LightningRods mid drive kit

LightningRods said:

I have some other tricks planned for the drive enclosures, but I'll make more progress before I start talking about it.
HAPPY 2071

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One of the elements of "mid drive is better off road" has never really been realised with this kit straight from Mike. The fact the mud or dust will turn your drivetrain into a disaster in 20 minutes of riding is one of the ongoing reasons I think hub motors still win. If you love your drilling holes and bending alu it's not too bad.

the new mount looks good! thanks for the explanation regarding reduction. a topspeed of 25mph is plenty, its climbing power i need. And if a smaller reduction means less stress on the driveline and less chain skipping, thats even better

looking forward to see your progress.
happy new year to you too!!

It's funny, that frame extension that DH bike manufacturers have been adding for the last ten years or so has been such an aggravation until now. I finally realized that it was an opportunity to make the drive tidier and stronger. The extra space that the frame dogleg creates makes it possible.

On the issue of gearing, the way I show the drive now has higher gearing, more for speed than climbing. If you have a 32t chainring and a 32t low gear sprocket in the rear, your overall gearing in low would be 15:1 and give you a top speed of about 16 mph in low. For single speeds I typically recommend 8:1 overall with a top speed of around 32mph. This drive will do 32 mph with a 16t rear sprocket instead of the more typical 11t. More teeth engaged in the chain, less likelihood of the chain jumping teeth under power.

Hey all,

Had a fun day out in the desert mountains of Yuma yesterday.!!!... Starting to shake this frame up good and getting the bugs out of her---

First thing happened was my head tube became loose on the trail and I couldn't get it to tighten up with my small set of allen wrenches, so I walked it around a few of the bike paths on the steeper hills just in case ...

Then about halfway back I heard the chain rubbing the tire and stopped to realized I had lost my chain tensioner on the left side---the one that holds the axle in place.. (I don't think i remembered to tighten it properly when i adjusted the new chain.. )---- i was able to limp her back to the truck and load up with no major difficulties.

All in all , another wonderful ride that got me back into prospecting country 20 times as quickly if i had had to walk in... I got a better idea of the area I had been walking in for the last month and things started to gel in my head about the way the washes from the mountains all go... It is totally different than walking in them individually and seeing them from above off the ridges.

The Terrene tires are doing their job and haven't leaked down since i had them installed --they are tubeless and when i got home last night i realized i had a big cholla cactus hitchhiking on the front tire---a good pull with a pair of pliers and into the trash that bomb went... I had been running 30 lbs max in them to make sure they seated well and that the sealant could get in every nook and cranny--BUT even if it was faster --it was ROUGH--
So for this ride I decided it was time to lower the pressure down and WOW what a difference---it was like gliding over softball sized rocks, sharp slates etc,,,, I am a believer in these tires so far--Thanks to Tim Kreuger at Terrene!

For Mike: Do you have any more of those little end-caps for the horizontal drop outs???-- I

was hoping maybe when you made those you had a few for spares ---or for another build. I just used a bent over washer and a flat washer for now--(pictures) I will have to hook up a decent camera to show you where i am riding--the Runcam 2 is the one i will have to use because i lost my GoPro black grrrr... Neither one really looks god to me-- Maybe a GPS drone would be fun--it could follow me easily out here because there are no trees..

Carry on!

Oh i'm still thinking of going to a susp fork if someone has any experience with them--Marin??---bowhunter???---5a.jpg[/attachment]

Looks like you've found a really great place to ride. I grew up riding dirt bikes in Southern California. I think I still have a couple of pounds of dust in my lungs from those days. You learned to ride fast because you didn't want to be in the dust cloud at the back of the pack.

Sorry you lost that adjuster. The frame maker had those made for the frame. Maybe contact them and see if they still have them. If not Surly and others make wheel tugs that will do the job. http://surlybikes.com/parts/drivetrain/hurdy_gurdy

Thanks Paul, for the post and all of the photos. I love seeing what people are up to with my mid drives.

