SRAM's new RED AXS front derailleur is engineered tightly enough around specific chainring sizes that eyeballing the alignment during install isn't really an option — the mech needs to sit at a precise height and angle relative to the outer ring, and this setup tool is how SRAM gets you there. It clips onto the derailleur cage and references off the chainring teeth, holding everything in position while you torque the braze-on bolt to spec. Without it, you're guessing at the 1-3mm cage-to-tooth gap that RED AXS shifting needs to work correctly.

There are two versions of this tool, and picking the right one comes down to which Pro Chainring you're running. The Red version (00.7618.179.000) covers 50/37T, 48/35T, and 46/33T chainrings — the standard-range options most riders on RED AXS E1 will be using. The Green version (00.7618.181.000) covers 56/43T, 54/41T, and 52/39T chainrings , which is the Pro-range side of the lineup for riders running taller gearing. The 52-56T tool also ships with a 0.7mm shim that gets used during the alignment process on those larger rings.

One thing to flag up front: this tool is specific to the current E1-generation RED AXS front derailleur and the Pro Chainrings that came with it. It's not a universal front derailleur alignment gauge, and it isn't cross-compatible with older eTap AXS front derailleurs or with Force/Rival AXS front mechs — those use different setup procedures. If you're building up a RED AXS 2x drivetrain from the box, or servicing one that's been knocked out of alignment, this is the tool SRAM's own setup documentation calls for.... Read More