Hub "Mid Drive" Build

[LI-ghtcycle]

Ok! Got my first real trip in today, and it started out like Gilligan's Island, and ended 3 hours later! (Ok, I DIDN'T get marooned on an island, but the wind nearly blew me back to Portland on the return trip!)

I took a bigger chance than I should have, and paid a bit for it, I mean I test road the bike Saturday, rode to church Sunday, and did I think to top off the battery?! .... no

So anyway, I got down the road a mile or two with about 2 hours before closing (City Bikes, my favorite destination on a Sunday Afternoon!) and although it was pretty windy, it was nice out, and I thought, since later in the week is supposed to be so wet, I should go today and look at what they have for front pannier racks.

What I DIDN'T realize at the time going North, was that the "little wind" didn't seem so bad because it was a south wind, and was pushing me along!

So, I normally try to not use more than 8-9 AH's of my 12 AH pack for longevity of the LiPo (maximum charge cycles) and I was starting a 40+ mile trip with 3 AH's already used!

So I thought, ok, no biggie, save the power for the hills, but then I got the E-Bike grin going and you know the rest!

One thing that was pretty sweet, was that "wasted" no-load speed going up to 38.7 MPH? Well, it came in QUITE handy going down Linn at 35+ and being able to actually have the motor help!

I have never before had a buss stop along this bombing run down the hill, and this time I was able to get right back up to speed thanks to that "wasted" gearing.

Good thing I was in a hurry and took the elevator since I wouldn't have stopped to check the fender I put on to help keep clothing out of the gap between the hub motor and my saddle, but it turns out it was a REALLY good thing that I decided to use a plastic one, because my back-pack was pushing it down enough to cause the plastic to have slot cut through it on the edge of the hub!

So I trimmed it and away I went!


Well, since I was in a hurry, I thought I would show this motorcycle that I could move too on the 20MPH alley leaving the elevator, and I pulled him and kept ahead of his !?!!?!?! silly self for 2 of the 3 blocks much to his surprise, and of course this wouldn't do, so he had to pass me to save face!

About another 1/2 mile and I trimmed some more, took a short run with no noise problem solved!

Then it started to rain! But it's ok, I remembered that I had a ski suit to wear (more of a shell, not heavily insulated) , and I figured that would be more than enough protection if it got serious, and fortunately for me, it was just a drizzle that never got serious, just enough to cool me down as I rode.

Being in a rush, I skipped the scenic route and rode on one of the busiest roads around 99E, so I didn't hear the tell tale sound of plastic being sawed again by the hub motor until about another mile or so, and at this point I just took the silly thing off.


I made it to City Bikes with about 19 miles on the clock, (had about 3 when I started, but I probably had at least 2 more the day before) and lucky for me, they had just about every front rack I had looked up on-line plus a few more!

Sadly, none of them fit the bill, too narrow, too flimsy, too whimpy to fit over my extra wide Big Dummie forks!

I was very pleasantly surprised at all the positive attention my bike got from the people at the shop, both workers and customers, everyone wanted to know everything about it! (I guess this shouldn't have surprised me too much since this is a shop primarily frequented by commuters, not "hipsters" or other bicycle purists) I am used to a slight attitude from most of the employees (I think it's just part of the "I'm tough, don't mess with me or try to tell me anything about bikes, cuz I've heard it all, and truthfully, many of them have) I seemed to have earned some respect.

SO .... I almost gave into the urge to buy some cheap used thing so I could ride with my back up straight, and then I realized that I could just put the fanny pack (this was what was actually touching down on the hub motor) on the rear rack, and being the blond that I am, I completely forgot this logical solution and headed to their second store in the hope there would be some rack at the "new stuff" store that would fit the bill.

The first time that the motor had worn through the fender, there was a nice polished edge to one side of the hub, and that was it since I was careful all the rest of the way to Portland, and it stayed that way.


I have to say I REALLY LIKE this set up!!

I rode it more at bicycle speeds (averaging about 15 MPH, and up to 28 going down hills on the bike path, just taking it easy using only the minimum power, about 3-4A) and I felt like Superman again, just like the first time I rode a E-Bike!

