LightningRods mid drive kit

Lots of questions. That’s good. The new drive has piqued your interest.

You can still have a freewheel on the right (pedal) side but it’s not necessary. The motor sprocket on the left just uses the B.B. axle as a convenient location to spin on its bearings. A regular ISIS spider will work fine on the right.

You can pedal without the motor running but you’ll be cogging it since the motor is directly connected to the rear wheel. Any time you have regen you’re going to be turning the motor when you pedal.

You can run the motor without pedaling. It will be like coasting on a regular bike. The freehub in the rear wheel will freewheel on the pedal side. Choose a pedal gear that matches your ground speed under motor and you can pedal along.

I’d like to see how possible it is to work with existing manufactured hubs before making custom billet hubs. The custom billet jobs are expensive to have made and if a cheap solution turns up I’ll be stuck with them. Simon’s approach is run a narrower manufactured hub and then space the rotor off of the sprocket. In the double left side rotor/sprocket setups I’ve seen, including the 165mm hubs I had made, the sprocket is inboard, the rotor is outboard. Here’s one of the available adapters: https://www.bicycledesigner.com/harmony-adapter---bolt-on.html

The prototype LHD drive shipped out to Simon yesterday. I’m having five more sets made the end of this week. I’ll post more photos once I have the parts.

This design really opens the door for higher power levels. Matt Shumaker has been running Astro 3220 power on the left side for many years. The difference with this design is that the kv of my motor is much lower and so the reduction can be way simpler.
 
Talking about the present setup, the first stage from motor to B.B. is 6.25:1. The B.B. driver sprocket is a 22t. Right now the rear wheel sprocket that I have with the 6 bolt rotor pattern is a 28t. That’s 1.27:1 for just under 8:1. That’s a nice all around ratio, especially with this much power.
I like belt drive and agree that this would be an awesome setup with a belt first stage. It’s a matter of packaging. I’ll look at options for belt drive. There would be less reduction in the first stage but that could be made up with a larger rear wheel sprocket.
How do people feel about pedaling without cogging vs regen? It’s an either or. An idea occurred to me today to work a freewheel into this mix if that’s what people want.
 
I would like a Peddle option with no cogging, I do that all the time on my bike with the little geared motor.
Regen on a bicycle for me does not make much sense, since I always let off the throttle long before coming to an intersection or a stop sign.
I can see how someone who races from traffic light to traffic light/stop sign , or who flys down hills very fast might like it though.

LightningRods said:
How do people feel about pedaling without cogging vs regen? It’s an either or. An idea occurred to me today to work a freewheel into this mix if that’s what people want.
 
Mike,

You have made this newer left side drive with your big block motor, on my next conversion I am trying to have the most power with the lightest motor possible. Like your small block or even a lighter weight RC motor, it does not have to be any of the expensive ones like the Astro, I talked recently with a RC Pilot and he said that H.K. has made improvements on their motors. I do not need the power some of your other customers need, 2.5-3 k would be enough with the lighter weight frame and street tires I have . And it would be nice to have something that goes fast , but only need a 6s/7s/8s pack at most to do that.

The advantage is I can fast charge a high c rate lipo as long is it is 6s up to 8s , 6s even faster with the current available chargers. charging now at 6.5 amps, would like to double or even triple that to make life easier.
 
Would like to see both available on the finished kit , as an option .

I would try regen if it did not add much cost and weight .

So a kit with a clutch, and a kit without .

How small and lightweight could a clutch be made ?


Powervelocity.com said:
Keeping regen would be critical for me, so I would not trade it for cogless pedaling if I had to choose. In theory, however, some kind of a clutch that disengages the drive unit from pedals would be great to have even more best of two worlds. In theory though. I don't know if that'll work well in practice until I try.
 
It’s interesting that you mention an RC motor because this LHD drive started out designed around a new RC motor that I have. I fell back on my tried and true motor because I saw my development time stretching too far out into the summer. Once all of the design work is done the RC motor might not work well. The small size and light weight is tempting, but will the motor handle the load of pulling a bicycle and rider without overheating or puking one of its little bearings? I’m really curious myself but intend to ease into that water.
I can make regen or freewheeling an option based on which bearing hub I install on the B.B. axle. I think that users going over 3000 watts would be wise to lose the freewheel more for reliability reasons than for the possibility of regen. I like regen as much for motor braking as for the recovered power. It’s crazy hilly where I live so regen is a big plus for me.
 
