PezCycling News - What's Cool In Pro Cycling : Zipp Firecrest 202 Carbon Clincher Review

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Zipp Firecrest 202 Carbon Clincher Review
Zipp have taken their Firecrest Aero shape down to a “climbers” depth 202. Of the words describing these hoops though, “Hot” ain’t one of em…


So if you’re web surfing Pez, you’re a hard core enough cyclist that you’ve heard of Zipp’s Firecrest tech and what that means to the total aero package for a wheel.

The interesting part for lots of people paying attention to bike wheel tech is that you’ve been hearing the high (and well warranted) praise from loads of Zipp competitors. With the loads of similar designs on the market, it’s as if a big group of wheel manufacturers suddenly decided “Zipp can’t sue all of us and we’ve had enough of getting a Toroidal enema for the past decade…”

The same tech used up the depth charts for Zipp works for the new 202.



And in this case, they added that little feature that instantly makes this wheel far more attractive to a much larger audience…

Clincher beads…



The brief stats go like this… 32mm deep, 24.62mm brake track width, 25.4mm max rim width, 1375 grams (625 front / 750 rear, though the test set was lighter), 125 PSI max pressure, 250lb suggested rider weight limit.

Now as depths go when the topic is aero performance, 32 millimeters might sound shallow, and even next to the mild depth of something like the 303 (below left), they seem quite dwarfish…



But just because the 303 are taller doesn’t mean 32 millimeters is shallow, any more than the fact that the 303 are a bit wider means that the new 202’s at 25.4mm are anything that can be called relatively “thin”…



On the road, these 32MM deep wheels suffer from cross winds about as much/little as anything that is normally described as “box section” or very shallow rims with half or less the depth (think Mavic Open pro, Ambrosio Nemesis etc.). The fact that the inside rim profile is shaped a lot like the 23c tire attached to the outside of the rim very simply doesn’t give a cross wind much to hold on to…

[Quickie Note: 20-23 section tires are best with the 202. 25 section tires are still good, but the max benefit of these designs comes when the rim section is 105% or more of the rim width.]



Combine the rounded inside and outside shape, the extra 4-5mm width and more than twice the depth of typical box section rims (generally 13-15mm deep) and the 202 destroys other shallow profile clinchers in aero performance (wind drag).

In fact when you look at Aero performance, the new 202 has drag figures roughly on par with Zipp’s toroidal shaped 404 from 2009 and BETTER performance than their Hybrid toroidal shape from the version prior to that.



Those older 404’s were class leading rim shapes that independently tested (and still test) better than all of the V shaped rims at similar (and many greater) depths and the Firecrest 202 beats them with far less at just 32mm deep.

Compare the 202’s Aero performance versus many current V shaped wheels at depths out-to 50-55mm and it’s impressive. Add that the 202 has a cross wind profile of rims in-to a depth of 13mm and you’re starting to understand how cool the Firecrest shape is.

More impressive still (at least for the true geek) is how Zipp created the Firecrest profile series of wheels.

A little known fact is that Zipp are very good at product development in general terms.

The Firecrest copies are easy to spot, but you’ve also seen Zipp’s designs with other manufacturer’s names on them for other components besides wheels. That development skill isn’t a magic trick.

Zipp employ more degreed engineers than many of their competitors have total employees.

Right now that count is @ 25. And they’re not FOC’s (fresh out of college). These guys come from Indy Car, LeMans LMP racing, NASCAR (which would make sense given Zipp sit near a murderer’s row of racing team talent in Indianapolis), missile guidance, circuit board manufacturing, chemical engineering… There are also master machinists, robotics experts…

You have many companies in the bike industry that don’t make anything and have a staff of foc’s / bike lovers whose primary concern is how to paint the part they found at the Taipei show… Zipp is so far removed that you would need something a bit larger than an old growth redwood tree to say they were “on the other end of the stick”…



And while this engineering investment is multiple times larger than many wheel companies entire operating budgets (marketing not included). Zipp continue to push the envelope and have been working with Intelligent Light / Fieldview and the resulting efforts are not special just as they relate to cycling.