The gearing makes a ton of difference, however, after this trip, if I decide to stick with a hub motor, I would be better off with an 8 X 8, but that might change once I get my 6S Nano Techs in to allow me to run 14S, that might make all the difference. I would really like more grunt on the low end, and I wouldn't mind gearing that gave me more low than high, and I really don't need to go 40MPH down hill under power (waste of power on a long trip but wow it's fun! )

My "not so windy" day was actually 15MPH and gusting up to 25MPH! Now that I was returning, I was having to burn precious AH's just to go on the flat!

Going back along the river sure didn't help, no cover, and half the time I could only manage about 7 - 9 MPH while pulling 2 - 3 Amps and pedaling moderately.

I started to realize that now it was MY batteries (legs going out) that were at stake as well, so now those AH's became even more precious!

I have concluded that a truly aerodynamic windshield is a top priority, even if it does look a little silly, and I saw somewhere in a post someone bought something for $40 or so, and that will have a huge effect on efficiency regardless of the fact that this bike won't go over 20-25 MPH most of the time.

Well, once I got to the half-way point to Oregon City, I was pretty beat!

I was about to climb the first big hill (2 miles about 7 - 10%) and I had forgot to pack a sandwich, so I reached into my emergency stash and ate all 4 granola bars!

The first hill wasn't so bad heading south, until I crested the hill, then the wind hit me full force! I barely could make more than 6 MPH on that steep grade and wind.

I have concluded that I need to double my battery capacity, as it is, I was able to get to the real hill with just 1 AH to spare, and it took most of my last AH going up this 2 mile monster, so I mostly tickled the throttle the rest of the way so that I wouldn't be pedaling against the DD & Nuvinci resistance (you know, I don't notice it usually, but this tired, it felt like riding on wet sand! ) and I managed to hit the garage having used exactly 9.02 AH's!

I am too tired to remember how to calculate Watt Hours, so maybe someone can refresh my memory, here are the stats:

45V (average voltage, started at 48 and ended at 44V)

12A average amperage

9AH used

46 miles traveled

If I'm not mistaken (and my tired brain probably is) this comes to ***EDIT***9 watts/mile.

However, taking 1 hour going, 2 hours coming back (with 3-4 stops along the way both ways) I think the average speed must have been dropped to around 8 -10 MPH.

[LI-ghtcycle]

Wow, that was one long rambling post!

It did however lack one important bit that I wanted to share, the torque arm that I put on to beef up the ones from the exercise bike (it's easy to just think steel is strong however, the drop-outs are really quite thin) and if I had not thought of that, I almost certainly would have had problems with chain tension. If I look really close, even though I have good, even ideal chain tension, I can see just the slightest sag on the chain drive side.

I will be building a second torque arm for that side too and then it won't be able to sag. Ultimately, when I have a custom rack built to hold it, I will design it so that if it were to loosen, it gravity would tighten the chain. I might be able to use the drop-outs that have motorcycle style tensioning from my nephews pocket bike for this, would make chain tensioning a real snap!

[LI-ghtcycle]

I might get some pics tonight up of the new torque arm and the build thus far, but I did some more testing, wanted to see what kind of efficiency I would get out of a fully charged battery going up the hill, and WOW with it on full under-drive, I was able to climb 12% at 7 MPH using just 20A!!

This is huge since normally I would be maxing at around 30A and only going 2 -3 MPH faster! (remember, this is a "touring cargo bike", so it's more important to be able to go up hills with out pedaling than anything else).

The second torque arm isn't really a torque arm however, I made it a tad short, so it's just acting as a tensioner more than anything, it's notched instead of having full coverage around the bolt, it sits on top of it, but this is just temporary.

I have a lead on what could be a VERY nice Lincoln welder for cheap from a friend, and I might have that be the "pay" for my neighbor's welding services, and I think first we are going to use some of the frames I have laying around to make the rear rack and attach the ends of my nephew's old pocket bike swing-arm since they have motorcycle style adjustable drop-outs, and that will be the first "production" rack for this build meaning it might end up as a permanent usable rack rather than just a test bed prototype like I am using now.

[LI-ghtcycle]

Got the new gearing going, and this time the gear calc is spot on! I think before I had the wrong RPM for the motor skewing the calc.

Right now with the 13T drive sprocket and 27T Hub sprocket, I am able to shift the Nuvinci gear ratio down to the point of 7 MPH and up to 29 almost 30MPH, so it's perfect!

