 The OB1 is my fairly new personal ride. If you see someone riding it around pittsburgh it is probably me because I only made one. I finally retired the "My Pretty Pony" that I have been riding for about 5 or 6 years. It was till going strong but it seemed to be time. The Pony was a longish bike with a 21" toptube. Its rear end could go to just under 14 inches. At the time that I made the frame I was into dirt jumping and these specs made sense. These days I have been riding more street and tech stuff so I wanted to go shorter. OB1's toptube measures a half inch less (20.5"). A bigger diference is in the rear. I designed it so that I could run a 36/13 gear with a full link removed from the (Pretty Pony's) chain length. It comes out to a tiny bit shorter than 13.75". The dropout slot allows the wheel to go up as far as 13 5/8" to make getting the chain on and off easier. Other than those changes most things are similar. The head tube angle measure 74.5 degrees. Seat is 71. I designed the dropouts to be pretty small and not very freewheel protecting. I wanted to shave a few ounces but I still cut/milled them from 1/4" 4130 plate. Special touches include two flame gussets and concave chainstay and seatstay caps. Other than that I am sorry to say that OB1 looks pretty plain. Other things I did to save a tiny bit of weight are, large vent holes, smaller headtube rings, 3/4" OD for seatstays insted of 7/8", machined BB shell, 1 3/8" OD x .035" wall toptube. Some things that I did not do to remove weight: no euro BB shell, no butted tubes, no .035" tubes in the rear end (all .049"), no integral headset. According to my pretty accurate shipping scale the frame weighs a little bit over 6 pounds. That's about a pound less than the Pretty Pony without sacrificing one tiny bit of strength, in fact the OB1 is probably stronger due to the use of .049" tubing.
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