which do you think is more likely:

-the guy tying to sell you his brand of bike was exaggerating or misrepresenting how slippery his bike was or making dishonest comparisons

-the vendor's non-uci surpasses anything trek, specialized, and cervelo have produced by a large margin and the uber-geek aero crowd here that measures drag improvements in grams is hopelessly deceived by superbike manufacturer marketing data and groupthink

There are little to no UCI-ilegal bikes that have the same investment in technology and aerodynamics that the current batch of UCI legal bikes do.

The last two data sets I saw on the Airfoil were from Cervelo and Kestrel in about 2007(so not the current airfoil) and 2009 respectively. The 2007 Airfoil was well behind the first iteration of the Felt DA which is the upper boundary on "good bikes". The 2009 data showed the new Airfoil close to the P3 but worse at most yaw angles and this data was from Kestrel.

Trek worked on the Speed Concept for about 3-4 years, with a ton of time in the wind tunnel. Most of the non uci legal bikes have likely never seen the insider of a tunnel for development purposes.

There are lies, damned lies, and marketing. Have some more kool-aid.

John

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If it's the Kestrel 4000 LTD you're talking about, I'm pretty sure it's UCI-legal.

There's been a number of non legal UCI bikes over the years - Softride, Lotus, Titanflex, Giant MCR, etc, etc, but surprisingly they never caught on in all that big a way with triathletes. Most triathletes have been conservative and have stuck with the UCI legal double diamond frame configuration. I believe Gerald from Cervelo once hinted that to get significantly faster than the P4 it would be necessary to go to a non legal frame design. In otherwards, under the current rules, there's probably not a lot more than can be done with bike frame design to make them more aero.

Until Cervelo rolls out the P5...

There's also the pretty significant issue of compatibility.

Look at something the CAT Cheetah, which doesn't actually test all that well aerodynamically in the tunnel. I suspect it's actually faster *as ridden* than many bikes because of the integrated drink system vs. bottles on the frame or in rear-carriers, but that's another topic...

What's notable about the CAT is that it has it's own custom hydraulic brakes. I *think* it also requires it's own special rear hub.

Or look at the Walser, now sort-of brought to market by Focus with one BIG change - it uses a normal crankset. The old Walser used a narrow-axle crankset. And the narrower BB shell that resulted in was a significant part of the drag savings, especially at lower yaws (which are typical for cyclists riding at 50kph+).

So it's not just the current rules. It's the current standards for hub-spacing, derailleur hanging, crankset-width, cassette spacing, etc. that also play a massive role in limiting design.

You can see the limits these parts play with things like brakes being the first to get integrated. Now aerobars are following suit. Cranksets could follow - both Specialized and Cannondale make their own, excellent cranks - but narrowing them up would affect Q-factor, which is a potentially big issue, and you also can't narrow them too much without it affecting chainline.

But do companies really want to make their own derailleurs? Shifters? Cassettes? Wheels? Hubs? I don't know. But that means until they decide they do, they need to play nice with the folks that do. Look at Cannondale and the Lefty fork. Great design, but it requires a proprietary hub design. Mavic bought in. But who else?

So it's not just double-diamond that's a limiter.

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"Non est ad astra mollis e terris via." - Seneca | rappstar.com | FB - Rappstar Racing | IG - @jordanrapp

I've never really understood why some of the companies who sell almost no bikes outside the Tri crowd (ex. QR) don't ditch the double diamond and make something scary-fast.

As you can gather from my screen name, I ride a non-UCI bike, but there is a lot more that could be done with the design as far as hidden cables, airfoil shapes, etc.

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ECMGN Therapy Silicon Valley:
Depression, Neurocognitive problems, Dementias (Testing and Evaluation), Trauma and PTSD, Traumatic Brain Injury (TBI)

A significant part of it is budget and know-how. It's not really that easy to make something scary fast. It requires time, knowledge, and money. The P4 cost Cervelo over $1million in wind-tunnel time alone according the Gerard.

Most tri-exclusive bike companies are struggling simply to survive. QR is not exactly in the best financial situation. You think they have the money to invest in a "throw out the rule book" bike design? Softride went bankrupt. What percentage of average triathletes even know what a Titanflex is?

Bottom line, the best and brightest minds in the bike industry go to the companies that can pay them - Cervelo, Trek, Specialized, Giant, Scott, Felt. And those companies are - or at least have been - interested in making UCI-legal bikes that can ridden by the maximum number of people.

Big budgets and engineering talent offer WAY more of an advantage than not playing by UCI rules.

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"Non est ad astra mollis e terris via." - Seneca | rappstar.com | FB - Rappstar Racing | IG - @jordanrapp

So it's not just double-diamond that's a limiter.

Get rid of the double diamond and suddenly we're in HPV territory. You can run your preferred component set on that, and average 38mph for 112 miles, assuming you have the right fairing :)

(i admit that the idea of racing with 2000 other people of whom some random number are 5 inches off the ground, prone and very unused to having bikes all around is bit unnerving).

I'm interested in seeing someone truly quantify that advantage. Sure, it sounds great on paper but I don't see it playing out in reality. So, how does that supposedly big budget and engineering talent offer way more of an advantage? I'd like to see real-life examples.

Note: There are plenty of good bike engineers out there who have no desire to work for a large bike manufacturer. For example, we already know for a fact that marketing design decisions are being made that are compromising good engineering principles. There are pros and cons to working for a company like Trek and Specialized and I would argue the cons are actually greater than the pros in many engineer's minds.

Also, if you can't achieve optimal comfort and power on a slack seat-angled frame, which many of us can't, then who gives a shit if that frame *supposedly* has slightly better frame aerodynamics? The amount of time saved with that frame is negligible compared to the lack of comfort and/or power in my experience.

Thanks, Chris

I guess that it comes down to if you believe that the above is the case. Right now there is a lot of time/talent/money trying to get the fastest frame that is still double diamond and fits into 3:1. Remove those constraints and step function improvements should be possible, not the incremental ones we are seeing. No data available, but the SC9 probably could have been 30sec.+ faster if they could have used optimal airfoils and not have had to camm tail to stay 3:1. We're all shoving aero bottles down near the BB as a hack for what should be aero and structural carbon there in a more optimized design.

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ECMGN Therapy Silicon Valley:
Depression, Neurocognitive problems, Dementias (Testing and Evaluation), Trauma and PTSD, Traumatic Brain Injury (TBI)

Shimano, Formula, and DT.

Unfortunatly there are no readilly available non-uci frames that have been tunnel tested and proven to be faster than a current superbike.

It was the mad TT bikes of the 90s that got me interested in cycling, and I'm sorry to see their passing. However looking at their designs you can see elements that have made it onto current top of the line rigs. e.g. Rear brake mounted above the chainset - check; cables entering frame together behind stem - check.

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"Here's how you run a marathon. Step 1: You start running. Step 2: There is no step 2." - Barney (How I Met Your Mother)