i started snowboarding in 2009. and when i rented i usually got around a 140cm. im 5 feet tall and 135lbs. when i bought a snowboard this year the guy said i should have a 148cm. ive now used my 148 twice and am falling way more than i used too. is 148cm too long for my height/weight?
I'm 5 ft 105lbs and I ride a 143 cm, board. 148 cm doesn't seem outrageous, but honestly, it's what you are comfy with! I have ridden down to a 137cm. I would ask around friends to see if someone has something smaller for you to try out see see if it works out better for you. It could also be a stiffer board than you are used to.
your chin is only a factor when landing harshly and slamming it into your knee.... or in relation to potential frostbite.
absolutely nothing to do with board size... board sizes are based on weight to height(center of gravity) ratios... bending too much board could potentially be a control problem for a shorter 140 lb'er while the same board could work out well for a taller 140'er.
if you're on a stiffer board you may want to consider a stiffer binding to get more response from your board.
i agree that 148 would be a good cruising board for a 135lb rider... my gf at 120 lbs and 5'3" rode a 149 burton feather perfectly fine, as well as a 2005 5150 dynasty.