You can get them in regular, uniflex or stiff, depends which ones you have/get.
Stiff shafts are for people who have a swing speed of around 90+ mph, so if you are happy with how you hit your driver you could get stiff shafted irons, but you don't have to. If you currently use regular shafted irons and you hit the ball either excessively high or tend to hook or pull it, you should go to stiff. For best results go get custom fit and they will be able to tell you which shaft is best for your game.
Take the grip off. If there is a green mark at the butt end of the shaft the shaft is stiff.
The difference between regular flex and soft flex graphite irons are the suitability to the needs of the golfer. Stronger golfers swing faster thus needing the regular flex. Ladies and seniors, on the other hand, need soft flex graphite irons.
A stiff flex is the flex of the shaft usually for swing speeds between 90 and 105 mph.
Stiff flex is simply a stiff graphite shaft. The flex of the shaft is basically how whippy it is, stiff has a little whip in it, but less than a regular. 60 would be the weight of the shaft, 60 grams.
I think the synergy is but i havent had a chance to use the stiff flex.
A wise man's guess would be Stiff Regular flex, between Stiff flex and Regular flex.
Callaway make this shaft flex, it is designed in between a regular flex and stiff flex shaft.
for longboards is flex 1 stiif or bendy
They would be extra stiff flex.
no
Stiff flex would be ideal. But you could try x-stiff to see which one is best for you.