Direct Drive #219 Pitch Monster Sprocket

mwkeefer,
My math shows the largest "reasonable" cog on a 405mm (20") bike rim is 143t

163t = the bead seat diam of a 20"rim.
 
Maybe I quoted the price in a confusing manner. It's a minimum order of 12 at the price of $45 each, then it's $39 if we can pull 24, but I am not seeing more than 8 being ordered and I am not gonna sit on 4 sprockets hoping that more will want one. Also, I found Acetal to be not as expensive as Delrin here: www.interstateplastics.com I am thinking with a sprocket this size, Delrin might not be necesary. This way, if I do it myself I even save $20.

I am still down to get these going, but we are gonna need 4 more sprocket orders to get a batch made at this price, otherwise I can go back and ask how much it would cost at 8 pieces. :oops: I'm in no rush, so I will wait another week to see if something better happens.
 
Hey E,

I think some peeps are waiting for a final design before jumping in. I wouldn't worry about a lack of #'s.
In the end some will double down if necessary to get it done. (I for one)
The alternative materials your exploring are cool too. Be interesting to get feedback on this... :?:
The mount type should be nailed also. Kinda like the multi-option design if it can be done sano... :?:
Cadoodelers jump in :mrgreen:
 
indeed, ill take two if we are short also.
with the disc brake mount will that be adaptable to fit a freewheel?
Again i would suggest a design that leaves us to make an adapter that fits our purpose, whatever that may be.
you definately can fulfil an order of 12 e so lets get cracking with a general design :) as an initial suggestion why dont we just copy the existing extron for mounting holes making our order unified and then evryone can make a mount for freewheel/disk/ whatever - if the part was available off the shelf we have to do that anyway?


D
 
Well again, some feedback would be nice to know what people need. As for me, I just want to be able to attach it to Gary's 3 speed hub adapter, so that means that internally the sprocket will have to fit over the hub, prolly taking any direct disk mount options off the table, but then Matt makes an adapter to do just that. I might suggest an inner diameter just big enough to fit over an eno freewheel.

Just a thought here guys, what if one of the members here could print out a piece of paper or sheet of plastic that had all the different hole styles drilled out to use as a template. I would gladly pay $10 for such an item. I don't know exactly how you would center it precisely but I'm sure there is a simple way. Enoob, keefer, thud?

We also aren't locked in to the Range of teeth (160-170) we could go bigger, but I don't want to go any smaller. I just threw that out to get a quote.

So please pm me or post what you need specifically: teeth, inner diameter, mounting style.

Thanks
 
etard,
Do you have access to a engineering supply house that will print drawings? (must have one in town somewhere) I will e-mail the the hole patterns to you & you can get them printed at full scale. no charge.

Are all the bicycle chain wheel patterns 5 hole? 104/110/130. (Miles?) :p

Any one know the bcd for the sick bike parts freewheel? (shoulda measured it when I made the broach guide for luke)

What about Garys adapter? bcd ?(4 bolts IIRC)
add 44mm 6 bolt iso disc brake
& my favorite, 5.25"bcd 6 hole Kart pattern.
what else?
 
If at least that big is mandatory for you, then my vote would be for 165t. My plan would be to grind 2/3rds of the teeth mostly off anyway, leaving enough just to seat properly. 165t gives both an odd# of teeth (not interested in matching tooth position on any tire change or taking the chain off for any reason), and is divisible by 3, leaving 55 full teeth on a very large dia sprocket.

Why the requirement of such a large diameter, because it would be nice to be able to run a 20" wheel too? Knocking a couple of inches off of the diameter will have only a minor affect on gearing. I'm in for at least 2 as long as the connection is something standard for bike parts. If Thud's tooth count is on target for a 20" wheel, then I'd prefer a 141t count. How does the resulting 15% steeper gearing really affect you?

A consideration is width at the chain and seat stays, because such a large diameter sprocket is likely to have a clearance issue for everyone except those of us cutting and welding on their frames.

