The Specialized S-Works Tarmac SL4, Part I
I’m going to start this post in a way that you’re not supposed to start a review—on a sour note. I didn’t see the need for this bike. Initially, it struck me as the inevitable result of the Specialized product machine. The template was struck some years back following the introduction of the Roubaix. The company alternates between a new Tarmac and a new Roubaix each year. In odd-numbered years Specialized introduces a new Tarmac, while there’s a new Roubaix in even-numbered years. Fall of 2011 required a new Tarmac.
When I first rode the Tarmac SL, I was not particularly enamored of the bike. I was a bigger fan of the Roubaix. I still think the Roubaix is the better bike for most non-racing riders. The issue for me was that I was accustomed to grand touring bikes; the two bikes I’d spent most of my miles on prior to first riding a Tarmac had relatively low bottom brackets and longish wheelbases. The Tarmac was a big change; the Roubaix less so.
It wasn’t until I began reviewing the Tarmac SL and the Roubaix SL back to back that I really acquired a taste for the Tarmac’s handling. I’d ridden plenty of bikes with handling as sharp as the Tarmac, and had disliked plenty of bikes with such quick handling. Well, “dislike” might be a bit harsh; they wouldn’t have been my first choice. The Tarmac showed me that with adequate stiffness (particularly in the fork and at the head tube) sharp handling needn’t make you nervous. By the end of the review I’d come to the conclusion I actually liked the Tarmac better in my favorite terrain—the canyon roads above Malibu. Here’s the post where I changed my tune.
Next, Specialized came out with the Tarmac SL2. I didn’t like that bike. It was okay on smooth roads, but anything rougher than a chick flick would rattle you like a paint shaker. It made chip-and-seal feel like the Arenberg Forest. That said, I know plenty of people who liked that bike.
Two years later Specialized came out with the S-Works Tarmac SL3. The biggest difference between those two bikes was in the rear end. The seatstays were flattened and reduced in diameter. And while I was told there were some changes in the layup of that frame, the folks I talked to didn’t go into too much detail. Broadly speaking, I was told that the layup was changed to permit more flex vertically while keeping the bike as rigid as possible torsionally.
So here’s where I have to address that trope of “vertically compliant but torsionally stiff.” It’s become a joke because some of the publications out there use it as a crutch to convince you that a Toyota Camry is a BMW M3. There’s nothing wrong with a Camry, but very few autos can provide the performance of an M3. That line about ”vertically compliant but torsionally stiff” rings hollow because at a certain point, if all bikes have that quality, then it ceases to be a way to distinguish bikes. And we know they aren’t all that way. There are real differences.
When I say I liked the SL3, I mean I loved that bike. Here’s that review: part 1 and part 2. It was one of my two or three favorite bikes I’ve ever ridden due to its particular constellation of road feel, performance, handling and weight. It didn’t need improving. When you’re putting out one of the best bikes on the market there’s a risk in trying to improve upon your work; there’s a real chance that no one will notice the difference. And the risk there is that if consumers can’t tell the difference between the old product and the new, improved one, they will begin to think what you’re selling is smoke and mirrors.
After assembling the S-Works Tarmac SL4 (and I’ll come back to the assembly in a bit), I went for a ride on the SL3. It was a short ride in my neighborhood, less than two miles. Then I jumped on the SL4, and did the same circuit again. I took care to make sure the tires were pumped up to the same pressure. The difference was not night-and-day, but the bikes were unmistakably different.
It’s common for fans of handmade steel and titanium bicycles to deride carbon fiber bikes for lacking personality, or sometimes it’s phrased as soul. When you’ve got a one-man shop, the marketing effort is pretty obvious. Land Shark begins and ends at John Slawta. As it should. But with a bike like the Tarmac, there’s quite a team involved and it’s not exactly possible to market a bike around every engineer and layup craftsperson who worked on the bike. And believe me, if you’ve ever seen someone doing layup, you begin understand that it really is a craft, just like brazing or welding.
The team responsible for the Tarmac includes some of the most knowledgeable people within their respective fields that I’ve met in the bike industry. And the resources that Specialized put into the bike are staggering. I was surprised to learn that each iteration of the Tarmac, from the original SL up to the current SL4, received its own set of molds. That’s a new set of molds every two years. That’s a lot of tooling. Consider that some Italian bike companies are still using the same frame shapes from six years ago.
So why new molds every two years? Easy. With each iteration of the Tarmac, Specialized has altered the frame shapes, slimming seatstays here, swelling the down tube and growing the bottom bracket there. Like other carbon fiber frames, the Tarmac is made from several monocoque sections that are joined after molding. With each new iteration, the locations of some of these joints have shifted based on what the engineering team has learned about the previous bike.
In talking with members of Specialized’s engineering team, they revealed that feedback from riders on the HTC-Highroad team indicated they needed to increase vertical compliance without sacrificing overall torsional stiffness. While riders said they liked the S-Works Tarmac SL3, the front end was a bit harsh for a 200k day. To that end, Specialized replaced the 1 1/2-inch lower headset bearing with a 1 3/8-inch bearing and decreased the diameter of both the fork steerer and the head tube. Another important evolution in the Tarmac is the move to Specialized’s OSBB design, which is essentially a press-fit 30. Such a large bottom bracket structure—and similar ones by other manufacturers—has eliminated bottom bracket flex that I once used to take as a given in all bikes.
Aside from the desire for a more gentle front end, one of the few criticisms sponsored pros had for the S-Works Tarmac SL3 was that the rear brake bridge wasn’t stiff enough, that the rear brake would chatter and squeal. To correct that, the brake bridge was beefed up and right at the brake bridge the seatstays were also beefed up.
I could tell you that the bike uses Specialized’s FACT IS 11r carbon—okay, I have told you that it has the FACT IS 11r carbon. But that didn’t help, did it? Information ought to answer questions, not raise them and while all that stuff signifies that the carbon fiber material and layup that Specialized is using is more sophisticated than anything they used in the past, it really doesn’t tell the consumer anything objective. Not a crime, but not nearly as helpful as they’d like us to think. The upshot—the part that matters—is that the S-Works Tarmac SL4 is the lightest frame Specialized has ever produced, that is, with the exception of the women’s Amira frame. My 58cm frame weighed in at 898 grams and likely came in a few grams heavier than the matte carbon version due to the number of coats of paint necessary to generate that bright arterial red.
Up next: the build, the ride, the bottom line.