rear wheel

Their combined efforts are among the best in any industry as the team just won the HPC Innovation Excellence Award… http://finance.yahoo.com/news/intelligent-light-receives-prestigious-hpc-141900190.html

Note the “HPC” above, as I believe Zipp are the first in the cycling industry to have installed an actual Supercomputer running Intel Xeon E7 processors to the tune of 80 computing cores.


front

Zipp do this because you very simply can’t develop product this effective without CFD, and the computing capacity required to run programs like this can’t be done without a super computer.


rear detail

Intelligent Light / Fieldview won an award working with RedBullF1 last year too and also count Ferrari and McLaren as partners. In the case you’re keeping track, that’s not just “a couple of F1 teams, they are the top 3 teams. These three teams have combined total points haul for these three teams that outscored all other teams on the grid combined by 456 points. While some wheel companies claim ties to F1 by using the material and or talking to a guy who used to work in that field, Zipp are working with companies actively providing solutions to issues stumping the current best of the field…

Ok, Back to the damn wheels…
Aero performance aside, there are more benefits to the latest rim design…

I’ve heard bitching in chat rooms that 1375 grams for the 202 Carbon clincher isn’t good enough.

What’s great news for you and I is that wheel tech has come along so much in the past decade that what used to be a fantastic weight for a set of clinchers is now only middling and people expect more (meaning less…). But you can’t take weight as a stand-alone measure for the 202’s (unless you’re a forum troll in which case you can pretty much ignore any/all the facts you wish).

You have to take into consideration that you’re getting the performance of a 50mm deep V aero clincher at 13xx grams…

You’re also getting a relatively more comfortable wheel because you’re getting the extra spoke length of a 32mm rim versus the shorter spokes used for a deeper section 50mm rim. (Though some of that spoke length is eaten up by hub design… More on that below.)

The wider tire contact patch / shape that comes from putting the same tire into a wider rim also makes for a smoother ride (versus same tire, tube and pressure on rims typically 3-4-5mm more narrow).

And with that relative comfort gain, you’re getting a MUCH improved durability with virtually all Zipp clincher profiles as Zipp have added their carbon bridge tech to the range. Better Carbon Bridge info is HERE .

Now all that performance / weight / comfort crap is nice, but perhaps the biggest differentiator for Zipp with the Firecrest 202’s versus other carbon clinchers is in braking.

Zipp very simply outperform everyone else at time of writing in handling heat deformation and its negative effects on overall performance and safety in carbon clincher rims.



It’s pretty simple to see that the braking surface looks a little different than the competition.



But it’s the raw materials and a specific manufacturing process that is critical here.

While other companies are machining their brake surfaces to try and get things smooth (cutting fibers because they can’t quite control smoothness in the molding process) and or adding coatings that simply wear off and / or are trying to use more material in hopes of preventing the warping and deformation that leads to nasty brake pulsing at best or rim cracking and tire blow off at worst, Zipp go a better route.

Zipp have partnered with the same folks that McLaren (and a few other F1 teams) use in creating a proprietary raw material and manufacturing process for the entire rim structure that very simply resists heat build-up and maintains strength/shape under the combination of heat and pressure better than anything else I am aware of in cycling.

It is possible to have a tire fail on any rim due to heat build-up, but it’s far less likely on Zipp Firecrest clinchers (in any depth) due to the typical heat related rim deformation typical of competitors wheels (where the clincher tire pushes outward on a heat weakened sidewall enough that it bends out enough to either fail completely or blow off the bead, or both…).



While the Firecrests resist heating better in the first place, in a situation where heat does increase beyond reason, the Firecrest clinchers maintain their structural integrity at temps higher than most cycling tires are designed to survive. Much like tried and true Alu rims, a heat blow out on Firecrest Carbon clinchers is down to the tire giving up rather than the rim blowing out.


Maxxy Pads
It takes two parts rubbing together to make a braking system work and Zipp have also updated the second critical part of this system, partnering with Swisstop for their own pad compound that is built to work well with their different brake track surface area, texture and rim materials.



