When Specialized introduced the Roubaix in 2004, it was the first bike on the market to combine top-of-the-line carbon fiber construction with a more relaxed geometry aimed at riders doing charity rides and centuries. Up to this point in time, the handful of bikes out there from the bigger manufacturers that combined a longer head tube for higher handlebar position, a longer than usual wheelbase and more trail for greater stability were made from aluminum and were rarely equipped with anything as nice as Shimano 105.
The implicit message seemed to be that if you weren’t fast you wouldn’t appreciate quality. The reality was simpler: For companies like Giant and Specialized, these early bikes had been aimed at a new wave of cyclists entering the sport, often as a result of events like the AIDS Ride. Getting these riders transitioned to a road bike from a mountain bike had been a significant achievement and there was little stomach on the part of risk-averse product managers to try to steer them into a bike 10 times as expensive as their last.
The road product development team recognized a need for a bike that combined the geometry found in the charity ride bikes with the high performance carbon fiber technology found in their top-of-the-line Tarmac. The Roubaix has been an unqualified hit among more than just the charity ride crowd.
The chicane in the chainstays really doesn’t flex much vertically, but aids in vibration damping
So how different is the Roubaix from the Tarmac? On paper, the differences seem minor, insignificant even. Just a few millimeters here, a centimeter or two there. Let’s compare a 56 in each:
|Seat tube length||53cm||51.5cm|
|Top tube length||56.5cm||56.5cm|
|Seat tube angle||73.25 degrees||73.25 degrees|
|Head tube angle||73.5 degrees||72.5 degrees|
|Head tube length||17cm||19cm|
Three dimensions are the big determiners for fit: the top tube length, the seat tube angle and the head tube length. Those first two—top tube length and seat tube angle are identical. What changes is the head tube length; its greater length gives riders the opportunity to adopt a bar position 2cm higher, allowing them to sit more upright without exposing too much fork steerer above the top headset bearing. As many of you are already aware, too much exposed steerer is at risk for breaking because of the greater leverage the rider can exert on the steerer from the handlebar.
So the bike offered a less aggressive position for greater comfort. The designers didn’t stop there. They increased the wheelbase length by more than 2cm by increasing the chainstay length and by using a slacker head tube angle and more fork rake, thereby increasing the front center distance as well. Practically speaking, this increased the distance between the rider and the wheels, cutting road vibration. More comfort.
The choice to go with a longer wheelbase had an added benefit. It addressed the rider’s more upright position and higher center of gravity (CG) which resulted in reduced weight on the front wheel (relative to the weight distribution in the Tarmac). Bottom bracket drop was also increased to help offset the higher CG; 2.5mm may not seem like much, but it’s enough to make a subtly helpful difference.
The Zertz inserts in the fork are angled to absorb more vibration
The longer wheelbase of the Roubaix means the bike won’t track quite as tight a turn as the Tarmac, but the fact that the slacker head tube angle is paired with more fork rake results in exactly the same trail as the Tarmac. As a result, steering input remains as crisp as the Tarmac’s.
Back to the issue of comfort. The Roubaix’s single most distinctive feature are the Zertz inserts in the fork, seatstays and seatpost. The size of those inserts and the way they are positioned in the fork and seatstays has changed since the Roubaix was first introduced in 2004. They are larger now and positioned more at an angle to the fork blades and seatstays to better serve their purpose, which is to interrupt the transmission of vibration.
I’ve met riders who doubt the Zertz inserts do what they are advertised to accomplish. Having ridden the Roubaix (in various iterations) more than 1000 miles and having ridden other, grand touring category bikes, I do believe that the Zertz inserts cut vibration transmitted through the frame. I often compare vibration—which is different from road shock—with the vibration from a lawnmower. While it’s not nearly as severe, I think the point illustrates the issue rather well. Anyone who has ever used a lawnmower with a two-stroke engine (as opposed to a push mower or an electric mower) knows well the interesting feeling your hands have once you let go of the mower. For a minute or more afterward your hands feel, well, like they are still on the mower. Sex aids wish they were so memorable.
Tomorrow: Part II