Specialized's New Sirrus Bikes Are the Next Evolution in Cycling: Comfort Is Key

The answer to the question above is most likely "No." After all, the two bicycles we will meet today aren't even on the market yet. However, this could very well be the next stage in bicycle frame design. Let's dive into the next generation of bicycles and what we can expect.

Now, from the very start, the one discerning feature of these two bikes is the framework. Yes, it's new, and it may very well be the basis for a new way of building bicycles. However, there's a bit of a problem if we look to explore the new Sirrus machines. Specialize makes very little mention of what's going on here. They're just calling this new design, in particular, the area where the seat tube splits, a Compliance Junction. All we have now is our knowledge of bicycle dynamics and frame design, so bear with me.

So, a Compliance Junction. About that. To understand what that means, we need to closely examine the words stiffness and compliance. In cycling terminology, compliance refers to frame or tube flexion under pressure, typically on a vertical axis. Then, there's stiffness, which is used to denote the flexion of tubes and frames on a horizontal axis. Compliance and stiffness refer to the same spectrum of "elastic deformation," so you can't say a particular tube is both vertically stiff and vertically compliant or laterally stiff and laterally compliant. But, because we rarely want a bicycle with lateral compliance, as it would buckle at the first corner you take, and always want a softer and squishier ride vertically, the two terms have grown to be accepted and used as such.

As for what all this means for the Sirrus frames, it is something extraordinary. By removing the lower half of the seat tube and creating a rhombus with the additional tubes, your ride is smoother or vertically compliant. For lateral stiffness, the "new" seat stays extend to the rear. In short, hits taken up by the rear wheel are to be absorbed by the new framework. Think of it as functioning like a leaf spring suspension on a car.

Let's picture just how this action works. Now, there you are, sitting next to your Sirrus. You swing one leg over and push. In the saddle, you're riding along, and with each stroke of your pedals, that rhombus buckles just a tiny bit, the action nearly invisible to the human eye. However, your butt will surely thank you for it, and so will your back. Suddenly, you hit a crack in the road, and instead of being bucked as if you're at the rodeo, the Junction works its magic yet again.

Now, designs with a missing seat tube do exist, but not necessarily like this. For example, Urwahn, a German bicycle builder, has done away with most of the seat tube and has transformed the entire frame into one compliant structure with, what I like to call, perfect stiffness. Oh, and rumors have it that Rondo will also be dropping something similar this year.

As for the Sirrus, to control just how bouncy these buggers may be, nothing more than carbon fiber is being used to create that Compliance Junction. Actually, the entire frame is built from carbon, including the fork. But it's not clear just how light the bikes may be.

Continuing our journey into the Sirrus, we need to consider the class that Specialized places these bikes in. I mentioned they're considered fitness bikes, and this means a bicycle designed for folks looking to get an excellent workout. It's not designed to carry you across finish lines or bring home gold medals; it's a machine for riding far after a hard day at work or on a Saturday morning routine.

Adding to its fitness capabilities are things like water bottle mounts to help you stay hydrated and pushing forward, up to 42c tires to bite down on tarmac or country roads, and a Future Shock vibration dampening system to ensure you're as comfortable as ever on the Sirrus. Things can even be taken further with racks, fenders, and cargo mounts on the top tube.

All this brings up a very clear question: why such a big push toward a comfortable bike? Well, the answer is straightforward. The more comfortable a rider is, the more they can stay in the saddle and burn calories. Speaking of burning calories, the 5.0 is equipped with a 1X drivetrain rocking an SRAM NX Eagle setup. The 6.0 is sporting SRAM yet again, but a GX Lunar.

Where to from here? I personally believe this could be the next stage in cycling evolution. My own interactions with seat tube-less bikes have turned me into a believer in the possibilities at hand. But how much are we going to be paying for something like this? I was amazed to see that Specialized is about to drop these buggers for no more than $3,000 (€2,700 at current exchange rates) for the 6.0 and $2,250 (€2,050) for the X 5.0. If you're looking for a new bike and one that sits on the cusp of cycling evolution, look no further.