I'm working with Electric God to see what kind of max power we can get out of the Big Block. Even though the Big Block runs very cool compared to most other motors we decided to port the end cases and give it a better shaft driven fan than the factory provides.

Here's a 3D print of the new axial fan that E-G and I designed:



It fits the motor shaft perfectly:



Cool air gets drawn in through the output shaft side due to negative pressure created by the axial fan on the other end. According to cooling experts (Matt) axial fans are the most efficient way to move air through a motor.



This is the fan that that the factory provides. It's meant to pull air in through the end grate on a plastic fan shroud and then push it over the cooling fins on the center case. We're trying to move air through the core of the motor so we flipped the fan to put the air dam on the outside. While we were at it we gave it larger vanes to move more air.



The fan ships out to E-G today. I'm sure you'll be seeing photos of the assembled motor very soon. He's also experimenting with delta/wye switching on the Big Block to see if we can have a two speed electronic "transmission" through one fixed gear ratio. The Big Block makes more torque in delta but should make 70% more rpm in wye. E-G was making nearly 60 mph in Delta so I hope he'll be okay with 70% more revs. It's hard to find good technicians!

LightningRods said:

E-G was making nearly 60 mph in Delta so I hope he'll be okay with 70% more revs. It's hard to find good technicians!

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:lol: Interested in the results, I think EG mentioned possible FET damage if 'shifting' between delta/wye under high load. Have you ever seen an example of controller damage as a result of delta/wye switching?

That is the major risk. E-G has blown several controller mosfets because of EMF back flow. He says that it shouldn't be too hard to filter out. A really solid solenoid switch, a back flow filter, and some way of disrupting the throttle signal so that people don't try switching under power, and "Bob's your uncle!". Or to translate into American English, "No problem!"

Thanks LR, I'm really interested in delta/wye. I'll need to do more research to understand the issues and mitigation.

In case anyone wonders about the absolute smallest possible 219 sprocket you can fit on a bb fw with enough space to take a 104 bcd bicycle sprocket on lightning rods big block mid drive kit with 83mm bb, it's 53t. A 34t bicycle sprocket is fractionally larger, 30-32t bicycle sprockets run into chain/fastener issues too.

Any smaller you will have no room for the 219 chain against a 104bcd adapter, and a guard clearing the crank, and the fasteners will probably have to be custom costing more than your sprocket.

I'm sure there are work arounds if you can get other spindles not stock, or run thinner bicycle chains. Basically you have to play with spacing between having double chains lining up with the js sprocket and rear.

This is based on lr big block kits made over a year ago. I have no idea if Mike has redesigned the bb to motor adapter since then for these dimensions. A possible future solution would be to chop where the fasteners hit and weld in a corner to make space.

Hope this helps the lr big blockers out there looking for maximum ground clearance.

Hi Mike, as i cant go riding the last months (had a accident with the bike, dont worry, bike is fine) i had the time to finish the drawings and finally start my next project.

Will build my first middrife-kit from scratch, and would like to do it with one of your Smallblock-Motors.

Can you give me some infos on the work you do on the motors;
- you do replace the original motor-axle, is the new Motor-axle now in the same Stainles-steel like the new 15mm jackshafts?
- can i order a Smallblock with 15mm axle and "feather key groove" like on the 15mm jackshaft axles?
- how much cost the additional temp-sensor?
- Can you change the wires to better quality ones?


My plan is to get 40amp cont. and 60amp peak to the motor, thats why i ask for the better wires.

Thanks, Föppel

Hi Stephen,

I have tried a couple of times to respond to your last email. My emails are bouncing back. We may have to PM here until the email gets sorted.

