Originally Posted by timcupery
So I've been thinking that Shimano Octalink road cranks (e.g., 5500-series Hollowtech 105) would be great for fixed-gear use. They're stiff, available in 165mm crankarm length, and giving proper 43.5mm road chainline with a 109.5mm bottom bracket, would give proper 42mm chainline on the inner ring if used with a 113mm bottom bracket. However, I've only been able to find Shimano Octalink bottom brackets in 113mm if they have the V2 spline, which is not compatible with 105/Ultegra/DA groups.
Octalink V1 exists in 4 sizes:
109.5 mm
112.5 mm
116 mm
118.5 mm
The two middle size were intended for the short-lived XTR version, and may be difficult to find.
Another option would be to use the 109.5 with a spacing washer under the right side mounting ring. The popluar washer for this is the Sturmey-Archer sprocket spacing washer, 1/16" (1.6 mm) thick.
Originally Posted by timcupery
This scheme would work with Sora or Tiagra double cranks (which use a 113mm V2-spline Octalink crank) if used with a 118mm V2-spline Octalink crank. But I'm mainly interested in the 105 and up.
Why? The V2 spline is superior! That's why Shimano changed the design.
Sheldon "Octalink" Brown