The breakout design catapulting Cervelo to a clear lead in the tri bike market was the P3 Carbon, introduced in 2005. This bike memorialized Cervelo's designs and geometry into the frame material everyone preferred. This bike had it all. Almost.
The nagging problem with the P3 was its "lowness." Its low front end versus its length. Stack and reach tells the story. The current P3, sold today, with a reach of 435mm +/-2mm, has a stack of 559mm. The original P3 in that length had a stack of 516mm.
Cervelo's initial response to the low front end of its P3 was the P2, that used the P3's geometry but simply added up to 20mm of head tube, such extra head tube taking the place of headset spacers, which was the "fix" employed by so many retailers to the P3's lowness.
The current P2, P3 and P5 geometries are very much like the Speed Concept, new Felt B Series, and other geometries designed to fill up the space between the top of the frame and the armrest, once the bike is built to properly fit the rider.
Was this industry response wrong? No. But there are two new realities in the world of parts and accessories that ought to impress themselves on how bike makers design their frames. One is the split-rail saddle that requires bike makers to now make sure their seat post hardware goes back far enough. This is contrary to the trend of the past decade toward steeper angles. It doesn't require a geometric change to the bike, because the rider is not moving back. Just his saddle is moving back. It does require attention to the seat post clamp, making sure there's enough forward travel for a standard saddle, and enough rearward travel for a split-rail saddle (like an ISM).
The other change is the availability of aerobars that very aerodynamically, comfortably, and sensibly pedestal up the pads. Further, these new bars pedestal the bars and the extensions as a unit, retaining the ergonomics of the aerobar.
You therefore now have two options, at least theoretically. Let's say you have a typical set of fit coordinates: 78cm of height from the BB to the top of the saddle, somewhere between 13cm and 16cm of elevation drop between the top of the saddle and the armrest. Option 1 is a bike with a frame that fills up that space. Very few or no spacers. Maybe a stem with an extension that is parallel to the ground (-17°). Or, an integrated stem (like that which comes on a Speed Concept) that is low-profile. And then a handlebar with a moderate amount of armrest rise above the centerline of the pursuit bar (60mm is typical these days). Very few or no pedestals under the bar/extension complex. Neat.
But there's another option, and it's made possible by the advent of these new aerobars that offer a slick way to pedestals the pads + extensions. Maybe the most obvious of these is TriRig's Alpha (just below). An aerobar like this opens the door to another kind of frame, and you might consider bikes like Storck's Aero 2 (highest above), or Canyon's Speedmax (above, just below the Storck). Can you see how low the front end of the Storck is, and how it might be pedestaled up to meet your elbows?
What's crucial here is that you properly match the bar with the bike. Let's consider HED's Corsair. I love this bar. But it would be a disaster on a bike that doesn't pedestal up the steer column, because the Corsair doesn't pedestal (it's got other virtues). But the Corsair is spec'd on, and is a perfect match for, Diamondback's Serios tri bike because the Serios, like Cervelo's P5, pedestals through aerodynamic "headset spacers" for lack of a more elegant term.
Bikes like those from Canyon and Storck really want either an integrated or aftermarket bar like the TriRig Alpha X, which can be pedestaled above the steerer but really wants to be pedestaled under the armrests.
Other bars like this would be Profile's Aeria (just above) and 3T's Vola (just below).
What is the downside to low front ends with tall pedestals? Low pursuit positions. If you find that a negative. It depends where you want the pursuits. But there's a fix to this, and it's a product not yet invented: pursuit bars that angle up to the hand position instead of (the typical) down. There are a few examples of flippable pursuit bars, and Felt's tri bikes have featured these in the past. But this requires the extensions to have no upturn.
Are these set-ups (frames with low front ends, with pads pedestaled) preferred? Are they better? That is, are they faster? This is the question. I've just heard rumors, whispers, from folks who know or ought to know, and many of them are bullish on the aeodynamics of low-slung missiles masquerading as frames, their riders perched up by pedestals. Andy Froncioni of Alphamantis has made comments like, "no contest" and "not a fair fight" in favor of low bikes with pedestaled aerobar pads, though it depends on the bar and the frame. And we've seen Bradley Wiggins riding like this for years, for what it's worth.
In my opinion the best-executed version of this is the Scott Plasma Premium, with one exception. The frame itself is not low. The stack for a corresponding reach is tall. Remember the Cervelo referred to above, with a reach of 435mm or so? In a Plasma of that length the stack is 600mm. This means Sebastian Kienle and other Scott riders have a very aerodynamic set-up, but without pedestals and, in some cases, even sizing down to get the front low enough.
Are there good examples of this right now? Maybe Andreas Raelert aboard his Cube Aerium (above), or Luke McKenzie on his Plasma Premium, on which he bucks the trend and is able to take advantage of that very slick Profile Design integrated bar that pedestals very nicely on that bike.
I'm often asked what I think the new trend will be in triathlon. As regards bikes, this might well be it. I think we'll have to sit back and make room for the folks at Alphamantis and other aerodynamic experts to weigh in. I'd like to know when and on which bikes riders enjoy an advantage, if there is an advantage to this motif, and just how much faster a rider might go. If there's enough gain there we might see a return to the long, low geometries of years past (and a boost in sales for Cube, Storck, Boardman, Quintana Roo, and other companies already making geometries that fit this geometric model).