John
 
thud your grandkids are gonna love you .

etard i would pursue thuds suggestion first as that will net you professional results the fastest , for the path your heading down you may want to also go talk to a mechanical engineering instructor at some surrounding schools and see if there are any students looking for a project . better yet find the school and just go ambush the students when class lets out and see if you can spot an student on a bike and your golden. i fully intend to set up my ambush after the holidays. :) even a decent highschool program may have a shop that could produce what your after.
 
etard,

whats the latest news on the monster sprocket?
im counting on this happening so i can complete my build.

D
 
D,

Well, now the holidays are nearly over and life can get back to as normal as life can get when you are trying to strap 20 pounds of electric insanity to a bike! :lol:
In regards to the sprockets, the guy can make the sprockets and cut the holes for the price I stated before, I would be willing to manage all the logistics of recieving payment, sending payment, and shipping sprockets (price quote did not include shipping). The only thing is, I asked those serious to pm me what they wanted, how many, teeth, and mounting style, and not one person sent me a message, otherwise I would love to have one of these in my hands. :twisted: But now, I think it would be better to just order a one off and pay the price penalty, rather than deal with all the other BS. I already have somebody lined up to make a CAD of the beast. So when school is back in session so will I. Haha. Peace, multiple reduction stagers!!
 
im really surprised by that!!
well can i join you in the price penalty and get one with ya? i want 165t mountable to a sickbikes eno.
who's doing your cad?
i would only need to see a drawing of the final design to send you payment - im hoping you go with lukes idea or similair to keep weight down and improve look?
let me know and i'll definately take one.

cheers,

D
 
Hi Guys,
This is an excellent thread. I'm considering the Astro 3220 motor on a 700C wheel/rim and direct drive has definite attractions. I need a 13:1 reduction to achieve 60kph at 6000rpm from motor.
This is doable with a 26 inch gear/sprocket on the wheel and about 2 inch gear/sprocket at the motor. Piece of cake (possibly) but with all the focus on #219 chain I forgotten why we're not considering belts. Is it because of the possible high torque at low speeds? And if I know I'm current limited might belts be the better option. Your thoughts please.
 
Hi G.K.

Yes, the limiting factor for belts is the torque through the drive pulley.

Smallest pulley for 8mm pitch would be 18t and would be custom.

Smallest pulley for 5mm pitch would depend on torque, but probably over 20t.

Both driven pulleys would be custom/diy.
 
Have you guyz considered using pulleys rather than belts? For memory the rear 5mm pitch pulley i have is ~155 teeth If you asked one of the ES metal casters nicely they might do a run of them for you cheapish... You can add the teeth yourself very simply.

KiM
 
**blows off dust**

well now that Thud is helping me with drive gear, Luke has made my eno's do their thing, there is just one leeeetle part missing from my build, hhhmmmmmmmmm?????

D
 
Hi Everybody,
I can generate these #219 chain sprockets for you with ease. Just let me know the 1) mounting bolt dia, 2) BCD, 3) center thru hole 4) number of teeth. I can provide you with a DXF, IGES, STEP or SAT file for a mchine shop. FYI I used .181" dia for the rollers. Did I miss anything? Please check my design.

165T%20_219.png
 
what material and costs Mclovin?
Any chance of composite?

D
 
Oh. Sorry. I guess I wasn't very clear. I can generate the CAD files for you so you can take it to a machinist and get one built. I'm not actually making these. But what they hey. I couls look into that. I'll do some calling around. I know a company that does some rather cool machining work with composite materials.
 
I have been thinking about this......
Any one care to evaluate a polycarbonite (lexan) over delrin (acetal) for a material?
The mechanical properties are very close...at 1/2 the price......totaly steath clear.....Bullet resistant ( :lol: ) I have cnc capacity to machine them.


(I should say the "boss" has capacity)
 
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