Safe's Electric Bike Project #001

[safe]

Version 5.0

Notice how there's nothing to jam up anymore. If the chain feels like jumping out of place it gets pulled back to the sprocket because it's between two wheels. So far it's been pretty good, but I realized very quickly while testing it out that when the last setup broke it threw the derailler into one of the spokes and broke it, so that's another repair that needs fixing.

 

[safe]

Murphy's Law?

Yikes... I get everything together and ride around for about 10 miles or so. The rear tire was not seating very well, so I fiddled with it and in the end got everything looking great. Then I pumped the tire up to about 65 lbs which is the maximum for the tire and about 10 lbs more than usual.

I start to ride and..... psssssssssssssssss..... you bet, all that pressure burst the tube wide open inside. Seems that the 24 x 2.215 tube doesn't like being expanded to 3 inches.

Not only that but these tubes have this green slime for thorn sealing and it got all over everything.

Sometimes the bike just wants to find a way to break...

It's funny how you can ride for a hundred miles or more and everything is fine and then you can have a series of problems that go back to back. Anyone else have this sort of thing happen? Things breaking in sequences...

 

[safe]

So far, so good...

Things seems okay now. I've done a couple of rides and everything is working fine. The new transaxle gear is an 18 tooth rather than a 19 tooth. What that does is it means than on the flat the bike wants to top out at 39 mph rather than 40 mph as before. In the beginning when I was doing all those speed attempts I was running a 22 tooth on the front which meant that the motor was still pulling strong at 44 mph if you could get it there. So I'm a little down on the top speed. Of course, that always means that I'm now much stronger on the hills and there seem to be no hills that stall the bike anymore. So all in all this is a good setup. It's not the best on speed, but it's more versatile in the conditions I'm in.

With an 8 Speed internally geared hub I'd have confidence that I could easily cover all the speed and hill climbing conditions on this bike. Since the next project bike will be more powerful, lighter and more aerodynamic an 8 Speed is sure to be enough.

I've just passed 1600 miles on it...

 

[EbikeMaui]

How much does your hub motor bike weigh?
This is considerd a bicycle in the california DMV laws.All it needs to be a bicycle in most states is a small 60 volt pedal dynamo.The total weight including 30 ah eMoli lithium pack is 110 lbs.It has a programable limiter/programable regen/200 amp off road power/ 40 mile range and videos with a price to prove it's the best ebike made.
Let's see some hub motor burn outs with all the riders weight on the ebike. :lol: This bike is a single speed geared for 45 mph.
http://www.electracross.com/Video/12-TireTest.mpg

 

[safe]

http://www.electracross.com/Video/12-TireTest.mpg

The new law goes like this:

"Electric bicycles with fully functioning pedals, no more than 750 watts of motor power output, and a top speed of 20 mph on motor power only, are to be treated as "bicycles", and are not subject to motorized vehicle laws."

So my goal is to sell a bike that can somehow make it under this motor restriction and speed limit (plus pedals) but make it so that aftermarket modification is easy to do so you can exceed the speed. The easiest way is to sell a bike as a one speed and then let people add a geared hub afterwards. :wink:

The electracross is a motorcycle and will either be illegal for the street or will require a motorcycles license. I've got nothing against motorycles and have owned them before, but I'm trying to push the limit of what a legal bike will do.

 

[safe]

Version 6

After about 400 miles the Version 5 transaxle bearings started to go away. Unlike in previous versions the other aspects of the transaxle worked great. The chain never skipped out of place. The bearings never completely failed, but when I took it apart today I saw that the bearing cups were deeply grooved and I was having to reset the bearings after every ride. (that was my clue that the bearings were failing)

Anyway... Version 6 will use the same "body" but I'm just going to try out some sealed bearings that are supposed to be for a scooter wheel. They don't fit the inside of the old transaxle, so I just welded over the tops of both sides and then smoothed it out. I'll weld on a surrounding bearing holding tube and that's much easier than trying to weld on the inside and then having to grind which never has highly precise results. Also, by placing the bearings a little wider it should be a little stronger.

I was afraid of this all along... the bearings have had problems ever since I upgraded to 1000 watts of power. More power, more stress on the bearings. My first transaxle did pretty well because in the beginning I had a 750 watt motor and a controller (and wires) that didn't really give out that much power.

With more power you break more stuff.

