0.001 interference per inch of diameter for a bearing. Readily available with home freezer to room temperature, especially if you us a heatgun/hair dryer on a segment of the bearing.

[StudEbiker]

Well, the Sachs is out and the Nuvinci is in. Still waiting on replacement flange bearings. The first order got lost in the mail. I'm hoping to make some progress on Wednesday.

[wineboyrider]

Well, the Sachs is out and the Nuvinci is in. Still waiting on replacement flange bearings. The first order got lost in the mail. I'm hoping to make some progress on Wednesday.

nuvinci.JPG

Pricey booger? What did she cost?

[StudEbiker]

It's one of the auto shifting developer kits that are being sold at close out for $149.99 plus shipping.

http://www.fallbrooktech.com/09_LEV_Kit.asp

[wineboyrider]

Wow that's pretty cool... wish I had the money I'd like to try one out, but builds are out for awhile now as I have to save $$$ for the old country. I am definitely looking forward to seeing how this one turns out...

[StudEbiker]

I had a chance to put the wheel in the Bike E today. It looks pretty good.

I'm not completely happy with the way the spokes are bending aroud each other, but this is how the guy at Nuvinci said that they were spoking these in 20" wheels. The wheel feels good, it just looks kinda weird.

I was concerned that the actuator housing wasn't going to have enough clearance for me to still be able to use my trailer mounts, but it looks like everything is going to clear fine.

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[amberwolf]

Just don't forget to tie the actuator unit down to the frame snugly. I almost forgot to plan for that when pondering my most recent scheme for the new bike.

[StudEbiker]

I tried to find a way to use that included bracket, but there wasn't any good way to use it. I will still need to come up with some sort of bracing for it I guess.

[LI-ghtcycle]

Looks good man!

Don't forget to let us know how much efficiency you get using that bad boy!

[StudEbiker]

I got the drive unit back together yesterday with a couple of cross supports to keep the plates from flexing which is what I think was the cause of the last meltdown. I couldn't get two supports along the bottom edge because of clearance issues, but it definitely feels stiffer now.

I also put the shaft in the freezer for 24 hours before trying to fit it through the new bearing. I then heated a quarter of the bearing with a propane torch. On the third tap of the well supported bearing the plate slipped onto the shaft almost down to the exact position I wanted it to be. Thanks for the tips Gordo, hopefully it holds this time.

I have to say, this is the third time I have mounted a "completed" drive unit to the bike and each time has felt a little better, but this is the first time that it feels the way I think it should feel. Hopefully this is a good omen.

Now I am trying to get the desktop application software for the Nuvinci installed on my computer. I might have to wait until Monday and call Nuvinci. I have some more wiring to go on the Nuvinci drive, but I think I should be able to make some test runs again sometime this week.

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[Hardcarve1]

With the spokes on the early units they said to have the elbow on all spokes to the the same side. I think if you did this you would not have the deflection as in your photo.
Alex

[StudEbiker]

With the spokes on the early units they said to have the elbow on all spokes to the the same side. I think if you did this you would not have the deflection as in your photo.
Alex

You are correct, but I called Fallbrook tech support and they said that they are lacing the developer kits in 20" wheels with alternating spokes. The guy I was speaking with even checked an Ego scooter he had nearby with a 20" wheel and developer kit and confirmed that it was laced with alternating spokes.

I'm actually kind of glad I ended up doing it that way, because the spokes seemed a little long. If I hadn't laced alternating, I'm sure I would have had spokes coming through the nipples.

[StudEbiker]

Well, I took it out again for a ride and for the most part I am happy with it except for the efficiency is terrible. 41wh/mi. A trip of 3.28 miles used 137wh. This is bad right?? The average speed was about 18mph with a top speed of 27.6 mph. It also doesn't seem to climb as well as I thought it would either. It is pretty quick on the flats, but for the most part I thought it would be more efficient and climb better. Maybe I can play around with the Nuvinci programming and improve things somewhat, but I think if I want to get into better efficiency I am going to have to go with two gears on the Nuvinci type setup. Two things that is awesome about how it is now is not having to shift and the pedal cadence is sweet and I can always help push the bike with the pedals when I want to. The next thing I will do is add a chain tensioner to the rear chain, but for now I am done for awhile. I'm just really glad it's working, and hopefully it will for more than a day this time.

[amberwolf]

It sounds lke it's just a gear ratio problem--maybe different ratio needed between motor and input to NV?

[StudEbiker]

I have a 19t #25 gear on the planetary, to a 48t #25 gear on the jackshaft, going to a 16t track cog on the jackshaft going to a 16t freewheel on the NV. A bigger #25 sprocket after the planetary would help with the hill climbing but lower my top speed right? I was aiming for a 27-30 mph top speed, but I didn't realize I would be giving up so much in efficiency & hill climbing to get it. . . especially going through a Nuvinci.

