Dave Krafft's new Race Bike
Dave's next racing bike is very light. (A few days after the meeting he added the rest of the parts to make it ridable, and it weighed in at 25 lbs. Very respectable for a bike with compound gearing. M.S.) "Pretty healthy step-up" on the compound gearing. Almost 200 gear inches at the top. Front handlebar extension tube saved a lot of weight by going aluminum.
Dave thinks the 1.75" x 0.035" main tube might not last too long, but he's only looking for one season as a race bike.(Mark disagrees. He's planning on a 2" x 0.035" main tube with about twice the unsupported span, and thinks Dave's frame should have a long life.)
Old Style TA cranks are about two inches narrower than typical new stuff. Narrower cranks mean he can have a skinnier shell around it. On the old TA cranks, the large ring bolts to the crankarm, and the inner bolts to the outer. However, these two weren't meant to go together, having different bolt circles. Drill, tap, lock-tite - now they fit fine. Crank arms are swapped left/right, for chain on left side to mid-drive. He swapped pedal axels and lock-tighted the threads.
BTW TAs were some very light cranks, they were used on the Gossamer Albatross and Condor HPAs.
Fork - Dave performed a "Jon Sharratt fork surgery" on a road fork. Not as pretty, but the same method.
The front end of the frame looks odd, because he wanted a high crank, but a low main frame tube. The low frame is to allow a low stepover height when entering and exiting after he gets a race fairing on it.
SRAM Quartz derailleur on back. Mostly plastic, it's VERY light. Plastic "Chain Watcher" to keep chain from falling off the inside tiny wheel of the mid-drive. Dave designs out as much crossover as possible, and only shifts on the back while racing. Keeps you from screwing up and missing a shift. A 650x23 rear triathlon wheel, 571mm in the bead-seat, with a very deep section. Got a good deal on the wheel, but tires are super-spendy. "Should keep 'em under 160 psi."
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