BikingBrian said:This thread went off on a tangent about tires, but the OP asked about the usefulness of wheel upgrades.
Aero tests show that the difference between the best aero wheels (ie, Zipp 808) and worst-performing wheels aerodynamically (ie, Mavic R Sys) is about 13-15 watts @ 50 kph. That equates roughly to a 0.5 kph difference in speed. Whether or not that is "worth it" is *completely up to you*. Smaller differences in wheel depth and shape will obviously have smaller differences. One thing that I can say for certain is that this difference is pretty much undetectable to human perception.
Having said that though, I'll gladly take that advantage in a TT, for example, as it could make the difference between getting on the podium or not.
For a non-racer is it necessary? Again, only you can answer that question
That was my original point that came out all weird but kind of on purpose! The difference between watts saved using expensive racing tires vs better wheels is nowhere near the same as you pointed out. Your not going to save 15 watts going from cheap tires to expensive ones, you might save 5 to 8 watts, and mid grade tires are the best deal because their cheaper the expensive ones and the watts lost is only about 2 to 3. And by the time you spend money on expensive tires that don't last as long as mid grade tires over the course of 40,000 miles you could have bought expensive wheels like the ones you mentioned and got a lot more watts in return.
But for a non racer expensive wheels is just eye candy with no practicable application, just as expensive tires are.