Belt Alignment Troubleshooting: Alpha 2Updated 12 minutes ago
The Gates SideTrack drivetrain on your Alpha 2 is designed to operate smoothly and quietly for thousands of miles. If you notice a noise emanating from the belt, such as a clicking or popping sound, while pedaling or backpedaling, then the belt alignment is incorrect and must be addressed.
A clicking or popping belt can result from improper wheel installation, a loose rear cog lock ring, an incorrect spacer stack on the freehub body, or a loosened dropout plate. Rest assured, we've been able to address all issues. And you can too!
Follow this tutorial to address a popping and/or clicking belt on your Alpha 2.
Tools Required
- 19mm wrench
- Gates belt whip (or equivalent)
- A basic strap wrench will likely work if you don't want to go in on a Gates tool.
- The Park BDT-1 is unlikely to work since we're working with ST, not CDC, CDN, or CDX.
- Park Tool BBT-9 or equivalent
- 4mm T-handle hex wrench
- 5mm hex wrench
- Cassette spacers
Troubleshooting
- Begin by ensuring the rear cog lock ring is tight per the maintenance suggestions (step 6)
- If this doesn't resolve the issue, move on to the next steps.
- Remove the rear wheel
- Remove the rear cog using the Gates belt whip and BBT-9 (or equivalents)
Belt and suspenders? How can you trust someone that doesnt trust their pants? JK. Hi! - A 14mm spacer exists inboard of the rear cog. Your goal is to use a different cassette spacer stack to reposition the cog inboard toward the motor. Play with different iterations of different-sized cassette and/or bottom bracket spacers. Our shortcut to success is a small spacer (2mm), a large spacer (4.5mm), the cog (flipped), another small/large spacer combo, and finally, the lock ring.
Factory 14mm Spacer
Small and large combo of spacers - Flip the cog (letters inboard) and install it onto the freehub body. Ensure the lockring has full thread engagement and is adequately torqued.
New spacer stack, who dis? 
I thought you said this was inboard? Tastes like outboard. - Note the new orientation of the cog on the freehub:
Lovely! - Reinstall the rear wheel and adjust belt tension if necessary.