when I were a lad I had the bright idea of renting a bike in Chaweng, Samui even though I wasn't licensed and had zero experience other than a half day on a scooter in Kuta, Lombok a few months earlier.
I don't know where Khao Phom hill is but I do remember a quite steep windy hilly section between Chaweng and Lamai that I traversed maybe ten times or so. a few times under the influence of alkyhol because young and bulletproof.
Thank Buddha I made it off the island alive and in one piece ????