TobyGadd

I successfully upgraded my Cannondale 29er Mountain Tandem (M/L frame) with a Gates Carbon Drive CDX timing belt. 66-tooth pulleys and a 250-tooth 8mm belt made for a perfect fit. The tricky part was getting the 5-bolt pulleys onto the FireX 4-bolt spiders. Fortunately, I found this awesome 104mm to 130mm BCD ADAPTER (104mm to 130mm BCD Adapter — TI CYCLES FABRICATION). Due to the frame not being as straight as one would hope, I also added a some chainring spacers to dial-in the chain line.

I figured that it was worth documenting this upgrade since I couldn't find anything about it anywhere on the web. Maybe this post will save someone a bit of time down the road.