> Works with a ten speed chains? Mmmm I wouldn't want to have to make > it work. 4mm width, must get tapered some for the teeth though.
Most high-quality chainrings step down at the teeth to a thinner width than the main body of the ring. Even in 1938, when the original Herse cranks were introduced, 4- and 5-speed chains were not 4 mm thick on the inside. (The exact measurement for 5-speed is 2.38 mm.) So the new rings are the same as the originals from the 1970s (which used modern chainring bolts instead of bolts and nuts), except that the teeth are a little bit thinner, and shaped a little differently to optimize shifting. > Quite light weight though - 540grams without the bolts. Wonder how > they did that? By putting material where it is needed, and nowhere else. Compared to the originals, we added a little material around the pedal eye (where cranks tend to break) and went to a net-shape forging process to ensure the strength in that area. (The originals were even lighter, but we figured adding a few grams to increase the strength would be prudent.) The downside of the net-shape forging process is that you need a separate forging die for each length, but I would not be comfortable riding such a lightweight crank where grain structure around the pedal eye had been weakened by machining the crank to length. Jan Heine Compass Bicycles Ltd. www.compasscycle.com -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
