LightningRods mid drive kit

You're not really asking stupid questions. We had a guy on this thread for quite a while asking stupid questions but he disappeared suddenly under mysterious circumstances. Cheekybloke maintains his innocence and I can offer at least a weak alibi for his whereabouts at the time of the disappearance.

You would not be served better by a hub motor for exercise. You still have the option of choosing different gears for different pedaling cadences. With a mid drive the motor speed is matched to your pedaling cadence. Serious cyclists have a cadence that they try to maintain by changing gears. A mid drive changes the gearing for the motor as well as for your pedaling. This keeps the motor from overheating and possibly burning up when climbing hills.

Don't confuse pedaling speed with pedaling effort. You have the option of providing more of the power at any crank/motor speed simply by pushing harder on the pedals. If you want a break you can roll on a bit more throttle or just put less effort into pedaling. The motor will carry you until you get your wind back.
 
Here's the new eccentric adjuster that I designed for the LunaCycle and Big Dummy drives. The first version of the Luna drive had an adjuster for the lower jackshaft that was almost impossible to reach without turning the bike over. This new adjuster is as simple to use as moving the tab to the correct detent. The jackshaft housing passes through the large hole in the center.

EccentricAdjuster.jpg
 
Cheekybloke maintains his innocence and I can offer at least a weak alibi for his whereabouts at the time of the disappearance.

I am innocent and the next one will cost you, no more freebies.
 
LightningRods said:
You're not really asking stupid questions. We had a guy on this thread for quite a while asking stupid questions but he disappeared suddenly under mysterious circumstances. Cheekybloke maintains his innocence and I can offer at least a weak alibi for his whereabouts at the time of the disappearance.

You would not be served better by a hub motor for exercise. You still have the option of choosing different gears for different pedaling cadences. With a mid drive the motor speed is matched to your pedaling cadence. Serious cyclists have a cadence that they try to maintain by changing gears. A mid drive changes the gearing for the motor as well as for your pedaling. This keeps the motor from overheating and possibly burning up when climbing hills.

Don't confuse pedaling speed with pedaling effort. You have the option of providing more of the power at any crank/motor speed simply by pushing harder on the pedals. If you want a break you can roll on a bit more throttle or just put less effort into pedaling. The motor will carry you until you get your wind back.
Click to expand...


Yeas but i think that just kind of proves my point :oops:

Your kit gives me just about 30mph/50kmh with a pedal cadence of 93rpm on a 26 inch tire if i understood it correctly?

First of all 93rpm is quite a high cadence for a fat bastard like me, and second of all i still need to do 30mph for most part of the journey to be able to get to work in time.
With a hubmotor that pushes/drags the bike along in 30mph i can chose the cadence( within certain limits of course) that's comfortable at the moment but the gear i choose to get that cadence wont affect the speed of the bike, right?
 
Andytheswede said:
Yeas but i think that just kind of proves my point :oops:

Your kit gives me just about 30mph/50kmh with a pedal cadence of 93rpm on a 26 inch tire if i understood it correctly?

First of all 93rpm is quite a high cadence for a fat bastard like me, and second of all i still need to do 30mph for most part of the journey to be able to get to work in time.
With a hubmotor that pushes/drags the bike along in 30mph i can chose the cadence( within certain limits of course) that's comfortable at the moment but the gear i choose to get that cadence wont affect the speed of the bike, right?
Click to expand...

I'm somewhat new to ebiking, but an old hand with bikes. Unless there's something different about an ebike you will be hitting 93rpm's regardless of where the motor sits as long as the gear ratio is the same. For instance, a gear of 50/14 will get you 30mph spinning at 93rpm's. If you are in excellent condition, and all other variables are not taken into consideration (weight, wind, terrain...) you could put out 200w for an hour and travel 30 miles. That would be a strong effort. Now with an assist you could put out less effort, and make up the difference with the motor, but the cranks will still need the same cadence in the same gear to reach that speed. Since the motor in the hub will only spin at the rpm of the wheel it could be outside of its efficient range, but a motor that drives the chain can be in its most efficient range while spinning the wheel at the same rpm. The only way to drop the rpm's is to up your gear, which would increase the effort needed to spin. That extra effort could be provided by you, or by the motor (regardless of where the motor is mounted in the system).
 
