Hello there! I am an owner of a 0615f in the philippines, I would like to know what will be the difference between a solas 13/19 & a 14/21? which pitch would be better for a closed course race? Thanks

When it comes to racing several factors come into play that dictate which one you should use. The layout of the course, the modifications to the craft, the conditions, you! The 13/9 will provide better acceleration. The 14/21 will provide better top end speed. If you race a tight, short course try the 13/19. If you race a big course with wide turns try the 14/21. You might find you need a combination of the two. Meaning you will repitch one or both of them.