RC reduction Simplified

[Thud]

Good evening gang,
I am building a group of 4 identicle bikes to keep around for when friends drop by & we feel the need to bang into each other motocross style in the back yard

I have been working on a few ideas regarding making rc drive systems as easy as possible....& bullet proof.
Here is the 1st idea coming to fruit & i thought I would unveil it here for reveiw & any input anyone may have.

some criteria:
as few parts as posible.
must have a tourque limiting feature.
must bolt on without any frame modifications.
Value engineerd to make it as easy to machine as possibe, I am hoping this will become a benchmark for price point & functionality.

Here is the 1st casting, Machined to accept the bearings & bored to accept a 63mm or 80mm motor (turnigy 80/XXX or 6374 or equivelnt)
excuse the layout dye.


The mount is designed to keep a .625" jack shaft nestled very close to the seat post & will fit seat tubes from 26-37mm.

I put more time on this bike around the property & getting the mail or bopping up to the corner store,(1/2 mile up the country road) Its a 24" Raleigh 18speed I put some bmx bars on & have a good time with. it rides so well I have been avoiding powering it. but I think its a perfect platform for testing this system.




I am sending a board member I cold pm'ed & offerd a beta unit to for an evaluation. I am waiting for the correct bearings & a few knick nacks befor it goes next friday.

I would like some input on a few things.
How is the critera list?
is a slipper clutch overkill?

I went with standard 5/8" shaft so thouse who wanted to use bicycle chain can get 30mm freewheel adapter. One of these & a 13t crossfire are about indestructable.
http://www.staton-inc.com/store/product ... 529-3.html
it will have a chain gaurd & I setteled on 4-1 for the primary reduction
#25 chain on the primary for cost considerations 15-60 to keep the chain noise minimal. (the motor will mwke more racket than chains from my experiance)

I have not included any pricing yet as I have a couple jigs to assemble yet that will elliminate some set ups....so i am still working out minimising machine time.
allright.....flame it up guy's whadya think?
thanks for looking.

[liveforphysics]

It is SOOOO awesome how you cast your own Thud!!! Woot!!! Do you have videos of the casting process or molds for them?

[Thud]

Hey LFP,
I have a video of me casting some suspension parts on my youtube page. same deal as these parts.
http://www.youtube.com/watch?v=d3GgtvsL ... ature=plcp

[Arlo1]

Cool thud. I cast a aluminum T handle shifter with the reverse/gear down lock out button and moving parts in Hi school that way. Very cool its lots of work and to anyone who doesnt want to pay thudster for all his hard work you can POUND sand lol.

[RWP]

Very cool Thud!
Good to see your simplified cast drive system ready for prime time. I really like how close your jack shaft is to the frame and I like the casting. I am going to use a torque limiter for my new drive system...I keep promising to post my latest work...maybe as soon as this weekend or next week. My new stuff is not cast or as simple as your very cool system.
Congrats!

edit: Is that a 24" Skyway wheel? How's that holding up?

[Miles]

I like it!

[TopCat]

Simple, straight forward, does what it says on the tin. Nice one Thud

Regards
Tom

[gwhy!]

Hi Thud,
This looks the bees knees but please can I suggest a option of a 12mm shaft as metric bearings tend to be a little cheaper and a little more easy to come by, also it would be nice if there was enough room around the outside of the smaller motor to fit external hall sensors. These are my suggestions ( for what its worth ) but both suggestion could be got around I like it very much , please can we talk about price and how many of the units can I have without the freewheel adaptor

[sico]

That's execellent Thud, I feel I may be stealing this idea for my own purposes if I ever get a moment to return to my RC development. But how do you tension the chain? Or is that proprietary?

Simon

[drewjet]

Awesome Thud. Once again I am amazed at your skill set.

Is this going to drive the rear wheel or the bottom bracket?

Will it have pedals?

I hate the #25 chain I have as a first reduction on my motor, I would love to see 219 implamented even though it is a bit bigger.

Sensored or RC ESC?

Will you use a through bolt to prevent the unit from turning on the downtube?

AWESOME!!

[drewjet]

Awesome Thud. Once again I am amazed at your skill set.

Is this going to drive the rear wheel or the bottom bracket?

Will it have pedals?

I hate the #25 chain I have as a first reduction on my motor, I would love to see 219 implamented even though it is a bit bigger.

Sensored or RC ESC?

Will you use a through bolt to prevent the unit from turning on the downtube?

AWESOME!!

[Thud]

1st. thanks for the props. to answer a few questions & clarify some stuff.

12mm shaft options: I will make a few "metric" versions of the units for the over sea's crowd who may want to give these a go.

