I dunno about that, I have this here 39t that definitely fits on a 144 crank:


OK jokes are dangerous, someone might think I'm serious. Yes 41t was the smallest that Campy made, and probably the smallest possible without using String Theory or higher dimensions. OK maybe a 40t could be made with some "compromises", like say if you didn't need it to be strong or durable, or run smoothly without the chain clunking over each of the chainring bolts.

Have you seen this website that lets you CAD your own chainring? Fun stuff. Here's what a 40t ring would look like on a 144 BCD.




Note that it helps that 40t is divisible by 5, so each of the holes is "clocked" the same relative to the chain bushings.

Remember everything inside the red circles is gone, drilled out, "air". How much chainring remains for transferring force? And the spider arms of the crank usually come up even higher (radially) than the red circles. Though maybe you could get away with severely trimmimg the spider arms to where the chainring holes are completely "daylighted", for chain crlearance above.. Still strong enough? Do you feel lucky? Actually I might just try it for yuks. Please stop me if it's been done already.

Similar deal with the 30t minimum for Campy triples with a 100 mm BCD — you can limbo under that a little, to 29t, if you compromise, in this case using 6 mm chainring bolt holes instead of the normal 10 mm holes. Here's mine, it works great:



Chainring originally by Willow, modded by me. Bolts are 6/4 Ti (of course).
In case you're wondering, the chain doesn't clunk against the bolt heads, they just miss, and it runs smooth & quiet. No downsides other than a PITA to make, all for one measly tooth smaller.

And some bragging rights? No, not even, when you can go buy much smaller granny rings any day, if you just give up on those hopelessly obsolete Record triple 100 mm BCD cranks. You can even even stick with Record but have a regular Strada drilled at 74 mm BCD, like any sensible person.

I hope no one will double-drill a "factory" triple, that already has holes at 100 mm. You could do that, and the crank wouldn't break, but (to quote Richard Nixon) it would be wrong. Or at least look dumb.

Mark B