Reviews > 404 Firecrest Carbon Clinchers

By Steen Rose

I was intrigued when I first heard about the new carbon 404 clinchers. Zipp has been an industry leader for years, and it had been a little surprising to me that they took so long to come out with a carbon clincher. Tubulars are lighter, but a pain. Clinchers are less hassle, but heavier. Carbon Clinchers seem to be the best of both worlds. As it turns out, it was worth the wait.

But before we get into that, a little bit of history is in order…

I used to have a set of Bontrager Race X Lite Carbon Aero race wheels. They’re light, they’re fast, and Steve ‘Grand Dad’ Tilford rides them, which is good enough for me. Two years ago, I borrowed a set of then-current-generation 404 clinchers for an out-of-town weekend. They weren’t as light as the Bontys, but on the Saturday morning ride, I could feel that they were faster. I spent a lot of time on the front, setting tempo, reveling at the feel of the wheels. I got to ride them in a race the next day, and I was even more impressed.

Not long after, my dad started cycling more seriously after a layoff, and asked me to keep my eye out for a set of nice wheels for him. I ran across a used set of 404 clinchers for $600 on Craigslist. I checked them out, checked with Dad, and with a promise of reimbursement, I bought them for him.

Then I made the mistake of riding them. Sure enough, they were as nice as I remembered, and noticeably faster than the Bontys. Fortunately Dad wasn’t picky, and agreed to take the Bontys instead.

All that is a long-winded way of telling you that I really like my current set of 404s, and those will serve as a basis for comparison for the new wheels.

I’m sure you want to hear about the fancy new wheels, so here goes…

First, two things that you probably won’t notice: they come in really nice cardboard boxes, and second, the rim strip is sweet. I’m a bit of a rim strip whore, and up until now you wouldn’t catch me dead with anything but a nice roll of Fond de Jante on my wheels. However the new Zipp strip is it’s equal, and it’s easy to install.

Another thing you might not notice are the hubs. These spin beautifully and are adjustable. I like my wheels to spin until slowly pendulum-ing to a stop with the valve stem at the bottom. These qualify.

One thing you will notice is that the Zipp Tangentes go on surprisingly easily (although 5 minutes in the dryer won’t hurt). Zipp tires are made by Vittoria, and getting Vittorias on my older Zipps is a pretty Herculean task, requiring those big honking Pedros levers. I don’t know what’s different here, but I like it!

First up is the safety issue that Zipp wanted to address before bringing a carbon clincher to market. A traditional carbon braking surface can build up a ton of heat, and this can be a very bad thing for a clincher tire. The carbon used in the braking surface is supposed to dissipate heat, addressing this major safety concern. Living in Texas it was a bit difficult for me to test this, but I did tackle a decent Hill Country descent with non-approved brake pads and noticed no ill effects or warming of the rim. Of note, these wheels will pass all safety standards without weight or brake pad limitations, and not all manufacturers can say that.

The most noticeable difference is the rim width. This is part of the new Firecrest shape, and it’s supposed to be much more aero. Supposedly the new shape makes the 404 as fast as the old 808, but it has some other benefits as well (it slices AND dices). Without going into too much technical mumbo jumbo, the new design addresses the fact that the inside edge of a rim is both a leading AND a trailing edge, and therefore better handles airflow. More on this in a minute.

Now for the ‘and dices’ part: as it turns out, the wider rim profile makes the wheel stiffer, stronger, and more comfortable. The 303 tubular was the first wheel to debut this profile, and it’s been winning races that typically destroy carbon wheels, like Paris Roubaix. I didn’t have any cobbles handy, but I did take the wheels on a few, um, detours. They performed flawlessly, and felt buttery over gravel, rock, and the best Texas chip and seal I could find. I purposely aimed for the biggest cracks I could find, to see if the wider tire bed really did make for a softer-riding wheel, and I was impressed at how little I felt the bumps. Afterwards, my conscience was pretty shot from the ‘testing’ I put the wheels through, but no truing was required.

My biggest complaint with the old 404s was weight, and the new 404s shed 101 grams with the loss of the aluminum cap. To be honest I would’ve liked to have seen a bigger difference. The lower weight opens these wheels up to more races for me, but for hillier races I’ll still leave them home.

