LightningRods mid drive kit

[--freeride--]

I would prefere a bike that has a flatter steering angle, 68°deg is state of the art on fatbikes that are good for high Speeds(e. g. surly Icecream truck). Although a more straight tube design.

Lol "state of the art" fatbikes built for speed? Forget steering angle...can you point me out to some speed rated fat bike tires?

I have done 50mph on the Luna Cycle frame pictured below with an astro mid drive and it felt stable on street use. 5 years ago i had a electric pugsley that could go 35 and it did not feel as stable and it was the motivation for building this frame. The mid mount motor bay, centralized battery pack, and stretched frame is the key. The lengthened cargo bike like frame make the bike remarkably stable at high speed and makes it less prone to unexpected wheelies at high power.

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Sorry I did not won't to offend the General concept of the Frame, i rode a real Long bike last year and it was the most stable bike I ever had.

A flater steering angle also makes a bike more stable, espacially at high speeds.

I did not mean to use a Icecream truck for the System, just the icecream truck has a newer Geometrie with a flater steering angle. A pugsly has an oldschool geometrie compared with the icecream truck.

I used a lot of angle Headsets
http://www.workscomponents.co.uk/
in my builds in the last year. That always made the bike feel more stable.

68° is an good angle for an Fatbike.

 

[LightningRods]

This is a good quick read about bicycle and motorcycle frame geometry.

http://calfeedesign.com/tech-papers/geometry-of-bike-handling/

In addition to having overly quick steering for high speed runs bicycle frames are also prone to flexing, which at high speeds can get pretty terrifying. If you've ever gotten into a "high speed wobble" on a long steep downhill on a bicycle you know what I'm talking about.

 

[stonezone]

Soooo....apparently under heavy acceleration, my 2 single speed cogs were slipping on the freehub body occasionally. I tried for about an hour to drill them in an attempt to bolt smaller cogs to the outside of each in order to expand the base, but apparently I need unobtanium drill bits, more time, or a tig...

Oh yeah I have a tig (I forget I have superpowers sometimes, what a dream tool)! In about 10 minutes I joined a 15t to each of my 20t cogs (didn't even need filler, the teeth worked.). I clamped each to the welding table to keep them from warping as much as possible. There was very minor distortion on each (flaring out toward the welded cog) that kept the 3/16 chain from seating as smoothly as before. A few minutes on the grinder and we have smooth operation again.

There is a bit of damage on the freehub body from the previous slippage, but it seems much more solid now. I think I may even add one more cog to each side to make extra sure it wont slip, ever. As of now, it doesn't seem to have any issues, but It may still under heavy load until I replace the body, and add the 2 cogs (after that there's no way it's going anywhere).

Right now, the 20t tops out at 20mph which seems slow for the road but will probably be perfect for trails and keep climbing under control. It's also keeping the battery draw way down so range should be decent.

I think I'm finally at a point where i can take this thing to the trails by my house and get off the road... I'll report back again and post some photos of the cogs, but anyone going single speed should do that.

I also worked out the tensioner, it's still slightly less than ideal and I have a buddy with CNC that is going to hopefully cut a model I have in mind that would be perfect.

 

[LightningRods]

I'll be interested to hear if you have the off the line and hill climbing performance you want with a 25 mph top speed. I would think the big block would make that possible, even at 48-50V. I'm planning a single run on my Lunacycle with a 35 mph top speed. That's going to be mostly a road bike though with very little low speed climbing.

 

[stonezone]

If you mean fun, steep trials-type/moto hills, then I don't think it will be doable without a clutch to maximize traction.. It's too easy to lose traction with the bike being so light and so much torque, without a clutch fine tuning your grip once momentum fades. I still need to spend some time really trying to dial in the throttle with my CA, but even best case I don't think it will give me control I need to maintain momentum over the bumps on a steep climb. Low speed and high speed control is still something I need to wrap my head around...

Do you know of any lightweight, manually operated clutch solutions that would be applicable to high powered ebikes? It wouldn't even have to be a wet clutch, a couple of dry plates might work since it would be used a lot less than regular vehicles since weight is so much less.... that's an engineering project well beyond me though, I can barely tune a derailleur.

