LightningRods mid drive kit

[emaayan]

is there a reason why you can't use the same trick with the 2 pushing bolts of the lower sheet, but on the upper sheet?

i mean have a plate connected between upper sheet really close the sliver allen bolt housing of the motor, and 2 short bolts pushing against the motor to counteract the forces trying to move the plates.?

 

[TriPhase]

For what it’s worth.

I read LightningRods long-view ‘At the End of the Day’ post yesterday, and from what I can tell he really nailed it on all points.

Before I go any further, let me say that I like the L-R Mid-drive A LOT. I’ve been following the drive’s development on E-S since the beginning of the year, and I put my order in for it a couple of weeks ago.

Anyhey, triangular load bearing structures are your friend; That’s why their used in bridges, cranes, the bicycle frame itself. And if large amounts of torque are in play, it’s best to keep the ’torque arm’ as short as possible. One could go the ‘Brute force’ method, but as Mike pointed out that would be a pretty inefficient solution that would add considerable weight.

No kit at this power level is really plug-and-play, and at this point it seems best to treat the situation as a ‘last mile’ problem. Depending on your bike and the power level you’re running, build an appropriate torque arm. I suspect most people who have been following this thread will have no problem doing this.

And then you'll have the coolest looking and performing mid-drive on the planet.

(Hey Mike, I know everyone and their monkey have given you suggestions for your drive design. And I know this suggestion would mean a major rework, but to shorten the secondary drive torque arm, how about just putting the jackshaft below the motor, not above? Yeah, I know... Sorry.)

Mike has been doing all the heavy lifting from day one, and I stand in awe. Issues come up and he addresses them, all transparently in this thread. And he cares about the people and kits that he's already shipped. Amazing.

 

[emaayan]

what about the rest who don't know how to build a torque arm?

 

[r3volved]

what about the rest who don't know how to build a torque arm?

This kit is clearly not for those people

 

[TriPhase]

Making a torque arm shouldn't be all that hard, it really just depends on your bike. One could attach a strut to the back of the upper sheet some distance from the down tube, use the down tube as the pivot point (not the best, but would work) and attach the other end to a solid midpoint some distance back in the frame. If it was located on the left side of the upper sheet the strut would then be in tension, for a strut that's better then compression. One can really build them in a variety of ways.

A number of posts ago one person used one of his flat bicycle tools as a wedge between the upper sheet, used the down tube as a pivot and over to the seat tube. Worked for him. Mike said

...If I were building one off custom bikes a torque brace would be simple. I could design a torque brace in 10 minutes and have one built in an hour...

Hey, emaayan, reading your posts I know you could do it no sweat.

 

[emaayan]

r3volved
i would tend to agree if this was written on the kit PRIOR to ordering, otherwise purchasing something online only to be notified you need to invest in building something else additionally to make it work is clearly bad practice, i'm pretty sure and hope that won't be mike's official response.

Making a torque arm shouldn't be all that hard, it really just depends on your bike. One could attach a strut to the back of the upper sheet some distance from the down tube, use the down tube as the pivot point (not the best, but would work) and attach the other end to a solid midpoint some distance back in the frame. If it was located on the left side of the upper sheet the strut would then be in tension, for a strut that's better then compression. One can really build them in a variety of ways.

A number of posts ago one person used one of his flat bicycle tools as a wedge between the upper sheet, used the down tube as a pivot and over to the seat tube. Worked for him. Mike said

...If I were building one off custom bikes a torque brace would be simple. I could design a torque brace in 10 minutes and have one built in an hour...

Hey, emaayan, reading your posts I know you could do it no sweat.

what you suggesting seems to already exists as part of another kit in bikemotive i'm hoping that's not it, because i have a triangle battery, and this would make a LOT more clumsy, then getting thicker plates.

they even sell it separately

unforutnetly their site seems to be done, but even if it was up, i could never order anything from them. no matter what address i specified.

 

[notger]

hi,

i see quite some solutions for the triangle issue in here

http://endless-sphere.com/forums/viewtopic.php?f=28&t=62397

i never used more than 2200 watts on mine and never had torque problems and did not even fix the whole kit at all on my downtube. (like you see on the photo)
BUT:
if you compare the short distance between the uppersheet-sprocket and the crankset-chainring in my "old"(not even existing anymore) kit

to this very long distance on the new standard version, and there are even longer extendend versions

in my geometrical understanding this long distance gives alot of torque on the whole setup, so instead of installing a torque arm i would bring the whole kit as near as possible back to the crankset again (like in the original gng kir or in the LRv1.1 sheets that i still use)

And also if you look at other high power mid drive kits like named before, they are extremely near the crankset and have very short chains there.
And an important point they made a lot of science and experiments around their kits (at least the guys from E-Go-Austria that I know)

So like said, i have fun building around and modding and also destroying this GNG kit.
And for sure it's nothing for people who do not have this fun, and rather have a ready to go kit.
But i agree in one point to emaaya,

Mike--> you should really inform people beforehand that your kit is nothing for people with no interest in screwing around !!