#25 over belts or 219p: since the #1 parameter is lowest cost possible, I havn't found anything as cost effective. belts have some strong arguments just on the zero maintance point....but belt tension reqiured on sometiong this size gets to be a burden on the 10mm bearings in smaller motors....& they cost as much a 3x more.
Drewjet- What is your #1 beef with your primary reduction? (& your stuttering a little bit today )
(on my bikes i will prolly have sensored controllers....but i am definatly chomping at the bit to test my 16cell thundercat )

Tensioning the chain: I have optomised the center 2 center distance to keep the proper chain tension for the sprocket set. A simple slipper guide will be all thats required to compensate for any wear during the life of the sprockets & chain. More pictures of it when it gets there.

Unit slipping on seat tube: these will be bored specific to the orders seat tube diameter. I have never had a proper fitting clamp like this slip under strain. But if for some readon some one would want to "pin-it" to the tube there is ample stock in the area for it. I have made a few clamping motor mounts for guys now (lurkers mostly) & not 1 has had an issue with the fit or slippage....(one guy didn't like that he scratched the paint on his down tube LOL)

External hall sensors: the photos are kinda poor. I was holding the 6374 with one hand in position & the 80mm motor was dangling from 1 screw. here is plenty of room for a specific hall bracket which will be available shortly after getting a few of these stocked.

This will work as a right or left side dive, or even a bottom bracke drive. The smaller clamping 1/2 of this uint can be used in a pair to provide 2nd stage of reduction. simple simon.
I really think a re-wound & terminated 80/85 would make a awsome BB drive set up & I will test that on my old FS Marin some time this summer.

Right now the big decision is to build or not a custom sized tourque limiter (incorperated into the main shaft) I have all the friction materials in hand & am picking up some stock this afternoon to make the prototype.

For the guys with a lathe & the ambition I will sell raw castings to play with also.

sneak peek priceing is looking like:
basic unit, bored to fit your tube with 4-1 reduction & a 30mm freewheel adapter $160.00 + shipping.
add the slipper & we are at $220.00

Do I need to provide 1 stop shopping for sprocket adapters to the rear wheel? I don't see myself getting into the RC controller sales buisness. I allways bargan hunt & cost compair with shipping figured in & often multi-source on stuff.....but I know some guys just want to get it over with.

I don"t plan to be 100% in the bike buisness, but I need to generate some soucre of funding to justify the race bike builds. I am filling as an LLC to get the tax benifits of operation working for this "hobby" business. I will add a link to a web site i have when i get the time to add proper info. Once I have a new Tax ID # I may be able to get some better pricing on materials also....win win.
(then i promise to not spam this section ever again LOL!)

Other things I have on the table:
external hall mounts,
disc brake to kart sprocket adapters.
freehub to sprocket adapters
splined crossfires for freehub attatchnment
Sealed battery boxes in fiber glass.

I am also re-working my home shop set up & attempting to get my (damned) cnc cutting metal in a satisfactory manner....that (IF, Maybe?) will get the 2-speed tranny's into a little quicker production. Those are a set up & parts fit nightmare for production.
(i am also building some motorcycle sized 2-speeds for testing in the next week....bring on the Perm132!)
I guess i just opend the door for a wish list.
thoughts? & thanks again.

[johnrobholmes]

Starting a biz? Awesome to hear!

I love the little drive, about as simple as it could be made!

[Brentis]

1st. thanks for the props. to answer a few questions & clarify some stuff.

...
This will work as a right or left side dive, or even a bottom bracke drive. The smaller clamping 1/2 of this uint can be used in a pair to provide 2nd stage of reduction. simple simon.
I really think a re-wound & terminated 80/85 would make a awsome BB drive set up & I will test that on my old FS Marin some time this summer.
...
sneak peek priceing is looking like:
basic unit, bored to fit your tube with 4-1 reduction & a 30mm freewheel adapter $160.00 + shipping.
add the slipper & we are at $220.00

...

Beautiful work.
I am considering BB mid-drive of 750-1500w, & as light & simple as possible, for a recent acquisition.

Introducing.....JPG (85.54 KiB) Viewed 2319 times

Light, simple, RC, BB driven NuVinci N171.
This sure would fit the bill. Especially with the C.A. RC development.
Cannot wait to see a couple examples in action.

Your pricing is very reasonable.
I have started another penny jar.
Best of luck expanding your empire.

[Byte]

Competition of Matt, huh? Only difference is; this one is for poor guys like me! hehe

Will follow this thread! Nice!

[gwhy!]

Sound very promising Thud and I hope things work out for you. If people are after something more the size of kart chain and sprockets (219) then maybe have a look at 8mm mini dirt bike chain and sprockets the prices are comparable with #25. Also why not bore out the casts to the max down tube size and then supply half moon shims for the different sized down tubes may help keep machining time down( I have had this sort of clamp slip on the downtube but nothing that a simple pin cant sort out ), just a though. And personally I would like to see a tad more than the initial 1:4 reduction so would a 50t #25 sprocket fit on the casting for example ? , And who needs a torque limiter that just limits the control and limits the fun factor

[Thud]

opps, mised one.

