Aero for the Masses: Zipp 404 Firecrest Is Wider, Lower-Pressure, and Still a Great Wheel

The Zipp 404 road wheelset has been an aero standard for 3 decades. Zipp has gone through six iterations, but it made massive changes last summer.

The newest Zipp 404 Firecrest Disc Brake makes improvements outside of aerodynamics, an attribute widely attached to one of the most recognized model names in road wheels. The 404 has enjoyed 3 decades in the spotlight as one of the most well-rounded road wheels ever produced. So, it was a surprise that Zipp made significant changes outside of the aero realm.

I tested the wheels for 6 months on my daily road whip, both on smooth urban roads and rough tarmac in the Hill Country of Texas. Although Zipp applied massive changes to the 404, it reinforced my opinion that they are among the most versatile road wheelsets ever produced.

The Firecrest 404 balances weight, aerodynamics, durability, and price amazingly well. And Zipp’s Total System Efficiency concept drastically reduced transmitted vibration, dramatically improving ride quality.

The Big Changes

The venerable 404 got wider, from 19mm to a 23mm internal width, but still sits at 58mm deep, like all 404s. And Zipp switched from hooked to hookless bead. These seemingly small changes compile to bring a massive one, something Zipp dubs Total System Efficiency (TSE).

The 404 always addressed wind resistance and gravity, but the 404 Firecrest also minimizes rolling resistance and vibrational losses with these updates. The wider internal width and hookless bead play well with the current crop of wider, higher volume tires and their prescribed lower air pressures.

How low? To a guy like me, who raced on tires inflated to as high as 145 psi, the recommended pressures for my 175-pound riding weight and 25c tires are astoundingly low: 70.8 psi in the rear, 66.6 psi in the front.

At first, I didn’t trust those low pressures, thinking I would hit a pothole and blow out a sidewall or damage a rim. Zipp insiders assured me that these pressures were safe and that I would immediately feel the effects of TSE.

Zipp retained its signature dimpling on the sidewalls of the rims for claimed aerodynamic gains, and the brand also states that the hookless bead cleans up the transition between the tire and rim for aero efficiency. Zipp also claims hookless beads require less resin for the same strength, improving the strength to weight ratio of the wheel.

The German-engineered ZR1 DB hubs are center lock and have 12mm thru-axle end caps. The front weighed a verified 690 g with valves and rim tape, and the rear tipped the scale at 800 g with an XDR freehub body. This represents a claimed reduction of 350 g for the set, which is significant at this wheel level.

The Zipp 404 Firecrest and TSE at Speed

TSE, ABLX dimples, hookless beads … all these techy-sounding features sound impressive, but do the updates do the Zipp 404 justice? The 404 was Zipp’s bestselling road wheelset for a long time, and it seemed risky to me to make significant changes — especially the TSE and corresponding lower tire pressures.

But half a mile down a blown-out country road proved how TSE could improve performance and, more importantly for me, the comfort of road rides. The constant chip seal rattle was gone, replaced by an almost luxurious feel.

I still felt connected to the pavement and was aware of cracks and small holes, but the annoying and energy-robbing vibrations were muted considerably. And the rougher the roads got, the starker the difference in damping felt.

Another valuable byproduct of the low tire pressures was the increased traction. The improved tire compliance to surface imperfections and the additional vibration damping exponentially increased the feeling of adhesion and confidence.

Braking, sprinting, and aggressively raking turns in situations where I was usually cautious were transformed into attacks. I cannot overstate how much more traction I felt l had in all circumstances.

Although the pressure numbers on paper may lead a cyclist to think the tire would squirm under sideload, I never thought or felt that. The wheel and tire combination felt appropriately stiff torsionally and laterally, and I felt a direct relationship between body input and bike reaction at all lean angles.

I could go on about how different TSE felt, but cycle-dorks want to know about watts! Zipp claims that the lower tire pressures reduce power losses from rolling resistance due to better tire compliance and vibrational losses from the reduction of vertical motion.

These two components of TSE translate to 4-watt savings according to outdoor testing commissioned by the brand. But again, the comfort factor was more important to me.

Are They Still Aero?

I don’t need my wattage meter to know that mid-section aero wheels like the 58mm deep Zipp 404 Firecrest are noticeably faster than non-aero designs on the flats.

The trade-offs for gaining aerodynamic efficiency are weight and stability in crosswinds. I didn’t have any issues with the weight as a sub-1,500g set of wheels was fine by me, even for climbing.

And the majority of the time, blustering winds from all angles, including being passed by semi-trucks, didn’t cause concern. But on a few rides, strong gusts from near 90 degrees required quick jockeying to keep from running off the edge of narrow, windy country roads. I find it necessary to perform such evasive maneuvers on most wheels at or near 60mm deep, but my gut feeling is that it was slightly worse on the 404 Firecrest.

Each Zipp 404 has always been aerodynamically efficient during their respective eras, and the 404 Firecrest was still very much so. But Zipp claims the new rim shape is slightly slower. With TSE, the wheel is still faster overall, as their independent testing shows.

But, again, the comfort factor from the lower tire pressures was a more significant positive for me than any other attribute.

But Wait, There’s More!

Lighter, faster, and more comfortable. What more could you ask from a wheel update? How about lower pricing?

Yep, Zipp lowered the MSRP of the venerable 404 Firecrest to $2,005 a set, down from $2,500. Yes, that is still a chunk of change, but it stands as a reasonable price for a premium carbon wheelset. For comparison, ENVE mid-depth carbon road wheels starting prices range from $1,750 to $2,850, and the same from Roval sits at $2,800.

Zipp backs the 404 Firecrest with its lifetime warranty, which covers failure while riding and defects.

Conclusions on the Zipp 404 Firecrest

It’s hard for me to fault the Firecrest 404. They aren’t trying to be the specialist climbing wheels or the slipperiest time trial wheels. And they aren’t super expensive nor a value carbon wheelset. The Firecrest 404 sits in the middle, happy to be good at many things but not the best at anything.

Does that sound like you? You like to ride fast, maybe race sometimes. You want aerodynamic advantages, but you also don’t want to give up too much when the going gets steep. You have a nice bike that you maintain and cherish, but your bank account has limits.

In cycling, technology changes things so quickly. Not too long ago, the thought of electronic shifting made me giggle. Now, I expect it on high-end bikes. Tubeless tires? Get out of here.

But the 404 has been the “standard” all-around aero wheel for most of my cycling life. And it’s the same as it ever was. The Zipp 404 Firecrest is a standout all-around road wheel.

Zipp Announces Major 'Watt-Saving' Upgrade to 404 Firecrest Wheelset

The Zipp 404 has been one of the most popular and successful aero road wheels ever produced. Zipp introduced them 3 decades ago and update them regularly, improving them with each iteration. Read more…