LightningRods mid drive kit

notger said:

LightningRods said:

62 rpm/volt for the Big Block
67 rpm/volt for the Small Block

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since one week I'm owner of an adaptto, an just tried it with my gng-mutant.
The adaptto has a feature called "autodetect" and it "detects" my orignial GNG to be 55 KV ?
might adaptto detect wrong, or did anyone of you ever check the KV of the LR or GNG Motors?


is there actually a Motor diagramm about this kind of motor somewhere around ?
Cause i just recently did some changes on my kit, and tried to calculate the cadence beforehand.
I'm still using bike chains in the secondary stage and 60Volt.
luckiely reality beatet mathematics and the calculated cadence of 245 rpm and 104km/h was not reality.
so i guess without diagramm and knowing the motors most efficient "zones" i can not make any realistic calculations.
But those calculations were made with 67 KV, who knows it might be 55, like adaptto "autodetected"

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I like reality best. Any engineer will tell you that things rarely work out exactly like the "specs". I suggest hooking up the motor to a drill and using a tacho and DMM to find your Kv.

spinningmagnets said:

There are about 6 billion people on this planet, and one billion or so speak Chinese.

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I reads this. It seemed outdated and I was compelled to look it up.
Current word population is 7.4 billion and about 1.4 billion are Chinese.

eTrailster said:

spinningmagnets said:

There are about 6 billion people on this planet, and one billion or so speak Chinese.

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I reads this. It seemed outdated and I was compelled to look it up.
Current word population is 7.4 billion and about 1.4 billion are Chinese.

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Ooh! Thanks for the clarity check! That made it all worth while. ;P

ElectricGod said:

I like reality best. Any engineer will tell you that things rarely work out exactly like the "specs". I suggest hooking up the motor to a drill and using a tacho and DMM to find your Kv.

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is there any "turorial" on how to measure motor KV exactly (with all the tricks and traps) ?
i could not find on in ES with the search function.

notger said:

ElectricGod said:

I like reality best. Any engineer will tell you that things rarely work out exactly like the "specs". I suggest hooking up the motor to a drill and using a tacho and DMM to find your Kv.

Click to expand...

is there any "turorial" on how to measure motor KV exactly (with all the tricks and traps) ?
i could not find on in ES with the search function.

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Go here and look up the "Drill Press Method". I use a cordless drill instead, but the results are the same.

http://www.bavaria-direct.co.za/constants/

low powered fun

[youtube]UPCC2Xweu4U[/youtube]

Here is my Big Block bike,
Giant DH comp
Monster T forks
Chris King hubs and headset
Hope 6 pot front brake 225mm rotor
Hope V2 rear brake 203mm rotor
3 speed cassette with 1/8th chain
32ah at 18s onboard

Santa came today...

I'm really lucky or something. I got a big block and a new girlfriend all on the same day!!! I'll have to convert her away from ICE! Breaking away at the intersections and leaving the cars in my dust should be convincing. 8)

cheekybloke said:

Here is my Big Block bike,
Giant DH comp
Monster T forks
Chris King hubs and headset
Hope 6 pot front brake 225mm rotor
Hope V2 rear brake 203mm rotor
3 speed cassette with 1/8th chain
32ah at 18s onboard

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That is a cool looking ride! I'm a bit jelly!

Love the look of the bike Cheeky. Can't wait to see how she performs. Especially a vid of you changing gears...

Only odd thing is the hookworm at front. But you are not going off road so... wouldn't matter.

Very nice build Cheekybloke! Did you have any issues installing the lightning rod mid drive kit to your frame? I have a free ride with a 40t chain ring, measures about 16cm in diameter. The ring just clears the frame bar that goes to the rear wheel. If the chain rings on the mid drive kit protrude out by a few cm from the BB then I shouldn't have any issues of the rings coming in contact with the frame. I have a 68 mm BB. Emailed Mike with the same question and some images but still waiting to hear back. Really looking forward to trying out the big block on my setup, I imagine Mike's pretty busy with orders this time of year.

ubergebertstag said:

Very nice build Cheekybloke! Did you have any issues installing the lightning rod mid drive kit to your frame? I have a free ride with a 40t chain ring, measures about 16cm in diameter. The ring just clears the frame bar that goes to the rear wheel. If the chain rings on the mid drive kit protrude out by a few cm from the BB then I shouldn't have any issues of the rings coming in contact with the frame. I have a 68 mm BB. Emailed Mike with the same question and some images but still waiting to hear back. Really looking forward to trying out the big block on my setup, I imagine Mike's pretty busy with orders this time of year.