That old skyway sucks off road! flexy old plastic wheel. (i was weak the one day it showed up on e-bay)
Its only on there to hold the bike up currently. I tore the bike aprt last fall to re-lace the bent up rear wheel. its going to get upgraded cranks & some freash DM24's in 24" skinned with holey rollers.

skyways have a kool factor.. but even the 20" on my original bmx are realy crap for any kind of performance riding....I can't belive any one ever raced the originals back in the day....I have never ridden a newer "carbon fiber re-enforced" skyway.....but have to think they are 100% better than the originals.

gwhy:
A 54t or 60t sprocket is the standard. I wouldnt want to run less tha a 13t drive sproket as the noise & wear go up exponetialy on the smaller sizes. So 4.6-1 is well within reach.
karts sprocket stuff in #35 is so plentiful & cheap its pretty easy to get to leagle speed reductions in 2 stages. less than 30mph on any wheel size out there.
The slipper is really for the benifit of the few who think they need to gear their bike for +30 mph. & like to hoon around town abusing the lightweight eqipment. The amp draws are enough to really tourture an rc speed controller in a worst case senario.

Competition for Matt? maybe a little but I suspect to a lesser degree. Guy's who can afford a $400+ motor & cnc'd bicycle jewlery prolly won't look twice at dull, rough looking cast parts & the simpleton aproach to engineering. this is an attempt at fueling the e-revolution with a lower price point option that is still in the quality range required.
I would love to be able to offer a whole "kit" for less than $600 sans batteries..... but really low priced motors that would work are going the way of the dinosaur fast. & its only going to get worse from here. Having options is nessisary for growth of the whole movment.

[Solcar]

...is a slipper clutch overkill?

I think so because it can be done with the electronics. I look forward to following this project.

[Brentis]

...Competition for Matt? maybe a little but I suspect to a lesser degree. Guy's who can afford a $400+ motor & cnc'd bicycle jewlery prolly won't look twice at dull, rough looking cast parts & the simpleton aproach to engineering. this is an attempt at fueling the e-revolution with a lower price point option that is still in the quality range required.
I would love to be able to offer a whole "kit" for less than $600 sans batteries..... but really low priced motors that would work are going the way of the dinosaur fast. & its only going to get worse from here. Having options is nessisary for growth of the whole movment.

+1
My thoughts exactly.
If I was to build a Showbike or eMotorcyle I'd look to Matt @ this time.
He builds CNC porn & worth ever penny I'm sure. You got to pay to play though.
What Thud has done is awesome & has a style all its own. I can finally afford & apply RC tech to my bike easily.
Matt makes Playboy
Thud makes Naughty Neighbors.
I love Naughty Neighbors
I thank you Thud for your effort to advance the ebike movement for rich & po'

[neptronix]

I second that.

Love recumpence's work, but i don't require that level of fit and finish.
The astro motors are expensive as hell too.

A cheaper option is a big market. I've been interested in an RC drive since i got here, but i don't have the space/equipment for machining. Would strongly consider a thud unit...

[REdiculous]

It looks to me like you could potentially put enough power through it to spin the drive around the seat-tube.

I think I'd put a hole on either side of the bracket for an optional bolt/pin. Users would need to drill through their seat-tube to get a pin through it, but then there'd be no way for the drive to twist.

It's good to see someone trying to hit a reasonable price-point, for sure. Keep up the good work because I may need one of these things before too long!

[E-racer]

This looks awesome Thud! Having 4 equal bikes is going to amount to endless fun as well!

[nicobie]

Way to go Thud!

This looks like a product that will appeal to a lot of people. Especially at that price point.

Glad to hear your going about starting a business the proper way. Working in the "gray area" is fine for awhile, but in the long run it's best to stick to the straight and narrow. Don't forget to put aside a bit for the 1st years quarterly's taxes. Start saving every receipt your family generates. You would be suprised how many you can deduct .

[kevo]

Great stuff Thud, always respected your amazing talent!

[spinningmagnets]

I really think a re-wound & terminated 80-85 would make a awsome BB drive set up

I agree completely! The size and shape are perfect. A lower kV as a result of the re-wind and re-terminate to Wye, would reduce the amount of reduction needed. The 80-100 has been used to race (PaulD, AJ, etc), but that is more power than the mass-market needs.

The lower kV added to a 20-inch wheel only needs a single chain from the motor to the rear wheel if you wanted to use it for an axle-drive. Even for a 26-inch wheel, you'd only need to add a second reduction (like your cast unit shown).

Outrunners have been connected to a 3-speed hub, and the gear-teeth were broken by the shock-load. If there was some way to electronically snub the throttle signal (for a gentle ramp-up) a 3-speed would survive, and that would be a great addition for keeping the controller/battery peak amp-load down (maybe add one of Matts air-fans?).

If fuel prices spike-up, and Chinese hub-motors are suddenly sold-out...the 80-85 is the motor that I would suggest for a US machinist to produce...