The only problem is with the smaller sprocket I have less clearance on the drop-outs of the test mount, but I have been busily trying to adapt a derailleur for the task, and it made a noisy mess, too much tension, and I finally realized I could use the 'bent riders trick and just used some small diameter ABS conduit for the chain to slide over (I might eventually have the chain go through a length of pipe on the final version) where it would have rubbed on the drive side, and just guarded a few places it might rub from time to time, and the chain is at an ideal not too tight or too loose tension even though I had to remove 2 links for the smaller cog!

I also got my Zzip Designs MTB fairing, and have been so tired, that I could barely get half of the tensioner experiments done, and the fairing has been sitting for almost 2 days now, hopefully I can have it installed today and pics to show!

Tomorrow is going to be very windy, so it will be a perfect time to test the fairing!

[LI-ghtcycle]

Ok, pics!

First, some of the torque arms & plastic chain sliders from ABS pipe:







I made this just today after nearly 2 days trying come up with a chain tensioner I liked.

The first was pretty promising, made from an old derailleur that I took apart, but even thought it did what I expected, it also had the chain much tighter than I would have liked, and made a horrible racket.

The final version was just pieces of 1/2" plastic conduit pipe cut in half lengthwise and zip-tied to the side of the drop-outs and the rack where the chain gets a little close. The drop-out on the drive side (first pic) is the only place that will be regularly contacted, but just barely, and it makes no noise as the chain is just the right tension, not to tight or loose.

Here is a link to the post for my Mid-Hub drive to see the latest pics of the bike:

http://endless-sphere.com/forums/viewtopic.php?f=3&t=25856

[amberwolf]

If you happen to find that the ABS wears quickly, try finding an old kitchen cutting board made of the white slippery type of plastic. It may be cast from teflon; I used pieces from one as chain guides on CrazyBike2's powerchair drive, and they worked wonders without catching the chain, and didnt' show any signs of wear when I eventually removed all taht and went to the hub drive back in October.

[LI-ghtcycle]

If you happen to find that the ABS wears quickly, try finding an old kitchen cutting board made of the white slippery type of plastic. It may be cast from teflon; I used pieces from one as chain guides on CrazyBike2's powerchair drive, and they worked wonders without catching the chain, and didnt' show any signs of wear when I eventually removed all taht and went to the hub drive back in October.

Great idea! I'll keep an eye out for some at the local goodwill, need to get a new fanny pack anyway. Hopefully the pipe won't show any wear to speak of.

I'm going to start cutting up old frames soon as I can and build a rack that allows the motor to be in a better position.

Really don't like having the high center of gravity, makes the bike far too tippy! Might get started on my front racks first if I can cobble something together until next week when my neighbor can do some more welding for me.

[neptronix]

Ahh yes.. maybe a smaller motor like a bafang or mxus geared hub would do better for weight balance. i think you can get them as light as 7lb. Half the weight, and you can bring it down closer to the wheel..

Of course they can't kick out the same amount of power tho :/

[John in CR]

Okay LI-ghtcycle, now it's time for the biggie now that you have the gearing dialed in. What kind of mileage are you getting with no pedaling? wh/mile on the flats at say 20mph. Did you run the motor before in-wheel for some directly comparable data?

[LI-ghtcycle]

Okay LI-ghtcycle, now it's time for the biggie now that you have the gearing dialed in. What kind of mileage are you getting with no pedaling? wh/mile on the flats at say 20mph. Did you run the motor before in-wheel for some directly comparable data?

Yep, I'll have to look back at my post in the efficiency post to get specifics, but honestly, I have to do some more riding to make sure the gearing is dialed in, yesterday I was so beat after trying to make a tensioner, that I only road across the street in the neighbors extended driveway back and forth, and with some wind skewing things.

[John in CR]

Even just a preview would be nice with existing gearing, you can always change the Nuvinci setting to get what looks the lowest current for that speed. In real world use we wouldn't be continuously adjusting the Nuvinci, would we? I'm just interested in whether it seems like you're taking a notable efficiency hit from the Nuvinci, or does it pretty much pay for itself for overall efficiency by allowing higher rpms, especially at the lower speeds. It would be great if the extra hill climbing ability comes with an overall gain, but it would be worth it to me even if it cost 5-10% overall.

