What's Cool In Road Cycling

Lake CX403 Shoes Review – The Carbitex Difference

Lake’s new CX403 road cycling shoes have added Carbitex fabric to the mid-upper to increase efficiency and lower weight. PEZ looks at how this shoe compares to our recently review d Lake CX402.

In many ways, the Lake CX403 is a lot like the CX402 that it superseded and that I previously reviewed. They both have a stiff carbon fiber sole. They both have kangaroo leather uppers. They both have BOA dial closures. And they both have a heat moldable custom heel cup. But one thing that’s different is that the newest version of the CX403 uses Carbitex in conjunction with kangaroo leather in the upper. On the white CX403s that PEZ reviewed, the Carbitex panels (black) are readily apparent.


What is Carbitex?
I’m sure PEZ readers have seen a lot of different “soft” products (for example, leather wallets and vinyl film/wrap) that mimic the look of carbon fiber.  Carbitex is a company born out of the question: “Is there a flexible carbon fiber composite that these companies could be using instead?” Most of the carbon fiber market is focused on rigid applications (like the stiff sole and heat moldable heel cup in the Lake CX403). Carbitex is all about harnessing carbon fiber’s properties in a flexible form factor.

lakeCarbitex is the brainchild of Junus Khan

Carbitex has three patented carbon fiber technologies that have unique flexibility properties with different applications across a range of performance footwear categories:

  • CX6:  No Stretch + Exceptional flexibility
  • AFX:  Stability and protection + Free range of motion
  • DFX:  Stiffness for response + Flexibility for awareness


According to Carbitex: Carbon fiber has the highest tensile strength of any commercially available fiber. And within its operating limits, it doesn’t stretch. Carbitex CX6 harnesses these key characteristics in an exceptionally flexible form – enabling carbon fiber performance in soft applications. CX6 provides these benefits:

  • Low stretch increases power transfer
  • No stretch under constant load
  • Quick power transfer enables rapid response
  • Virtually no elongation enables precise control

lakeDifferent shoe applications of Carbitex

One way to describe Carbitex CX6 is that it’s a very flexible carbon fiber fabric that can bend but it doesn’t stretch. Flexible but stiff is another way to think about it. Some properties of CX6 that make it suitable for use in shoes:

  • It can be cut with standard composite cutting tools. Utilizing computer controlled cutting tables for part cut nesting and fiber orientation control is also possible.
  • It can be sewn to itself in combination with leather, other fabrics, and foams.
  • It can be bonded with hot melt fusing films, water based cements, and water based primers.
  • It is UV resistant.
  • It is resistant to water absorption and can be used in humid/damp environments.
  • It is solvent resistant.
  • It is typically stable when it comes into contact with greases, lubricants, and oils.
  • Its inherent water and weather resistance inhibit microbial degradation.
  • Rivets, zippers, and accessories can be applied to CX6.

Carbitex CX6 is what Lake has incorporated into the CX403 as panels in the midfoot section of the shoe.


Lake CX403$549.99

I know, I know … nearly $550 for a pair of cycling shoes! That’s Jimmy Choo territory. Understandably, the Lake CX403s are not shoes that every cyclist can afford. But for those who can (and are willing to pay top dollar), they have a lot on offer.


Here’s what Lake has to say about the CX403:

  • CX/TX RACE Last – Featuring a slightly narrower toe box and tighter heel than the Competition last and less overall volume than the Sport last. Designed for very high-cadence riding & higher pressure and a slimmer fit.
  • OUTSOLE – Custom Fit Carbon Fiber sole. Men’s regular width available in a 3-hole or for Custom Order only Speedplay specific cleat pattern for use without adapters. Replaceable heel strike pad.
  • UPPER – Klite Kangaroo leather and Carbitex CX6 Carbon Fiber Stabilizer Support panels help keep the foot stabilized, control stretch, and allow for increased power transfer. Lined with Perforated Kangaroo leather for great fit and feel.
  • CLOSURE – Dual Side mounted Push/Pull IP1-S BOA lacing system.

Lake doesn’t spec weight for the CX403s, but mine weighed in at 323 grams (so 646 for the pair) — more “substantial” than featherweight

A word about Lake sizing

No matter what size you wear in other cycling (or street) shoes, don’t assume that will be your size in Lake shoes. Lake has their own sizing system that starts off with this caveat:

This size chart is for reference and for best fit, trial and error fitting may be necessary for proper comfort. Perfect sizing through online dimension sizing is not guaranteed. Shoe sizing is not a perfect science as we all have unique foot dimensions. These variables in foot shape are individual to each of us and may require sizing up or to a wider shoe.