 

[Lowell]

Quality bearings are worth the extra dollars...

http://www.bocabearings.com/

 

[safe]

Quality bearings are worth the extra dollars...

http://www.bocabearings.com/

I already have these bearings and so I might as well try them out. The way I'm building this it will be easier to change things because if I don't like the bearings I have now I could wipe everything back to flat again and install bigger bearings. The last bicycle bearings lasted for 400 miles and it was the metal that simply fatigued and began to allow grooves to form. Properly hardened steel bearings and cups should be fine. The ball bearings never failed at any time, it was always the cup. They seemed to have used some really low grade mild steel cups... typical of an inexpensive bicycle. It would not surprise me that if I was starting with a higher quality bicycle bearing and cup to begin with that it never would have failed. It's like my 6 speed freewheel cluster. The original failed in about the first 50 miles. The Shimano replacement is up to 2000 miles and going strong. There is a wide range of quality in the bicycle world... and unfortunately the way the hub was built the cups were stamped into the hub so that they could not be removed. I had to nearly destroy the hub (now transaxle) just to get the old cups out. I cleaned it up a little, then welded it all flat and ground it smooth. At this point I'm starting with a clean slate.

The other aspects of the transaxle have been the best yet, no chain problems, the alignmemt has been good, the gear ratio is just right, it's been a good version. In fact it's been just about trouble free until the bearings started to dig the grooves.

This is the sort of thing that is a "long term maintenance item" that you can't know until you get several hundred miles on the bike. It's possible that the new bearings last 500 miles before failure. If so, then at $5 I might decide to simply have spares around and just replace them every 500 miles. If it's every 1000 miles that's even better. The main thing is to make things easily replaceable so I can stop all this grinding and reworking. The last alternative is a complete redesign which means even more work and time.

Do I want to divert all this time from Project #002 back to Project #001?

No, not really, but if I don't fix Project #001 then I don't have anything to ride.

I also got some elbow and knee pads recently and they manage to fit underneath my leather jacket top and my simple Levi's for bottoms. On cold days I've worn an extra layer of clothing underneath my pants, but it's really hot now and so being able to just use the knee pads will be nice. On the really hot days I can ride around with elbow and knee pads and just shorts and a t-shirt. On those days you take it easy... if you crash like that it's the same as a cyclist crashing... (lot's of exposed skin)

 

[safe]

Things went well...

The mounting of the sealed bearings to the outside of the transaxle seems to have worked okay. The tolerances are close, but not perfect.

Question:

"Will 'Locktite' work well enough to keep the sealed bearing stuck in place as long as the mounts are sturdy? Does 'Locktite' hold up to pressure loads pretty well? If not, what options do I have to get a sealed bearing really firmly stuck so that it won't allow any play?"

The play is such that I can just barely wiggle the sealed bearings into the mounts, but once in place they do find some level of movement. I could heat them up again and do a little gentle molding to get the tolerances a little closer, but then I end up grinding things back again just to get the bearing in place. Also, I haven't painted it yet and the paint would likely smooth out imperfections and get me closer. This is one of many cases where my machining capabilities aren't enough to get to the level of precision I'd like.


http://www.loctiteproducts.com/products/detail.asp?catid=10&subid=48&plid=154

 

[Lowell]

Loctite sleeve retainer (green) might work. You could also knurl the axle surface to enlarge the diameter, and then press fit the bearing on.

 

[safe]

Loctite sleeve retainer (green) might work. You could also knurl the axle surface to enlarge the diameter, and then press fit the bearing on.

There's also the possibility of me welding extra material underneath where the bearing goes and then grinding it smooth. Right now it's bearing on top of threaded rod... which is just begging for long term maintenance problems. I was thinking about the exterior surface of the bearing to the transaxle, but the interior issue is there too...

 

[safe]

I went ahead and welded, then ground smooth the areas under the bearings. Now it's a more solid fit and unlikely to wear with time. One side is welded solid to the axle and that way you can set one side with a nut and then adjust entirely from the other. I didn't have much room anyway, so this just makes things a little easier. I slotted the axle, so I didn't have to change anything on the bike. (it's a bigger axle than before) Everything got new paint and a new color... black... which will make it easier because it was hard to keep the grease from the chain from getting on the gold color before without it looking bad. I'll have to wait a while for this paint to dry because it's epoxy paint rather than my usual paint. Epoxy paint seems to take longer to dry, but as I recall when it does finally dry it's pretty strong. I got some Locktite (a clone product actually) that is supposed to withstand 2500 lbs/sq inch which compared to some of the others I looked at is pretty strong. The others were more like 500 lbs/sq inch if they even listed it at all.

 

[dirty_d]

youd probably be better off if you built yours like mine, i just bought a 3/8 shaft and sprockets to fit along with flanged bearings that fit into a mount i made its easy to swap out different sprockets for differet gear ratios, although i made the stupid mistake of using a 3/8 D-shaft if i made another i would definetly use at least a 1/2 or 5/8 keyed shaft not a D-shaft. i had problems with the shaft flexing and the sprocket slipping on the shaft so i had to weld an additional locking collar to one of the sprockets for more grip, a keyed shaft would solve this and make swapping them out a hell of a lot easyer, if you were going to use a bicycle sprocket to go to the rear wheel you could buy some keyed collars and weld different sized sprockets to them. the best solution like you said is just straight to the wheel.

