We used to make tube splitters in stainless steel and in titanium when the framebuilder needed retrofit a frame to a belt drive or vice verse. We stopped making these because it was too costly for both us and our customers. I still get inquires and want to know where to point my customers or to let them know that everyone else is handcrafting their own fix.
For clarification, I’m referring to the splitter/couplers that are used on the seat stay.
Looks like the Cast spliter option is from Allotec:
Available from Frame Building Supply:
Many years ago, maybe 10? I designed some and had them made in small quantities (in 17/4). They were originally just for our own bikes but we got enough enquiries that we started to sell them to other builders. I think we eventually gave the design to Peter at Ceeway and I think he continued to have them made but it’s so long ago the details are fuzzy. I don’t know if he still sells them but it’s worth asking.
Coco - I was one of those builders that bugged you about splitters recently. I ended up finding 16 and 19mm through Ceeway just recently. Steven, not sure if these are the design you mentioned but they are very, very nice. 17-4 stainless, 3-Piece (which is nice for slipping a belt through the SS). Message me if anyone wants pics or more detailed dimensions.
(Scroll about half way down the page and you’ll see them)