Emaaya -> just as an reminder again, I take your LR-kit whenever you give up!!

greets

Gernot

 

[fulmar]

hi,

every suggested solutions /torque arm or thicker plates/ boils down to stiffness of the kit. Simply said "the problem is not that torque force
exist, but that it is transfered to the places when it can't be handled properly". I suggest to redesign big tubes /spacers/ betwen left and
right sheet.Their end should be widenend somehow. Just my two cents.

 

[LightningRods]

Hey Guys,

Thanks so much for your suggestions. I took the afternoon off of the forum yesterday to de-tox a bit and to give myself a chance to think. I got my new halogen work lights installed so that I can see to make parts while underwater this winter.

This is a complicated snarl of rope to untangle. The geometry isn't hard. Most of you obviously get what's going on. Where it gets complicated for me is trying to deal with existing inventory, new ideas and parts that are obsolete before I can get them shipped. Thanks jdevo for making the point that we are trying to go places the humble GNG was never meant to go. I take that as no excuse, because I want to go there as much as the rest of you. I am not trying to make "a better GNG". I'm trying to make a kick ass mid drive that resembles the GNG like a Porsche 996 resembles the original VW bug.

So to untangle this trucker's snarl and move things forward I've come up with two different solutions. The first uses my existing parts supply, gets my inventory cleared out, and ships kits as quickly as possible. The second is a clean sheet rework that tries to jump from fixes to solutions. I'll make all of the upgrades as retrofittable as possible. The reason that my reworks haven't been more radical in the past is that I hate planned obsolescence. I'm so sick of computer and software companies I'm about ready to go unibomber on them. I will do my best to leave as few people behind as possible.

I realized yesterday that we can double up on the upper sheets. That is, two sheets can be installed side by side on each side. That takes the metal thickness from .1046" to .2092". That's the equivalent of 5 gauge steel. Brute force enough for ya? I'll have to modify a few minor parts and the second reinforcing right hand sheet can't go all the way down to the motor bolts, but we should be looking at a 2x strength increase right there. Bam!

On the bottom sheets I've already started modifying the adjuster brackets to have two adjuster bolts rather than just one. This is really a fairly simple fix. I'll fit the best hardware that I can to the current sheets and with the two bolt adjusters we're going to call that good enough for People Who Know How To Use Hand Tools. At least until I ship my current stock and get new sheets in.

Next phase- the gloves are coming off. I have had just about enough of this GNG crap and intend to send the last of the gremlins back where they came from. There will be newly designed sheets, thicker metal, bigger and better hardware, a totally new upper frame mount, and an optional TORQUE BRACE for you freaking loonies who can't wait to get on to the business of cooking motors. Seriously. What is wrong with you? :wink:

Those of you who play nicely, who try to help the group and not play pin the tail on the horse's ass with me, will get lavish preferential treatment and awesome parts. Those of you who annoy me, who make a mess of things and blame it on me, will not.

 

[LightningRods]

if you compare the short distance between the uppersheet-sprocket and the crankset-chainring in my "old"(not even existing anymore) kit to this very long distance on the new standard version, and there are even longer extendend versions
in my geometrical understanding this long distance gives alot of torque on the whole setup, so instead of installing a torque arm i would bring the whole kit as near as possible back to the crankset again (like in the original gng kir or in the LRv1.1 sheets that i still use)

The distance between the driver and driven pulleys was much too close on the GNG, and contributed to the pulley skipping. I like the compact design too, but it doesn't allow enough room for the belt drive.

I don't have longer than stock upper brackets, I have longer lower brackets. Many of the new bikes have a curving front downtube that makes the motor hang down much too low. The long lower bracket gets the motor past the frame curve and higher up for better ground clearance.

 

[spinningmagnets]

an optional TORQUE BRACE

For those who are new to this thread, and who may incorrectly assume that this kit should have had a torque brace from the beginning...Christerljung has used 100V on a modded GNG and has been popping wheelies in Sweden from the very start.

