Hello, aspiring freestyle beginner here, wondering what fin size to choose for entry level moves. Was looking at K4 Bubble fin. Board is JP Freestyle 99, stock fin is 22cm. Sail size 5.0, Rider weight 80kg. Should I go to 20 or 18cm? I'm worried that I will be underpowered on the 18 in normal conditions (16-20kts)
Regards
18 for sure, you will want to go shorter in the long run. Learn to sail with the shorter fin at the start and it will make the transition easier 
Tbh you'll find the k4 fin is pretty underpowered for its size, there are better fins out there. I had the 18, didn't rate it. Might be okay as a fin to step down to when the wind picks up, but I sold mine.
my main fin is a royal flush original version.
it's a quality fin. planes early, has excellent top end, goes upwind well and has plenty of acceleration.
I use it as a single fin and as the middle fin on a thruster setup. I'd go with the royal flush if it were me. choco also say it has more grip than the starfish which is important for lower wind sailing and heading upwind.
I think if it gets to being a struggle to decide between the v1 and v2 then you're overthinking it. get whichever because only you are going to know which one you like the most.
unfortunately you just gotta try one but do it with the belief that choco make great fins and those royal flush fins are excellent fins.
re size I just don't know. you're much lighter than me and I've got no idea what you are already doing. my thoughts are if you are not planning then you're not doing tricks so on the bigger side is better. looking at the choco site, they themselves are saying the 15 and 17 are highly technical fins which i'd think is probably a reference to them being so small.
given that I'd go the 19 or the 21 and probably the 21.
Hi gryphonas.
It sounds like you have the 22cm freestyle fin that JP used for several years pre (and including) 2012. This fin does nothing well, so to speak, while other board brands were supplying better fins with their boards at the time. Not sure why they persisted with it for so long.
2013 and 2014 model JP freestyle fin (both identical) is much much better imho - planes earlier and accelerates faster, and is 20cm.
A thin 25 - 27cm race/speed fin with a narrow cord, cut down to 18 - 22cm will likely be noticeably better than the 22cm jp fin.
If you cut one to ~22cm to begin with, get used to that for a while, then slowly trim it down more, it might make the transition to a dinky fin a bit easier
i learnt vulcans, grubbies and forwards with a 27cm freeride fin, so it is certainly possible to do it all with a longer fin, but everything slides more effortlessly with shorter fins. I think a day spent comfortably planing on a bigger fin, which allows you to attempt tricks, is better than a day spent barely planing and unable to attempt anything because the fin was that bit too small :)