But a hubmotor doesn't use the gears on the bike,and a geared hubmotor does not spinn internaly with the same speed as the wheel,only the outgoing axle does?
 
Andytheswede said:
But a hubmotor doesn't use the gears on the bike,and a geared hubmotor does not spinn internaly with the same speed as the wheel,only the outgoing axle does?
Click to expand...

Yes, this is all true. While the geared hub motor may have a "different" optimal speed it still suffers from having an actual speed that is dictated by how fast the wheel, and therefore the bike, is going. A mid drive can be run closer to its optimal range because the gears can be changed in order to keep its RPM's consistent.

Regardless, if you want the motor to assist your power input and you want to go 30mph you will need a gearing that will allow for whatever your target pedaling cadence is. If your goal is to go 30mph, and you don't plan on pedaling the mid drive will be more efficient, run cooler, and use less power. Of course, only if you change gears to keep the motor in its efficient sweet spot.
 
I hit slightly higher than 30mph using a rear 16t in 24" tire at 72V (large chainring). Small chainring will hit just over 20mph at the 16t rear cog. I can apply peddle force up to about 25mph and then it starts to go slack and its ghost peddle only above that.
- Small block kit

Hope that helps a bit.
 
Ok,so with by bike where would the sweat spot be with the smallblock kit?
I presume not near its maximum output effect of 30 mph with a 26 inch tire and 48volt battery?
 
I don't use PAS, but I've found (at 72V) <=2500w limit and real low throttle ramp gives a good peddle pressure for an assistive feel. At high volts it has a ton of power, so I've had to tune it back pretty far for my assist.
The kit does add some significant weight to the bike and unpowered peddling isn't all that fun at all as a fixie :D
 
First of all 93rpm is quite a high cadence for a fat bastard like me
Click to expand...

The one way to lower the cadence while still using 48V, is to change the small sprocket on the #219 secondary drive to a smaller 11T unit. Once that is done, you would have to reduce your voltage, and em3ev.com sells a 36V pack that can be populated by optional high-current cells.

If you are assembling a custom LiPo pack, you could combine a 6S and 5S pack in series to make an 11S pack (3.6V-4.1V X 11 cells = 39V-45V). Balance charging could be accomplished by two RC chargers and one power supply, and bulk charging is easily accomplished by a a custom-ordered unit from ES member icecube57.

Of course, if you are not climbing steep uphills, you may not need the complexity of a mid drive.
 
spinningmagnets said:
First of all 93rpm is quite a high cadence for a fat bastard like me
Click to expand...

The one way to lower the cadence while still using 48V, is to change the small sprocket on the #219 secondary drive to a smaller 11T unit. Once that is done, you would have to reduce your voltage, and em3ev.com sells a 36V pack that can be populated by optional high-current cells.
Click to expand...

and that will still give me 30mph?
:?:
 
and that will still give me 30mph?
Click to expand...

Doing that would lower the pedal cadence at full throttle. From that point, you could still achieve 30-MPH, you could raise the top speed even more if you went to a large BB chainring (52T? 60?) but a large chainring might not fit on your frame, if it would interfering with the chain-stay.

Once the chainring was as large as you can fit (the most desirable first option), you could then reduce the size of the small sprocket at the rear wheel (not desirable). The smallest common sprocket would be an 11-tooth, but at high power an 11T would wear out rapidly, and then the worn sprocket would damage the chain rapidly. There would also be frequent "ratcheting/skipping" by the chain.

If you could be happy with a longtail cargobike, Mike has a mid-mount kit that allows the motor to bypass the BB, so the pedal-cadence can be anything you want, and pedal-cadence is very easily changed with cheap and available sprockets.
 