Right now (on 15s) off the line it wants to wheelie, and I have to use extreme throttle control (I've seriously never flat out pinned it, 20s would be nuts). The top end is maybe a little slow for a lot of uphills (paved and low grade), and back when I had my 7-speed on, this kit easily did 40mph up the steep paved road I live on (and seemed like it could have pulled twice that geared properly). You did very well with your motor choice, cheers!

I have 2 18t cogs that I would like to test but need to order the 2 smaller cogs for my above mod first. I do think i'd like just a little more speed (maybe 23-25mph), and also, an 18t would fit the upper roller on my tensioner better. Right now, when the suspension compresses a bunch and the tensioner swings forward, the upper roller I added shifts a bit too close and i'm losing maybe 20% of it's range. Too much faster and I'd spin out as soon as things got steep.

Overall, I love all the tweaking and tuning I've been doing with this kit and bikes (i think my GS is on the verge if dumping me though, seriously). I'm learning a ton and enjoying every step, but I was thinking about it, and there is no way a beginner or whatever could make this combo I have usable (except for the the dying breed of intelligent, eager to learn, and not quick to 'place the blame on others' type novice). The BB kit on certain bikes is likely doable with less tuning than I've done, and the standard kit absolutely (I think most anyone could get it working without the torque stressing everything well beyond bicycle design). Maybe you'd need to offer the BB kit like an Apple product and either sell the whole bike or only support specific frames... similar to the "You our our hardware and software or it simply wont work".

 

[LightningRods]

The thing with the big block is that it's very much like big American V8 gas motors. You can tune it for torque and reliability, or you can tune it for an insane amount of power. If you run a small controller on the big block or govern it back with a C-A it won't be a handful. There is about a 5 lb weight penalty over the small block so the user needs to determine if they need the power potential of the big motor.

I'm going to be putting big blocks in both the Lunacycle mid drive and the Qulbix mid drive that I'm working on now. On the Lunacycle I plan to install ceramic bearings, port the case for air cooling, keep the factory shaft driven cooling fan and see what kind of power I can get out of the big motor. The Lunacycle has a long wheelbase so it won't be as wheelie prone as downhill bikes. The Qulbix is built like an 80cc MX bike with big wheels. It's really stout and should be up to whatever the big block can put out. I plan to run both bikes single speed for starters.

 

[beast775]

Im excited for the Qulbix bike.

 

[LightningRods]

Me too!

 

[stonezone]

This is fun, we're all winning.

 

[izeman]

I guess for reasonable torque (power) control you better use a proper controller. Especially for mid drives kelly controllers outrun the xie chang ones by far. Tried both and they are like night and day.

 

[stonezone]

I have a 48v brushed kelly for my Oset 20" and it's got slightly better throttle options than the Lyen on my LRBB but still not ideal. Is there something that can manage the throttle better than the CA that other people are using? Also, is there a CA throttle mode that people generally prefer? I'm still on pass-thru and it's working well enough after calibration but I had to tune out a bit of the top end. If I increase the ThrO->MaxOutput any more than where I have it now, I get a quick lurch on it's way to 100% (at about 95%). This doesn't happen with the throttle plugged directly into the controller (bypassing the CA). So i'm basically only getting 90% of the power that I am without the CA, but a bit more throttle control (although I still want more to make partial throttle hill climbs easier).

I need to put some more time into it (re-read all the CA docs, re-calibrate) and test the other throttle modes if the word is that there is reason to. They mention improvements to higher throttle oscillations which may be what i'm experiencing....

SZ

 

[LightningRods]

Forum member Denisewa did quite a bit of work with improving throttle response and controllability a couple of years back. She observed that quite a bit of the throttle's rotation was wasted with no response. She also noted that full throttle came on before the end of the throttle rotation. She used two different resistors to tune out the dead spots at either end of the throttle. Since she used her bikes for low speed trials work this was especially important to her. According to Denisewa the Magura throttles responded the best to tuning.

I'm not sure how the CA3 modifies the throttle signal. It may already be doing something similar.