 

[safe]

...the best solution like you said is just straight to the wheel.

Yeah, at this point there's plenty of the "monday morning quarterbacking" about how to build such a thing. The things I've learned are:

1. If you plan to go from your transaxle to a derailler your best bet is to contain the gear with two flat circular plates spaced just wide enough for the chain to clear, but little more. If the chain tries to skip out the chain guide brings it right back in. (reject chain guide concepts where the chain can get jammed)

2. At 750 watts a low quality bicycle hub bearings are just barely able to handle the power without breaking. At 1000 watts those same bicycle bearings (and cups) are simply too weak to handle the power. You need something closer to bottom bracket bearings to handle the load.

3. Whenever possible mount your gears so that they can be removed or reset with some kind of bolts. Most sprockets come with some kind of bolt based attachment and you should stick to that. This way you can get the sprocket perfectly centered and reduce chain slack.

But the real "bottom line" is to redesign the bike from the beginning to not need a transaxle in the first place. Direct drive from motor to rear hub is the way to go.

Also... I was looking at buying new parts and starting over and realized that for the price of all the parts ($10 here another $15 there) you could simply buy a multispeed rear hub. So even on a cost basis if you are starting from scratch the transaxle idea is a waste. For me it cost me nothing but time because most all of the parts where free, but all that time could have been spent better.

"Just Don't Do it!" is the main message...

 

[safe]

Riding Again

Went for a quick 10 mile ride to test the transaxle and it seems smooth and strong. Only time will tell how well it holds up to long term use, but the precision bearings seem better right from the start. The play that you normally have to worry about with a loose fit bearing doesn't exist with the sealed bearings. As long as the bearings are held in place (without needing much pressure) they will roll without play until they wear out on the insides. The paint had built up enough extra material that all I did was lightly tap the bearings into place and unless play develops they won't need the Locktite. I did use Locktite on the inside bearing side. Basically it seems solid now. No play at all.

So we will see...

 

[safe]

After the first few rides the transaxle started to loosen up a little and so I took it off to see what was going on. Seems that the paint on the inside next to the bearing wasn't very strong and basically chipped and fell out. After a little cleaning I put the bearing back in and this time tried using some Locktite on the outside of the bearings between the bearing and the transaxle. After two rides it's been solid. So one can say that Locktite is definitely stronger under pressure than most paints... which makes sense.

The precision bearings are really smooth. Now I'm getting more power out of the motor and less "groaning" from the transaxle whenever I load it up with torque, though it still seems like a bad idea compared to direct drive from motor to rear wheel. It's quite possible that for the time being this bike is in good working order, but I'll put on some more mileage before I pronounce this version of the transaxle a "success".

On my private racetrack (I call it that, but it's just a circular road course that was abandoned when they abandoned a housing project) I've been improving my exit speeds on my high speed sweeper turn. In the beginning I was exiting the turn at about 16 mph, then it was 19 mph, then 20 mph, and now I'm just getting into 22 mph exit speeds. I'm entering the turn at about 39 mph. It's a 180 degree turn that starts out a gentle sweeper and slowly tightens up. The tendency is to want to go in fast and more or less stop and take the exit at slow speed, but if you carry your speed then all of a sudden you have this extra momentum coming out the other side. So now I'm starting to go up one gear on much of the track. It's been fun.

The tires are really working great now. They are finally worked in and you can lean into just about anything. In fact, I really haven't even gotten them to break loose for awhile because they are sticking so well. The warm weather helps... it would be great if they made an even more soft and sticky compound for Road Racing electric bikes. Oh well... one can dream...

 

[safe]

What is 3.23?

The number of miles away from home when my bike got a flat today. Fortunately I was doing my ride at sunrise and it was still pretty cool, but having to walk home 3.23 miles was not what I had planned for the morning.

I haven't taken it apart yet, but if it's like previous tube failures the hole or rip will likely be on the inside next to the rim. For some reason I've gotten three flats on the same road within a quarter of a mile from each other. An unlucky stretch of road I guess. :?

Anyway, my problem is that I bought 10 tubes for $3 each and they were the standard 24" x 2.125" size. My tires are 3" and really need the special tube size that matches it. So it's time to get the bigger tubes and hopefully make this problem either go away or become less frequent. (maybe switch to a motorcycle tube?)

As for the "transaxle" it's going great! I've put on about 300 miles to the bike since putting it on and it's smooth and quiet. Other than flats the bike is becoming pretty much carefree...

 

[xyster]

The number of miles away from home when my bike got a flat today. Fortunately I was doing my ride at sunrise and it was still pretty cool, but having to walk home 3.23 miles was not what I had planned for the morning.

You're old and retired, the walking's good for you.

