Preworn teeth, and only every second one at that, in future Shimano chainrings

[Andre Jute]

The image is from BikeRumor
http://www.bikerumor.com/2016/02/01/is-shimano-losing-teeth-to-make-lighter-better-shifting-chainrings/
where the editors explain:
"Want to reduce weight? Cut drag and friction? Easy, just remove every other tooth."

Yup, and pre-degrade the teeth, which will save 9.137529 (recurring) nanograms of mass.

Joking aside, there's a good deal of technical interest in that article of possible ways to lay out driving teeth.

[Bill C]

looks a lot like inch pitch, i spose it uses an i-chain  ? it will be elliptical chain rings next, this modern tech stuff where will it all end?

[mickeg]

I have seen track chainrings that look like that in the past, but that was not for derailleur bikes.

I took the attached photos in the Smithsonian Institute in spring 2013, a museum in Washington D.C.  The camera I had does not have a good flash, so I was trying to take photos without the flash, but it was quite dark so the photos are pretty poor.  Sorry.  The first two photos have a vintage bike with that same tooth pattern on the chainring.  I do not recall for sure, but it is possible that this was a Wright Brothers bicycle.

The third photo, is that a chainglider?

[Bill C]

some more pics here http://bikecult.com/works/chainwheel.html

[Andre Jute]

It looks like early cycling manufacturers soon agreed on an inch-pitch, Bill.

That surely looks like an early Chainglider, George. Presumably the wax model is of Major Taylor, the early cycling hero.

[il padrone]

It looks like early cycling manufacturers soon agreed on an inch-pitch, Bill.

That surely looks like an early Chainglider, George. Presumably the wax model is of Major Taylor, the early cycling hero.

Major Taylor was a black man 

[Andre Jute]

Presumably the wax model is of Major Taylor, the early cycling hero.

Major Taylor was a black man 

[il padrone]

Guess my colour-blindness is playing up. That dummy does not look black to me