 

[stonezone]

Just back from my first trail ride and oooh boy is this kit a weapon. I'm still having freehub slip but that's either because it was damaged before I went to the 3/8 base or I may need to add another 3/16 (probably will as it wont hurt. The gearing is a tiny bit slow sometimes for flat out speed runs but usually if im going that fast its on a DH and gravity alone is enough. I might try 18t just to squeak a few more mph out of the top end but some of the steeper sections will probably be unmanageable.

LR, you should jump on a plane and take her for a rip ASAP.

I'll play with my CA some more... calibrating it as you reat the voltage in realtime lets you fine tune the end points but I wish you could do something like RC where you can adjust the throttle curve and expo.

still winning (Ill post some video if it comes out worthwhile).

SZ

 

[sascha2770]

Hey folks, wanted to have some opinions on how to mount this battery pack on the downtube:






Sick of backpack battery and now I wanted to mount it down there.
I Know it looks like crap but it holds good, now I wanted to tighten it with some hose clamps and get rid of the lashing strap.
Maybe 4 or 6 of them around the modified bicycle rack Some rubber that the batterys don't get damaged.
Already broke 2 cells while looking how I could mount it, shit...

Please don't judge me, I'm a poor student^^
I wish I could make it better but money is an important factor^^

What should I do?

 

[stoo]

use the cad method[cardboard aided design!] make a few models then you can try a few things with no cost/loss. its a beast of a ride ,that frame looks awesome..heres my cad just to get an idea before the aluminuim is bought...

 

[Andytheswede]

LightingRods,
would you still be able to pedal - even if it is "fake" pedalling?

Yes. It will be like 'windmilling' when you're coasting downhill faster than you can pedal. The freewheel will be ratcheting and you won't feel any pedaling resistance. But the crank will turn at the speed you choose to pedal.

"What do you mean, officer? I was pedaling at 45 mph, not running on the motor!" Don't expect me to post your bail. :lol:

Yea but is there any setup where one could pedal along in,lets say 50km/h?
Im building a daily commuter based on this kit and a paratrooper pro and it wouldn't be a bad thing to get some exercise while getting myself to work.

 

[--freeride--]

Forum member Denisewa did quite a bit of work with improving throttle response and controllability a couple of years back. She observed that quite a bit of the throttle's rotation was wasted with no response. She also noted that full throttle came on before the end of the throttle rotation. She used two different resistors to tune out the dead spots at either end of the throttle. Since she used her bikes for low speed trials work this was especially important to her. According to Denisewa the Magura throttles responded the best to tuning.

I'm not sure how the CA3 modifies the throttle signal. It may already be doing something similar.

You may be able to improve something, but the kelly can do current controll and the other controllers can't.
So you will never get a good throttle response on a high power System.

Current control is like on a gas engine you tell the Controller via throttle how much fuel/current he should put through the engine.

Speed controll would be you tell the motor the exakt speed he should do. And then a Controller tries to adchieve that exakt Speed.


Try to do exactly 10mph on a System that does 60mph. You go over a bump, the motor pushes full power, because he sees your request for 15mph then. You release the throttle the Motor sees 10mph again and shuts down because you allready go 12mph...

So this will on/off blasting with no controll.

Putting a CA on top could make it a Little better, but will add another controll Loop with delays and strange things the system does, you really don't want to have with a high power system.


A Speed Controller allready has a build in control Loop, it tries to controll the Motor to adchieve a Speed. So the Controller puts in Current to achiev the Speed. With a CA you tell the CA a current, the CA tries to controll the Speed to get a sepecific current from the Motor, so you have two controll Loops one in the other. They can outrun each other or overshoot...
That might result in going full throttle when you don't want to...

So the much better way is to get a Kelly and leave all that controll loops out. This way the Motor does exaktly what you tell him.

 

[LightningRods]

Yea but is there any setup where one could pedal along in,lets say 50km/h?
Im building a daily commuter based on this kit and a paratrooper pro and it wouldn't be a bad thing to get some exercise while getting myself to work.

The Rohloff Speedhub is the best answer for your Paratrooper. With a high gear of 1.467:1 normal bicycle final drive gearing that produces a 40km/hr top speed would yield almost 59 km/hr. My small motor has a top speed of just over 50 km/hr @ 50V, 30A. The large motor is much faster.