Anyway, my problem is that I bought 10 tubes for $3 each and they were the standard 24" x 2.125" size. My tires are 3" and really need the special tube size that matches it. So it's time to get the bigger tubes and hopefully make this problem either go away or become less frequent. (maybe switch to a motorcycle tube?)

We've already run through some 3" options in this thread or another.
Here's three (again). If I may say, you seem to have a thing for being cheap to the point it costs you more. Penny wise and pound foolish, as they say.

http://www.universalcycles.com/shopping/product_details.php?id=1195&category=597
http://www.universalcycles.com/shopping/product_details.php?id=1190&category=597
http://www.universalcycles.com/shopping/product_details.php?id=4344&category=597

 

[safe]

I made up an order to an online bike shop and bought all the things I've been postponing at once. I got a spare tube just in case, but no more because if the replacement turns out to fail then I'll be wanting to try a variety of other brands to see what works.

1 Wheel Master Pro Spokes UCP 9-5/8in ......$14.84
2 Pyramid,Down Hill 24x2.35/2.75, Shra.......$15.42 (largest they had)
1 Pyramid Rear Hub Axle 3/8x185mm 26 T...$ 4.29
1 Rocket, 43T, BMX, Silver Alloy Chain.........$15.31
1 KMC Z410 chain, 1/2x1/8. Color: silver......$ 6.99
1 KT coaster brake hub sprocket, 18too........$ 2.98
1 Penis Enlargement Kit with booklet.............$ 6.45 (hey, that's not my bag baby :lol: )

 

[xyster]

1 Wheel Master Pro Spokes UCP 9-5/8in ......$14.84
2 Pyramid,Down Hill 24x2.35/2.75, Shra.......$15.42 (largest they had)
1 Pyramid Rear Hub Axle 3/8x185mm 26 T...$ 4.29
1 Rocket, 43T, BMX, Silver Alloy Chain.........$15.31
1 KMC Z410 chain, 1/2x1/8. Color: silver......$ 6.99
1 KT coaster brake hub sprocket, 18too........$ 2.98
1 Penis Enlargement Kit with booklet.............$ 6.45 (hey, that's not my bag baby :lol: )

No wonder you don't have the money for the important stuff like proper bicycle tubes. As long as it keeps you away from vacuum cleaners...

 

[safe]

Oh behave...

 

[safe]

I've crossed 2,250 miles on the bike now. Everything is working great and I've been riding two and sometimes three times a day, so I've been able to put on those last 250 miles pretty fast. Actually my wrist is a little sore from all the riding, so that's why I took today off (after two morning rides) from working on the #002 Project. I hope my wrist feels better tomorrow... it's in retrospect not a very good idea to make my wrist sore if I've got sanding to do. Hmmmm... to be 20 again and be able to do anything and recover instantly...

 

[safe]

With the riding season winding down I'm starting to think of what modifications need to be done on the #001 Project for next year. When the fairings get done on the #002 bike I'll make a spare set and throw them on the #001 bike. But I'm also thinking that I might want to try out MCL on my existing bike since I know it really well and would therefore have better feedback about how well it performs. So here is my existing powerband using the standard 40 amp controller followed by what I would get from a MCL (motor current limited) controller at 50 amps. At first I'll just leave the gearing alone, but from the spreadsheet I see that I could potentially get up to 44 mph as a top speed. But that would hurt my hill climbing ability, so initially I'm going to be conservative and stick with the old.

We will see... (too many people are calling me on my theories so I feel the need to prove that it works)

Assuming all goes well I'll be getting a 200 watt increase in peak power.

 

[safe]

Wiring Frustrations

A few rides ago I noticed that things started to deteriorate on the #001 bike. At first I thought it was the throttle and replaced that, but that didn't help. For a while I was content to believe that it was the 20 degree drop in temperature that lessoned the strength of the batteries (and that is sure to be part of it) but after probing a little on the wiring harness I first found a few spots where the wires had worn through the protective tape. So I fixed the exposed spots. Then the bike completely dies. In the process of handling the wiring harness it exposed another problem which was that a soldered connection had come loose. So I fixed that. Now I'm wondering how many other connections are "suspect".

This is pretty much how last year ended... my original wiring harness went bad and the original controller also went bad just as the season ended.

The idea presented above in the last posting is a good thing to do in the winter when you can tear down the complete bike and do things like inspect the wiring harness and test everything to make it right. Maybe a new paint job and the fairings too.

I've got 50 more miles until the 2,500 mile total, so I'll ride it a few more times and then be satisfied that the season is over...

 

[Toorbough ULL-Zeveigh]

If you think this is frustration now, wait untill you have a battery pack with no solid connections between the cells.
Vibration is hell on any iffy connection & the rule is if it can work it's way loose at all it's guaranteed that it will.
I'm open to the idea whether conductive paste will work but remain skeptical.
BTW, you don't consider for a moment that your SLA's may be EOL?