Last week I was invited to a small media camp that gave me the opportunity to spend some time on the Cervelo R5 and be among a select group of people to have actually ridden the Cervelo P5 time trial bike. Now, I don’t ride a lot of time trial bikes, but I’ve ridden enough of them over the years that when I climbed on the P5 I knew instantly that this was a cut above, an achievement befitting Cervelo.
I say befitting Cervelo because few companies have spent as much time in the wind tunnel in pursuit of the most aerodynamic of bikes. It’s a short list of companies that play in this particular arms race and Cervelo loves to point out that their engineers outnumber their bike models. Of course, the alternate view is that with so few bike models, how is that their competitors can make anything even close? Nevermind. I’m not going to answer that today.
What’s apparent is that this frame features far more aerodynamic shaping than its predecessor, the P4. The front triangle features a very deep aero section behind the head tube and the top tube expands downward as it reaches the head tube. Similarly, the junction between the seat tube and the top tube is much larger and features far more aerodynamic shaping than its predecessor. I hesitate to use the term “fairing” because that would lend the impression that these sections are more aerodynamic than structural in function. And obviously that can’t be the case.
Why? Well this little UCI-issued decal is why. Honest to blog, I don’t know how this design was approved by the UCI. Not that I think there’s anything wrong with the bike. On the contrary, it’s truly remarkable. No, the UCI’s rules regarding aerodynamic shaping strike me as nonsensically as the woman at the park today who was bitching loudly about kids, including my two-year-old, breaking the rules for riding bikes in the park, but I digress. Are these rules really doing any good? I’ve long maintained that the UCI’s primary argument against technological advances—rider safety—is a red herring. No company wants the PR black eye that would come from an insufficiently strong bike folding up during a sprint. The resulting press—and falloff in sales—would be far worse than any punishment the UCI could hand out.
The Aura base bar, stem and extensions are a Cervelo design produced by 3T. I’m told there are three different height mounts for the extensions. What I rode was the highest of the bunch and while it was good for a first ride, with a bit of time on the bike I’d swap the extension for something a bit more diminutive. The Aura also include two opportunities to mount a water bottle cage, either on the stem or between the extensions. Gone is the P4′s special water bottle. But at only 38cm in width, that base bar made out-of-the-saddle efforts feel a bit sketchy.
Most TT bikes smooth the transition from the seat and down tubes to the BB, but Cervelo chose to keep the seat and down tube profiles thin and suddenly bulge the frame right at the BB. It might seem counterproductive to stiffness, but when you look at those tree trunk chainstays, you can begin to understand how the bike delivers great stiffness under power.
The P5 is also notable because only one cable is evident—for the front brake—even when using a mechanical drivetrain. And for the Garmin-Barracuda riders who are on the bike (not all have made the switch because so few have been produced), even the Di2 battery is hidden from the wind. The Magura hydraulic brake system is said to be maintenance-free, but that would suggest it requires even less work than traditional brakes, which is tough for me to believe. I can say they aren’t easy to adjust; at least, not until someone who knows the system walks you through them.
Naturally, the only way to get the rear wheel to achieve it’s snug nest behind the seat tube is with track-style dropouts, which makes changing a wheel nearly as fun as ferret-legging, though not nearly as fast.
For the P5, Cervelo went with a less aggressive fit. Per size, the P5 has less stack and reach than the P4. Presumably this is to make the practically unavailable bike (there appear to be fewer than a dozen in circulation) more attractive to the hoards of triathletes who are lining up at Cervelo dealers to purchase the P5 when it does become available in wider numbers. And as built, this P5 goes for $6k. While that’s a lot of money, I was honestly surprised that it wasn’t more.
The bike I rode was a 56. This was a huge 56. With the saddle positioned all the way forward on the rails and with the seatpost inserted all the way into the frame (which is to say, the shortest possible distance from the BB to the saddle), the saddle height was 78cm. Put another way, to fit on the 56, you need an inseam of at least 32 inches.