BTW, the small block would fit right into these mounts. It’s an inch narrower and five pounds lighter. If I ran a small block I would gear it lower and run at least 20s to have more rpm. The big block will pull more amps and so makes more torque with higher gearing and less volts. You can get 3000 watts out of the small block easy at 20s.
 
Interesting new kit. I was thinking about something similar, when I posted this: https://endless-sphere.com/forums/viewtopic.php?f=2&t=94605 My main goal would be mid drive regen.

Yet the feedback I got is correct pointing out the hassle of 2 chains on a single wheel. I did some simple test on my commuter, and getting the wheel out is really a mess - even more painful than a hub motor. Not to mention the difficulty to tension the chain, and the loss of the rear disc brake. Also, the second chain + 2 sprockets weights over 1KG! If we add it to the motor and drive-train weight, it come close to high power hub motors, which are much simpler to set up and very reliable. That's what stopped me from moving forward with this project, but maybe you can do things differently ?
 
Don't let other people's opinions discourage you. When I was just starting out a prominent ES blowhard informed me in no uncertain terms that 219 chain was too small and weak to handle the power of an electric motor. He further told me that someone else would have already thought of it were it feasible. I took the time to actually research the facts and found that 219 chain is as strong as much larger #35 chain and far stronger than bicycle chain. Four years later 219 chain is still serving me very well. Many DIY builders and several manufacturers now use 219 chain. Don't listen to "experts".

The hub motor vs. mid drive argument is too well worn to even bother going through again.
 
LightningRods said:
Don't let other people's opinions discourage you. When I was just starting out a prominent ES blowhard informed me in no uncertain terms that 219 chain was too small and weak to handle the power of an electric motor. He further told me that someone else would have already thought of it were it feasible. I took the time to actually research the facts and found that 219 chain is as strong as much larger #35 chain and far stronger than bicycle chain. Four years later 219 chain is still serving me very well. Many DIY builders and several manufacturers now use 219 chain. Don't listen to "experts".

The hub motor vs. mid drive argument is too well worn to even bother going through again.

Strange story; at least where I live 219 chain is considered bullet proof in the kart world. Anyway: as I said, I'm curious to see if you come up with a way to make life easier using 2 chains. My dream drivetrain would be all-belt: 20 mm industrial belt on the primary reduction, and centertrack gates on BOTH sides of the BB. Clean an powerful, plus it would eliminate the frame twisting of a single gates belt setup, which is often an overlooked problem. But finding 2 sets of cog + chainrings with different size, + 2 belts with the EXACT same length would be quite a challenge. And the price .. ughhhh

I also second what has been said earlier: it would be nice to have lighter motor options in the 1-2KW range. I saw one of those "small blocks", and I'm convinced the manufacturer could shave off at least 1Kg by making the shell thinner, and drilling hole in un-needed steel parts. Same goes for the bafang btw - not sure where this trend to overbuild motor casing comes from.
 
The karting guys call #219 “100 mph chain”. In their world the light weight of 219 let’s it spool up faster to higher speeds than the heavier #35. One thing about experts, their knowledge bandwidth is often narrow and they don’t like to venture out of their comfort zone. Go into a typical bike shop and try talking to them about your DIY ebike project.

Belt drive is clean, quiet and, when everything is set up perfectly, low maintenance. Alignment is critical, tension is critical, changing gearing requires not only a new pulley, but a new belt of a different length. As you observed in some types of belts, like the Gates Carbon Drive, the number of available belt lengths is limited. My first mid drive design had a belt primary with a tensioner that also allowed for belt lateral tracking. Almost all of my customer support work was helping people deal with belt adjustment. Those who got it wrong burned through $30 Gates belts at a frightening rate. Belt drive still interests me but I feel that I have to come up with an automatic adjuster to take the customer out of the adjustment equation. GNG tried a spring belt tensioner, but like most of their design work it was badly executed.

