This was a fun lesson to learn! Luckily it was a far more hilarious than dangerous experience. It broke at about 1mph as I hopped up a tiny asphalt lip, less than a quarter mile from an aid station at Grinduro PA. I was bummed to not finish the race since I had been doing quite well, but was happy to walk away all smiles and no scrapes. This was my third frame and I have thankfully learned a lot since then!
Here’s what I think went wrong:
- I built with a totally un-spec’d Nova pre-bent down tube, backwards. I am thinking I cut off too much in what was supposed to be the “BB end” of the tube and maybe got into the butting transition.
- I had replaced the head tube after first brazing it in crooked, so the down tube went through two heat cycles.
- The lower two internal routing ports were right next to the fillet on the HT/DT joint and likely saw the most flex/stress.
- None of the routing ports were reinforced in any way.
- I was absolutely ripping it down some very chunky singletrack earlier.
I don’t think this is an “internal routing is cancelled” sorta thing since it’s a bit of a perfect storm of things done wrong, but I’ll definitely be way more careful about how I poke holes in the down tube going forward. I’m happy to have learned this lesson on a personal frame and not a customer’s!