I have a gsr crank and a type r crank right here at my desk lol and there is a difference between the 2. Originally the gsr crank spun a bearing so i had to find a crank and I got the type r. the stroke on both cranks are exactly the same (87.2) opposed to the si (77) but the type r crank looks to be a bit beefier and it definitely has better counterbalancing. It also weighs a bit more too and the balances arch out a bit more than the gsr.