Tested: Cervelo S5
The Canadian brand is setting a new paradigmJuly 15, 2011
The press launch of the new Cervelo S5 was a unique one for LAVA; rarely is it of merit for a triathlon publication to attend a road bike launch. Joined by industry colleagues, Cervelo CEO and co-founder Phil White and legendary Tour commentator Phil Liggett, we were pleased to get the chance to test the S5 and determine its relevance to the tri market, a segment that has fairly embraced the aero road bike market for its transitionary utility in hilly tris. And after a few hours over two days in France on the S5, we’re complicit: this bike is going to be on the top of triathletes “must-have” lists in short order, a highly attractive option to add to the quiver of any triathlete, whether for winter base miles, in-season hilly course racing.
On its face, the S5 is purely polarizing; the UCI says it exists well within the double-diamond limitations, but in spirit, it’s an advance from the old-school look of the traditional road bike. The front end is everything you would expect in an aero road bike: a nice bladed fork, a deep-section downtube—all good. But behind the headtube? Pure time trial bike; a fully-faired seat tube. A faired rear brake. Lowered downtube. While Specialized marketed the Venge as “More Bike than Aero,” there’s no question what the primary drive of the S5 is: more aero than anything.
Of course, there were some likely traditionalists with heads cocked, trying to make sense of this funky new design. It’s ok; give ‘em time. But the triathlete in me smiled.
Of course, was no surprise when Team Garmin-Cervelo time trial specialist Dave Zabriskie—king of unconventional—wearing a funky new sprinters aero helmet on the road stage, would also ride the S5 in the race-opening road stage. And it was of greater impression when Thor Hushovd rode his yellow jersey version (one we hope becomes available to the public in a limited run, because it looked slick) to lead out teammate Tyler Farrar to a stage victory on stage three.
As a group of journalists stood in the brisk morning sun on France’s Atlantic coastal region about to embark on a short but telling ride, there were looks. Some embracing, but many simply trying to get their heads around the bike they were looking at.
Cervelo’s debut of the S5 was a groundbreaking one. Indeed, the road bike market has caught on that a.) aero road bikes are just faster, and b. they can be built to handle with the agility of a crit bike and climb with the best as well. To create that, the S5 was the work of entire Cervelo engineering squad, including race engineer Damon Rinard, and of course Cervelo co-founders Phil White and Gerard Vroomen.
The name “S5” (coined to skip the unlucky number four in the Asian culture) also holds virtue on five key tech principles found in the bike:
-A dropped downtube (for greater aerodynamics as wind flows off the front wheel and onto the downtube
-A downtube lower section featuring a flattened trailing edge, optimized for greater air flow with water bottles in place. In fact, the frame feature three equidistant bottle bosses on the downtube, allowing riders to select from high or low bottle placement.
-A rear wheel cutout that has to date the greatest resemblance to a time trial/triathlon bike than any other, with no token spacing; it’s a good, tight fit on a 23mm tire.
-Cervelo’s stiff BBright bottom bracket platform
-A seatstay/seattube junction “shoulder” that shields and optimally transfers air around the rear brake caliper.
And we’ve seen Cervelo’s University of Washington Wind Tunnel numbers when compared to its own previous industry leader aero road model, the S3; 36.8 seconds savings over 40k (or one minute, 23 seconds over a 56-mile half Ironman bike course). A carve of 92 grams of drag. A 9.2-watt measurement in power savings. A fit variance of 20mm fore and 20mm aft on the offset seatpost. And a succinct white paper to tie it all together. As always, Cervelo brings its homework to class, with lots of scribbles outside the column to show its works is its own.
Other details of note on the frame include smaller features that some may have lost, including an aero seatpost with a cinch bolt akin to that found on the Cervelo P4Evo that angles in for greater bite, but also so you can get a torque wrench on it.
White said that as rewarding it is to bring the S5 to market, it was an engineering nightmare. “You have tubesets doing things they’re not supposed to do… like our seatstays do as they meet the seattube as a shoulder. It’s just unnatural.”
Hell, the whole bike looks like an affront to the classicisms of Coppi and Merckx (again, despite the fact it fits within the UCI’s constraints). Hey, sometimes advancement spiritually hurts; get over it.
The frame’s stiffness obviously brings about concerns about over-stiffness. After all, it is a road bike, not a time trial bike where unforgiving ride is an oft-accepted element. White tells LAVA the seattube’s transitions help create a greater degree of high-frequency vertical impact dissipation.
That’s actually true; paired with the BBright bottom bracket and the amount of deep aero tubing, there is going to be an inherent rise in stiffness—wanted for torsional drive (key for a Hushovd or Farrar sprint), but unwanted vertically for comfort.
But it’s not a spike as some may be fearing. Indeed, it’s much stiffer vertically than your existing road bike, but certainly more forgiving than, say, the P4, and not a filling-loosening ride by any means.