With that in mind, here’s how to figure out what size Lake shoe:

  • Take your foot measurement In a standing position while wearing your cycling socks.
  • Step 1: Trace your foot onto a sheet of paper. After you trace your foot take a ruler and make a line to mark the furthest point on all four sides as shown below.
  • Step 2: Length measurement (Points 1 to 2 as shown below). Use a millimeter ruler to get the measurement of the longest distance from heel to longest toe (first or second toe).
  • Step 3: Width measurement (Points 3 to 4 as shown below). Use a millimeter ruler to get the measurement of the widest distance of foot from side to side.


  • Step 4: Repeat steps for other foot as your feet may be different sizes. Typically you will want shoes that accommodate your largest foot the most comfortably.
  • Please Note: for accurate measurement please obtain a 3 digit millimeter measurement. For example, 267mm or 26.7cm will provide the correct amount of data. Accurate measurements cannot be obtained from only 2 digits. For example, 26cm does not provide enough data to determine size.
  • Add 5mm to your actual length measurement to get recommended size; it is not necessary to add any additional mm to your measured width.

And to make things more complicated, sizing is different for different model shoes based on which last is used: Comfort Plus, Sport, Competition, Race or Winter. That plus whether your foot measurement is standard width, wide, or extra wide. Given Lake’s admonition about shoe sizing, I would highly recommend “try before you buy” in person or make sure you can return/exchange shoes if you’re buying online.

The size numbers on the box doesn’t mean anything unless you know your actual foot measurements

In my case, since my Lake CX402s were size EU 42.5 (my foot length measurement is 268mm including the additional 5mm Lake recommends and my width is standard width) I went with the same size for the CX403s since they’re both built around Lake’s Race last. I was confident that would be the right size (but was also prepared for the possibility they wouldn’t be) and out of the box they actually fit a tad better than my CX402s. But just to give you some idea of how Lake sizing is different, I wear a US size 9 in pretty much every pair of shoes (cycling or otherwise) I own.

The whole is something besides the parts
As you would expect (or is that demand?) from a shoe costing nearly $550, the Lake CX403 has all the bells and whistles. In that respect, it’s not much different than other high-end cycling shoes that also cost top dollar. It’s how all those bells and whistles work together that matter and make the Lake CX403 the high-end cycling shoe it is.


The foundation of the CX403 is its carbon fiber sole. Unlike a lot of other shoe manufacturers who rate their shoes on their own stiffness scales (that aren’t comparable since there isn’t a universal carbon fiber stiffness rating), Lake makes no such claims. But rest assured that they’re plenty stiff!

The carbon fiber sole is a thing of beauty

Drilled for 3-hole cleats with plenty of fore/aft adjustment (Lake also make a 4-hole Speedplay cleat version of the CX403)

Air intake at the front, six “exhaust” ports midfoot, and another air outlet at the heel for “flow through” ventilation

That stiffness means you can put down the watts. But it doesn’t come at the expense of comfort. If you remove the fairly standard insoles, instead of an exposed cardboard or carbon fiber last, the entire bottom of the inside of the shoe is padded. The result is cushioning that is more uniform and evenly distributed all along the bottom of your foot.

All that blackness is padding where you would ordinarily see the shoe last

The soft and supple kangaroo leather upper also makes for a very comfortable fit/feel. I know “fits like a glove” is a mixed metaphor, but it’s the appropriate description for how the CX403 feels on my foot. Where I really appreciate it is in the forefoot/toebox area. Lake’s Race last is on narrow-ish side to minimize/eliminate any unwanted foot movement. My toes weren’t squished and there’s just enough room for them to spread out a little.

A “toe bumper” to avoid scuffing up the kangaroo leather

Getting that upper to fit tightly enough so that your foot doesn’t move in the shoe but comfortably enough so that it doesn’t cut off blood flow is adjusted via two BOA micro-click adjustable dials. It’s worth noting that the Lake website says BOA IP1-S dials, but the pair of CX403s I got had BOA’s latest generation Li2 dials that are marginally lighter and lower profile plus are a tad more micro-click adjustable.


If you’re new to BOA 2-way dials: push down to engage, turn forward to tighten, turn backward to loosen, and pull up to release. It’s also worth noting that it’s not just the dials but the entire BOA system — micro-adjustable dial, super-strong lightweight laces, and low friction lace guides — that allows for a precision-tuning to find the sweet spot that optimizes tightness of fit to maximize power and efficiency with comfort that allows circulation so you can keep pedaling.

BOA | HIW | Li2 from BOA® Fit System on Vimeo.

