The grooves are very similar to Premier boards, except much sharper. The middle groove is deep and wide, definately perfect for rail locking.
As for the concave, nothing went "wrong". The kits are fine, the team just agreed on how it wasn't worth spending on for our customers. We all felt it didn't noticably improve feel or flipability in any way, and only added unecessary weight to the board. We've all been riding without concave for years now, and we don't feel we have any problems doing flip tricks.
At first we were going to leave it on because it had been announced and all the concave kits had already been manufactured, but considerong how none of our riders wanted the concave top, we figured our customers should also get what we beleive to be the best. Or atleast the possibility to have a board without it, which is why it doesn't come stock on the boards anymore.
I know everyone's going to be skepticaly about this, but we wouldn't have thrown away so much money if it really was as good as everyone hoped.
For those of you who are still convinced they need it, it'll be up for purchase on the ambition site, but it's honnestly not a feature we recommend spending on. Invest in some X-treme grip instead, or a good pair of shoes. That'll make a real difference.Remember, all pre-ordered Smage of Gerlach boards are getting a free concave kit. If you don't want the free kit anymore, e-mail us at firstname.lastname@example.org and we will refund the price difference.