CAD drawing of a chainring

[PolyTube Cycles]

Hi,

before I strain my limited CAD abilities, does anyone have CAD drawing of 56 and 39 tooth chainrings? Perfect would be with a 4 bolt 110mm system (not MTB, which is 104mm) but I would settle for the standard Shimano system.

Thanks in advance.
Kevin

[Brian Chapman]

Hi Kevin,

I don't know if you've already played with this tool but it might be
of help.

http://gear-calculator.com/html5/chainring.htm

Good luck,
Brian Chapman
--
Chapman Cycles
Pawtuxet Village, RI
http://www.chapmancycles.com/

[Johan Larsson]

I would also be interested in cad drawings of both chainrings and sprockets, or tooth profiles in a cad format. Or some info on what to think about when it comes to tooth profiles... Tooth profiles on older cassettes and freehubs look deceivingly simple compared to modern ones with their ramps, cut-outs and shifting aids, but I guess it's still a very specific shape. (See attached picture for an example of a tooth design I like.) Chainrings also come with different tooth profiles of course, and overall I'd like to have reliability and a long life, and not care much for ease of shifting.

Johan,
Sweden

[PolyTube Cycles]

Hi Brian, Thanks for that link. Unfortunately, it doesn't solve my problem because I need an actual drawing I can use in TurboCAD.

I'll explain my problem and maybe someone has a better Idea. For my Pavo Puzzle Poject (a complete road bike made of broken carbon parts) I fixed a Zipp Vumaquad crank set. The one I got has a compact ring set, which I just can't get used too. I would like to put 39/53 rings on it but buying the originals will cost around 350.- € and have to be sent from the US. The crank has a 4 hole mount with 110 mm diameter. The plan is to make and adapter (out of carbon of course!) to mount an Ultegra ring set. Just holding it together it looks like the bolt holes might interfere with each other. So, I would like to model it an look for a position the works. Alternatively I could just cut the bolt hole tabs off and make a new inner ring.

In either case, I need the drawing to make a cutting template. Or can anyone think of a better solution?

Cheers
Kevin 

[M-gineering]

On 7/23/2014 8:21 AM, PolyTube Cycles wrote:
> Hi Brian, Thanks for that link. Unfortunately, it doesn't solve my
> problem because I need an actual drawing I can use in TurboCAD.
>
> I'll explain my problem and maybe someone has a better Idea. For my
> Pavo Puzzle Poject (a complete road bike made of broken carbon parts)
> I fixed a Zipp Vumaquad crank set. The one I got has a compact ring
> set, which I just can't get used too. I would like to put 39/53 rings
> on it but buying the originals will cost around 350.- € and have to
> be sent from the US. The crank has a 4 hole mount with 110 mm
> diameter. The plan is to make and adapter (out of carbon of course!)
> to mount an Ultegra ring set. Just holding it together it looks like
> the bolt holes might interfere with each other. So, I would like to
> model it an look for a position the works. Alternatively I could just
> cut the bolt hole tabs off and make a new inner ring.
>
> In either case, I need the drawing to make a cutting template. Or can
> anyone think of a better solution?
>
> Cheers Kevin
>

You've got an idea, the parts, presumably a pair of calipers and some
sort of cad program (prefer Draftsight myself). If you can't figure out
if your idea will work in 15 minutes, you should invest in some CAD time
to improve your skills;).

Shimano road rings use a 110x4 pattern but rotated 45 degrees so you
could machine an adapter but it will need recessses to restore the chainline

Or you could bolt 5 x 110 to your crankset, and make an adapter for 4
chainring bolts to three spider legs
--
mvg

Marten Gerritsen
Kiel Windeweer
Netherlands

[PolyTube Cycles]

 you should invest in some CAD time

to improve your skills;).

Can't argue with that ;(
 

Shimano road rings use a 110x4 pattern but rotated 45 degrees so you
could machine an adapter but it will need recessses to restore the chainline

Actually they use 133 x 5. But, no mater how I turn it, one of the 5 tabs always comes too close to the crank hole. I'll cut them off and bond a carbon ring with correctly spaced holes for a proper job. Should look cool too!
 