Maybe it’s due to the fact that I look at the bike as both a racer and triathlete, not an athlete out for a randonee joyride. I want 100 percent power transfer, and that stiffness is a full relay on the S5. It’s our thinking that triathletes, familiar with stiffer rides, will rather enjoy (instead of complain about) the greater stiffness in the back end. Want comfort? Go after Cervelo’s RS; there’s your comfort bike.
As for the flattened bottle trailing edge (as well as the unique two position options via three bottle bosses on the downtube) it’s a shocker how much advantage is found there.
“We made the frame more aero with that flattened section,” and it did deliver a 14-gram savings with a bottle on the downtube, White tells LAVA. “But do you want to guess know how many grams of drag an Arundel bottle has on the S5 seattube? Zero.” That is, you can run a bottle with zero drag detriment. Pretty cool.
We had a chance to look over Tyler Farrar’s race-set S5 at the Garmin-Cervelo team hotel in Tiffauges, and with race wheels on (see photo at top), this thing is a damn battle axe.
Aerodynamically, I’m most impressed with the rear brake coverage by the seatstay. Cervelo maintains that as slick as integrated brakes are, day-to-day functionality can leave much to be desired, and that for the most part, as un-aero as standard calipers look, they aren’t a major disadvantage. To that end, Cervelo’s rear stay “shoulder” is a brilliant windbreak for the caliper in the back. Sure, there are more valuable advances throughout the frame, but that one sticks out for us.
Our press ride out of stage one finish town Les Herbiers was just an hour and a half (though LAVA had an exclusive early ride the day before with Cervelo sponsorship manager Tom Fowler and a local semi-pro charged with taking us out without getting us lost on the beautiful, winding roads of Western France), but over flat smooth roads, some town cobbles and country rollers, we learned a lot.
The biggest thing you can say about the S5 is to expect the unexpected. The power transfer in the back tells your senses “tri bike,” but the nimble handling in front reminds you: road bike. It doesn’t take long to want to test out the rear end’s stiffness, on climbs and in what would constitute an aero position. We didn’t have clip-ons, but did our best to improvise with forearm riding.
A hallmark of the Cervelo brand is ride quality from a steering standpoint, and the S5 delivers. Around sweeps, out of the saddle, steering is fantastic. Climbing? No dramas; we tested the team version, which was impercievable from any round-tubed road bike we’ve hit an ascent aboard, but at 990 grams for a frameset (specifically, the top-shelf VWD, or Vroomen White Design version), Cervelo says it’s 80 grams lighter than the S3, making it certainly lighter than most aero road bikes out there, a testament to the engineering to be able to shave weight in unnecessary areas to get it lighter.
But on the flats? This is where it is separates itself from other aero road bikes. We felt the same, but asked one Dave Zabriskie what he felt, and how it will relate to triathletes that will find its geometry great for the hills, but its features of even greater utility on flat sections.
“It’s more aero than other peoples bikes, so mentally, that’s an advantage, especially when a guy like me is up front pulling breaks back all day,” Zabriskie tells LAVA. “When I put my head down and do my little tuck and let it roll, it really goes pretty fast.”
Of note is a headtube that’s taller than Cervelo’s predecessor S-series bikes by 6 millimeters—but in reality, it’s not taller. The rise is due to the fact that the fork is shorter (from axle to crown) by 6 millimeters, which is due to the new dropped downtube. Geometrically, the S5 and R-series bikes (R3, R5 or R5ca) have precisely the same stack and reach. So while it may look like a taller bike, it ain’t; it has the exact fit parameters one of the R-series bikes.
Of course, this none of this is of major consequence to triathletes who invariably end up placing spacers under their stem anyway. And among the Garmin-Cervelo pros, the only person thus far on the S5 looking for deep drop (by way of a negative 17-degree stem) among the Garmin-Cervelo riders was sprinter Tyler Farrar. He hadn’t ridden the bike during the race as yet, but Hushovd and Zabriskie seemed to be doing just fine on the standard setup.
To close the ride, Italian Cervelo distributor Allesandro beckoned me to wind it up on our return to Les Herbiers. It was the perfect chance to see how it would ride as a triathlete would intend it; flat-out on the flats. With the saddle in the fore position (zero offset) at about 75 degrees of seat angle, I lay my forearms on the bar tops and motored. And therein exists the unexpected; I felt like I was riding a P3 or P4, the stiff aft unyielding. Aside from a bit of steering waver (the head angle is for more upright road riding, so is a bit more nervous, but moreover it was due to the fact that I wasn’t set stable on aerobars), the S5 rides like a P4; stiff and fast. So side-by-side, Allesandro and I ripped straight toward Les Herbiers with my Garmin Edge 500 reading 36.7 miles per hour. It not only felt fast, it was fast.
All told, we’d be lying if we said we weren’t looking forward to getting this one in office for a proper test on American soil. Fortunately for us, White said that wouldn’t be a problem, as we will be testing the ultralight (990-gram) VWD (Vroomen White Design) model.
Check in later at lavamagazine.com for a Q&A session with Phil White on the development of the S5, which is available now in Cervelo retailers. You can find more on the S5 at S5.cervelo.com