What are your thoughts on doing a VE test swapping a GP TT and an Attack between the front and rear wheels? I'd have to check my weight distribution, but assuming it's 50/50 wouldn't this be a valid approach to teasing out the aero differences between the tires as the crr of the system wouldn't change? Or would it change since the drive forces are being put through the rear wheel (which could make the TT look even worse as a front tire choice)?

Hopefully Zipp has improved the compound that they use in their tires. Historically they have rolled slow.

https://www.bicyclerollingresistance.com/...tangente-course-2017

Maybe Zipp can coax Hutchinson into doing a production run with their new 11Storm compound?

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.

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?

Well...just to make sure I wasn't missing something...I went back and looked at the post to which you were replying to, and they were actually discussing the original 22C Attack model, not the GP4K...and there was nothing in there about it being "superior" to other tires, just that it had "tested well".

You might want to make sure you aren't knocking down straw men here ;-)




I'm not sure what this has to do with what you say you're only talking about above (aero performance), but what exactly is it you are "noting" about the Crr of "tubeless tire after tubeless tire"?

From what I can see, aside from one fairly fast-wearing exception (which happens to be the ONLY tubeless tire currently constructed similar to a high quality clincher, or "open tubular), basically all of the road tubeless offerings still can't hold a candle Crr-wise to high quality non-tubeless clincher models running latex tubes (don't forget to take into account that Jarno tests with butyl tubes, and thus his non-tubeless results have a 2-3W bias high in that respect).




Maybe...maybe not. I know for a fact that the original prototypes for the Tangente Course and Speed models had more of a parabolic shape to them than what was eventually put into production. That shape worked GREAT aerodynamically (and, ironically for this discussion, was basically patterned on the shape of a GP4K), but it had the downside of resulting in higher Crr (due to the extra tread thickness in the center) along with it garnering some adverse feedback from test riders about the handling effects (too much "tip in"). The tire was basically "detuned" aerodynamically to address those short-comings. So, to imply that they are making the aerodynamically "best" tires for their wheels is most likely a stretch. I'm sure they work quite well with their wheels, but I don't think absolute best aerodynamic performance was the design driver for their tire products.



The ironic thing is that the aero rims which the Conti models like the Attack and GP4K don't perform on very well are older, narrower models. Conti tires tend to run "oversize", and it's actually the newer, wider models of aero wheels that match up better (as long as folks don't go overboard on the GP4K sizes, and put 25s or 28s on a wide rim...and then start getting tire widths into the "gravel width" range ;-) Put a 23C GP4K on something like a Hed Jet+ rim and it will widen out to ~26mm, or more!

point taken - certainly - on which tire we're talking about here. i jumped to a conclusion.

but on the assertion, what does this mean: "The prior version tested very well in the tunnel." just, that sentence. if you say that, without qualification, that's like saying 292mm spokes fit very well. fit what very well? they certainly fit some wheels well, but it depends on the rim, the hub, and the lacing.

Oh...and what about the question about tubeless Crr? What are you "seeing"?

Description of Continental Grand Prix 4000 RS Folding Tire - 25-622 - Tour de France Edition
In a limited special edition for the Tour de France. The powerful tyre in the field, faster, with a thinner tread and lower weight than the standard GP 4000 S II model.
The focus of the GP4000RS is: speed! Due to less rubber on the tread the tire is faster than the standard one and in total 10g lighter!

The downer is that it's only being offered in a 25mm version whereas a 23mm would be much better suited as a front tire.

I would like to see a 24mm GPS 4000 SII

Not sure if this test has been posted; looks good
https://www.bicyclerollingresistance.com/...nd-prix-4000-rs-2018