This new pad is different in a couple of key elements.

First – The pads themselves are a fully custom compound/formulation. The goal was a pad that had the same wet drag as Shimano’s wet weather specific carbon rim pad supplied to pro teams. That alone isn’t tough to do, but Zipp wanted better modulation than the pad that had become a benchmark for many people in Swisstop’s Yellow Kings. Swisstop delivered and that pad became the Platinum last year.

[Swisstop also launched their updated and better Black-Prince Pad following Zipp’s platinum launch, and that’s also a very good pad, though it’s not the exact same formulation. One of the difs is in Zipp’s name, as their pad contains actual platinum that acts as a catalyst during pad curing.]

Second – What’s the “EVO” stand for?

The pad’s design addresses several critical improvements, mostly to do with shape.

The pads are thinner…



That allows for more clearance for the wider Zipp profiles. While many brakes will work in any case, the leverage sweet spot goes out the window to some degree when you blow open the brake arm adjustment in order to take larger rims. This thinner stack brings your braking adjustment closer to its designed sweet spot (check with your brake maker though, as some aftermarket brakes are now being designed for wider rims).

The pads have a larger surface area.



That’s a biggie. Zipp’s new pad formulation also acts as a much better heat conductor and the Rims resisting heat up better in general, but having a larger surface area spreads heat to @17% more surface and that extra surface exposure means the temps on your wheel under braking will run 15-50% cooler on average.

And the new pads are groovy.



Bike brake pad groves haven’t had a whole lot of thought toward heat versus shedding water, but Zipp split duties here to have the first set of grooves shed water and, given brake pads do a pretty good job of this in relative terms, the next two groves are aimed at reducing heat.

So yeah, The pads are important as well, and I would guess that you’ll see even more brake pad development from the market place in the coming months (where “development” means a company will run to their supplier and ask em to “do what Zipp did”…).


One area where the competition have not followed Zipp is in hub design.
But then most wheel companies have no ability to design and or manufacture hubs. Again you’ll think about the quantity and quality of engineering investment required and that answers the question “why don’t most companies have their own hubs” fairly well.

That said, there are some very good hubs to be spec’d OE and there’s nothing wrong with companies saving the design and build hassle, but just because a company has chosen a name brand hub to lace their rims to doesn’t make that hub better.

One of the gripes about Zipp wheels that always gives me a chuckle is about stiffness. To some, that’s down to Zipp’s hubs not allowing for a stiff build.

This is forum / chat room stiff-mistake number two about Zipp.

A couple of things help stiffness in hub design: flange height, and spacing are chief among them, and it’s said that Zipp fall short here. Actually they fall tall… And wide.


CLICK HERE for a full sized view.

This is a who’s who of the best hub designs on the market and Zipp have higher drive and non-drive side flanges than DT, D Ace, Campy and King, wider center right spacing than the rest, wider total spacing than all but Chris King, larger axle diameter than all and equal to Chris K.



In general, taller flanges mean shorter spokes and wider spacing means better stability.


Something else to consider is the material sourcing of some hub designs that are assumed better. It’s a bit of a twist when the company with “Swiss” in their name is using Far Eastern sourced bearings, while Zipp use Swiss.

None of that is to be critical of the other hubs listed here. I just ordered a custom set of wheels made with DT hubs and I’m betting that my legs wear out before the two sets of King hubs I have can no longer be serviced. Shimano and Campy product speaks well for itself too. My point is that Zipp’s hubs have been under rated for quite a while relative to aftermarket product that is assumed by some to mean that it’s “better”.



In fact most of the Chat room “rating” you hear today has nothing at all to do with these hubs.

Again because Zipp actually design and manufacture their hubs, they have been making running changes to the 88/188 series hubs without many people noting them.

There have been 8 changes in the last 4 years to the current iteration of the 88 and 188 hubs.

The hubs have performed well and you can very likely count on a new design in the near future as Zipp constantly develop…

The rims are also in house product and you’ve seen a lot of profiles rolling out as the Firecrest concept runs its course. They also have the ability to make running changes to the rims and one of the things they’ve always been fairly good at is rim stiffness…

This is forum / chat room stiff-mistake number one about Zipp.