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He's been pretty responsive to me. I've e-mailed him a couple of times today and gotten responses.

ubergebertstag said:

Very nice build Cheekybloke! Did you have any issues installing the lightning rod mid drive kit to your frame? I have a free ride with a 40t chain ring, measures about 16cm in diameter. The ring just clears the frame bar that goes to the rear wheel. If the chain rings on the mid drive kit protrude out by a few cm from the BB then I shouldn't have any issues of the rings coming in contact with the frame. I have a 68 mm BB. Emailed Mike with the same question and some images but still waiting to hear back. Really looking forward to trying out the big block on my setup, I imagine Mike's pretty busy with orders this time of year.

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Thanks for the kind words, my bike took a long time and a lot of pennies.
Not to mention many hours of head scratching.
R.E bb question, all bikes have different chainstays so chain ring spacing would be slightly different on every one.
The kit from Mike will pretty much bolt straight on if you can use a spanner and have any common sense with a bike.
Darren, the Cheeky One.

My new hub was born 25/4/2016.
[youtube]pSPOXidWVwM[/youtube]
I only pray it lasts at least a month. After I posted my idea on this thread about an off road race, I put it into action. I have about 4 other riders who have said they are attending. This will be a true test with out analogies about cars and what not... I designed the course which is the normal stuff I do. I have an advantage there and know the terrain. But will the bike hold up? I hope I win! I am running 3kw 10ah, some of these guys are like 20ah 5+kw, so I will get blown out of the water, but imagine myself like the hare and the tortoise with heat management.

The event is in a month https://www.facebook.com/events/1181918735175952/

I see, it will be 10km NW of Brisbane. Nice idea and good luck.

I rode the southern part of the race track yesterday on 30a. You can see how much it bogs down. I was keeping it under 2.5kw for longevity, but race day will need that extra 10a. Not only that to have a real chance I need to add in a couple of teeth or drop a couple... First choice, would love to go to 32t at front but paco at cyclone charges $100au for 2 sprockets.... the 32t would enhance pedal cadence too.
I have an 18t instead of 20t rear sprocket, but I really don't want to lose teeth = I might start skipping again or chain slap on swing arm will increase....

Other option is an extra tooth on the JS.

This vid has the gopro out of the case which is great for sound quality, at 30a you can really hear every change in elevation. 4kw is my ideal but most probably will kill something again...
[youtube]wwAmTBrSUTY[/youtube]

Good to see you back in action john.

LightningRods said:

...You may find that a Corvette with rear transaxle can run a smaller driveshaft inside of it's torque tube, but the rear axles will have to be the same strength as a 'Vette with a front mounted transmission. Once the motor goes through reduction, wherever it happens, torque increases.

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Yes, the rear axles would have to be the same strength, but is that a common point of failure on an ebike? With a large reduction up front, I'm mainly concerned about fatiguing chainstays/seatstays and secondarily breaking chains and wearing out chainrings/sprockets. I'm not sure what sprockets everyone is using in the rear, but if people used larger rear sprockets (like those available in the 11-42T cassettes) and/or smaller motor-to-crankset chainrings, people could run their bike chain faster, reducing the load on the chain and other components. I doubt people are using their largest rear cog in 3000+W systems, so this could mean they could run a slightly lower reduction up front.

This concept has already been tested over in the Cyclone thread. There is one user running the motor to a 44T on the crankset while a 48T drives the cassette. Because of this, he can use larger sprockets in the rear cassette, and the strain on the chain is significantly reduced. He's running 6600W.

I also recall a thread about running a LightningRods mid drive at high power, and they were breaking the swingarm pivots of their full suspension frame, so they resorted to using a solid bolt. If they ran less of a reduction, I imagine they wouldn't have broken the swingarm pivot.

LightningRods said:

With a lot of my more recent mid drive designs I've been intentionally not running the motor power through the chainwheel.

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But then you can't shift gears anymore unless you add a dedicated transmission for the mid drive right?

LightningRods said:

On a conventional mid drive we reduce the motor 30:1 and then overdrive it back up 1:4. It's much better to run a straight 8:1 reduction on the motor and avoid all of that stress at the chainwheel.

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You could also run a lower ratio so that you wouldn't have to overdrive it as much. This way the motor can still use the bike's gears.

LightningRods said:

For the same performance, whether the watt ratings are the same or not, a high rpm system and a low rpm system have to produce the same twist (torque) at the rear wheel.

