|
|
Subject: SRAM (formerly SACHS) Power-links
From: Jobst Brandt
Date: May 12, 1999
The SACHS Power-link can be separated easily alone but not when in a chain. The link is designed not to open by axial compression alone, typically when a new chain is used on worn sprockets, where skipping over teeth can cause inertial compression by the trailing chain. To prevent this occurrence, a recess around the head of the stepped pin makes more than a half circle, preventing the pin from sliding in its slot. That means the side plates of the link must be pressed together, taking up side clearance, to raise the head of the sliding pin above this retention.
To open the chain, find the link, make an upside down U-shape of the chain with the link as the cross bar, the adjacent chain hanging down, grasp the link diagonally with pliers across the the corners to which the pins are fixed, not the corners with the keyhole slot. Pushing the side plates together assists removal but is not essential, the diagonal force having a lateral compressive component.
Before using a Power-link, put it together to see why it does not readily slide from closed to open position. Road grit makes this even more difficult.
[Power Links are available for 8-speed and 9-speed chains. The 8-speed ones work also with Shimano chains, in my experience. The 9-speed ones are reported to cause skipping when used with Shimano chains. 10-speed Power Lock links are good for only a single use. There are other brands besides SRAM, which work with different chains: see the glossary entry on master links. -- John Allen]
More Articles by Jobst Brandt
Next: Aligning a Fork
Previous: Electronic Shifting
Last Updated: by John Allen