[amberwolf]

It might lower your top speed; it depends, though. Might try it and see, if it's easy to change out.

Alternately, maybe try setting up the current-sensing idea I posted in the NV dev thread, using the CA current-controlled throttle to instead help control the NV shifting?

[StudEbiker]

It's not easy to change out, and I don't have a CA. One thing I wasn't sure about when I was programming the NV controller is when it asks for the input power sprockets number of teeth. Well, I have a 52t at the cranks, but a 16t on the jackshaft. I used the 52t sprocket as my input sprokets # of teeth. Could this be causing a problem?

I set the rpm target speed of the cranks at 75. Maybe I need to reprogram using the 16t as the input power sprocket and let the target rpm be what speed I would like the jackshaft to be spinning at for better efficiency.

[LI-ghtcycle]

There has to be something drastically wrong to get that kind of abysmal efficiency.

I would shoot for a 20 MPH speed with the NuVinci in a 1:1 ratio, do you use the pedals on the same final drive chain through the jack-shaft?

Also, if your using the same tooth sprocket from the final drive as the NuVinci, you might just be too high geared.

If you can tell me what RPM you get to the rear wheel (as if you just had a regular wheel and no IGH) I can maybe help you figure a good ratio?

I don't know anything yet about programming the auto shifting, but that has worked out very well efficiency wise for Drewjet, might ask him how he has his programmed.

I wonder if the easiest way to get a good ratio on the rear wheel might be to buy a 27T sprocket from Staton Inc, after all the NuVinci freewheels internally, so no real need for a FW there at all at the hub.

[amberwolf]

Could this be causing a problem?

I'm not sure. I guess you could experiment and see.

How easy is it to just pedal, without any motor input, especially at startup? If it's hard, it's probably not set right.

[StudEbiker]

Yep, I just played around with it some and that seems to have been a big part of the problem. Now, acceleration off the line is good and efficiency seems to be MUCH better (it's late, I'll have to take it on a longer ride tomorrow), but top speed now seems to be about 15mph.

Also, once again, the pedals can't keep up with the jackshaft.

Anyway, it seems like all is not lost. I think before I was trying to pull a hella tall gear. So much so that I think I prematurely aged a nice new chain. I was very surprised that it stretched as much as it did in such a short ride, now I now why.

With a little more playing around (and a bigger front chain ring) I think it is going to behave the way I want it to so I'm pretty happy.

Edit: I just spent some time playing around with the configuration editor and I think I have a few things figured out that I didn't before. I'll have a chance to try some of the new settings out tomorrow and see how it goes, but I think I am on the right track.

[StudEbiker]

Well, I plugged in some new numbers on the NV shift editor and things are much better now. I still want to get some long term wh/mi numbers, but I just took the bike up a huge hill and it did very well. On the flats it's top speed was 26mph which was right where I had set the NV shift table. I may lower that top speed to get better hill climbing. I was able to set the shaft speed where I was able to keep up with it on the pedals by splitting the difference of the ideal jackshaft speed and the ideal pedal speed. I guess I am losing some efficiency at the motor but gaining some input of the pedals. I don't like the feeling of always just spinning the cranks so I think that is a compromise I am going to have to live with until I can find a larger front chain ring. I will try to get some good numbers this week. It's not really the efficiency of taking it up a huge hill on a test ride that I'm concerned with so much as how it will behave under my normal riding conditions. I will zero out to odo and ride it for a week and see what I come up with at the end of the week.

[LI-ghtcycle]

Good to hear! Good luck and keep us posted, sounds like you are getting it dialed in.

[StudEbiker]

Well, I haven't had much progress lately on this bike. The weather has gotten colder and my motivation for working on it hasn't been very high lately. Also, I bought a 12AH Headway pack from Neptronix to use specifically for this bike. Using my other pack was not going to well. I had originally planned to use a Cell_man A123 pack on this bike, but Nep offered too good of a deal on the Headway pack for me to pass up.

Once I got the battery, I started thinking of the best way to mount it. I saw where Neptronix had been carrying it in a Topeak bag and I had the same model laying around here too so I started thinking of how best to mount the Topeak rack to the Bike E.

It wasn't too difficult at all. I ended up drilling six holes in the top of the Bike E's frame rail, but the rack is solid. Now that I have the rack on, I should be ready to start testing it again and getting the NV hub better dialed in. So far I have been really disappointed with the efficiency of this bike, but I'm going to try and emulate Drewjet's shift table that he posted on the "Cheap Nuvinci" thread and see if that makes a difference.

I also relocated the controller to the side of the frame too. Where I had it was good for protecting from water and keeping it hid, but it was hitting me in my lower back and it wasn't getting good air flow at all.

[mwkeefer]

Come on brother... I want to see this puppy running, test data,funny anecdotes and no injuries while riding!

Regards,
Mike