2009-01-26

Bicycle Ten Project: Sizing



When I used my Fuji Aloha CF2 frame to build a road bike, I was left without a time trial bike. The Aloha CF2 geometry did not let me get forward enough (doing so would require a $150 seatpost), and the head tube did not let me get low enough. It does make a brilliant road frame. To fill the gap, I purchased a used "Motobecane Nemesis" frame. It's the same exact frame as the older 2006 Fuji Aloha. It's aluminum, fairly stiff, and not particularly light at about 1680 grams. It gets the job done. I was able to use many parts from the old TT rig, and spares for everything I didn't have. The only new part that I needed was a front derailleur, since this bike uses a braze-on attachment.

The bike was filthy when I got it in the mail, and the spacers were cold welded to the aluminum steerer! It's amazing how corrosive human perspiration can be. A star nut setting tool was the correct tool to force the steerer and spacers apart.

Anyway. The frame uses a 27.2mm seatpost, meaning I can use existing seatposts to get the geometry I want. The top tube length is 560mm, the seat angle is 76 deg, and the head tube is 112mm long (I think). By lowering the aero bars, and dropping the pads to the lowest possible position, I get what looks like a good time trial fit! My back is flat, the angle of bend in my arms is about 110 degrees, and the saddle is the correct height (slightly too high if anything, but my hips don't rock at all, and I'm used to a high-saddle position).

I even took a short video of a sprint on the stationary trainer. I discovered that using a disc wheel on the trainer is a bad idea: the wheel acts as a huge resonating chamber, and finds every single harmonic through the frame. It was unbelievably loud.