Tech: Installing Truvativ’s HammerSchmidt
You’re totally pumped on the new Truvativ HammerSchmidt. You rush out to your bike shop the day it arrives and run home with a box-o-HammerSchmidt under your arm like it’s Christmas morning. Now all you have to do is put it on your bike and go shred, right?
Well, sort of.
SRAM’s Eric Schutt stopped by the Bikemag mothership the other day to show us how it’s done. We rolled tape to share it with you.
Installation is best left to experienced professionals, but if you’re thinking about HammerSchmidt there are a few prerequisites.
First, you have to start with a frame with ISCG 03 or ISCG 05 tabs on you bottom bracket shell—the two industry standards for mounting chain guides. While the two standards dictate precise locations for mounting tabs to be positioned around the bottom bracket shell, the degree of accuracy to which frame manufacturers have met those standards has varies wildly.
Secondly, you’ll need a frame that plays nice with the granny-gear torque vector action of the HammerSchmidt. In layman’s terms—you need the main pivot of a single pivot, for example, has to line up with the HammerSchmidt’s 22- or 24-tooth single ring. Problem is, this rules out a lot of virtual pivot point bikes and single pivot bikes optimized to work best in the middle ring. HammerSchmidt will still work on these bikes, but the torque from the granny gear chainring position likely will create some funky-freaky influence on the suspension.
Lastly, if you go out and buy HammerSchmidt you’ll be running home with three boxes—not just one. The biggest box is for the crank arms and internal planetary drive system, the next is for the proprietary shifter and the last is for the proprietary bottom bracket (which needs two bottom bracket tools to install—one ISIS-style and the other Hussefelt/Shimano style.