Plot spoiler: These are the finest wheels I’ve ever ridden in my life.
There. That’s out of the way. Now that I’ve eliminated any sense of drama from this review, I can get down to the matter at hand and discuss the experience of riding Zipp’s standard-bearer wheelset.
There’s an arms race in cycling that’s been escalating over the last 10 years. I think back on the most I could spend on a set of wheels or even a whole bike 10 years ago versus the colossal $2700 that these wheels go for and I choke. There’s nothing else in my life that has escalated as badly over that time, save the housing market and we see what happened with that. Somehow, I don’t see Zipp, HED or Lightweight wheels suddenly dropping in both price and value—not now, not in the future.
The math on this is difficult to avoid. For that much money you could outfit an entire Girl Scout troop with iPhones. Or you could provide the entire U.S. Army with bubble gum. Or you could purchase a single set of wheels that would do more to improve your performance than an extra two hours of training per week can.
These wheels are so sophisticated I could probably write about them for the rest of the week and not divulge any of Zipp’s trade secrets. The 404s possess three distinct features that have caused me to come to the conclusion I did.
First and foremost is the Firecrest rim shape. While I am aware that one of Zipp’s competitors claims to have arrived at the rounded rim profile at the same time as Zipp, the fact is when Zipp came out with Firecrest at Interbike in 2010, their competitors talked crap about the silly shape. The trick to Firecrest is that it treats the half of the rim behind the axle as a leading edge and that blunt shape improves the rim’s aerodynamics dramatically. The most surprising aspect of this is what is called vortex shedding.
Those of you who have ridden deep-section carbon rims and been buffeted by the wind have experienced vortex shedding. Every time the airflow attaches to the rim surface and then breaks free from it the wheel is buffeted and you feel it at the bar. That’s not even the most dramatic feature of the Firecrest shape. This is:
It’s more stable in a crosswind.
The rim shape causes a change in the wheel’s center of pressure. It’s a crazy term for the point of leverage the wind has on a wheel; it’s a very east-to-feel phenomenon. Ride a deep-section wheel in a crosswind. If the wind is blowing from right to left, you’ll be steered to the left. That’s because the center of pressure of most wheels is forward of the steering axis. Firecrest, on the other hand, shifts it almost in-line with the steering axis. Ride a Firecrest wheel in a crosswind and you’ll feel almost no pressure on the wheels. It’s a bit more complicated than that, as the way a rim sheds a vortex changes slightly as the wheel spins; the center of pressure can actually shift behind the steering axis slightly, steering you into the wind instead of pushing you across the road. It’s a remarkable sensation and results in a real increase in confidence compared to riding other deep-section wheels.
How good an idea is Firecrest? Well, after bagging on it as crazy, both HED and Enve have moved all their wheels in that direction. And while competitors may be trying to emulate the vortex shedding properties of Firecrest, they can’t copy the golf-ball-like surface of the ABLC (Aerodynamic Boundary Layer Control) that keeps the air moving by the rims.
If you were to buy a set of 404s for only one reason, Firecrest would be it. No other deep-section wheel I’ve ridden is as stable as the 404 Firecrest.
The Carbon Clincher technology is my next most favorite feature of these wheels. The time I spend in Malibu riding with friends means I’ve either personally melted or seen melted wheels by every manufacturer except Zipp and Easton. Last summer a small group of us did the now notorious descent of Las Flores Canyon. I rode the 404s and didn’t have a bit of trouble, despite some firm braking at times. After reaching the bottom I waited more than five minutes for a friend to arrive. He was concerned his ultra-zoot wheels from a certain German manufacturer would melt, so he stopped three times to let them cool off. Granted, this guy weighs a good 30 or 40 pounds more than I do, but if you can’t take a mountain descent on a set of wheels, what good are they?
Other than the fact that they don’t melt—which is reason enough to take note—they do have one other detail that make these clinchers pretty killer: The rim width. Roughly 25mm wide, any clincher you mount on these wheels can be removed with no tire lever (sweet) and gives the tire a much wider footprint, increasing traction without—I’m told—increasing rolling resistance (amazing). There is a however, here, however. Setting up brakes for a rim this wide isn’t easy and you have to adjust the brake shoe angle because of the angled braking surface. Swapping out these wheels for another set is going to result in at least a half hour of work, if not more.
The wheels’ next best feature are the 88/188 hubs. They are an improvement on the previous iteration of the hubs with which I experienced near constant creaking. Really effing annoying. These are stiffer and don’t creak. What is more impressive is how these things roll. Zipp uses grade 10 ball bearings in the hubs. That is, they are accurate to .10 of an inch. That 2.5 times as round as the grade .25 balls used in Dura-Ace and Record hubs.
You may not think that’s particularly impressive, but I can say from experience that when I’m inside a group, the combination of superior aerodynamics and fast-rolling hubs causes me to hit my brakes to modulate my speed because I begin rolling up on riders in front of me when we’re coasting.
My set weighed in at 1562 grams, just a couple grams off the advertised weight. I’ll call it even. The combination of aerodynamics and weight mean that they are not only killer on the flats, but they are light enough to be reasonable climbers.
Engineers at two different bike companies told me off the record they have taken a number of wheels to the wind tunnel to test with their TT bikes. Both said that tire choice has a huge effect on aerodynamics. Even so, both also said that no other wheels they have tested are as versatile as the 404s.
Here’s the strange thing I’ve noticed about riding with the 404s. While I have many friends who will train on heavy wheels and save the good stuff for race day, in reviewing these wheels, I didn’t have that luxury. I needed to get miles on them right away. Oh, and I’m not really racing, so there’s that, too. With the addition of the 404s, the increase in aerodynamics gave me enough of an edge that I was able to get to the front of the group rides more easily. That, in turn, gave me the ability to stay at the front more. The upshot may seem counterintuitive; the wheels didn’t make the ride easier for me. They made it easier for me to get to the front and flog myself more, rather than sitting in the pack just trying to hold on to my spot. It seems I train harder with faster wheels.
Honestly, suffering more—not less—is the last thing in the world I expected to have happen.