Excellent thread ... very useful information even though some of the weights on the latest tire types isn't filled in.
I've known about the effect of lighter tires since the mid 1970s when I was racing BMX. Back then (for at least a minute and a half) the undisputed lightest 20 inch BMX tire was the Schwinn "chevron" white sidewall tire.
During the week many of us would run "super heavy duty" inner tubes (4x thicker on the outside circumference) which were also known known as "thorn proof" tubes. We'd also run heavier knobbies during the week, as well as thicker spokes and heftier rims. Come race day on the weekends, we'd switch over to our race day wheelsets (lightest rims, 60/80 dual thickness spokes, those Schwinn gumwall tires, and the thinnest cheapo inner tubes that we could find at the local department stores like "Fed Mart").
The difference between our weekday wheel sets and race day wheel sets was enormously obvious. The bicycle felt like a completely different machine with the race day wheel/tire combos. The heavy wheel/tire/tube/spokes during the week was like doing a physical workout since every aspect of the heavier wheelsets would really make all of the muscle groups used to propel and maneuver the bikes work far harder.
Point being is that the lighter wheelsets was something that produced a very profound difference in how the bike would accelerate and handle ... something that you could really feel in every way without having to "convince yourself" with obscure mathematical formulas. The most profound difference was noticed with the light weight Schwinn gumwall "chevron" tires. If all you did was adopt those tires without switching tubes, spokes, and rims you could still really feel the difference. Switching from thorn proof tubes to $1.98 thinwall tubes made the 2nd greatest difference.
Outside rotational weight produces the most noticeable change over things like titanium rotor bolts that are so close to the rotational center of the wheelset. I know that for absolute certain. However it's also true that going with the lightest tires/rotors/rotor bolts/caliper bolts (et al) has a large effect on unsprung weight. Back when I raced in S.C.O.R.E. off road desert racing in race prepped 4x4s the old rule of thumb regarding unsprung weight was "1:10" ... meaning removing 1 pound of unsprung weight was equal to removing 10 pounds of sprung weight when it comes to overall handling and suspension efficiency in the high speed rough.
Given a choice between super-high-buck light weight wheels or lighter tires I'll opt for the lighter tires every time for my motorcycle. It's the obvious choice for the privateer racing their motorcycle on a budget as well.
Never Quit, Die Falling Forward
1996 900 CR. ...Go, Blow, Or Put A Hole In The Fence.