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True, but what would you say are the most common failure points?

robocam said:

People keep talking about a power limit of bicycle components, but torque is what kills components, not power. You could just speed up the chain to increase the power without putting additional strain on the chain. For example, if you ran a higher voltage to get things spinning faster, your components shouldn't be under as much stress (assuming you also run less current so that the torque is reduced).

This is the concept behind the torque tube (equivalent of a driveshaft) in the Corvette. It turns at engine speed. It doesn't have its torque multiplied by the transmission because the transmission is in the back over the rear wheels. Because of this, it is of a much smaller diameter than a typical drive shaft.

People need to be running their motors and chains faster to make components last longer. How do you do this? You run smaller bike chainrings up front and use larger sprockets in the cassette. You're not likely to break a chain by running it faster, but you sure will break it if you pull too hard on it.

So what I'm saying is that people should try not to always equate certain wattage levels as automatically being dangerous to bicycle components.

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John Bozi said:

...Not sure if you mean less reduction on the jackshaft? You could do that with a bigger sprocket on the right side and a bigger rear sprocket. I am not sure if you are running this kit and how you go about pedal cadence...

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I'm referring to anything that would reduce the strain on the chain. I used to care about pedaling. Now, not so much. My input is insignificant compared to the thousands of watts of power from the motor.

John Bozi said:

...power or torque still needs to meet the rachets and pawl system somewhere regardless of sprocket sizes if you want a decent top speed.

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I'm not sure I understand what you're saying. If you reduce the gear ratio to reduce the strain on the chain, it will result in your having a higher top speed.

don't think you are either

I for one have no problems with the chains and sprockets.

So forget talking about them as being the weakest links.

Forget everything and concentrate your focus on one point.

The rear hub mechanism.

Dump 5kw into it. I have done that and everything else was doing it's bit, but that mechanism doesn't careless what sprockets and chains were doing. That bit doesn't care what voltage or amperage was running.

That bit just knows 5kw is smashing its little rachets, pawls and bearings.

Not sure how else to explain this to you.

I was not aware that people were having issues with the rear hub. That would explain your video. What hub did you blow up before? I was initially concerned about my freehub, so I bought a spare, but I've never needed it.

The reason I want to reduce the strain on the chain is because I can see my chainstays flex when I apply power. I do not want my aluminum chainstays to snap from fatigue while I'm at speed. I don't have any immediate problems with chains or sprockets either, but reducing the strain on the chain will allow certain components to last significantly longer.

John Bozi said:

...I for one have no problems with the chains and sprockets.

So forget talking about them as being the weakest links.

Forget everything and concentrate your focus on one point.

The rear hub mechanism.

Dump 5kw into it. I have done that and everything else was doing it's bit, but that mechanism doesn't careless what sprockets and chains were doing. That bit doesn't care what voltage or amperage was running.

That bit just knows 5kw is smashing its little rachets, pawls and bearings...

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I've done both a Mavic and Nuke proof. Both would have experienced at some point in their short lives 4-5kw. Even if for a short periods. There is really no way in the world to compete with a hub motor on an off road race unless you were going to do 3 metre jumps or continuously climb only.

My question to you is how much power are you running through which hub too?

As for swing arm flex or chain stays and pivots warping. I am totally with you now. you are speaking of concerns high powered mid drives have to deal with that hub motors don't. Yes a hub motor will make suspension squat as it shoves the bike forwards but it doesn't do what a mid drive do: pull the swingarm forward toward the bottom bracket. This is what I was trying to explain to SM as a perpetuated myth that he is apart of. High powered Mid drives are not essentially better at dealing with suspension issues. They are at low power or when not powered on his roller coast rides but when it comes to loading the power on car analogies don't cut it.

John Bozi said:

I've done both a Mavic and Nuke proof. Both would have experienced at some point in their short lives 4-5kw. Even if for a short periods. There is really no way in the world to compete with a hub motor on an off road race unless you were going to do 3 metre jumps or continuously climb only.

My question to you is how much power are you running through which hub too?

As for swing arm flex or chain stays and pivots warping. I am totally with you now. you are speaking of concerns high powered mid drives have to deal with that hub motors don't. Yes a hub motor will make suspension squat as it shoves the bike forwards but it doesn't do what a mid drive do: pull the swingarm forward toward the bottom bracket. This is what I was trying to explain to SM as a perpetuated myth that he is apart of. High powered Mid drives are not essentially better at dealing with suspension issues. They are at low power or when not powered on his roller coast rides but when it comes to loading the power on car analogies don't cut it.