Zipp’s rims are regularly compared to a couple of competitors as being flexi “because they rub my brake tracks when I sprint with incredibly poor form that would make Djamolidine Abdujaporov cringe…”

Quickie lesson here for the folks that spout and or reinforce this particular misinformation…

Stiffer rims are more likely to rub brake tracks because they maintain their shape better and flex less between the road and the brakes. As you toss your bike to one side, a softer rim will flex at the road and not press on the brakes on the opposite side your leaning toward… A stiff rim will hold its shape and rub the blocks.



A stiff wheel system combined with some of the flexi chain stays and whisper thin seat stays that seem to be catching on will also see some rubbing…. But whatever the case, a more flexi rim will be less likely in most cases to rub your brakes.

Another down side to flexi rims is that they are more frequently flexing under lower loads than big sprinting efforts and that flex is not only pushing your tires off line a bit, they’re also causing your tires to ride on the stickier rubber that runs along the sides of today’s high performance dual compound tires (hard and fast in the middle, and soft on the sides).

In any case, stiffness of the 202’s is, like all depth profiles, a designed and measured feature that Zipp have actually dialed back to some degree…




But did you ride the damn things?
The new 202’s are a good choice when you look at em a couple of different ways…

They’re either pretty damn light relative to the deeper section clincher wheels that compete aerodynamically and or they are loads more aerodynamic than any of the box section clinchers that come in lighter. These wheels are also a fair bit stiffer than many of the lighter shallower clinchers.

If it were not for a couple of other wheel companies doing the Firecrest shape thing, the list of wheels that compete for the full list of benefits with the new 202’s would not exist. You’re very simply not getting as nice a wheel without the Firecrest shape and that’s at virtually any depth. Zipp were already at the head of the field in aerodynamics when they made the BIG investment in R&D it took to get to the Firecrest shape.

If you’re on anything near a 50- 60mm deep traditional v shaped rim, you’ll love what you’re getting with the new 202’s… You’ll have very similar speed holding, but with the shallow profile you’re going to likely drop weight at the rim, enjoy better acceleration and be (or not be…) blown away by the ability of these wheels to ignore cross winds…

Aside, the braking on the 202’s with the new Evo pads is the best braking on any carbon clincher I’ve tried to date, and I don’t think you can name a wheel that I haven’t tried to date.

Here in Phoenix, we get regular summer rides at temps near or over 100F degrees and the tarmac temps are through the roof. We’ve had more than our fair share of pulsing snatchy carbon clincher brake tracks in the summer and we’ve also had the occasional heat blow out.

This is the third pair of Zipp carbon clinchers that I have miles into and I’ve not had anything approaching an issue.

It’s not that I consider these on par with Alu rims for braking, it’s that I don’t consider them when braking at all. I just don’t think about it…

These rims running on these pads, even in Arizona heat have performed perfectly.

You see a lot of trash talk in forums and chat rooms about carbon clinchers and a lot of it is pretty accurate relative to braking and heat failures. But I’ve not seen a single instance of brake related failure with a Firecrest product. That plays well alongside Zipp’s claim that they have not had a single heat claim for a Firecrest product. And the number of wheels Zipp is putting into the market would very simply stun many people.

All that said, for my terrain, I still like my 404 tubulars and clinchers. But if I had any sort of consideration for cross winds here and or lived near some shorter and or much steeper climbs, the 202’s would be a fantastic choice. I would also take them if I were less caring about all out speed holding and more concerned with the comfort that comes with longer spokes and a shallower profile relative to a 404 and easier / quicker handling and acceleration than comes with the lower rim mass/weight than the 404 clinchers… The real problem for my terrain comes when you toss the 303 in the mix (both tubular and clincher), but that’s another review…

You can learn more about the Firecrest line up, as well as a lot of new product in the form of bars, posts stems etc. at Zipp.com

Have Fun,
Charles Manantan

 

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