I didn’t get a chance to weigh the bike, but it felt light for a TT bike, like steel road bike territory. The other thing I noticed was that it didn’t ride like a paint shaker on the gnarled roads of Sonoma County. I rode through quite a bit of broken asphalt and was impressed that the bike didn’t have the unforgiving ride of many of Cervelo’s other aero designs, such as the SLC-SL.
All that is well and good, but frankly, there is only one thing to do when you climb on a rig of this sort: drill it. I wasn’t thrilled to learn (upon entering the shower) that I’d given up some skin from my fruit cup, but this is one of those go-fast machines that is ill-suited to the Sunday tour. There is little as compelling as free speed.
Did I mention this is the bike David Zabriskie just rode to victory and the yellow jersey at the Amgen Tour of California? Well, now I have.
Action images: Robertson/VeloDramatic
The years went by, I kept riding my bike, but I still have no hoverboard. Corporations: If the hoverboard is real, please don’t release it. I have kids now, I understand.
Over the years, I’ve followed a number of the technological advances that were supposed to be just around the corner for bikes that excited me almost as much. One of the biggies was electronic shifting. Electronic shifting, from Mavic, really never felt like it was going to take off. Finicky, prone to malfunctions, expensive—when it worked, it was great. When it didn’t, it was a mess. I figured electronic shifting would never hit the mainstream.
Then Shimano Di2 came out. Campagnolo EPS, 10 plus years in the making, was available. With the release of Ultegra Di2, its safe to say electronic shifting has left the realm of just around the corner, and hit mainstream. Sometimes, the advances we think will never come really do become reality.
The other big item I’ve been waiting for is disc brakes on road bikes. You’d think, being a well understood technology, we’d have them by now. With them now legal for cyclocross, it may just be a matter of time—mechanical discs are already making inroads, and while solutions for using hydraulics are a little hokey now, we’ll probably see something available sooner or later. If I keep saying any day now, sooner or later I’ll be right.
One thing I never saw coming was hydraulic rim brakes. I’m trying to decide if they are a technological advance, or just a Mektronic on the path to disc brake Di2. Or EPS—no allegiances here.
Magura’s announcement as a sponsor for Garmin-Barracuda started the rumors flying. Magura confirmed their re-entry in to the road hydraulic market with a hydraulic rim brake, the RT8, initially available as a time-trial only version (RT8TT) mated to the Cervélo P5 time trial frame. In a few months, we’re told, it’ll be available without the Cervélo for both road and TT use. How that’ll work in a world where most people use integrated brake/shift levers remains to be seen. Details are just around the corner, I’m sure.
Before we discuss the merits of Magura’s offering, it’s worth understanding a little about hydraulic brakes. For the dirt-phobic, this may be the closest you’ve come to them, and while it’s unlikely you’ll be seeing Magura’s offering on your group ride any time soon, you’ll probably hear discussion about it.
Hydraulics are pretty simple. A typical hydraulics system of any form is composed of a master cylinder, one or more slave cylinders, incompressible fluid like mineral oil or DOT, and hydraulic cable to connect them. Each cylinder contains a piston. Press the piston in the master cylinder in, the incompressible fluid moves out of the master and in to the slave, and the slave piston extends. Simple. Attach a brake lever to the master cylinder piston, and use the slave cylinder to actuate a brake pad, and you have the makings of a hydraulic brake.
There are two different kinds of hydraulic systems employed in bikes. Most hydraulic discs use the “open” system, where there’s a reservoir attached to the master cylinder to manage fluid fill levels in the system itself. Lots of braking can heat the fluid, causing it to expand and overfill the system. The same excess braking also contributes to pad wear, requiring more fluid in the system. The reservoir takes care of managing these levels.
In a closed system, there’s no reservoir. Just the master cylinder and slave cylinders, and a fixed volume of fluid.
