Just made a New Set couple weeks ago...
It takes about 1/2 hr. to convert a set to a 3 strap binding...
4- 10/24 x 1" bolts with lock nuts, used to Lock the Highback in an upright position
2- 3/16" x 1" bolts with lock nuts and 2- 1" fender washers to hold 3rd strap on to top of highback
2 Top Straps made from Leather, Nylon whatever with ratchet buckles, basically an attached Booster Strap
You do not need a Stiffer boot with the 3rd strap... You can adjust the strap when you are riding from tight for Groom to loose for Pow
The major improvement for me is that the Ankle is removed as the primary Joint and the addition of the 3rd strap moves the force
up toward the Top of the boot... My Son carves circles around me without a 3rd strap, so No you do not need one to Carve in SB.
I started snowboarding so I could Surf down the Hill... The combination of the 3rd strap, snow conditions here and the Style of Surfing
I learned many years ago on a longboard all came together for me personally and I feel fortunate to have enjoyed it all these years.
The Forward flex is "similar" to a HB while the Lateral Flex is similar to an Old soft HB with a Sidewinder binding or plates. I ride with both feet in the 45 degree range which is Not what you are supposed to do with SB and if I was riding Duck I would not ever have needed a 3rd strap to begin with. The reason I do not use HB is they are to exact or to stiff Laterally to let me Play the way I like, which is a personal preference. This will be season 27 with this set up... I know what I like and it is fine with me that I live in this world somewhere between conventional SB thinking and HB thinking. This is not a promotion or an attempt to get ANYONE on this SITE to convert to a 3 strap binding or my way of Riding. I can not achieve the same dynamics as my HB friends on certain slopes or conditions but that is OK, because at the end of the day at the end of the run we are All Smiling...
I appreciate my HB friends here for allowing me to share my Stoke as I certainly would not fit anywhere else?