We are currently modifying the stock factory motor axle rather than machining from scratch. It turns out that stainless steel is not as hard as the factory shaft. I also do not use stainless steel on the jackshaft axle. That is now 15mm diameter 4140 chrome moly steel. This seems to be the ideal material. If there were a need we could make a 4140 motor shaft to your specifications. The factory motor shaft can be machined to either 12mm or special order to 15mm with an exposure of 27mm.

I'm not sure what a "feather key" is. You can order either the Small Block or Big Block with a 15mm motor shaft with a 4mm square keyway. We have custom made 219 driver sprockets with a 15mm bore/4mm keyway as well as freewheel hubs with the same bore dimensions.

The 10k temp sensor is $20 with wiring harness and 2 pin JST. Installed in the motor ready to run it's $40.

Changing the phase wires is very time consuming. I've done it. Unlike the GNG motors my motors have the factory recommended amount of air space inside so there is room for the thicker wiring. We can discuss this by PM. I'm not keen on doing this work but can if you would rather pay someone than do it yourself.

I don't think that your power goals are unrealistic. I plan to get a sinusoidal controller and try running the Small Block at 100v 40a. I have no doubt it will do it. One of my power users is running the Big Block at 130v right now without difficulty.

I'm sorry to hear about your accident. You said that you were doing 30 km/hr, hit the throttle too hard and your Small Block equipped bike ran out from under you? I'm glad that it's running that well but sorry that you got hurt in the process. Hopefully you will be all mended by the time the nice weather is back.

I'm working on the parts order for your friend. We should confirm the width of jackshaft housing that you need.

Cheers,
Mike

LightningRods said:

I'm working with Electric God to see what kind of max power we can get out of the Big Block. Even though the Big Block runs very cool compared to most other motors we decided to port the end cases and give it a better shaft driven fan than the factory provides.

Here's a 3D print of the new axial fan that E-G and I designed:

It fits the motor shaft perfectly:

Cool air gets drawn in through the output shaft side due to negative pressure created by the axial fan on the other end. According to cooling experts (Matt) axial fans are the most efficient way to move air through a motor.

This is the fan that that the factory provides. It's meant to pull air in through the end grate on a plastic fan shroud and then push it over the cooling fins on the center case. We're trying to move air through the core of the motor so we flipped the fan to put the air dam on the outside. While we were at it we gave it larger vanes to move more air.

The fan ships out to E-G today. I'm sure you'll be seeing photos of the assembled motor very soon. He's also experimenting with delta/wye switching on the Big Block to see if we can have a two speed electronic "transmission" through one fixed gear ratio. The Big Block makes more torque in delta but should make 70% more rpm in wye. E-G was making nearly 60 mph in Delta so I hope he'll be okay with 70% more revs. It's hard to find good technicians!

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That fan looks familiar.

Thanks for sharing your expertise, Matt. I never would have gone with an axial fan on my own. I was "sure" that a curved blade fan as is used for moving air through a radiator would have been more efficient. E-G says the airflow through the motor is great.

Any updates on the dogleg mount yet? This great thread has gotten too quiet lately :wink:

Hi DirtEV-

I'm nearly finished with a completely new mid drive based on the drawing that I did for you previously. This one is single stage to the chainwheel, and uses all aluminum mounting sheets. I'm still using the same motors for the time being but I may branch out and try some others as well. Stay tuned.

Mike

Very excited! Let me know when it's done

I picked up a big box of laser cut parts today. I have ten of the new single stage drives, ten of the new swingarm drives for the Qulbix, and a couple of custom drives for customers. I was able to get one of the single stage drives put together today and take it out for a quick run. I believe that this drive has huge potential as a high performance platform. Electric bikes need different rear gears than human powered cycles do. Up until now we have been over-reducing the electric motors to try to integrate them into a standard human powered drivetrain. This has created huge limitations. The mid drives that I've made for the last four years won't go faster than the standard gearing allows. Customers complain that they are wearing their small top gear sprocket out. I saw 25 mph today in first gear (a 34T rear) on my Specialized 29er. Second gear would be a pretty ideal gear for a single speed "fixie" bike. Likely top speed in second- 30 mph +. Tomorrow, when it stops raining, I'll get out on the open road and see what the other six gears can do. I'm thinking that an 8 speed with a 50T low gear is going to be perfect. A 20-22T rear gear is going to be as tall a gear as you would want. Think about the advantages of a 22T high gear compared to an 11T top gear. Which do you think will handle more power?

