Big manufacturer's like fuji-ta do a range of strength options for frames depending on how light the customer wants the frame and more importantly how much they are willing to pay. Unsure myself about the strength variation of the different hinge designs they do but it's clear they will fit a additional strengthening section between seat tube and bottom of downtube plus another additional plate between underside of top of downtube and headtube. You see them either fitted or not fitted to the same frame designs. It's an additional process and obviously adds to the cost of the frame. My point is I don't think manufacturer's are unsure what makes a strong frame they know exactly what to do but have to balance it with manufacturing costs and performance of the bike. Yes a hinge design can be improved but to be certified the bike will have to undergo a series of tests of the frame.

Anyway I was going to ask if anyone had seen any good videos on the Tern factory or factories. Can't seem to find any. Easy to find Brompton or Dahon but I was just interested to see their processes and whether aluminium frames are manufactured in-house or bought in. It can be another factor where a supplier of poor frames is simply dropped and orders go to another factory. Alternatively they originally bought in the frames, then later started manufacturing them in-house to a lower quality at least initially. I'm just making the point other factors may be in play rather than simply poor hinge mechanism replaced with improved hinge mechanism.

I can't remember the brand but it won't clearly state the aluminium of its frames, gives the aluminium some meaningless generic name because it juggles frame manufacturers for the same model and some are 7005 and some 6061 depending on manufacturer and end market.

Actually I remember now its Specialized with their A1 Premium Aluminium which of course doesn't exist as a real aluminium material. Sometimes with frame recalls you need to know the frame number not just because of when it was made but who actually made it. If the frame recall doesn't effect all bikes sold over the same timeline then multiple manufacturers may be involved.

I'm pretty sure when Tern started they were buying in frames, I think I read it somewhere or saw it on a video and considering their hydroformed design etc they look pretty much state of the art for aluminium. It's certainly possible they made the investment to bring in such technology but considering their high retail price I think they could certainly afford to pay another manufacturer to manufacture their frames.

I'd also point out that companies like btwin design their own frames but have them made by large manufacturers in China like fuji-ta. The big recall of btwin e-bikes that meant 4 years of bikes had to be recalled was their design and fuji-ta's own designs are nothing like those of btwin. If Tern designed their own frame and fuji-ta followed their specification exactly I don't think you can really criticise the actual manufacturer. Not that I'm saying that is the scenario for sure.

Just as an example of a folding bike, Btwin originally bought in a generic fuji-ta designed folding bike to rebrand as their own. It's a common design you see under many different brands with or without additional strengthening.



They then replaced it with their own design which no one else sells.



My point here is creating your own unique design is higher risk. Using a tried and trusted design that has been used by a huge number of brands means its gone through all the feedback of companies complaining of where a frame has failed for them and where they are getting returns etc. You have a process of improvement. The process of overhauling the frame designs every year to remain fresh on the marketplace is not always a good thing.

Also on the bike above it clearly cost Btwin to design their own frame, their design is more expensive and they have lowered the quality of components to compensate. What was a entry level Shimano derailleur is now a no brand generic derailleur and other parts have been lowered in quality. On the single speed version you do not even get folding pedals now. The earlier Hoptown model was far superior even if dull styling.