[John Murray]

a little program to draw any kind of chainring..... chose # teeth, # and radius of bolts, elliptical or round...

http://moz.geek.nz/mozbike/giles.html

not a true CAD print out.... a drawing for drilling etc....

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[Thomas]

Hey, I'm not sure of much, but I also use turboCAD and find it dead-simple to just draw a circle of X diameter and center secondary circles around the primary circle to represent the chain-ring bolt-holes and that is about all you have to do beyond choosing how thick you want the arms in the various dimensions...
    I could do one up for you in TurboCAD if need be if you tell me to, I think all the dimensions you need are stated below in your messages...
    HOWEVER, one thing you must allow for is that if you are getting these waterjet cut or laser cut, they will most likely not come out exactly as drawn, it will be very close, but, as example, my requested 8.08mm slot was actually 7.95 by the time I got it back...
    check in with your cutter to see what the error is, it seems consistently off across all 5 cutters I have used, but not consistent in HOW MUCH off    =(
   Good luck!
Thomas  www.kokoPedli.com

You've got an idea, the parts, presumably a pair of calipers and some
sort of cad program (prefer Draftsight myself). If you can't figure out

if your idea will work in 15 minutes, you should invest in some CAD time to improve your skills;).

Shimano road rings use a 110x4 pattern but rotated 45 degrees so you could machine an adapter but it will need recessses to restore the chainline

Or you could bolt 5 x 110 to your crankset, and make an adapter for 4 chainring bolts to three spider legs
--

 

Shimano road rings use a 110x4 pattern but rotated 45 degrees so you
could machine an adapter but it will need recessses to restore the chainline

Actually they use 133 x 5. But, no mater how I turn it, one of the 5 tabs always comes too close to the crank hole. I'll cut them off and bond a carbon ring with correctly spaced holes for a proper job. Should look cool too!
 

Or you could bolt 5 x 110 to your crankset, and make an adapter for 4
chainring bolts to three spider legs
--
mvg

Marten Gerritsen
Kiel Windeweer
Netherlands

Unfortunately, it doesn't solve my problem because I need an actual drawing I can use in TurboCAD.

I'll explain my problem and maybe someone has a better Idea. For my Pavo Puzzle Poject (a complete road bike made of broken carbon parts) I fixed a Zipp Vumaquad crank set. The one I got has a compact ring set, which I just can't get used too. I would like to put 39/53 rings on it but buying the originals will cost around 350.- € and have to be sent from the US. The crank has a 4 hole mount with 110 mm diameter. The plan is to make and adapter (out of carbon of course!) to mount an Ultegra ring set. Just holding it together it looks like the bolt holes might interfere with each other. So, I would like to model it an look for a position the works. Alternatively I could just cut the bolt hole tabs off and make a new inner ring.

In either case, I need the drawing to make a cutting template. Or can anyone think of a better solution?

Cheers
Kevin 

[Mike Mcdermid]

Go check my flikr we just started making chainrings and have 3d cad and drawings

[Thomas]

On 8/10/14, 2:02 AM, Mike Mcdermid wrote:
> Go check my flikr we just started making chainrings and have 3d cad and drawings

Mike, perhaps a link to your flikr would be useful to some of us ...
Thomas
www.kokoPedli.com

[Mike Mcdermid]

https://www.flickr.com/photos/compositepro/

http://instagram.com/mmc_engineer

if anyone uses solidworks 3d cad i have a model which you just type the bolt pcd in and number of teeth and it will auto generate the ring for you so you can save it as dxf autocad etc

[PolyTube Cycles]

Thanks to those who helped me (on and off-list). 

Mike, I envy you for your CNC setup!

Cheers

Kevin

[Adam Sklar]

Hey Mike,

Any chance I could grab that from you?

Thanks!

[Mike Mcdermid]

Aye I will send it

[Dan Chambers]

Hi Mike,

I'd be interested in the SW model, too.

It's one of those things which I've been meaning to get around too...

All the best,

Dan Chambers

[Mike Mcdermid]

[Mike Mcdermid]