Also contributing to both fit and comfort is Lake’s custom heat moldable heel cup.  Here’s how to get it custom fitted:

  • If using a conventional oven, pre-heat to 200F/90C for 5-10 minutes. If using a convection oven, pre-heat to 180F/80C for 5 minutes. Once pre-heated, use oven gloves or heat-resistant hand protection to place one shoe (you do this one shoe at a time) on the oven rack (on its sole). Allow the shoe to heat 3-4 minutes in a a conventional oven/4-5 minutes in a convection oven.
  • Remove the shoe from the oven (again, using oven gloves or heat-resistant hand protection). You should be able to flex the upper parts of the heel counter; the materials in the heel area should be pliable but not soft.
  • Put the shoe your your foot (wearing cycling socks).
  • Shape the shoe to your foot while seated. Apply pressure using just your hands/fingers to the moldable zones (Drawing A). Make sure you a leaving smooth surfaces with no sharp edges.


  • Let the shoe cool down on your foot for about 15 minutes and check that the closure pressure is still where you would like. If not, tighten as needed. If you feel any pressure points in the moldable area, re-heat and re-adjust as necessary.
  • Repeat the above steps for the other shoe.

Not to be mistaken for baking a cake

I know it sounds a little scary/daunting putting $500+ shoes in the oven. But having done it with my Lake CX402s, I can attest that it’s a relatively simple and straightforward process. I’ve actually heat molded my CX402s several times (to fine tune the fit) without cooking or otherwise destroying them (only once in the oven so far with the CX403s). And the result is a comfortable, solid, and secure fit with no heel slip.

The Carbitex difference

Flexible but not stretchable

What makes the Lake CX403 different from almost every other cycling shoe is the use of Carbitex CX6 in the midfoot section of the upper (as of this writing, Scott is the only other manufacturer with a road shoe that uses Carbitex). This is where the shoe closes around your foot and the trick is to hold it securely in place to prevent it from lifting or swimming/rolling. The flexible but no stretch properties of CX6 make it an ideal material for this purpose.

Carbitex CX6 panels help keep your foot in place — especially under high power output applications on the upstroke (think sprinting)

It’s not an apples-to-apples comparison because the closure design and BOA lacing pattern are different, but the difference between the CX403 and CX402 is readily apparent. With the CX402, I really have to crank the midfoot BOA dial to get a tight/secure fit. Conversely, the CX403 required relatively minimal dial tension for a tight fit without sacrificing comfort. With the combination of kangaroo leather and Carbitex CX6, I just needed to take the slack out of the cables, snug them up to the equivalent of “hand tight,” and then just 2 to 4 micro-clicks to get everything tight enough.

With shoes, there’s a lot of focus on the stiffness of the sole for power transfer but it’s not the be all-end all. Yes, you need a stiff enough sole, but your foot also needs to be comfortably “locked in” to pedal efficiently and with power — whether you’re sprinting, climbing (in or out of the saddle), or laying down watts setting tempo. At least for my feet, the Lake CX403 delivers on both counts.

More bendable than Bend It Like Beckham

My maiden voyage in the Lake CX403s was on what I call my SouthARLdennes loop on my Wednesday Night Hill Ride. It features a lot of shorter but steeper (double digit grade) climbs with not a whole lot of flat in-between. Definitely terrain where you need a shoe that doesn’t waste watts. Let’s just say that any lack of watts wasn’t because of any deficiencies with the Lake CX403s. My legs and lungs may have been screaming on some of the climbs, but my feet were comfy and locked in the shoes without feeling like they were being held in via vice grips and whatever watts I could muster up felt like they were being directly transferred to the pedals. Lots of out-of-the-saddle “power” climbs and I didn’t feel any lift or movement in the shoes. I have to attribute at least part of that to the Carbitex CX6’s no stretch, firm hold.


Same but different

PEZ readers will know that I was more than just a little enamored with the Lake CX402. So I can’t help but use the CX402 as a point of reference.

Left: CX402; Right: CX403

I’ve logged lots of miles and long rides across all sorts of terrain in the CX402s and they’re about as good as it gets in terms of riding and keeping my feet happy. The CX403s are just as good, so what I wrote then about the CX402 is just as true now about the CX403:

But something magical happens when you clip in and ride. All that tightness/firmness just seems to disappear. Even with the BOA dials cinched down a good amount, my feet don’t feel like they’re in a vice grip hold. The toe box doesn’t feel as constrictive. There are no hot spots or pressure points. My analytical intuition tells me that your foot is weighted in the shoe differently when you’re pedaling versus sitting or standing and that’s why they feel so different riding.

Put power down on the pedals and you can feel the direct power transfer and how stiff the carbon fiber sole is. But the built-in cushioning softens the blow so you don’t feel that stiffness “pushing back” directly on the bottom of your foot (more like as if the sole was a composite material with some flex). This is particularly noticeable on out-of-the-saddle efforts up steep climbs. And the more miles you ride, the more you’ll appreciate the lack of “carbon sole fatigue.”

