Originally Posted by
abshipp
VO doesn't seem to shy away from spending money on tooling. I mean, over the past few years they've come out with what, 3 or 4 new frame models? All selling at less than a $1k price point with lots of braze ons, etc, so there's got to be a decent amount of stuff being made. The way to get costs down that low is to streamline the process, which implies lots of fixturing.
Regarding the chainrings in particular, I wonder if the ramp/pin design for a 46/30 chainring set is "common industry knowledge" by this point so there wouldn't be much engineering involved.
Ramps and pins are overkill for me, that's for sure. The bike they are on has downtube shifters, so shifting under load just isn't a thing that ever happens. I think I just bought the VO ones because they were the most economical
I do kind of wish I would have gone with the TA rings, and just a little bit smaller. I think a 44/28 or 44/26 would be pretty perfect for how I ride that bike.
With a set of rings that small on a relatively standard road frame, you can (depending on the frame) get close to having the front mech cage interfere with the chainstay. Several factors:
1. with a smaller chainring radius, the cage moves closer to the BB since they seem to work better with just a few mm gap between the cage and teh big ring.
2. One of the ways to design a cage that can handle a 16 tooth (46-30, 50-34, et cetera) is to make a long cage that sticks out far behind the BB axis, and closer to interference with the chainring.
3. The chance for interference is worse with a larger BB drop. With an 8 cm drop the chainstay sweeps up higher than for the now more common 6.5 cm geometry.
If you look back at Jan Heine's bike designs you can see he designed a short, deep cage that does not hang out behind the chainring. I think this is the best way to go for a 40-24 or 42-26, or smaller.