They're wrong.

ENVE are the only ones saying it. Most likely, this is marketing to justify the fact that until a few months ago they didn't have a disc wheel for sale, claiming that their rear wheels are "as fast as a disc". Now they have a disc, but claim that only fast time-triallists will need one.

A disc will be faster, in most situations, especially for a rider of your calibre.

In my local Norseman imitation, the Israman, with 3000+m of elevation (and a net altitude gain), a disc is always the faster option. I'm sure the real Norseman, for a strong cyclist, will be the same.

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ZONE3 - We Last Longer

Ignore everything ENVE says about disc wheels.

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Enve is wrong, a disc is always faster, but they continue to pretend otherwise for marketing purposes.

A more relevant point to consider is that all discs are extremely close aerodynamically. I really depends on frame setup as to what is fastest. I have no doubt the Roval 321 is a solid choice and that you are pretty limited in the realm of disc-discs but the Hed Jet disc-disc is equally good at a lower price point. In the near future I suspect we will see other disc-discs enter the market and drive the price point down.

Enve still claims that a disc is only faster when going above 43 km/h, now that they finaly have made on. I was just curious the reason for that claim.

When I do the math on this a disc will give lower CdA, which in my calculations will go faster regardless of the speed (if added a lot of extra weight and the course is hilly that is another issue of course). But I respect Enve a lot as a brand and know I might be wrong in my calculations.

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I've run into people talking about Enve being wrong about disc wheels several times. That makes me think that Enve is a stupid company. I do have several wheel sets and disc is the fastest based on my experience. Why don't they just listen to people with actual experience? Are they that stupid???

In my trip to the windtunnel in 2013 I tried a Zipp 808 rear vs Zipp Sub9 and it lowered my CdA from 0,210 to 0,208 at 0 degrees Yaw and 0,232 to 0,230 at 7,5 % yaw, about 1 %. According to BestBikeSplits that would reduce my time on the 180 km Norseman course with 39 sec, and the 103 g added weight of the Roval 321 would cost 7 sec, reducing the total gain to 32 sec.

Could the benifit really be that small?

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You are correct.

Something else that people don't realize is that at slower speeds (eg 15 mph), one could argue that a disc would be more beneficial than someone at 22-24 mph because the slower rider will be out on course for much longer. The force of drag equation shows that the faster you are traveling, the more drag one would save than someone slower. But that is an instantaneous time and does not account for the entire duration over the course.

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It wouldn’t surprise me if the deep wheel was nearly as fast as a disc in some conditions. The BBS model has never seemed to show much difference using a disc in place of a deep wheel.

Your wind tunnel testing accounts for translational drag differences between the deep wheel and disc but not rotational drag differences or watts to spin. The spoked deep wheel adds drag from rotating spokes that the disc does not have. Quantifying the watts to spin drag is not something that is commonly available. Kraig Willets tested this with BikeTechReview and only offered the results to those purchasing the report.

BBS has stated (specifically on here) that their model underestimates the benefit of a disc wheel compared to a deep wheel.

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my fastest lap on the sprint tri course are on deep wheels (Enve 7.8) my fastest times on the local TT course are with disc (super9). I'm still a believer of disc is faster overall...barring some huge steep climb only course.

Their marketing guy pigeonholed them when they didn't offer a disc. Now they sort of have to live with and tip-toe around his statements.

Always go disc. Their data doesn't include watts to rotate and the system effect (gives turbulent air coming off the bike and rider something to attach to). My opinion is that a disc wheel is ~5 watts faster in the aggregate than a fast 80mm rim at "mortal" speeds. Many others tend to agree.

I was in the market for a disc wheel, initially looking at ENVE but I noticed that their disc's are only recommended for 43km/hr riders. I have since decided on another company as their discs are recommended for all speeds. I'd like to thank the ENVE marketing team for being transparent and educating me on their products!

you need to get faster then....

That is my recollection as well. But I thought that Ryan had mentioned working on improvements to the model w/r to discs and I have no idea where they stand with that effort so I based my post on what I have found for my past inputs. I didn't race much this year so I haven't been running BBS as frequently.

So I guess we need to inform them that their disc wheel are also faster than their 7.8 in all condition?

Yes and no and it depends. That stated, the difference between a disc and and 80 or 90 rear isn't as large as most people think. Here's Flo's own data where they calculate the difference from a 90 to disc at 31 to 62 seconds, and 60 to disc at 38 to 82 seconds at the IM distance. So for a 70.3 you're looking at half that. I stopped using a disc when I factored in the logistical issues with pumping it, and carrying tubes of different lengths compared to the front, versus the real world benefit I was getting. Run a dual H3+ set now. If I lose 30 seconds or so... I don't give a shit. But I realize 30 seconds could be the difference in another person qualifying or winning. So I'm not discounting the time saved but for my purposes of finishing in 4:59:48 vs 4:59:12 are inconsequential to me.

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Don't forget that Flo's data (and most other data) is wheel-only testing. Watts to spin, etc. are not included.

I know there's more time to it but I think most people think slapping on a disc versus a 60/80/90/trispoke rear wheel amounts to 5 minutes faster or something. It's just not anywhere close to that. Is the disc always faster? Yep! Everything considered (watts to spin, aero, etc.) the savings still only amount to somewhere between a few seconds to what... maybe 90 seconds at most for a 112 mile ride. Arguably a big deal for some, and not for others.

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Favorite Gear: Dimond | Cadex | Desoto Sport | Hoka One One

A disc vs an 80 or a 90 is worth ~20 seconds over a 40k by my reckoning. If you're fighting to podium in an Olympic that's not time to be trifled with IMO. Different race priorities for everyone I suppose.

Dont forget to factor in all the time you lose braking on turns with a disc, that is if you know how to ride a bike properly...

I've been same Sprint Tri several times and disc has been always the fastest. I couldn't go over certain speed, but after I switched to disc. Voila!

But what of it was 5:00:01 vs 4:59:35?