What the brochure doesn't tell you is that the regular cage and the GT cage are interchangeable and the the swap is easy. This had two advantages. Raced you last race but love that bike? Buy a triple and get your hands on a GT cage. Or, just riding the bejessus out of the bike and absorbing a few crashes while you are at it. Wreck the RD? Almost always the damage is to the parallelogram or the cage, not both. Go to a shop and ask to look through their box of trashed Cyclone RDs. Pay them $5 for one with the half you need in good shape.

I kept a Cyclone going 25 years and who knows how many miles doing the $5 rebuilds. It saw both style cages. My only gripe with the Mk I is that it couldn't handle 130 OLD. (130 in 1975? Who'd a thunk!)