Originally Posted by tetonrider

the nosecone shiv only proved to be more aero than the UCI-legal shiv TT at yaw > 7*. it is slightly slower than the shiv TT between 0 & 7.

the newer model shiv (tri) was designed to allow triathletes to store more $hit in their frame rather than hanging off of it, as well as to be easier to work on and to fit more people (it's a much taller frame vs the shiv tt long & low, so it appeals to a lower common denominator). it's slower than the shiv TT from 0-7 and slower than the nosecone shiv >10. they viewed it as a win because it added features that many customers wanted while doing a pretty good job with aerodynamics. the UCI-legal thing doesn't matter to a large set of customers.

for a rider actually doing TTs (not ironman triathlons @ 20mph), >10 yaw -- even >7* yaw -- is not all that common. (yes, yes, there are examples to the contrary, but a rider going 27, 28, 30mph needs to experience pretty high winds at actual ground speeds, which is not as common as we tend to think.