Cable stretch is inevitable with new builds and fresh housing, and the traditional solution is tedious: shift through the gears repeatedly, adjust the barrel, repeat until the cable settles. The Park Tool BT-2 Cable Stretcher eliminates that break-in ritual by pre-stretching cables before you button everything up. Clamp the tool onto the cable, pull the lever, and the initial stretch happens in seconds instead of miles.

The tool works on both shift and brake cables, which makes it useful during complete builds or when you're replacing just one line. Shift cables stretch enough during the first few rides that indexing goes off—annoying for the customer and a callback for the shop. Brake cables stretch less dramatically but still enough to require lever reach adjustment after bedding in new pads. Pre-stretching addresses both issues before the bike leaves the stand.

The BT-2 uses a simple lever mechanism with replaceable jaw inserts that grip the cable without damaging the strands. You're pulling against a fixed anchor point, so the stretch is controlled and consistent. The tool handles standard 1.1mm and 1.2mm shift cables as well as 1.5mm and 1.6mm brake cables—essentially every cable diameter you'll encounter on road and mountain bikes. It won't work on compressionless housing or internal cable systems where you can't access a straight run of cable, but for traditional setups it's significantly faster than the ride-and-adjust method.... Read More