I’ve worked in the bike industry for more than 20 years. In that time, I’ve had more exposure to Specialized than any other brand. It began even before I entered the industry; the first bike I purchased as an adult was the Expedition, a serious touring bike by any standard. The first shop I worked in was a Specialized dealer and I assembled scads of Allez, Sirrus, Stumpjumper and Rock Hopper bikes. I had the opportunity to ride a carbon Allez for a weekend and considered larceny one Sunday evening. When I joined the staff of Bicycle Guide I spent some time on a few different Specialized models, most of which were made with M2 metal matrix. I’ve logged as many miles as possible on the Roubaix since it was released.
All the while, I’ve watched a gradual, though subtle, shift in the geometry of Specialized’s sport bikes (what they term “competition”) from the old Allez to the current Tarmac.
Compared to the early bikes I built and occasionally rode (not counting my Expedition), Specialized’s sport bikes build today have a slightly shorter wheelbase, slightly higher bottom bracket and slightly less trail.
Once a 58cm top tube bike’s wheelbase drops below 100cm, its trail below 57mm, and its BB drop below 7cm, I have traditionally filed it under “crit bike.” That is, I’ve seen it as a somewhat more extreme expression of the standard sport bike, something skewed toward a style of racing peculiar to the U.S.
I’ll be honest and say I’ve shied away from riding bikes with this sort of geometry. In years past I found other bikes with this flavor of geometry to be all-out sketchy on descents. They made 35 mph feel like 55. To the degree that I could select bikes that comported with my taste for Italian stage race geometry, what I’ve chosen to call grand touring geometry, I did so.
I suggested doing the back-to-back comparison (call it a shootout if you must) to Specialized because I was curious to see how different the two riding experiences would be. I assumed that I’d like the Roubaix better and was honest with them about that. To them, that presented no problem.
The question on my mind when I first climbed aboard the Tarmac was whether it was a bike really suited to about 50 percent or just 10 percent of the population. I was curious to know just how some of the best bike riders on the planet were getting down Pyrenean descents on a bike that seemed, on paper, to be less well-suited to the task than its stable mate.
The first few rides I did on the Tarmac were with a morning group ride here in South Bay called the Pier Ride. It’s a jaunty little 30 mile spin over what is for my neck of the woods a very flat course (just shy of 700 feet gained) and in season will average a little more than 20 mph with warm up and cool down. Done properly, I arrive home wishing it were the end of my day, not the beginning.
The first thing I noticed about the bike was that in turns, because I was on a bike more similar in geometry to what other riders were on, I followed the line of other riders more naturally; I didn’t find myself swinging a touch wide and then correcting. After a week or two of this I noticed that I was focusing less on the turns and more on how hard I could pedal through them because I wasn’t thinking about actually following another rider’s line.
The next thing I noticed was how colossally stiff the bike was at the BB and in torsion. On the hoods, out of the saddle and delivering each and every glimmering watt I could muster was delivered unabridged to the drivetrain. A frame that flexes under hard pedaling or out of the saddle efforts has an organic feel to it for me; a little bit of detectable give conjures the feel of older wooden furniture and how it may flex a bit despite a sturdy construction. The Tarmac was so rigid and efficient as to summon thoughts of health club Nautilus machines.
You can only get flowing lines like this with monocoque construction.
Here’s what you need to know about Specialized’s carbon fiber bikes. Specialized uses a system of partial monocoque sections to build its bikes. All of the bigger guys do this. The IS in FACT IS means integrated system and Az1 (pronounced “as one”) is Specialized’s particular method of reducing the number of joints in a frame.
In Specialized’s case one piece includes the top tube, the head tube and all but a few inches of the down tube. The next piece is the rest of the down tube, the bottom bracket and all of the seat tube. The seatstays and chainstays are formed separately. Ultimately the Tarmac and Roubaix frames are made from six discrete sections, not counting dropouts. These joints are epoxied and then wrapped with additional carbon fiber to increase joint strength.
The 12k weave that you see in the finish of the Tarmac Pro and Roubaix Pro is essentially cosmetic; it provides a small amount of impact resistance, but it provides no structural support to the frame. It is, in short, an impediment to breaking the kilo barrier. You may have noticed the unidirectional carbon fiber finish in the SL2s and the new Tarmac SL3. That top layer is structural. Think of it as the bike equivalent of the “Visible Man” kit from when many of us were kids.
Next week: Part II