But concerning using this kit at 50V X 25A = 1250W (the minimum I recommend, and also what I will be using), it's not so much the input watts that this kit is about. It the torque that results at the rear wheel when climbing a steep uphill (the kind that melts other motors). Imagine a given motor with a 1:1 sprocket set driving the left side of the rear wheel at "X" input watts

Now take that same size and model of motor and select a Kv with fewer wraps of thicker wire so that it spins exactly twice as fast at the same input voltage and watts. Then...swap-in a 2:1 reduction to the rear wheel. The result has the motor spinning twice as fast, but the input watts and rear wheel speed is the same. However... rear wheel TORQUE has been dramatically improved (almost twice as much).

The original GNG motor (about 10% smaller than the current small block LR), uses a 21:1 reduction, but Mike? he is using a 33:1 reduction. Chew on that for a minute. Some guys will be using 72V-100V (and it's a fun world because of these pioneers), but...when using an affordable and easily "fit-able" 50V pack...the rear wheel torque will be off the charts.

 

[notger]

Yess, that are words !!!

someone once saied you are too good to ignore a specific active member in this thread (not beeing named now )

And now we can see what this steel-hard ebike buisness made out of you a real man an not a helpful and understanding wimp anymore (joke)

For real,.. i'm very exited what yor further developements are and i'm always willing to buy some of you old stock stuff whenever you do not need it anymore to weld and file around again.

greets

 

[emaayan]

notger stop looking at my kit, you a'int getting it (well at least not until i'll get better parts) if you think i've been waiting for 6 months for something just to hand it over after 3 weeks, you clearly under-estimated my obsessive factor. as long as their a deterministic solution that doesn't require me to start experimenting on creating parts on my own, i'm here to stay.

i like screwing around, building this kit reminded me of my old lego days, but i draw the line when it comes to resources and knowledge i don't have, like welding, and creating new parts.

mike i'm glad you're going for the thicker plates, i've already emailed you about the new sheets ,but i'm willing to wait the required time plus my annoyance factor for the improved lower and upper sheets as well as the new pulley, i already have 2 planetary gears on reserve and i'll try to take it easy on my current one . i'm guessing the waiting time would be around 2 months or so. once i get all the new parts i'll sell notger my current ones.

the next stage seems to fit usages of 72v and beyond volts and using those to the fullest sound like they destroy my gears before the they twist the kit, so i'm not really anxious about that, i just wanna commute to work in 1-2 pieces, not race on the highways.

 

[jdevo2004]

.
I realized yesterday that we can double up on the upper sheets. That is, two sheets can be installed side by side on each side. That takes the metal thickness from .1046" to .2092". That's the equivalent of 5 gauge steel. Brute force enough for ya? I'll have to modify a few minor parts and the second reinforcing right hand sheet can't go all the way down to the motor bolts, but we should be looking at a 2x strength increase right there. Bam!

I am so glad to hear this. Just to be clear are you going to tack weld them together? If so, then sign me up for some new thicker upper sheets, I want now!

I am glad you have taken my critique of the problem as constructive rather than personal. I have been playing with this kit for a couple of months and have been out on the trail riding it hard almost every day that I can. I just came back from a 1.5 hour ride just now. I am having a blast with the kit and just because I am noticing some small issues that need to be addressed does not mean that I think the kit is bad or that you have done something wrong. The great thing about this kit is that we as a community can speak directly with its creator and affect change for the better.

Seriously though, I want to buy the upgraded sheets asap.

 

[LightningRods]

Jdevo you're a good developer. I think that you can help us make this kit better.

My plan is to drill holes at strategic spots on the additional inside sheets and then plug weld through to the outer sheet. They are already held together by the jackshaft and other parts but I agree that they will be more rigid if they can't slide against each other.

I'm finally starting to get some good design ideas flowing. I think we're going to whip this. I'll post concept drawings as soon as I can.

 

[sparkz]

The original GNG motor (about 10% smaller than the current small block LR), uses a 21:1 reduction, but Mike? he is using a 33:1 reduction. Chew on that for a minute. Some guys will be using 72V-100V (and it's a fun world because of these pioneers), but...when using an affordable and easily "fit-able" 50V pack...the rear wheel torque will be off the charts.

Yes! This is what I have been waiting for. I am determined to build a monster climber of a bike. I have a geared hub motor setup with 5:1 internal reduction, and have almost melted it at 2000W several times on the trails in Marin. Not to mention having to replace the gears every few months. Mike's kit is not just for would-be land speed record holders. Serious "mountain ebikers" should be camping out in front of his workshop.

