This Spanish company is wonderfully inventive and clever. It offers three bikes to triathletes, priced at $1800 for the Aletta and continue up through the Ora and the Ordu, which can cost $6500 fully decked out.

Geometrically, you can see the difference between one sub-50cm bike and another. Consider the Kestrel Airfoil Pro above, with its 47cm size offered with 650c wheels and with a head tube of 47cm. Now consider that bike's direct competitor from Orbea, the Ordu, in its 48cm size. One would think these are similar in size, with only one centimeter between them.

Not so. The Ordu's 48cm is built atop 700c wheels. Building a small bike with these larger wheels means the head tube needs to be 5cm shorter than the corresponding bike with 650c wheels. In other words, a 700c bike with a 9cm head tube and a 650c bike with a 14cm head tube are about equal in their "stack." The Ordu's 48cm bike has precisely that, a 9cm head tube. But the Airfoil doesn't have a 14cm head tube built into its 650c wheeled bike, it has a 7.6cm head tube on that bike. That means the Airfoil Pro's head tube top sits about 6.5cm closer in elevation to the bottom bracket than does the Ordu.

This doesn't matter if you don't need your aero bars to sit low. But if you're Natascha Badmann, or Lori Bowden, or Paula Newby Fraser, your Ironman races were won with a fairly significant amount of drop (armrests sitting at least 8cm and as much as 11cm below the top of the saddle on bikes this size). No way can that happen with 700c wheels, which is why these women never rode 700c tri bikes.

Let's look at the other issue for which it's hard to engineer on smaller bikes. The Airfoil pro has a 72.5 degree head angle. The Ordu in this size has a 70.5 degree head angle. Why so shallow? Because Orbea rightly understands that it needs to kick the front wheel further in front of the rider, to guard against shoe overlap. Even then, the Ordu has 2cm of extra top tube length versus what the Airfoil Pro grants its rider.

Part of the difficulty associated with Orbea's small frame geometry is that it starts with a 75 degree seat angle. Were the seat angle steeper, the whole front of the bike would be pushed further in front of the BB, and the shoe overlap problem largely goes away. But Orbea is hamstrung by the UCI rules requiring its bicycle racing time trialers to ride with their saddles 5cm behind the BB. This is a grossly unfair rule for smaller riders, who get penalized in ways that taller riders do not. But Orbea didn't write the rules, and must design according to them.

The tri market does not have to obey these rules, however, and while Orbea's plight is understandable, the problems that attend the smaller rider are just not solved by bikes with 700c wheels. So, while the Ordu and Ora are terrific bikes, it is hard to recommend them for the optimized tri position in their 48cm sizes, and the 51cm size is a maybe, depending on how low the rider needs his armrests to go. Read more about Orbea's tri bikes here.