8 speed with 50 tooth low, ( Largest Cog ) ?

I know of the Sram EX-1 , but it is 48 tooth at the largest cog . And at this time the whole kit is expensive at $ 600 Full Retail. ( at least as of last year )

... https://www.sram.com/sram/mountain/family/ex1#sm.00000r7yw35juleqcqm7jubkl0muj

... https://www.worldwidecyclery.com/products/sram-xg-899-e-bike-x-glide-cassette-11-48-8-speed?gclid=CPSDxq6mxtMCFYS3wAod97EMDw


Are you saying from motor to 50 tooth front chainring ? then back to the rear cassette ? ( 50 tooth front chainring to 34 rear cog ? )
or
Motor to reduction ( how many teeth ) to the 50 tooth front chainring ? then back to the rear cassette , largest 34 rear cog ?

Sorry, I was blending different components in discussing my theory. The largest rear sprockets available are 11 speed. This 46T from Shimano would provide a great low gear and is very affordable:
http://www.jensonusa.com/Shimano-XT-CS-M8000-11-Speed-Cassette

If you wanted to have a full 50T low gear this sprocket from One Up will give you those 4 extra teeth. Maybe worth it, maybe not given the cost:
https://www.oneupcomponents.com/products/50t-shark-sprocket-18t-1x11

I'm working on developing my own 8 speed cassette with 8 stainless steel sprockets ranging from 50T to 20T. I like 8 speed because the sprocket spacing is wider and the sprockets themselves are thicker than 11 speed. Plus we really don't want all of those gears. Too much shifting.

The way my single speed works is with 12T to 75T #219 primary reduction (6.25:1) and then a custom 22T stainless steel chainwheel driving the rear wheel. It bolts directly to the back of the 5 bolt flanged freewheel. A human powered bicycle needs an overdriven final drive because we can only produce about 100 rpm for any length of time. Normal final drive is between 3:1 and 4:1 O.D. That will give you a top speed between 25 and 32-33 mph. On a powerful mid drive it makes no sense to reduce the motor 30x and then overdrive it back up 4x. It creates huge stresses at the chainwheel and has people wearing their 11T rear sprocket out.



As you can see I've also taken some steps to keep the chain on the front sprocket. I've made a few test runs on this drive now and it shifts through all 8 rear gears with no issues. Second gear would be a nice single speed gear for use on fairly level ground. The 34T low gear starts out well and climbs steep fast hills well. I'd like a lower low gear for slow and steep work.

Here are some speed comparisons between a standard 30:1 two stage drive with 48T chainwheel and my new drive:


If you really must pedal with the motor at full throttle you want a two stage reduction. If you want a 3 mph "granny" first gear that will pull an elk on a sled up a tree, you want a two stage reduction. But for normal tearing around, and especially trying to get some top speed, it just makes sense to reduce the motor less.

Good to hear that you are working on making your own 8 speed cassette.

I am not interested in a 10 or 11 speed cassette , even though those items above that you link to , look good for a good price, ... but not really wanting 10 or 11 speed chain with/on a mid drive system.
I have plenty of experience with a 10 speed chain stretching and braking while just pulling around a dog on a trailer behind a non motorized Road Bike.

I do like my 10 speed in rear and 2x chainrings in front on my rear hub motor Road Bike, But for a mid-drive your designing/making a strong rear cassette with 20 to 50 tooth is just what we have been waiting for .

I was planing on making my mid-drive with 9 speed because I could start of withe 34 tooth large cog in the rear , However I would be happy with just 8 , since/ because your design would be stronger and up to 50 tooth.

What is the most affordable rear derailleur that would work with a 50 tooth cassette ?

I also like your crank design,

Is there a freewheel somewhere in the crank that I do not see in the picture ?

When you posted about a month ago that you will have some news soon, I have been getting back to this section of E.S. each day,

Your front chainrings you posted in picture above is good news. ( for the RC motor Crowd your making the same front chainrings with a 52 or 54 tooth would be a seller, when combined with a freewheel between it and the smaller chainring )

LightningRods said:

I'm working on developing my own 8 speed cassette with 8 stainless steel sprockets ranging from 50T to 20T. I like 8 speed because the sprocket spacing is wider and the sprockets themselves are thicker than 11 speed. Plus we really don't want all of those gears. Too much shifting.


As you can see I've also taken some steps to keep the chain on the front sprocket. I've made a few test runs on this drive now and it shifts through all 8 rear gears with no issues. Second gear would be a nice single speed gear for use on fairly level ground. The 34T low gear starts out well and climbs steep fast hills well. I'd like a lower low gear for slow and steep work.

Here are some speed comparisons between a standard 30:1 two stage drive with 48T chainwheel and my new drive:

If you really must pedal with the motor at full throttle you want a two stage reduction. If you want a 3 mph "granny" first gear that will pull an elk on a sled up a tree, you want a two stage reduction. But for normal tearing around, and especially trying to get some top speed, it just makes sense to reduce the motor less.

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You are definitely an artist..i can see it in everything you produce!

The main issue with these big sprockets is having the upper jockey wheel clear them. On my own bike I'm going to experiment with a longer billet aluminum derailleur hanger that will position my standard 8 speed derailleur the same distance from the 50T that it currently is from the 34T. I'll report on how that works out. There are large capacity derailleurs available that don't cost a fortune. Interestingly enough, since we are going single front chainwheel we don't need a super long arm cage for the range of gears we're going through. I've been happy to read online that +1 gearing is becoming very much in vogue, with one front chainring and a wide range of gears in the back. This plays right into our hands. Too much of it is 11 speed, unfortunately, but there is also some good 8 speed work going on. I'm hopeful that the superior strength of 8 speed will keep it from becoming extinct like 5 speed.

There is a White Industries HD flanged freewheel behind the 22T chainwheel. With 1/5 the reduction torque and 1/4 the overdrive resistance I'm thinking this freewheel will last a long time.

I'm not sure that I'm following your comment about a 52T chainwheel for the RC crowd. Big driver chainwheels create huge driveline stress. I finally figured this out because I had the bright idea to build a drive with big reduction to create a slow pedaling cadence, and then a very high two stage overdrive final drive for high speed while pedaling. Everything broke. 3000 watts x high reduction meeting high resistance overdrive bent steel like it was butter. The stress point was right where the two met. I realized that I had created an "irresistible force meets immovable object" situation. When I lowered the reduction and overdrive I stopped breaking parts. Mid drives have outgrown the "power assist" designs that they started with. If you want to pedal keep the power under 2000 watts.

Another system that I'm working on is a single speed rear sprocket on the right. I've created large rear wheel sprockets with Shimano spline centers in them for people who want to retain their free hub. I've also designed 6 bolt disc brake flange sprockets and a billet 6061 alloy hub with brake flanges on both ends. You can use BMX chain, #35, 40, 420 or 41. I also plan to make #219 single speed final drive sprockets. With a solid billet hub and 219 or 4x chain you could run 20+ horsepower to the rear wheel. I'm shopping for low kv 15kW motors now. With this much power on board there will be no need for multiple gears. A seatbelt maybe, but not multiple gears.

Sorry there was a delay on the development of this drive. I have too many projects going at once. I've designed and built two custom drive systems over the past month.

pkirkll said:

You are definitely an artist..i can see it in everything you produce!

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Thank you!