Jim This is a fun law of sines problem. As we all know the theoretical top tube length is the one that tells you about fit, since it's the level distance from the seat tube to the head tube. But since you asked, here's how you set it up:
We've got a triangle with three sides with lengths a, b and c. It has three angles: A, B and C that are opposite each of the three sides. The law of sines tells us that: a/(sin A) = b/(sin B) = c/(sin C) What this means is if you know a few of these, you can calculate the rest. The triangle I'm drawing has two top tube lines that intersect at the head tube: b = the ACTUAL TT and b = the THEORETICAL TT. The third side is c = the short line along the seat tube that connects the two top tube sides. Angle C opposite line C is the slope of the actual top tube = 6 degrees Angle B opposite the actual TT is the seat tube angle = 71.8 degrees Angle A opposite the theoretical TT is the rest = (180 - 71.8 - 6) = 102.2 degrees Since we know A, B, C and a, we can plug into the law of sines and solve a/(sin A) = b/(sin B) b = (sin B) * a/(sin A) b = (sin 71.8) * 57.5cm/(sin 102.2) = 55.88cm On Friday, June 27, 2014 7:55:51 AM UTC-7, Jim Bronson wrote: > > What's the (non-theoretical) TT on this frame? The TT listed on the > Rivendell geometry charts is theoretical. > > > On Fri, Jun 27, 2014 at 1:23 AM, Tony Lockhart <alockh...@gmail.com > <javascript:>> wrote: > >> *For Sale: 54cm Soma San Marco *(included: Tange headset, downtube cable >> stops, triangle frame bag) >> >> Sizing - fits just like my 56cm Sam Hillborne (and 58cm Simpleone) and >> has a stand over height under 32 inched with 700x28mm tires. You can >> probably squeeze in 32mm tires with fenders or 40mm tires without fenders >> (please verify this before you commit to purchase). >> >> >> <https://lh4.googleusercontent.com/-ENtKc4hZYrc/U60GywKjFBI/AAAAAAAAA5A/_mBsogrHIBI/s1600/P1170119.jpg> >> >> <https://lh3.googleusercontent.com/-1GpF95XPqfY/U60HFh3zHhI/AAAAAAAAA5I/gzCyl5a4Rec/s1600/P1170120.jpg> >> >> I purchased this frame in September 2012 and it has seen very light >> commuting use in Southern California (stopped using it in June 2013). Aside >> from very light scuffs from daily use, the frame is in great condition >> (mechanically 10/10 and cosmetically 8/10). When built up, the bike has >> never been neglected, dropped, dinged, or crashed. During the time I used >> the bike, I had different types of racks installed (VO rear rack and Nitto >> front rack). >> >> >> <https://lh3.googleusercontent.com/-iyQC7jKdYzs/U60I8SjM_HI/AAAAAAAAA5g/TlS1rvuPc-c/s1600/P1170116.JPG> >> >> <https://lh6.googleusercontent.com/-BqoqWVQd1Vg/U60Ioqnyl3I/AAAAAAAAA5Y/ewxoo5ilWJo/s1600/P1170115.JPG> >> >> >> I'm selling this frame in order to clear out garage space. I also do not >> have enough time to ride my Sam and SO, so it just makes sense to let >> someone else truly enjoy it. The reason I'm rating the frame cosmetics as >> 8/10 is because I ground off the lawyer tabs and the rear dropouts have >> some paint chipping from mounting wheels. Aside from those issues, the >> frame looks as good as when I purchased it. Here are some detailed pictures >> of the dropout areas: >> >> >> <https://lh3.googleusercontent.com/-ZP4PzuoXX9s/U60KTDU1WVI/AAAAAAAAA50/kJkiXmK5VR8/s1600/P1170117.JPG> >> >> <https://lh5.googleusercontent.com/-oZk4-k9wbdA/U60KHq5RQgI/AAAAAAAAA5s/z83vSJpPfR4/s1600/P1170118.JPG> >> >> <https://lh5.googleusercontent.com/-oZk4-k9wbdA/U60KHq5RQgI/AAAAAAAAA5s/z83vSJpPfR4/s1600/P1170118.JPG> >> >> >> *Price: $575 for local buyers, $650 shipped* >> >> >> >> -- >> You received this message because you are subscribed to the Google Groups >> "RBW Owners Bunch" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to rbw-owners-bun...@googlegroups.com <javascript:>. >> To post to this group, send email to rbw-owne...@googlegroups.com >> <javascript:>. >> Visit this group at http://groups.google.com/group/rbw-owners-bunch. >> For more options, visit https://groups.google.com/d/optout. >> > > > > -- > Keep the metal side up and the rubber side down! > -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to rbw-owners-bunch+unsubscr...@googlegroups.com. To post to this group, send email to rbw-owners-bunch@googlegroups.com. Visit this group at http://groups.google.com/group/rbw-owners-bunch. For more options, visit https://groups.google.com/d/optout.