Maybe you mentioned it before and I missed it, but how is the chain sound?

[AussieJester]

If you happen to find that the ABS wears quickly, try finding an old kitchen cutting board made of the white slippery type of plastic.

Its polyethylene AW....

KiM

[LI-ghtcycle]

Even just a preview would be nice with existing gearing, you can always change the Nuvinci setting to get what looks the lowest current for that speed. In real world use we wouldn't be continuously adjusting the Nuvinci, would we? I'm just interested in whether it seems like you're taking a notable efficiency hit from the Nuvinci, or does it pretty much pay for itself for overall efficiency by allowing higher rpms, especially at the lower speeds. It would be great if the extra hill climbing ability comes with an overall gain, but it would be worth it to me even if it cost 5-10% overall.

Maybe you mentioned it before and I missed it, but how is the chain sound?

Well, first off, I don't have a wind tunnel or any other real impirical way to give anything more than my anecdotal experience, that being said, from the get go, I have noticed a slight decrease in efficiency in the form of a slightly slower top end, say 2-3 MPH less on my top end, however, it has been more than off-set by ability to gain efficiency on the low end.

I'm not sure what you mean by not wanting to adjust the Nuvinci continuously? I love the fact that I can dial it in to the exact gearing ratio that is most comfortable/efficient for both my legs and motor and I can do it with out having to think about it, it's one of the main reasons to get a Nuvinci IMO, because you have nearly infinite "gears" with-in the range that it spans.

I have definitely noticed already a pretty big gain in the hill climbing efficiency, I would say it's about 20-30% more efficient with the amount of watts needed in the past with-out it using the same hub motor in the wheel.

Now it's even more efficient since I can gear it down so low, but until I get some weight on it, I won't really know the full extent of it's increased efficiency, the best base-line I can say now is once I have my cargo pod/panniers built and loaded with the same amount of weight I had when I went to get the Nuvinci wheel built, and see how many watts it takes to take it on a day that isn't so windy (14 MPH steady just when I pulled up 20 mins or so ago, and we have gusts up to 40MPH!).

As far as chain noise, what noise! It really isn't noticeable, no louder than any other bicycle chain, even with the 13T. Chain wear might be a different story, it seems to have stretched considerably today, but that could just be because I have 4-6 links from an ancient exercise bike, that reminds me, I better go buy another chain so I can have all new links, I think the old stuff is starting to stretch.

I only went 5 miles so far today since I realized after hitting the goodwill looking for a plastic cutting board and new fanny pack, I reached for my air horn at one point "just-in-case" and it wasn't there!

I had forgotten to re-attach it when I installed the fairing!

It worked out anyway since the chain is so stretched now it seems like I could take out a link! Hopefully that is just the old chain, not the whole chain stretching!

Anyways, I'm going to just have the lock nuts hold the chain tight long enough for a trip down to the bike shop and get a another chain, then I'll see about adapting the drop-outs from my nephew's pocket bike to my test rig so I can really tighten up the chain right. There just isn't a real good spot to put a tensioner with that I have now, no good places to attach one.

[LI-ghtcycle]

Well, all I can say is if this were the Myth Busters show on Discovery, and the question was "do upright bikes benefit from handlebar mounted fairings?" then this baby is ..........















CONFIRMED!!!!!






I just had a nice little trip nearing the end of the day starting at about 4:15 PM, and I took my usual route to the bike shop, then to the hobby shop to get my loaner charger so I can send back my Hyperion to be warrantied, and I got to test the gamut!

First, I went along with traffic after leaving my house, got up to about 20 MPH before turning into a nearby housing development, then soon down my favorite hill, and a special treat!

There just happened to be a guy in a recumbent bike in the bike path, so I thought sweet! Lets see if I can catch up to him and maybe even pass him! (he was almost a full block ahead of me, but I imagine he doesn't go for broke down this hill, most cyclists are afraid to)

And then I noticed I had a light but noticeable headwind, so I thought, oh well, at least I can see what it will do under these conditions.

To my surprise, I went down the hill with something between a 5 - 10 MPH headwind according to weather underground (we have had a pretty sporadic yet dominant SE wind most of the day, calm much of he time) I still made it up to 37 MPH going down (normally in these conditions I would be lucky to get 33 MPH) kept the cars at bay behind me, AND passes the 'bent at the point where things start to flatten out, he was really kewl, gave me a big thumbs up!