I have a lot of people ask me if aero wheels really make a difference, and the answer is an emphatic ‘yes.’ As a cyclist, you spend over 80% of your energy overcoming aerodynamic drag, so anything you can do to decrease that will make a noticeable difference. For years, cyclists have been preoccupied with weight, but the truth is that aero trumps weight, as gravity is actually third down the list of forces you have to overcome.

A traditional aero rim is designed to smooth and stabilize the airflow coming off the tire as the wind ‘sees’ the front of the bike. A deep ‘v’ shape does a pretty good job of this, but a bulged shape does even better. This is the hybrid-toroidal shape of the older 404 that has been around for a while. It’s pretty good, but as we’ve learned more about aerodynamics, some flaws have become evident.

First, the tire has to be close to the width of the rim, or you get turbulence, and turbulence makes you slow. A HED 3, for example, is really fast with a 19mm tire. Unfortunately, a narrow tire doesn’t ride as well as a wider one; it has a higher rolling resistance, is less comfortable, and handles worse than a wider tire.

Second, the traditional view of airflow only addresses the rim as a trailing edge, behind the tire. However, half the wheel is always a leading edge, so Zipp has designed the Firecrest rim with that in mind, smoothing the airflow in both directions over the wheel.

A final refinement is in the curve of the rim to better handle crosswinds. A crosswind creates sideways pressure against a wheel, making a deep-dish wheel hard to handle. The new shape decreases that amount of pressure that forms, making the wheel more stable in crosswinds.

So, that’s the technology, but how does it ride? As we discussed, it’s stiffer, stronger, and more comfortable (it dices) but most importantly, it slices through the wind. There’s one particular stretch of road where I most notice the benefit of the Zipps. It’s a crosswind section that produces a moderate yaw angle (the angle of the wind that the bike ‘sees’), and I seem to float along effortlessly at 23mph, much to the chagrin of the group, which is usually single-file behind. This was the first place I headed with the new wheels, to see if I could tell a difference. It’s not scientific, but I floated more effortlessly.

I’m used to the difference between my training wheels and 404s; I know when I put them on about how much faster they are. Going from the old 404s to the new Carbon Clinchers was that same feeling all over again. In fact, the new wheels are supposed to be as fast as the old 808, and you can feel it, especially at higher yaw angles.

Speaking of yaw angles, I had my wife ride the wheels on her tri bike on several occasions. If anyone is susceptible to steering issues with deep-dish wheels, it’s lighter riders in an aero position. I put on a set of Mavic Open Pros, and we decided that if she was the least bit uncomfortable from getting blown around, we’d stop and swap wheels. There was one day in particular where I thought for sure she’d want to change, but she never brought it up. I bailed on the ride mid way through (she was training for Ironman, and riding a ridiculously long way). I offered to switch the wheels for the rest of the ride, as the wind was just supposed to pick up throughout the day. She declined, grinned, and told me she was keeping them… I guess I’ll be riding the old 404s for a bit longer!

So, are they worth it? If you aren’t currently riding aero wheels, then the answer is an unequivocal yes. It’s a great all-around wheel that will stand up to everyday use and makes sense across a variety of conditions.

If you are already own race wheels, I’ll leave you with this: I’ve never been more excited about a set of race wheels; not when I got GP4s, not when I got Heliums in ‘99, not when I had the first set of Ksyriums in the city a few years later. In the words of Ferris Bueller “it is so choice. If you have the means, I highly recommend picking one up.”

Steen has been competing in cycling and multisport events for 15 years and coaching for 5. His coaching blends his passion for sport, his extensive experience, the best coaching practices and the most current information and technology to help athletes achieve their goals. Steen is a 13-time State Champion and 3-time National medalist in cycling.  His background includes triathlon, mountain biking and cyclocross, but today he focuses mainly on triathlon in the early season and road cycling later in the year.

Racing at an elite level while coaching (, and being married to a triathlete in grad school with a 60hr/week job. His coaching philosophy is focused on balance and perspective and getting the most out of limited training time by making every workout count.

3 commentaires
  1. Oli,

    Si je ne me trompe pas, le nouveauté de ce produit réside plus dans sa forme que le fait qu’il soit full carbon. Le pourquoi Zipp prétend que cette roue est aussi performante qu’une 80 mm standard.