[Joe G.]

1687 and 5400 have been running 30t GT2 with 15mm belts inside of tubes for the past three years with no failures. It's overkill and we know it, but we like zero failure systems. Our resource set does not enable us to take the meticulous tensioning steps that a team running right on the edge like 971 does, so we like the insurance. When we were doing research for our switch to belts, I believe we saw some pretty spectacular failures in 18t systems.

If clearance is your concern, perhaps consider an alternate form of structure. We do full sheet metal chassis builds with a multi-piece tube which contains our belts, and one of the many reasons that we love it is that we can make our channels any size we want, instead of being limited by commonly avaliable extrusion profiles. The tube height is often a pretty ugly decimal, but it doesn't matter for our fabrication process.