Just a heads up for those who might have seizing issues using certain bottom bracket with the Riro crankset. Awhile back I was having issues using my Riro crankset with my BB86 frame using a ZTTO thread together bottom bracket. I noticed with the preload adjuster ring (on the non-drive side crank arm), it would seize up when trying to tighten the crank. I opted to remove the preload adjuster all-together, and lo and behold it fit. Though I'm wondering what might be causing the crank to seize considering there is perhaps less than .5mm of difference with and without the preload adjuster? As mentioned on here before, it might have to do with certain bearing sizes?
Anyways, the next issue is that it leave the adjuster threads on the crank arm exposed. I ended up using a black flat rubber band that come with new tires. The ones I have (rubber band from a set of Panaracer tires) was a perfect fit to cover the threads and when the crankset is torqued to spec, creates a nice weather seal.
Hope this helps for those who might be having issues!