Unusual elliptical chain ring

[New Mexico Brant]

This is from a Feb. 1898 The Wheel :

 

[juvela]

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The Durham product takes it name from founder of the enterprise Roger Durham.

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Darren -

You have done an outstanding job with the description and images of your friend's item but have not told us if it's dentition is intended for 1/8" or for 3/32" chaine.

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[New Mexico Brant]

Why not try a square?

 

[Kickstand3]

Why not try a square?

View attachment 1069480

Wild !


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[49autocycledeluxe]

I'm thinking if that were a good idea we would be doing it today. I gave myself a headache trying to figure the physics of it all and what it would actually do.. I'm going to go lie down.

 

[juvela]

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Then there is the wheelbuilder's chainwheel...

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[Cowboy in NC]

Found a picture finally late 40s- made in Miami, Fla. ---Cowboy ------Notice is Skiptooth...

 

[dnc1]

Nice to see so much interesting info on this subject! Cheers people!

 

[Andrew Gorman]

I have one similar to the Durham, but with a double chainring. Since I don't even like Biopace rings I haven't put it on a bike. I have thought about turning it into a clock.

 

[dnc1]

Very nice @Andrew Gorman, please don't turn it into a clock!
What age do you think yours is?
I'm seeing 52 teeth on there, do you measure these things as you would a conventional chainring?
What cranks would it fit?
Here's a vintage twin ring example....