Every few months Whit @Meriwether Cycles hits me up for help on a cool project. In this case… A titanium, fat bike, drop bar, twin tube, klunker, with sliding dropouts. This bike wins the custom framebuilding bingo card.
This is the first time I have seen CAD being used to sequence the compound bends to achieve the twin top tube + s bend stays.
- all 3 bends must be done in one shot
- Tire clearance for fat bike tires
- Cobra bender is limited to 36deg w/ 19mm titanium
- Bends must have enough overlap at the seat tube miter
- Left and right stays must be exactly same (done in tandem)
- titanium means expensive mistakes
Whit sent me bikeCAD which I converted 3D in order map out the bends and tire clearances :
From there, I created the sequences of 2D drawings which show the:
- bend location
- bend angle
- phasing angle
Thanks to the CAD, I knew it was physically possible, but we still had a three-hour call to figure out how to do the bend sequence in real life . Whit caught a pretty big issue: due to springback, the Cobra bender maxes out at 36deg w/ 19mm titanium tubing. The first draft had the SS-TT bend at 37degs! We ended up massaging the geometry and bends to bring it to 36deg.
This is all Whit’s work, so make sure to give him some kudos. I am always impressed by his level of fabrication skill.
I’m really happy about how this one came out!