If you’ve looked at the Gates Carbon final drive belts much I’m sure you saw that the chain stays have to allow for the installation of the belt. Most bike frames can’t use it. It’s an elegant idea, especially in the lower power range. It does have a lot of limitations. It’s better for an OEM bike manufacturer than someone like me trying to retrofit onto a range of bikes.

Both of my present motors have lightweight aluminum cases. They weigh next to nothing. All of the weight is in the steel armature with magnets and the copper windings. I’m sure that some weight could be engineered out of the internals of these motors. The cases are not the problem. You’re talking ounces, not pounds.
 
qwerkus ,

I have been looking at mid-drive motor designs for a couple of years now, waiting for the newer, U.S. West Coast designed kits to become available . ( Tangent Dave's is available now but over my budget in price )

From what I have read there advantages, and disadvantages to each design

Example :

For a higher power and torque and travel speed mid-drive ... the left side with the kart 219 chain and sprockets would be best. Higher Power just destroy's a typical bicycle chain and chainrings and cogs. In the case of a left side system you power your way up hills.

For lower power set ups , like 2k and under and for someone who is easy on the gears the right side using the bicycles gearing/drivetrain is better , going slower and using less energy to go the distance. Frequent changes of the chain and chainrings and cogs is the downside of that design though.

The best design for me,
However it has not been designed yet ,
is a longer swing arm where a motor can fit on top of the swingarm right in front of the rear tire, where the sprocket of the motor is in line with the center cog of the rear cogset, and the cog of the motor and the rear cassette is made for a 219 chain . And ... where a newer designed rear derailleur is also made for shifting a 219 chain. In other words , Not , a bicycle drivetrain ... a new full # 219 drivetrain system.

This design will have the advantages of both systems . Although we might have to keep some spare Rear Hub Cassette Freehub Body .. Paws available to change out, until a newer designed custom rear hub is also made that will handle the higher power better.

Now I am waiting on someone here in the U.S. or Europe to make all this happen.

In the mean time Mike and others here in the U.S. are very busy on their current designs, which are an improvement over what else is available .

So for the present time, do you want to use the gears ? ( live near Mountains )
Mikes current right side drives using a small/medium/large block motor .
or
Do you want to go faster down the road / up hills , in which case the new left side he is working looks good.
 
I don’t want to sound like one of those expert naysayers that say things can’t be done. Here are some of the challenges in making a #219 cassette (I’m assuming with derailleur):
- In order for a derailleur to work the chain has to have a fair amount of side flex. From the reading I’ve done the chain also needs to twist on downshifts to larger sprockets. Sort of like lifting your inside butt cheek to get up into a tall truck. 219 has tight tolerances and thick side plates. It doesn’t side flex much and it twists pretty much not at all.
- A derailleur by design needs a chain that will tolerate a lot of cross chaining, or not running straight. If you get 219 even a little out of a straight chain line it runs super noisy and wants to derail automatically.
- The pitch of 219 is .303” instead of .500” like the rest of the derailleurs on the planet. This means making all new jockey wheels and cassettes.
- Even in the world of bicycle chain if you compare single speed chain and sprockets to derailleur chain and sprockets you’ll see that derailleur chain is weaker and more flexible, and that the sprockets have much shorter teeth that penetrates less in between the rollers. This contributes to chain skipping under power.
- A built in problem with derailleurs is that on the smallest sprockets, where the fewest teeth are engaged in the chain and loads are the highest, the cage spring is also the most slack. This combination of factors is why derailleurs fail hard when you’re trying to push a lot of power for high speed on an 11t rear cassette sprocket.
My personal OPINION is that the inherent design of derailleurs makes them unsuited to strong chains and sprockets, and therefore to powerful motors. Most internally geared hubs also can not take power too far beyond what a human can produce. The exception is the very expensive Rohloff Speedhub. I have several customers running 3000 watts through them with no issues.
Running a high powered single speed mid drive is a step towards being like a geared hub motor. High amps provide the torque and high voltage provides the speed. Low powered mid drives are way more energy efficient and more bicycle like. A high powered single speed mid drive or big hub motor is just going to murder the little shifter mid drives in terms of acceleration.
 
