So I flipped my belts “inside out” and I noticed the inner taper is way off on these dos belts. The ribbed belt is the stock pirelli belt. It’s from the 80s and I’m pretty sure the bike had like 1000 plus miles on it from the ODO when I got it if I remember correctly. I’ll double check tomorrow but even age could cause shrinkage I was getting anywhere from 8.5-9 mm I’d bet new they were 9.2mm.
The new DOS belt (smooth) is significantly thinner. Both belts outer “wider” edge is 13mm so the taper is way off and it’s deff not gripping the way it should. I’ll contact dos about it and see if I can get some of their nos pirelli belts if I send these back.