Is it possible to fit a 36T chainring on a 34T frame? I'm thinking of building a bike from scratch around a Commencal HT AM 2018 frame, which normally comes with a 32T front chainring (1x setup) and says it takes 34T max. However a 36T would be ideal for my riding style, and the difference in radius measured at tooth tips between 36T and 32T chainrings is less than 9 mm (by calculation, roughly 72.9 vs 64.8 mm). Given such a small difference, I think 36T  would fit based on this photo, which features a 32T chainring (you can see more of this bike's photos here):



However, I have no practical experience, and it would be a pretty expensive schooling if I bought a good chainring and found it does not fit. Anybody knows whether this would work?
I think you will have to go with Commencal's specified max chainring size.

Radius of chainrings at center of chain rollers is:

32t: 64.8mm

34t: 68.8mm

36t: 72.9mm

If tooth profile is the same, the tips of the teeth will be a constant height above the center of the rollers, so a 36t ring will be approximately 8mm greater in diameter than a 32t - as you calculated.

Doing a rough analysis on the photo you provided: the gap between 32t ring tooth tip and frame looks to be about the same as the depth of a tooth.



If we assume the tooth depth is the same as the chain roller diameter of 7.9mm, you only just have 8mm clearance. If the chainring does clear, any frame flex will likely result in the ring hitting the frame.