Gemini Beta Road

The road bike was finally completed. A nice comfortable road bike. Solid.

A note on seat tube angle. Some will instantly comment on the 71 degree seat tube angle on this frame. This frame was designed for use with a 0mm offset seatpost. Using a traditional 25mm offset post would have resulted in a 73 degree seat tube angle. 73.5 degrees with a 30mm offset seatpost. It is important for the novice designer to remember that the two work together along with the saddle to place the sit bones in the right position in space. Many people do not understand this.

For reference, this ended up being the exact fit that I would have on a Giant TCR Advanced SL 0 medium-large (53.5)¬†with a 20mm offset post and an additional 5mm spacer under the stem. Very different bikes in the end but it shows that while this geometry look nontraditional, the fit is in line with what’s going on out there.

For folks not used to looking at road bikes with rise stems, sorry. It’s hard to be a dinosaur after the meteor hits. Stacking a bunch of spacers under a stem is for blithering idiots. So you can relate, I could instead use a -6.0 degree stem with an 80mm length and an additional 40mm of spacers to achieve nearly the exact fit shown here. …but I’m not that dumb. Comparing to a 54cm Specialized Roubaix Compact which has the same front center as my bike, my fit would require a -6.0 degree and 100mm stem, the exact stem the bike comes with stock. Ha!

Segmented drive side on OX Platinum chainstays. Super lateral stiffness. Custom bent.

IS41/EC44 tapered headtube brings the HT diameter down to 1.500″ for improved aesthetics over ‘beer can’ head tubes.

Seatstays are bent very slightly.

BB86 bottom bracket.

Dimensions on print reflect 700x25c tires.