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A well designed middrive would get around those issues. Either by having the motor on the swingarm near the pivotpoint, behind or infront. Or by having the pull vector inline with the swingarm.
That will remove almost all tendencies to compress any suspension. The crucial point is that unsuspended mass destroys handling when it starts to get bumpy.

What is it about hub motors that make them superior in an off road race?

I'm not running as much power as you are ("only" around 2400W), and I'm using a Shimano M756. But I do have a 42T cog in the cassette. When I had my motor (a Cyclone) going to a 48T on the crankset, even with 29" wheels, my bike was popping wheelies even using the middle gears of the cassette (they were driven by a 32T on the crankset). So then I reduced the 48 to a 44, and that tamed it down a little. This is why I can't see people using their largest rear cogs with high power ebikes (3000+W).

For now, I bought a Cycle Analyst to limit my speed (I can't control myself), so that I won't kill myself. I have this fear that my chainstay will eventually snap. I'm not limiting the current because it's just too much fun. For all I know it may last several years like this, but seeing the rear go sideways scares me (like seeing an airplane wing flap around). I have considered a steel frame, and I'm also looking into downhill frames. My current frame is a Trek HiFi Pro 29.

John Bozi said:

I've done both a Mavic and Nuke proof. Both would have experienced at some point in their short lives 4-5kw. Even if for a short periods. There is really no way in the world to compete with a hub motor on an off road race unless you were going to do 3 metre jumps or continuously climb only.

My question to you is how much power are you running through which hub too?

As for swing arm flex or chain stays and pivots warping. I am totally with you now. you are speaking of concerns high powered mid drives have to deal with that hub motors don't. Yes a hub motor will make suspension squat as it shoves the bike forwards but it doesn't do what a mid drive do: pull the swingarm forward toward the bottom bracket. This is what I was trying to explain to SM as a perpetuated myth that he is apart of. High powered Mid drives are not essentially better at dealing with suspension issues. They are at low power or when not powered on his roller coast rides but when it comes to loading the power on car analogies don't cut it.

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How does one design a middrive around those issues? You can choose a frame that might better suit your application, but all a middrive does is turn your crankset. A typical full suspension frame is designed to minimize pedaling-induced suspension bob, and they do this by placing the pivot point where they think you'll use your chain the most frequently (typically the 2nd chainring up front, around 32T). Since you can shift gears, there's no way the pivot point can be placed in a location that eliminates pedaling-induced suspension movements in all gears. But that's not really the issue.

The main issue with middrives is that the chain pulls on the right of the rear wheel, so there is no way to eliminate that counter-clockwise rotational force the rear triangle experiences. The middrive will always be trying to pull the rear to the right. The only way around this is to either put the rear cog in the middle of the rear wheel (not possible), or drive both sides equally (by having a cassette on both sides).

Also, the right chainstay can fail due to forces of compression, especially if your chainstay isn't straight. Mine is not straight, and I can see it bend. My frame is virtually identical in design to the one in this photo (mine is aluminum).

http://fcdn.mtbr.com/attachments/29er-bikes/860373d1388980885-2011-trek-superfly-100-elite-frame-image.jpg

As you can see, the right chainstay is curved. When I apply throttle and brake, I can make the curved part touch the bottom bracket. If my frame breaks, I will look into something tougher like an all mountain or downhill frame. I just hope it doesn't snap while I'm at speed.

Wheazel said:

A well designed middrive would get around those issues. Either by having the motor on the swingarm near the pivotpoint, behind or infront. Or by having the pull vector inline with the swingarm.
That will remove almost all tendencies to compress any suspension. The crucial point is that unsuspended mass destroys handling when it starts to get bumpy.

John Bozi said:

I've done both a Mavic and Nuke proof. Both would have experienced at some point in their short lives 4-5kw. Even if for a short periods. There is really no way in the world to compete with a hub motor on an off road race unless you were going to do 3 metre jumps or continuously climb only.

My question to you is how much power are you running through which hub too?

As for swing arm flex or chain stays and pivots warping. I am totally with you now. you are speaking of concerns high powered mid drives have to deal with that hub motors don't. Yes a hub motor will make suspension squat as it shoves the bike forwards but it doesn't do what a mid drive do: pull the swingarm forward toward the bottom bracket. This is what I was trying to explain to SM as a perpetuated myth that he is apart of. High powered Mid drives are not essentially better at dealing with suspension issues. They are at low power or when not powered on his roller coast rides but when it comes to loading the power on car analogies don't cut it.

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