Tom A. wrote:
I do recall that the aerodynamic properties of the GP4000S II were an accident but it was an accident that prompted many wheel manufacturers to design around that tire and at least one tire manufacturer (Schwalbe) to investigate the effect of tread patterns on aerodynamics (Schwalbe Ironman). WRT Swisside, the fastest tire was an Attack put on backwards. However, the margin of drag reduction versus an Attack run forwards or a GP4000S was rather small.
BTW, Flo tested against more tires than anyone else I'm aware of!!!! https://flocycling.com/aero_tire_study.php
I count twenty tires.
thx. i didn't see that. i saw another one from FLO, but not that. you realize that, while very marginal, the schwalbe outperformed the 4000 on that, yes? until you got to 12.5Â°. and you've also seen all the data on how, past 12.5Â°, you're pretty much no longer in a race conditions you'll see more than 2 or 3 percent of the time. so, if on THAT graph you're looking for the fastest tire, the 4000 is the fastest tire by far in conditions that you'll almost never see
which, again, isn't to say the 4000 is anything other than a great tire. and i'm sure by the end of this thread i'll have said (according to some people, who will no doubt fail to read the thread) that the tire is shitsville.
but look at the post to which i originally responded. what i'm saying is, no, i'm unwilling just to stipulate to the 4000's ubiquitous aeroness.
Are you looking at the 23C or 25C GP4K?...'cuz by my eye, the 23 is basically tied at 5deg and below, and then beats the 23C Schwalbe One above that.
Of course, once you add in the Crr effects (see the other Flo interactive chart I linked to above), it's not even close. Both the 25C AND 23C GP4K handily beat the Schwalbe by ~3-4W (for front wheel alone) across the board.
So...the point isn't that the GP4000S is THE
lowest drag tire out there. However, it IS pretty darned fast in that sense, even in regards to tires that came out AFTER it and blatantly copied some of its aero "secret sauce" (accidental "sauce", or not).
Again, the reason it's held up as a default "hard to beat" choice, especially if no other data is present, is because of the COMBINATION of pretty damned good aero, pretty low Crr, AND having better than normal (for fast tires) durability. It's that simple.
Anyway, the post you were responding to merely said the GP4000S performed really well in wind tunnel tests. It does. It may not be THE best, but it's close enough that it's other properties (including price) make it somewhat of a "gold standard", especially for long-course, age-group triathlons.
what i'm saying is, i find it hard to believe that the tire performs well de facto. i'm sure it does perform well in certain circumstances, but if you place that tire on rims that have different inside bead distances, the tire will change shape every time. and depending on the rim you stick it in, it's going to perform better or less well.
again - 3rd time in 3 posts - i'm not saying the tire is not a great tire. i'm not saying anything about rolling resistance, price, availability, sex appeal, or whether it smells better than other tires in its competitive set. i just am pushing back on the post to which i replied, which seems to assert that this is a de facto superior tire aerodynamically (to other tires, i assume), without any qualification.
for example, i just put a tubeless zipp tire on a tubeless zipp aero rim yesterday, and was happily surprised that it goes on more easily than most tube tires. this instantly makes that a combo worth considering, as i note the crr of tubeless tire after tubeless tire.
so, i don't know, but must assume that zipp is making tires that perform well with its rims aerodynamically. there's the products people talk about, and the products people buy, and in the kona bike count zipp is on more bikes than the next 10 wheel brands combined. in the real world people live in, which is zipp's world, is conti the most aero tire? i don't know. maybe.
i'm just not willing to stipulate that the conti beats everything aerodynamically. value? all things considered? most of the time? probably so. but, aerodynamically? it's certainly the equal of most tires most of the time at 10 degrees and below, but on the fatter rims i'd prefer to ride? maybe they are?