Over a 40k how much difference would there be time wise?
Right now i am riding a Blackwell Research disck which is basically the old zipp one as i understand it. I also can’t do the Sub-9 cause im on a p3c
Thanks.
I’ve had people argue wth me on this fact, because I can’t state my source, so take this as you will and for whats its worth, but please do not argue.
The shape of the disc that works best is also based on the frame you mount it on. Flat discs work better with some frames while a lenticular disc will work better with others. This also applies to the new “bulge” discs. This all has to do with the air flow as it passes “gaps”, chain stays, seat stays, their shape and the distance between the disc surfaces and the frame parts.
I believe, and its been stated before on this forum, that wheel and fork combinations change the aerodynamics of the two. What front wheel works best is somewhat dependent on the fork you have. Its the same with a rear disc, it depends on what frame you are using.
Okay cool. that helps, i wont argue cause i have no idea lol.
So i guess the real question should be does a buldge disc decrease drag on a p3c compared to a flat disc?
I am also interested in this last question if anyone knows.
Okay cool. that helps, i wont argue cause i have no idea lol.
So i guess the real question should be does a buldge disc decrease drag on a p3c compared to a flat disc?
Well…FWIW, if you look at what discs were used with the P3Cs with CSC (and now apparently Cervelo TestTeam based on the camp photos) you’ll see that even though they had Zipp as a sponsor, they STILL used the flat Zipp disc. That may or may not be a clue.
I have a hunch that frames that do a good job of “sheltering” the rear wheel (such as the P3C) don’t necessarily gain anything from the “bulge” effect since the air over the front portion of the disc is already “handled” pretty well. Other frames, that take a different approach (the new Look for example…wide gap, large opening at the seatsay juncture) may have more of a benefit from the “shaped” discs. But, like I said that’s pure speculation on my part. After all, one can’t forget that even rear wheels, such as discs, are tested by themselves (i.e NOT in a frame) during tunnel testing.
Of course, we also have Jens (Heycke, that is) telling us that his 808 rear wheel with a cover was the fastest rear wheel he ever field tested, flat an lenticular discs included…so, who knows what to think? 
With the tolerances being so tight, would they be choosing the flat disc due to it working better with their frames and not just on an aero basis? I’ve heard that the Sub9 wasn’t as stiff and that stronger riders felt that it flexed.
It’s just a guess, but I think the advantage of the bump is from the trailing edge – in which case, frame differences might not matter so much.
You can get a good look at a Bulls ass by sticking your hand up there, but I would take the butchers word for it…ya know, ya know, ya know what I mean vern?
I raced a P3C with a Sub-9 disc for the first 2/3 of last season. Never a rub of any kind. It was tight, but I centered it properly with the dropout screws. I have heard that there’s some variability in manufacture and some have turned out a bit wider than others. That variability drove me freakin’ nuts. The brake track on mine was horribly uneven and braking was downright trecherous (very grabby … almost threw me a few times braking hard for turn-arounds). I was never happy with the wheel.
I switched to a Hed Jet disc (non-C2) for the last third of the season and started recording PRs at nearly every event I did. However, I also went to a Jet 90 C2 on the front and swapped out my Wolf fork for a 3T Funda … so lots of variables.
I race flat discs on my 650c bike and I’ve used them in the past on my 700c bikes. I greatly prefer the ride characteristics of the Jet because it’s just a conventional wheel with a carbon fiber skin over the spokes. It rides like a normal wheel. It’s more compliant (less harsh) vertically and yet stiffer laterally. It has a very different sound from a flat disc … a sound I prefer.
The fastest TT I ever did in my life was when I was using a Renn 575 on my 650c P3sl, but that was just one of those nights. Wind just right, atmosphere just right, apparently I was just right. But that’s a fine disk and I still love to race it.
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Would you stop asking me i’m not lookin up your ass…