Granted, Specialized has more than a little skin in the game when it comes to making the “disc brakes for road bikes” argument. Four of California bike maker’s most popular models — the Tarmac, Roubaix, Diverge and Crux cyclocross bike — have at least one disc brake option. But even if the Big Red S is a little biased, this wind tunnel test is worth a look. In the video below, Specialized goes inside its in-house facility to find out how much slower a disc brake equipped Tarmac road bike is compared to a Tarmac with a traditional rim brake set-up. And while we can’t sign off on their findings with absolute certainty, we’ve spent enough time riding road and ’cross bikes with disc brakes to say without hesitation that actual braking performance is superior — especially in wet conditions. So is the trade-off worth it? You be the judge and let us know what you think in the comments section below.