LightningRods said:
The karting guys call #219 “100 mph chain”. In their world the light weight of 219 let’s it spool up faster to higher speeds than the heavier #35. One thing about experts, their knowledge bandwidth is often narrow and they don’t like to venture out of their comfort zone. Go into a typical bike shop and try talking to them about your DIY ebike project.

Belt drive is clean, quiet and, when everything is set up perfectly, low maintenance. Alignment is critical, tension is critical, changing gearing requires not only a new pulley, but a new belt of a different length. As you observed in some types of belts, like the Gates Carbon Drive, the number of available belt lengths is limited. My first mid drive design had a belt primary with a tensioner that also allowed for belt lateral tracking. Almost all of my customer support work was helping people deal with belt adjustment. Those who got it wrong burned through $30 Gates belts at a frightening rate. Belt drive still interests me but I feel that I have to come up with an automatic adjuster to take the customer out of the adjustment equation. GNG tried a spring belt tensioner, but like most of their design work it was badly executed.

If you’ve looked at the Gates Carbon final drive belts much I’m sure you saw that the chain stays have to allow for the installation of the belt. Most bike frames can’t use it. It’s an elegant idea, especially in the lower power range. It does have a lot of limitations. It’s better for an OEM bike manufacturer than someone like me trying to retrofit onto a range of bikes.

Both of my present motors have lightweight aluminum cases. They weigh next to nothing. All of the weight is in the steel armature with magnets and the copper windings. I’m sure that some weight could be engineered out of the internals of these motors. The cases are not the problem. You’re talking ounces, not pounds.

Yes, already know that though I would no say that cdx belts are low power: I asked gates, and they say it's industrial grade material up to 3KW, though higher power means higher tension. My point would be: IF I get an expensive custom made mide drive kit, I'd want it to be fine tuned for belt use and ideally weight under 3KG for around 1000-1500W. The rest, I can take care of. But as mentioned: belt drivetrain is expensive, so I guess my next build will be either gates + bafang or chain + lightningrod ! So count on me to continue following your work.
 
LightningRods said:
I’m working on a Gates primary for this drive with automatic spring tensioner. Maybe you can have both.

Hmmm. AFAIK springs have a tendency to oscillate, and induce more slipping. You'd need a hell of a strong one, which is going to produce friction and lower the overall efficiency of the drivetrain.
Why not simply use a rocker design ? Out of all belt adjustment systems I saw, I find this the most elegant.

8pQ9gvm.png


Not sure if the (rough) image is clear enough: instead of moving the entire motor to tension the belt, you swing it laterally around a fixed pivot. There is no sliding bracket, so the entire thing can be fastened onto the lower tube like usual. The pivot bolt is the main anchor, and should be strong enough. The adjustment bolt can be coupled with a lateral screw (like this one) to make things easier

For an instance, here is how it works on bikes:

Alternator_Dropouts.jpg
 
LightningRods said:
You mean like the drive I'm building right now for the Surly Big Fat Dummy?

Well, if it works like the following pic, than yes:

fVRGfhA.png


Though I'd rather avoid an extra bracket around the motor, and directly use the motor-case threads as pivot / adjustment bolt, if possible.
 
Yep that’s how it works. Just like an old school alternator v-belt adjuster.

The motor case bolts are M5s. My pivot and cinch bolts are M8s. I like my setup.
 
Interesting, I should have mentioned that when I was thinking about a custom made # 219 chain compatible rear cog set , that I was thinking about about 5 speeds , and a derailleur that had a few machined parts that replaced regular parts that would handle the issues you talk about here.

If it is too much work to make / have made front sprockets and rear cogset that is # 219 chain compatible then ...

Another option is to use the new 8 speed chainring/chain/rear cog , that Sram made for E-Bikes.
And
Design a rubberized crush drive , like that used on the rear wheel of motorcycles , in order to soften the force put though the drivetrain .
For those who do not ride motorcycles here is a youtube video that shows what the crush drive rubber parts look like ... https://www.youtube.com/watch?v=aNTtmp-N1-E
I have been thinking about this for a few years now since I work on my motorcycle and after seeing on of these on my back wheel I thought there will be a place for one of these on a mid-high power bicycle in the future .
design a small version that is directly on the shaft of the motor. If it would be better somewhere along the drivetrain other than the motor then put it at the location that works out best.

I still would prefer a mid drive where the motor is located on the rear swing arm in front of the rear tire, and that will shift along 5-8 cogs on the rear cassette.
So then instead of a # 219 drivetrain, the E-Bike Specific drivetrain that Sram makes , along with a crush drive in the system.
And do not even have a 11 tooth rear cog, more like 13 t or 15 tooth as the smallest.

With a crush drive perhaps then a regular 8 speed cassette with the 11/12 and 13 tooth cogs removed and two larger cogs near the hub located , ( like what Wolf Tooth Designs makes and sells )
https://www.wolftoothcomponents.com/collections/cassette-cogs/products/49t-gc-cog-shimano-11-speed

( Made it 8/9 speed compatible though )


LightningRods said:
I don’t want to sound like one of those expert naysayers that say things can’t be done. Here are some of the challenges in making a #219 cassette (I’m assuming with derailleur):
- In order for a derailleur to work the chain has to have a fair amount of side flex. From the reading I’ve done the chain also needs to twist on downshifts to larger sprockets. Sort of like lifting your inside butt cheek to get up into a tall truck. 219 has tight tolerances and thick side plates. It doesn’t side flex much and it twists pretty much not at all.
- A derailleur by design needs a chain that will tolerate a lot of cross chaining, or not running straight. If you get 219 even a little out of a straight chain line it runs super noisy and wants to derail automatically.
- The pitch of 219 is .303” instead of .500” like the rest of the derailleurs on the planet. This means making all new jockey wheels and cassettes.
- Even in the world of bicycle chain if you compare single speed chain and sprockets to derailleur chain and sprockets you’ll see that derailleur chain is weaker and more flexible, and that the sprockets have much shorter teeth that penetrates less in between the rollers. This contributes to chain skipping under power.
- A built in problem with derailleurs is that on the smallest sprockets, where the fewest teeth are engaged in the chain and loads are the highest, the cage spring is also the most slack. This combination of factors is why derailleurs fail hard when you’re trying to push a lot of power for high speed on an 11t rear cassette sprocket.
My personal OPINION is that the inherent design of derailleurs makes them unsuited to strong chains and sprockets, and therefore to powerful motors. Most internally geared hubs also can not take power too far beyond what a human can produce. The exception is the very expensive Rohloff Speedhub. I have several customers running 3000 watts through them with no issues.
Running a high powered single speed mid drive is a step towards being like a geared hub motor. High amps provide the torque and high voltage provides the speed. Low powered mid drives are way more energy efficient and more bicycle like. A high powered single speed mid drive or big hub motor is just going to murder the little shifter mid drives in terms of acceleration.
 
I really like #219 chain, but the thing I like most about it is that the fine tooth pitch gives you more reduction in a smaller diameter sprocket. My 75t chainwheel 219 is about the same diameter as a 44t 1/2” sprocket. Space is almost always limited on a bicycle so compact is good. There are 1/2” chains that are as strong as 219, and stronger. They’re not bicycle chains.
The trick in building a strong derailleur type driveline is to build it so it shifts really crappy. I mean you can hardly get it from one gear to the next. That’s because the chain is too stiff and strong and the sprockets have tall teeth and no pins or ramps. The strongest setups typically need an old school friction shifter because the slick indexed shifters won’t shift them. As is often the case we want to go the opposite direction the pedal bike manufacturers are going. They want a slick shifting 11 speed, we want a high capacity 4 speed.
An intermediate solution is to use my original right hand drive version of the Single Stage. By using less motor reduction and then running on the larger rear sprockets we increase the power capacity of a normal indexed shifter cassette. The SRAM XG-899 works great with the RHD. You just can’t pedal with the motor.
I make two different swingarm drives now. Both of them have the motor under the swingarm because the lower shock mount is in the way on the top. It’s totally possible to design a swingarm that moves the shock mount to make room for the motor on top. So many projects, so little time.
 
Can anyone confirm if a Sabvoton controller works well with the lightning rods big block? Im about to order the big block single stage kit and would like to try a controller that uses FOC.
 
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