The linkage is similler to specialized FSR, but the rear piviot is on the seatstay vs. the chainstay.
I understand this design is essentially a single piviot and suffers from "brake jack" is this all or are there more disadvantages of this design?
Transition Dirtbag, Kona Roast 2002 and specialized BMX
Not much imo.
And no it isn't like the fsr. It is missing one key feature. The horst linkage. Which is required to be in front of the dropout and below the dropout. Changing the position of this changes the riding characteristics drastically. It will perform like a single pivot. The biggest problem with it is going to be, under braking, the suspension will lock. This will, during braking, turn the bike into a ht for time. That said, sme people don't notice so it isn't as big a deal for them.