 

[Deanwvu]

Yea but is there any setup where one could pedal along in,lets say 50km/h?
Im building a daily commuter based on this kit and a paratrooper pro and it wouldn't be a bad thing to get some exercise while getting myself to work.

The Rohloff Speedhub is the best answer for your Paratrooper. With a high gear of 1.467:1 normal bicycle final drive gearing that produces a 40km/hr top speed would yield almost 59 km/hr. My small motor has a top speed of just over 50 km/hr @ 50V, 30A. The large motor is much faster.

I've also looked at the Schlumph high speed drive. It's a front "chainring" with a planetary overdrive built in. Hit a button, and you have a 2.5x overdrive, all on the same chainring.

Combine it with a Rohloff in back and you have something like a 1300% gear range, with little overlap.

http://www.cyclemonkey.com/schlumpf-innovations.shtml

(you'll also have more $$$ in your drivetrain than some people spend on a car)

 

[LightningRods]

The Schlumph won't work with my regular mid drive where the motor drives through the bottom bracket. It will work with the Lunacycle and the cargo bike mid drives that are between the BB and the rear wheel. In the case of your Big Dummy with the drive behind the BB, the Schlumph would end up just changing your pedaling cadence. You're not going to produce enough power to override the connection between the motor and the gearing of the final drive. You can fine tune your pedaling cadence with both the secondary reduction on the mid drive and the gearing from the BB chainwheel to the mid drive. Once you have that where you like it the best place to change gears is the final drive where you can affect the motor and pedal gearing together.

 

[eTrailster]

I've also looked at the Schlumph high speed drive. It's a front "chainring" with a planetary overdrive built in. Hit a button, and you have a 2.5x overdrive, all on the same chainring.

Combine it with a Rohloff in back and you have something like a 1300% gear range, with little overlap.

(you'll also have more $$$ in your drivetrain than some people spend on a car)

Connect them with a Gates carbon belt drive.

 

[Deanwvu]

The Schlumph won't work with my regular mid drive where the motor drives through the bottom bracket.

Of course! I don't know why I automatically thought of your Luna/BD drives... Yes the Schlumph has no use with your BB drive.

 

[LightningRods]

Probably because you're at the head of the line for a Big Dummy drive!

The Carbon belt drive would work great from the BB to the mid drive for pedal power only. The bicycle spec Carbon belts can't handle the combined output of the motor and pedal power. A motorcycle spec belt drive would be perfect if there were enough room for the big belt. The one failing of belts is that they're wide for their power capacity compared to chain drive.

 

[eTrailster]

Try to do exactly 10mph on a System that does 60mph. You go over a bump, the motor pushes full power, because he sees your request for 15mph then. You release the throttle the Motor sees 10mph again and shuts down because you allready go 12mph...

So this will on/off blasting with no controll.

Your bump analogy suggests some kind of cruse control is at work. Why would a bump cause a motor to go full power? External forces such as bumps and inclines effect speed, but do not effect throttle control or motor output. Well, not unless the bump changes throttle position by moving your hand or you change throttle position to compensate.

I'm expecting my small block soon and am starting to consider throttle options. It's my novice understanding that throttles can either be hall sensor or potentiometer based. The Magura that Mike mentioned I believe is a potentiometer. It seems the Domino throttle solved most of the complaints about the Magura. The Domino is what comes on the ZERO. It is the most water resistant throttle available and the zero throttle position activates regen. This is what I would like to use if it is compatible with the Len controller and CA. (Please help anyone) I will add a kill switch for safety. I think most of the Wuxing throttles are hall sensor units. Although they have safety benefits, they are junk construction. If you are using a hall effect sensor based unit, perhaps you would be happier with a potentiometer. Then again, I could be wrong about everything.

 

[LightningRods]

I think all of these throttles including the Chinese cheapies are 5k Ohm potentiometers. It's a matter of quality, not difference in design. $15 for the cheap throttles, $50 for a Magura, $90 for the Italian made Domino.

http://www.electricmotorsport.com/domino-twist-grip-throttle-with-microswitch.html