 

[t0me]

That's my preferred use too. 40km/hr is great for me, but working through tight technical single track needs low gearing.
My kona works great. I'm expecting my L/R Giant Anthem to be even better, with more juice on tap, and quieter too.

Looking forward to building it

Got everything except the LR kit now! The waiting is killer, so frustrating!!! patience is a virtue though and I suspect that the longer it takes to ship, the better it'll be when it does.

 

[Gab]

Mike's kit is not just for would-be land speed record holders. Serious "mountain ebikers" should be camping out in front of his workshop.

I don't think it will be any speed demon from the first build reports it may have a lot of torque but not speed , from the recent build here:

http://endless-sphere.com/forums/viewtopic.php?f=28&t=61364&start=25

by givitago » Mon Oct 20, 2014 10:53 am

So I tried upping the phase amps on my controller. It did increase acceleration slightly but still did not rival the Mac. I think I can accept that this kit seems more like a tractor than a dragster.

jdevo2004 wrote:
Up your watts to 2000 and see how that affects acceleration? Is your cycle analyst set up properly? Throttle out up rate 20 volts, Throttle out down rate 20 volts, Throttle out fast rate 20 volts, Throttle out fast thrash 0.00 amps. Power limit Amp Gain 60, Power Limit Watt Gain 60.

Yes, that is what I did when I reprogrammed the controller. It did help some, but not enough for me to sacrifice the difference in range. For the most part, I only notice the slower acceleration on the road so I can live with it. Regarding the CA, I tested with pass-through mode which shouldn't have any power limiting. I have a very fast ramp rate setup as well. I think perhaps the MAC motor is just a snappier/more efficient motor. I"d expect it to be as there are fewer moving parts.

 

[sparkz]

Watched the video. The bike had no trouble on the gnarly uphill sections. None of the groaning (litteraly) and grinding noise my bike makes. I can't wait!

 

[Nacent]

I'm not Sure thicker sheets is the best solution for further production kits,but it will probably work it will be kinda heavy and it's not ideal placement of material for good strength to weight ratio. This is a case where adding thickness isn't as effective as adding a web. Two plates separated by a distance have a very poor torsional rigidity but if you add a web that connects the two you increase the torsional constant a fair amount with little material.

I did some quick FEA on an approximate model of the sheets to give an idea of what sort of twisting is happening and to give me an idea where to place material based on where the highest stresses are.

I would suggest adding webs something like this they could be a bolt in thing on one side, if your looking for a weld-less design. It reduces the stresses and displacement by 40% and would require alot less material. doubling the thickness of the sheets reduces the stress and displacement by 60% so it will work but wouldn't be preferential to those looking for a light kit. In any case if your running anything over 2000w i'd imagine something needs to be done as its causing fairly significant plastic deformation.

 

[LightningRods]

Excellent analysis. I totally agree with the correct geometry vs. thicker/heavier material approach. I may end up doing a blend of both approaches.

 

[spinningmagnets]

I don't think it will be any speed demon from the first build reports it may have a lot of torque but not speed

Where this kit really shines is on an off-road full-suspension hill-climber. That being said, the chosen factory gearing, and the fact that Mike worked very hard to make sure to include two chainrings...it shows that he is focused on the first round of production kits appealing to the off-road crowd. A crowd that he is very familiar with since he lives in Oregon.

If you change the #219 drive sprocket from a 12T to an 18T, the reduction goes from 33:1 to 17:1...which roughly doubles the rear wheel top speed without change the entire system to a higher voltage. There are other tooth-counts available to fine tune the system to your personal desires, but...if it is a street speed E-bike you want...72V should easily provide 40-MPH with the motor barely getting warm.

 

[Gab]

If you change the #219 drive sprocket from a 12T to an 18T, the reduction goes from 33:1 to 17:1...which roughly doubles the rear wheel top speed without change the entire system to a higher voltage.

But doing that wouldn't it mean you lose half the torque and also double the load on everything ? it seems people are having flexing problems now, if you double the load it will surely cause lots more problems ?

 

[LightningRods]

But doing that wouldn't it mean you lose half the torque and also double the load on everything ? it seems people are having flexing problems now, if you double the load it will surely cause lots more problems ?

You'd halve the torque and halve the load. I don't recommend it. I'm working on fixes now that will stop the flexing. Stand by.

 

[Gab]

You'd halve the torque and halve the load

Surely if you double the top speed you also double the load on the whole system and not half it?