SO.... the next part of the test doesn't really come until the trip back UP that monstrous hill!

After going around down town OR City, to the hobby shop then back to the base of the elevator and chatting with Al and Steve at Classic Cycles, I headed up the elevator around 5:50 PM (I almost always take the elevator, so this is part of the normal routine, sure I would have used more energy going up the first steep part of the hill, but the elevator still doesn't spare me of the steepest part of the nearly 2 mile long hill which is 12%).

One thing that I have started to realize at this point in the ride is that the motor doesn't really pull much until I hit about 60 - 75% throttle, so it's definitely running at a efficient range with the new gearing!

I take the same path on the sidewalk up the steep part of 7th street mainly because it's the most direct route, and I don't have to take Linn (the same path I like to go down) that has a really narrow bike path along a winding narrow road with blind corners where cars usually creep into the bike path while turning, and I don't have to worry as much about stopping along the route as 7th is a main through street.

When I start to approach the DQ I know I am going to have to gear down to the smallest ring in front (22T) of my pedal chain to make this hill, and to my surprise, I really didn't have to add anything at all!

Since the motor is now running in such a efficient way, I really don't need to add any pedaling at all, and it's going 10 MPH on the steepest part, 12% with ease, at only 15AMPS!!

This is FIVE amps less than before for the same performance!!

And here is where I got really excited!

The total trip was 8 miles, I used just 1.79 AH!!!!

That makes 86 Wh's for 8 miles, so just 10.75 Wh's per mile!!!

So you want to know if the gearing is the real change worth noting or the fairing, well, to that I'd have to say both! Reason is, going down hill, with the gearing of the motor maxing at 30 MPH no-load speed, it's not adding anything going down, and it's just my pedaling adding another 7 MPH going down hill into a pretty good head wind, AND going up hill, it's probably more about the gearing on the 12%, but I'm sure that the fairing still helps!!

As far as testing with-out the fairing too, sure, I'll get around to it, but it's gonna have to be a really warm day since I'm really loving the extra protection given to my hands, and when it's 50 F , it still gets too chilly for my hands in even my favorite neoprene gloves.

To compare, this kind of a trip typically would take an average of 1 AH per mile when including that big hill climb so, in other words, normally that would have taken 8AH's, and I used less than TWO!!!

I have to say with today's results being even much much better than yesterday, as far as I am concerned, this fairing has been worth it's weight! If I wanted similar performance by just getting more battery and voltage, I would have paid more than double, and I would have added twice the battery weight as I have now, in other words, I might not need to go 14S after all, 12S might just be fine especially considering it's a very real possibility that 12 AH's can do the work of 24AH's!

[neptronix]

No freaking way O_O...

In a way, it makes sense that your efficiency is higher.
Hub motors do have an efficiency range, and if you keep them at peak efficiency, you can really go far on less amp hours.

By the way, do you cycle in the crouched position the entire time, or upright? i hear that makes a big difference.

[LI-ghtcycle]

No freaking way O_O...

In a way, it makes sense that your efficiency is higher.
Hub motors do have an efficiency range, and if you keep them at peak efficiency, you can really go far on less amp hours.

By the way, do you cycle in the crouched position the entire time, or upright? i hear that makes a big difference.

My riding position is the same as it has always been, slightly forward, I make no attempt what so ever to crouch, the fairing does all the work, however, once I get the helmet I want, I imagine I will have less drag, as a MX helmet with the large visor on the top must cause a good deal of drag.

I think the real difference the fairing makes is in that the slightly forward angle of one's chest when riding makes a rather large "pocket" much like if you had a piece of cardboard about the same width facing the wind, this makes a very high drag "sail".

The fairing eliminates this largest section of drag from the equation, and all the rest is really insignificant by comparison, so that is why I notice a big gain (this is just my thoughts, not anything specifically told me by Karl at Zzip Designs).

[Gordo]

If you happen to find that the ABS wears quickly, try finding an old kitchen cutting board made of the white slippery type of plastic.

Its polyethylene AW....

