smontanaro 

Are the profiles of the teeth for track chainrings (and cogs) different than their road counterparts (let's ignore all the *Glide stuff)? I mean other than the 1/8" v. 3/32" width. I always assumed the teeth on track rings and cogs were a bit taller, since shifting isn't required. I've never bothered to check though, and can't find anything on the nearly infinite www to support or refute my perception.

repechage

I don't think there is an appreciable difference, the area above the tangent of the chain roller does not take any stress, the higher teeth may help guide the chain if the chain is loose...

3speedslow

I'm thinking the main diff is what you already mentioned, 1/8 vs 3/32".

ThermionicScott 

I don't have a link to support this, but I've read that chainrings/cogs for pure single-speed operation (track, coaster brake, etc) will have more of a "soft-V" tooth valley where the base is no wider than necessary to accommodate a chain roller. I would imagine that this gives the most strength for a given sprocket width, and possibly allows a chain to apply more even force on multiple teeth as it elongates.

With derailleur systems, the teeth can take on different shapes. Shimano's "W-Cut" chainrings had noticeable flat spots in the base of the tooth valleys, supposedly to make them quieter and more efficient.

P.S. I'll gladly accept correction from experts if any of the above is off.

Darth Lefty 

There was plenty of experimentation by many manufacturers as to tooth shape, to improve shifting. Pastor Bob will likely chime in. He cleaned my 1970s Regina which has teeth shaved on the side, and I think I have a freewheel around here that has the groove in the teeth. The outer ring on a Schwinn Ashtabula-style double has a shift ramp pressed into it, though technically that's not teeth.