Alpha X Tunnel Tests, Part 1
Alpha X vs. Superbike
Our primary aero goal with the Alpha X was to provide superbike speed to entry-level bikes. That is, we wanted to enable owners of entry-level bikes to upgrade to superbike speed with our bar, saving themselves thousands of dollars in the process. So we selected two bikes of the same manufacturer, one costing approximately $5500 more than the other. And what we've shown is that adding the Alpha X to the low-end bike allows it to match (and beat) the aero performance of the top-shelf one. The Alpha X can truly turn an entry-level bike into a superbike.
This is the big question of the day: can the Alpha X provide superbike performance to an entry-level frame? The answer is a resounding YES. The data really speaks wonders about what this bar is, and we couldn't be happier with the result. Compared to the P5, the P2 + Alpha X setup was on average about 45g grams, or nearly 5 Watts faster across the board. This was a result we had not expected. At best, we hoped to catch the P5, but never thought we might surpass it. To be clear, we're not trying to say anything negative about the P5. It's a fantastic bike, and what we wrote in our full review of the bike is still true. Rather, what we're trying to emphasize is just how GOOD the Alpha X is. Want a superbike? Buy the entry-level version and add the Alpha X, saving yourself upwards of $5,000 in the process. You'll be just as fast ... or maybe even faster.
Just as important as bike-axis drag, we'd like to touch on an aspect of aerodynamic drag that is rarely reported. You might think of it as cycling's "dirty little secret." What I'm talking about is wind-axis drag, otherwise known as side force. It's the component of drag acting to push you sideways. We've all felt this force on particularly windy days; it's what gets you out of aero, forced to grab your base bar to control your bike until the wind dies down a bit. The reason I think of it as a "dirty little secret" is that, for increasingly-deep-section frame members, this force increases dramatically. The deeper your frame members (or wheels), the more side force you're going to feel in the wind. And once the wind kicks up enough that you're forced out of aero, it's game over; you're losing a LOT of speed needlessly, and those ultra-deep frame members aren't doing you any favors. Ensuring your side forces are within your ability level can mean the difference between being in aero, and nearly doubling your drag by coming out of it. Yes, it's that significant.
So how does that play into our story about the Alpha X? Well, in our comparison setup between the complete P5 and the P2 + Alpha X, we will see that for the bike-axis drag (the component of wind slowing you down directly), the TriRig setup came out slightly ahead. This alone is an amazing result, because it means you can get the same speed (or better) out of a P2 + Alpha X than a setup costing many thousands of dollars more. But when we look at side forces, it comes out significantly ahead. When the wind picks up, you can stay in the aero position longer with the Alpha X. This result was surprising, and wildly encouraging. It means you can not only achieve superbike performance with an entry-level frame and an Alpha X ... you can beat it. You're going to stay aero longer, defy the wind, and simply go faster with the Alpha X.
To bolster our conclusions about our aero data here, as well as to get a reference against our previous tunnel testing with Alpha Classic, we did some additional comparisons pitting different aerobars against the Alpha X. Hit the jump and have a look: