From the pages of Velo: Time Travelers
The American giants face off in the wind tunnel and on the road
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Editor’s Note: In April 2011, we unveiled VeloLab, our in-depth bike and component testing program that combines objective, lab-based metrics with on-the-road evaluation. In the 18 months since, we’ve tested more than 25 bikes, from sub-$1500 budget road racers to the bikes of the WorldTour. The following cover story first appeared in our August 2012 issue and pits two top time trial bikes against each other: the Trek Speed Concept 9.5 and the Specialized Shiv TT.
A look at the fastest human-powered machines on two wheels
With 101.4 kilometers of time trialing in this year’s Tour de France, the bikes ridden in the race of truth will be more important to the general classification contenders than in recent years.
The amount of time and money that big teams and their associated sponsors invest in making their riders faster against the clock is significant. Rider position and appropriate wheel choice have a considerable impact on the speed equation, but the frame and fork (or module in the case of some) determine how easily a rider can achieve his ideal position. With that in mind, the VeloLab set out to see who might have an advantage before the clock even starts.
Both Trek and Specialized took part in our test. We had hoped to test Cervélo’s new P5 and BMC’s time machine, but neither was available in time for testing in the wind tunnel or on the road.
We sent both bikes and a control set of wheels (a Rolf TdF60 front and a Zipp Sub9 disc rear with 21mm Vittoria Corsa CX tubulars) to the A2 Wind Tunnel in Mooresville, North Carolina, to see how they stacked up against the wind. Both bikes were set to the same position and then the saddles were removed. No pedals or bottle cages were installed.
After that, both Caley Fretz and Nick Legan channeled their inner Miguel Indurain and took to the roads of Boulder, Colorado, to see how the bikes handled and how easily they could find their preferred positions. Here’s what they found.
From the side, the Speed Concept appears to break fundamental aerodynamic rules.
It looks neither sleek nor smooth; gone are the teardrop-shaped tubes and ultra narrow profiles, replaced with blocky, square-tailed forms that seem anything but aero.
Turn to the front though, and view the frame as the wind does, and the Speed Concept is a masterpiece. It cuts a slim figure and boasts one of the cleanest front ends in the industry, with a fully integrated front brake and slick cable routing.
The UCI’s 3:1 rule, article 1.3.024, states that, “a fuselage form shall be defined as an extension or streamlining of a section. This shall be tolerated as long as the ratio between the length and the diameter does not exceed 3.” Those blocky trailing edges are known as Kamm tails, cut-off profiles with carefully tailored edges designed to make a UCI compliant tube perform like it is much longer and narrower than it actually is. The UCI also stipulates that all main tubes must be at least 2.5cm in diameter. With the Kamm tails, you get low drag figures into a headwind and even better performance in crosswinds.
Specialized Shiv TT
by Nick Legan
When the Specialized Shiv was initially launched, it looked a bit different than the bike we tested. It had a nosecone, or at least that’s what the UCI eventually labeled it. But according to Specialized’s aerodynamicist Mark Cote, the Shiv TT, launched in 2011, is actually faster in a headwind and only slightly slower in a crosswind than the previous nosecone version. A new front triangle and fork meant that the nosecone wasn’t necessary.
It also meant that the Shiv became much easier to work on. The front brake is now easily accessed. What about the integrated brakes on the Speed Concept or the BMC? Wouldn’t that be faster? Well, Cote has an answer to that as well: “The juice isn’t worth the squeeze. There aren’t substantial gains; there are gains there, but they aren’t huge.”
Riders like Alberto Contador and Fabian Cancellara have used the Shiv to great effect. We set out to see if it was a better time trial weapon than the Trek Speed Concept (a bike both Contador and Cancellara have also used).
Quantitative Testing: 24/30 points
The Shiv is actually a bit faster in a pure headwind than the Speed Concept. Their driveside yaw results (a measure of the drag at different wind angles) are virtually identical, too. But the Trek performs four to five watts better on non-driveside yaw angles (46 grams at 10˚). That’s not a huge difference, but over the course of 100-plus kilometers of time trialing, it could be a decider.
Subjective Ride Quality
Comfort: 5/10 points
Comfort isn’t really the name of the game with time trial bikes. But the contact points on the Shiv are particularly harsh. The arm pads are very wide, but in practice the rider’s elbows only make contact with a very small portion of the pad. By comparison, arm rests from Profile Design or Syntace are plush.
Acceleration: 8/10 points
The huge bottom bracket area of the Shiv ensures that power is transmitted efficiently to the rear wheel. Specialized’s solid time trial chainring stiffens up the S-Works crank appreciably as well.
Handling: 7/10 points
The Shiv is a straight-line machine. In the aerobars, it’s easy to avoid road obstacles, but with so much weight on the front of the bike the Shiv doesn’t turn easily. It requires a lot of rider input. But that’s a good thing — you don’t want a time trial bike to be twitchy. That said, other bullet bikes from Cervélo or Giant that we’ve ridden in the past handle a bit better.
User Friendliness: 10/15 points
This is where the super slippery front end of the Shiv loses some points. It’s great that it performs so well in the wind tunnel, but the fixed position base bar and single width extensions limit adjustment severely. In my case, when running the arm rests narrow, to my liking, the extensions sit wider than the arm rests. The ability to rotate them in would have helped significantly. Cote admits, “It’s a fine line between adjustability and integration.”
The fixed base bar is a limiter. Specialized ships a myriad of spacers to put the aerobar extensions in the necessary position, but that doesn’t help with the basebar. The Shiv is only available with a single length stem (and a fairly long reach basebar), so reach is determined by frame size. Thankfully, Specialized offers the bike in six sizes. But you’ll want a very careful bike fit before you order.
Otherwise, working on the Shiv is a treat compared to the Trek. Its cable routing works wonderfully, and with its exposed brakes, adjusting between training and race wheels is much more straightforward.
Value: 15/20 points
Sold only as a module (which includes the frame, fork, headset, bars, stem, brakes, bottom bracket, crank and seatpost), the Shiv allows riders to use derailleurs and saddle, pedals and wheels they prefer. Those are good options and lend value in the form of choice. But the $6,100 price tag still makes us balk.
Weight: 5/5 points
Regarding weight, Specialized’s Cote says, “We designed the Shiv to be as light as possible. Contador’s built right at 6.8 kilos. Cancellara’s, with a disc and a (Zipp) 1080 front wheel, only weighed 16.1 pounds.” The Trek is chunkier, not typically a big deal, but a lighter bike never hurts.
Trek Speed Concept 9.5
by Caley Fretz
Quantitative testing: 30/30 points
The Speed Concept and Shiv are nearly identical at low yaw, with the Shiv only slightly ahead. When wind blows from the rider’s right, the drag figures remain tightly packed. As the wind swings to the left, though, the Speed Concept steps ahead, by 46 grams at 10° and 113 grams at 15° — about 10 watts at 50kph. That difference is enough to give the Trek the edge.
Subjective Ride Quality
Comfort: 7/10 points
Comfort on a time trial bike is all about proper positioning and good contact points. Trek’s aero extensions and arm pads offer quite a bit of adjustability. Higher and lower, forward and backward, and side-to-side pad adjustments are all possible. The pads themselves are large, squishy and cup the forearms well.
Acceleration: 8/10 points
The wider, blockier Kamm tail tube shapes do wonders for overall frame stiffness, and the Speed Concept was one of the best out of the blocks that we’ve ever tested.
Handling: 6/10 points
Trek’s stiff chassis aids high-speed cornering, but handling is still considerably worse than any road frame. While TT frame geometry is designed for straight-line stability rather than cornering prowess, poor cornering is poor cornering whether it’s designed to be that way or not, so we can’t give the Speed Concept many points here.
User Friendliness: 8/15 points
Time trial frames are notoriously unfriendly to their users. When brakes are integrated, as they are on the 9-Series Speed Concept frames, unfriendly turns to downright nasty.
Brake adjustments require a third hand. What should be a quick adjustment for rim width can take forever. In fact, we had to switch to ultra narrow pads just to get the Zipp Sub9 disc into the frame at all, even with the brakes opened up all the way.
Cable routing is a similar story. If you’re not a highly competent mechanic, best to leave it to the professionals for your own health.
Front-end adjustability is decent, with plenty of arm rest adjustment but few extension adjustment options. Certainly, as with the Shiv, get a good fit before purchasing.
Value: 18/20 points
The complete Speed Concept 9.5, which uses Trek’s top-of-the-line 9-series frame, can be picked up with a Shimano Ultegra kit and Bontrager low-profile aluminum wheels for $50 less than the Shiv frame module. Though you may want to upgrade some things, like the wheels, that’s still an excellent value relative to other top-end frames on the market.
Weight: 5/5 points
The Trek module is lighter than the Shiv, and despite the fact that the particular package we tested uses Shimano’s rather chunky Ultegra group, it’s still a relatively light ride overall.
The battle between the Shiv and the Speed Concept is a tight one, each with its own strengths and weaknesses. But in the end, Trek’s use of the innovative Kamm tail tube shapes and its better price point allowed it to pull ahead.
The Speed Concept was faster in the tunnel, barely, but added to that victory with its above-average stiffness and comfortable contact points. But it lost out around the corners and took a big hit in user friendliness— it is, without a doubt, one of the most difficult bikes we’ve ever worked on.
The Shiv handled well, produced lower drag figures at low yaw angles, was easier to work on and considerably lighter, but its big price tag and higher non-drive side drag hurt its overall score.
Wind tunnel results
Given the way the numbers played out in the tunnel, if you were riding into a crosswind from your right, ideally, you would want to be on the Shiv TT. For the return leg, with the same wind conditions, (now on your left), switch to the Speed Concept and save 10 watts on the way back. Despite the radical difference in the way the bikes look, with our control wheels, it seems the bikes were created with similar yaw angles in mind.
BMC, Pinarello and Cervelo
The Trek and Specialized are by no means the only slippery bikes that will vie for top TT honors in July. In fact, depending on who you ask, neither of them will be ridden to overall victory. At press time it looked more likely that a BMC, under Cadel Evans, or a Pinarello, piloted by Bradley Wiggins, would take those honors. Cervélo’s new P5 will surely help the Garmin-Sharp team as well. Here’s a peek at those bikes.
BMC timemachine: BMC Racing, Cadel Evans
The timemachine (all lowercase is correct) served Evans well last year. With integrated brakes, complete internal cable (or wire) routing and an internal Di2 battery box, BMC has taken integration to the next level. That also means that it’s very tricky to work on. The massive seatpost is very easy to access though, in contrast to the complex stem setup.
Thanks to its seatpost that features massive fore/aft adjustment, the BMC can accommodate both time trial and triathlon saddle positions.
Pinarello Graal: Team Sky, Bradley Wiggins
The Graal is actually becoming a little long in the tooth. In 2010 it replaced the Montello in the Pinarello line. The curved tube shapes and oddly textured down tube set the Graal apart from virtually every other time trial bike on the planet.
Team Sky produces custom aerobars for its top riders with integrated Di2 shift buttons, increased adjustability and, likely, improved aerodynamics.
With a hidden front brake mounted on the back of the fork crown, the front end of the Graal is pretty tidy. A standard rear brake makes working on the bike easy.
The strange bumps on the down tube of the Graal are likely more about aesthetics than aerodynamics, but the look is great. And with the lanky Wiggins aboard, the Graal has no problem going fast, though it may be the slowest frame used among the favorites.
Cervélo P5: Garmin-Sharp, Dave Zabriskie
Cervélo’s P5 uses a creative interpretation of the UCI’s 3:1 ration rule to build a very aerodynamic frame; in fact, it doubles it occasionally. The P5 was unveiled with Magura’s R8TT hydraulic brakes early in 2012. With two different handlebar setups, one for TT and another higher set for triathlon, Cervélo looks to serve both crowds with the same frame.
The brakes, when outfitted with Di2 or EPS, mean that cable routing issues and the associated kinks are a thing of the past. That’s a good thing on time trial bikes, which often have substandard brakes and shifting thanks to tight cable routing.
Ryder Hesjedal used his P5 to win the Giro d’Italia overall in the race’s final time trial. Days before, Dave Zabriskie also rode a P5 to win the Amgen Tour of California time trial and later defended his national title aboard the same machine.