Anyone got one of these Y-frame folders? They look cool but I'm not sure what the practical difference between it and the regular straight frame (dahon launch, zizzo, fnhon blast) are. There's not a whole lot on the English internet about them and it seems difficult to get a built up bike with one whereas litepro's site sells the blast.

I owned a Fnhon Monsoon frame, but ended up selling it without ever building it up. I didn't like the top extension tube due to its vulnerability when folded. In Al-alloy, I'd go for the FnHon Blast instead.

Ya I was wondering about what happened with it. I spent a couple hours scouring Indonesian youtube and facebook groups and I still don't think I've ever seen a single picture of one actually folded lol.

For the blast do you know if the Litepro website does Black Friday sales? folding bike /fnhon bike/litepro bike – Litepro official store I don't want to order one a week before it goes on sale XD

I do not know, sorry, for I've never shopped there.

Having two sets of tubes or structural elements like that, increases the frame "depth of section" in longitudinal bending, and this being a cube (x^3) relationship I think, means a little increase goes a long way, so should give the frame great strength for better fatigue life in the long term, and also reduce stress on the hinge.

I achieved essentially the same thing but reversed, with a typical (high-position) monotube (Dahon Speed), and then adding a tension cable underneath (a la Dahon Deltech feature on their newer frames), which can be very slender as it is in tension and not compression. This provides a full "main triangle", so now the hinge is loaded mostly in compression and not bending. The cable or line simply bends easily when folded. Dahon is slow in making available an aftermarket version of Deltech so I improvised one from kevlar line, can also use UHMWPE (AmSteel, Dyneema, et al) as all are high strength and very low stretch.