These thoughts about the CX402 are also the same for the CX403:

The Lake CX402s are all-day comfortable pedaling (hammering, if you choose) … The almost surreal comfort could be considered a marginal gain of sorts. It doesn’t make pedaling any easier, but it somehow makes suffering just a little more sufferable. Plus it just makes common sense that a more comfortable shoe is going to allow you to pedal both stronger and longer.


Although my overall impressions of the CX403 are a lot the same as the CX402, they’re not the same shoes. That’s apparent visually with the CX402’s black-on-white color scheme versus the CX403 being more predominantly white (except for the black Carbitex panels). To my eye, the CX402 is a little more flash/bling with a glossy finish on the carbon weave sole and external heel counter versus a more subdued matte finish on the CX403. And at least to the naked eye, the shoe shapes are subtly different with the CX403 seeming to have a slightly wider and more rounded toe box (this would account for my toes not being squished together too tightly).


The biggest difference between the CX403 and CX402 is the design of the shoe closure and BOA lacing. On the CX402, the forefoot BOA dial controls the closure across the forefoot and the front part of the midfoot and the midfoot BOA dial pulls a strap over the instep (much like a ratchet instep closure on pre-BOA shoes). On the CX403, the forefoot BOA dial pulls a relatively wide flap across the forefoot and the midfoot BOA dial pulls a relatively wide flap (probably twice as wide as the strap on the CX402) across the entire midfoot. So I could adjust and fine tune the fit more exactly as needed across separate parts of my foot. With its no-stretch properties, the Carbitex CX6 in the midfoot area also contributes to being able to fine tune the wrap around your foot (and one of the things I’ve noticed is less need tighten the shoe up over the course of a long ride).

Completely separate forefoot (top) and midfoot (bottom) closure/adjustment for a more fine-tuned fit

The result is that, for me, the CX403 is an even more comfortable fit than the CX402. They were more comfortable out of the box and even more so once I heat molded them. Plus I found them more comfortable just to wear. Whereas I said: “comfortable” (as in a pair of slippers) is not a word I’d use to describe the CX402s just wearing them, I found the CX403s to trend more towards slippers in how they feel on my feet just wearing them.

The heel pad is replaceable if you wear it out from clattering around on coffee shop floors

If I have one “complaint” about the CX403, it’s the same one I had about the CX402:

The only thing I really seem to notice riding the CX402s is the arch on the insoles. I have relatively flat feet and OEM insole has just enough arch support that I can feel it. Not to the point where it’s a bother or uncomfortable, but I can feel it’s there – probably more so when grinding a gear uphill in the saddle.


It’s not totally the insoles’ fault, however. The heat moldable carbon wraps around starting in the arch area and that means there’s essentially no give there, which makes it feel firmer/stiffer than it might otherwise be.

Below the red dotted line is what you can custom heat mold

After a handful of rides, the insoles seem to have “broken in” a little and adapted to the shape of my foot a bit (or maybe my foot has adapted?) I can still feel them under my arch but less so. Time will tell, but I know I always have the option of swapping in a pair of cycling-specific insoles I have that are designed for those of us with lower arches.

Dead sexy part deux

IMHO, the Lake CX403 is a good case of “don’t fix what ain’t broken” but still making an improvement on what was already a good thing to make it better.


But is the CX403 worth spending nearly $550? To paraphrase: spending is in the eye of the rider/consumer. If you had your eye on the top-of-the-line shoes from other shoe manufacturers, you’re already looking at pretty much $400.

If $550 isn’t a bridge too far (either because you have the disposable income or are willing to live off of ramen soup for an extended period of time), who are candidate riders for the Lake CX403?

  • If you’ve tried on everything from everyone else and just haven’t been able to find a pair of cycling shoes that comfortably fit your feet, the CX403 with custom heat molding might be the pedaling bliss you’re looking for.
  • If you’re a racer who demands the ultimate in stiffness and comfort, the CX403 delivers the goods.
  • If you’re a serious roadie who puts in loads of miles and/or rides a lot of centuries, grand fondos, and sportifs, the CX403 has what I call “beyond comfortableness” for long rides.


It’s not my place to tell you how to spend your hard earned $$$, but if you do decide to fork out big bux for the Lake CX403s, I seriously doubt that you’ll be disappointed.

Still dead sexy … if not sexier IMHO


Note: If you have other experiences with gear or something to add, drop us a line. We don’t claim to know everything (we just imply it at times). Give us a pat on the back if you like the reviews or a slap in the head if you feel the need!

PezCycling News and the author ask that you contact the manufacturers before using any products you see here. Only the manufacturer can provide accurate and complete information on proper/safe use, handling, maintenance, and or installation of products as well as any conditional information or product limitations.

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