Hi Michael, and all...
Ive been keeping " my head down" so as not to be "dissapeared" too... :( :p :lol:
But i finaly Have all the parts and am starting to build... and as much as i searched couldn't find the thread on disassembling the small block.
if i remember, it was about changing bearings... but i need to know how so i can put in a temp sensor and 8AWG leads.
So if anyone can point me in the right direction?
Thanks


_________________________________

moderator edit: 9-minute GNG motor disassembly video here:
https://www.youtube.com/watch?v=WFbMbHrMTIc
 
Oh.. and one more thing - just a bit of "Bike Porn"
i couldnt get any store here to sell me a BB spaner for the ISIS BB... and didnt want to wait for one from overseas...
So i made my own at work! Laser cut it out of 3mm 304 Stainless Steel!
...Now i realize i need one for the Jackshaft too..
Michael? since you laser cut all your parts anyway - as a service to your customers.. you could offer spaners for both these nuts? at a low cost? just an idea..
Tim

IMG_0172 (Mobile).JPG

IMG_0175 (Mobile).JPG
 
This BB wrench has been posted before but obviously it's time again.

http://pedros.com/products/tools/pedal-crank-and-bottom-bracket/bb-wrench-shimano-8-notch/

I haven't made a video showing the disassembly of the motor and NO I'm not getting tagged with another task right now. I'm just barely getting my nose above water as it is. There's something wrong when you're excited about a three day holiday weekend because it gives you a chance to catch up on your work.

When taking these motors apart the number one thing to watch for is breaking the output side motor case. The bearing flange is held on by nothing but Chinese prayers and will pop off of the case if you look at it the wrong way. The bearing often comes out of the case with the motor shaft. When you try to press or pound it back in the case will want to cave in unless you support it from the back. It wants to die.

The thermistor is a worthwhile mod. I already include them on the big block motors. Now that I'm shipping orders reasonably quickly (down to 45 days lead time currently) I may start offering them as an option on the small blocks. Like a lot of things, it's not hard, it's just time consuming.

Try to confirm that all of that fat gauge wire will fit in the limited space inside of the case before tearing the factory wiring out. My motors have more room than GNG motors do for fatter wire but it's still tight. I plan to port the side cases for ventilation on a street big block. I will probably run the phase wires right out the vent holes on the sides.
 
OK Michael, Thanks for the warning.. would rather not open the motor at all' if it wasnt for the temp sensor - i could just make the 8AWG connection outside the motor case..
but if im going to be in there anyway..ill see if its possible - and post some pic's too.
Are the cases glued closed? also? it looks like it from the outside..
Tim
 
The end cases have a bit of silicone sealant around the flange. Nothing serious. The main thing holding everything together are all of the interference fits inside of the motor. When the motor comes apart it's always a crap shoot which will come apart first.

If you just want to access the wiring side of the motor actually it's not that hard. Remove all six allen case bolts. Use a drift to tap the thin back cover off of the main center case. There is a bearing in the middle of the case that is interference fit onto the end of the motor shaft. Be careful to move the back cover evenly so as to not damage it. Once you have opened a gap between the end case and center case, use two blade screwdrivers to pry the back case off, applying pressure from opposing sides. The interference fit between back bearing and motor shaft will make some scary creaking and popping sounds but should come right off. Once the back case is off you'll have full access to the motor wiring plus the best spaces for installing the thermistor.

I have replacement end cases if the worst happens. :D
 
Hello Mike,

I'm still waiting for an invoice for the spare parts.

I don't think that this is the right place to ask for it but you are not responding to my emails.

I can understend that you are busy but you are the only one that can supply spare parts for your kits.

Thank you
Rotem
 
LightningRods said:
Here's the new eccentric adjuster that I designed for the LunaCycle and Big Dummy drives. The first version of the Luna drive had an adjuster for the lower jackshaft that was almost impossible to reach without turning the bike over. This new adjuster is as simple to use as moving the tab to the correct detent. The jackshaft housing passes through the large hole in the center.

EccentricAdjuster.jpg
Click to expand...

the first pieces i made looked similar with relatively small pitch. Personally i am really happy if i can adjust the chain as precise as possible. In the end i used almost 270°and a pitch of around .5mm with more than 30 teeth. Sorry i have no pic at hand, below is one of the earlier ones, but it already has the fine pitch
I like the angled piece to push it with bare fingers!

file.php
 
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