Did you try flipping the belt direction? Not sure if they allow or even advise that, but it would be a simple test.
Originally Posted by
dvs cycles
I was thinking that too. Are the belts directional and did it get reversed in reassembly some time?
They are apparently directional; however, in talking with a dealer who has installed the belts any issue would become apparent during installation as described in
Co-Motion's Gates Belt FAQs:
If your belt is tracking properly, there should be zero to 1/2 millimeter gap between the belt and the outer guard on the sprocket. If you see a gap, this would indicate which direction to reset the lateral alignment of your crankset. You may want to try reversing the direction of the belt before making any changes- if you do so, remember to never derail the belt as you might derail a chain, always loosen the eccentric and slide the belt laterally off of the sprockets. There may be a slight difference in the cut of the belt when its driven direction is reversed, so we have found reversing belt direction to be effective in some cases. If you still see a gap, or the belt derails after reversing the belt, readjust your crankset's lateral alignment accordingly.
The
Gates FAQs also addresses belt noise, but it's the intermittent nature that seems to defy logic on the alignment issue:
My drive is squeaking or making noise, what’s the cause, and how do I fix it?
The belt can make noise when forced to run hard against the flanges on the sprockets. This can be due to sprocket misalignment, wheel misalignment, or run out in the drive caused by damaged components. Spraying water on the belt may quiet the drive for a few minutes, but the permanent solution is to correct the alignment or replace the damaged components. Another possible source of noise is a loose front sprocket. Using thread lock on the sprocket bolts alleviates this problem.