Left by itself, pressing the master cylinder piston in moves the slave piston out, where it will happily stay. The “normal” solution involves using specially shaped gaskets, designed to “twist” along with the piston. When there’s nothing pushing on the master cylinder piston, both pistons will want to retract to their normal positions, giving the behavior you expect from brakes. Springs occasionally augment this sort of system.
The upsides to hydraulic brakes are numerous: low friction, one-finger braking. Great modulation and control. Consistent performance, devoid of changes due to cable stretch or wear. Most of all, they’re powerful—by tweaking the ratios of width and height between the cylinders, a mechanical advantage is achieved—1 pound of pressure at the master cylinder can exert many multiples with a proper design.
The new RT8 brakes are a somewhat unorthodox brake design, if we confine ourselves to the notion of how disc hydraulic brakes work.
Magura has had a rim brake product line for years, targeted at the tandem market. These offerings, and it appears the new RT8 as well, utilize a “closed” hydraulics system. The master cylinder has no reservoir. This isn’t necessarily a problem, assuming environmental conditions stay pretty constant; heat generated by braking shouldn’t feed back in to the slave cylinder the way it might in a disc system, which directly actuates the pad. Pad wear is still something of an unanswered question in the RT8—this could very well be handled at the brake lever by adjusting the travel of the lever blade, or limiting the retraction of the piston.
So is it better?
Magura’s brake should offer stronger, quicker actuation with less effort than a typical brake. Depending on the terrain you ride, this may be a major advantage, or make no difference at all. For the cyclist who finds them selves climbing—and therefore descending—major heights, hand fatigue may be a serious problem. We haven’t seen a road brake lever yet from Magura, however. At the moment, unless you find yourself regularly descending on your time trial bike, this likely isn’t a major problem.
Power isn’t a major issue with modern road brakes. Enhanced modulation may allow a lighter touch ducking in to corners, and that could possibly lead to some speed advantages for the racers among us. Possibly. With situations where the brake selection itself is causing braking problems, then the RT8 might be a major advantage—with some time trial bikes utilizing low-travel lever blades connected to center pull and single pivot designs to smooth cable routing and reduce frontal profile, the uncompromising power of the RT8TT will be a welcome change.
Aerodynamics have been heavily touted for the RT8′s, with Cervélo playing a role in their design. It’s not an advantage afforded to it by being hydraulic, but may shave precious microseconds off times. We’ll have to wait for some testing to confirm this.
The Magura design may have one neat side effect. It hasn’t been discussed, but the closed hydraulic design of the RT8 may allow for multiple master cylinders. In an open system, where the master cylinders have reservoir, having a one master cylinder compress will cause the other’s reservoir to, over time, soak up the excess fluid in the system. In a closed system, so long as there’s no air in the system, there’s no place for the fluid to escape. Bleeding the system would bring new levels of pain to an at times trying process, but in theory, once its set up, it would work fine. I’m certainly curious to see if anyone is going to try mounting brakes on both their base and extension bars in a time trial. The ability to brake from the extensions and maintain an aero position could be an genuine advantage.
It’s less clear if the Magura brake will help with are the major issues big descenders have: rim sidewall damage, wearing out pads, and blowing out tires. Discs, by relocating the braking surface away from the tire, are the best hope we have for solving that issue once and for all. That and better technique.
Under certain conditions I can see some potential upsides to Magura’s RT8 brake. Quicker actuation, more power and better modulation with less fatigue sounds like a win, if these are problems that plague you. Improved aerodynamics don’t do much for the recreational cyclist, but may be a win for those at the point where fractions of seconds matter. The multiple lever concept sounds cool, but whether anyone cares remains to be seen. We’re still left using the rim for a braking surface, though the enhanced modulation the Magura should offer might compensate a little for those with marginal descending technique.
It’s an interesting product, and one I’m curious to hear more about as details emerge. It’s unlikely, however, to satiate my desire for discs—or hoverboards.
Photos courtesy of Magura