KiM

AW, Kim;
We have found that the 55US GAL plastic food grade barrels are made of the same stuff (HDPE) and are almost indestructible. The food industry can only use them once so they sell for $5-$10 from yogurt or jam makers. We used it for ski-skins on snow machines to slides on lumber chains. The links of a lumber chain are 1.5" X 4", run 24 hrs per day carrying lumber in a mill. A strip of barrel last @ 10 years.

[LI-ghtcycle]

If you happen to find that the ABS wears quickly, try finding an old kitchen cutting board made of the white slippery type of plastic.

Its polyethylene AW....

KiM

AW, Kim;
We have found that the 55US GAL plastic food grade barrels are made of the same stuff (HDPE) and are almost indestructible. The food industry can only use them once so they sell for $5-$10 from yogurt or jam makers. We used it for ski-skins on snow machines to slides on lumber chains. The links of a lumber chain are 1.5" X 4", run 24 hrs per day carrying lumber in a mill. A strip of barrel last @ 10 years.

Perfect!! Thanks for the tip!!

I just happen to have a black 55 GAL drum of that stuff! Good thing I didn't find a cutting board at goodwill!

[AussieJester]

If you happen to find that the ABS wears quickly, try finding an old kitchen cutting board made of the white slippery type of plastic.

Its polyethylene AW....

KiM

AW, Kim;
We have found that the 55US GAL plastic food grade barrels are made of the same stuff (HDPE) and are almost indestructible. The food industry can only use them once so they sell for $5-$10 from yogurt or jam makers. We used it for ski-skins on snow machines to slides on lumber chains. The links of a lumber chain are 1.5" X 4", run 24 hrs per day carrying lumber in a mill. A strip of barrel last @ 10 years.

I actually have a couple of meter square 10mm thick sheets of polythene i bought it for my DiY CNC build
I think i sent a couple of strips of it to AW in a package too IIRC? Slippery stuff and wears well is good for chain guides for sure. Don't know of the drums you speak of though Gordo don't think we get them like that in OZ.

KiM

[amberwolf]

I actually have a couple of meter square 10mm thick sheets of polythene i bought it for my DiY CNC build
I think i sent a couple of strips of it to AW in a package too IIRC?

Yep; if I hadn't already had the cutting board pieces in place, I'd've used some of what you sent for that. However, since it's still intact I can use it for other guides on whatever middrive I come up with for CB2 or it's descendant.

[Gordo]

I actually have a couple of meter square 10mm thick sheets of polythene i bought it for my DiY CNC build
I think i sent a couple of strips of it to AW in a package too IIRC? Slippery stuff and wears well is good for chain guides for sure. Don't know of the drums you speak of though Gordo don't think we get them like that in OZ.
KiM

The other source of HDPE I just recalled was natural gas line. Comes in many sizes and colors. Very thick wall. I have pushed a piece of AL pipe inside the HDPE and then a bearing in the pipe. With a grove in the plastic you have a good guide roller.

[LI-ghtcycle]

I'm really glad that I have this recorded in the "Efficiency" thread, so that I can be sure that I'm not just excited and exaggerating!

http://endless-sphere.com/forums/viewtopic.php?f=3&t=6615&start=60

Here is the trip I took to Portland to have the Nuvinci built, using the Amped 9 x 7 rear hub motor while it was still in the rear wheel, and the efficiency was about 13 Wh/Mile, and now with the mid drive, 7 Wh/Mile!

I did want to correct something however, I confused myself thinking that at one point I had a 30A controller with 9 x 7, I think this is because I tested a different kit recently that does indeed have a 30A controller, so some of my conclusions were incorrect based on that, however, I am still using a watt meter, and that will keep track of the watts properly no matter what the controller's amps.

I have switched from getting a disc front brake hub to a Sturmey Archer 90mm Drum Brake hub for the longevity of the brake shoes more than anything, but being sealed from the weather, I think this will be a huge asset as well, since not even freezing rain would prevent normal operation of the the front brake, not to mention I won't need adjusting/servicing for many thousands of miles!

Don't get me wrong, I have nothing against disc brakes, but for the lack of maintenance and still have comparable stopping power to good front V-Brakes (when they are in ideal weather/operating conditions) and a proven track record being used on heavy cargo bikes, AND allows me to avoid the whole QR skewer dilemma since it has a solid axle, it's a perfect choice for me.