Originally Posted by
banerjek
If most of the nonracing cycling population are even more honest, they'd probably find that a 46/36 would probably meet their needs even better. They neither have any hope of spinning out the top end nor being in conditions that would make a larger difference between the rings optimal.
I almost always spin out a 50x12 on descents, keeping up with traffic. No big deal - bikes are faster in tight corners, cars on straight sections. Hwy 1 descending from the coast towards Sausalito CA is one example. But I don't think it matters much, I'd always spin out whatever I have on the bike anyway. 40 or 37mph... doesn't terribly matter.