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Carbon Fiber SL Insoles
Carbon Fiber SL Insoles
Maximum Support for Precision Performance
Regular price
$ 120.00
Regular price
Sale price
$ 120.00
Unit price
per
New for 2026: Designed for high-load activities in close-fitting footwear.
Ultra-firm support for plantar fasciitis, overpronation, and other foot pain. Everything you love about Carbon Fiber, in a low-profile build. Built with a lightweight carbon fiber plate for maximum stability and control. Now upgraded with a Precision Heel Cushion for added comfort and moisture-resistant top cover.
Available in four arch heights for a precise fit, with replaceable top covers to extend the life of your insoles, forever.
90-day Returns
HSA/FSA Eligible
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Met Pad Compatible |
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Million Mile Guarantee |
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Fitting Guide
Order insoles in the same size as the shoes they will go in. Print out our guide.
- Arch Height Guide
- Insole Measurements
- Short Insole Measurements
- Wide Insoles Measurements
- Size Conversions
Arch Height
Choose between low, medium, high and extra high arch heights by comparing your wet footprint.
| Your Wet Footprint | Describe Your Arch | Arch Height |
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My arch is flat when I stand or sit. | Low |
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My arch is flat when I stand but appears when I sit. | Medium |
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My arch is close to but doesn't touch the ground. | Medium |
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My arch is high off the ground when I stand. | High |
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My mid-foot barely touches the ground, if at all. Sometimes, my footprint is two pieces. | Extra high |
Regular Insoles
Applies to Pace Insoles, Ramble Insoles, and Dash Insoles.
Imperial Measurements
Metric Measurements
Short Insoles
Applies to Pace Short Insoles, Ramble Short Insoles, and Dash Short Insoles.
Imperial Measurements
Metric Measurements
Wide Insoles
Applies to Pace Wide Insoles.
Imperial Measurements
Metric Measurements
Insole Size Conversions
| Tread Labs Size | United Kingdom | European | Japan/China |
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| Men 4-4.5 Women 5-5.5 |
3-3.5 | 35-35.5 | 22.5-23 |
| Men 5-5.5 Women 6-6.5 |
4-4.5 | 36-37 | 23.5-23.5 |
| Men 6-6.5 Women 7-7.5 |
5-5.5 | 38-38.5 | 24-24.5 |
| Men 7-7.5 Women 8-8.5 |
6-6.5 | 39-39.5 | 25-25.5 |
| Men 8-8.5 Women 9-9.5 |
7-7.5 | 40-41 | 26-26.5 |
| Men 9-9.5 Women 10-10.5 |
8-8.5 | 41.5-42 | 27-27.5 |
| Men 10-10.5 Women 11-11.5 |
9-9.5 | 42.5-43.5 | 28-28.5 |
| Men 11-11.5 Women 12-12.5 |
10-10.5 | 44-44.5 | 29-29.5 |
| Men 12-12.5 | 11-11.5 | 45-46 | 30-30.5 |
| Men 13-13.5 | 12-12.5 | 46.5-47 | 31-31.5 |
What's My Arch Height?
Finding your arch height is as easy as looking at your wet footprint. See how it's done.
| Is your footprint between arch heights? Start with the lower arch and see how it feels. Free exchanges make it risk-free to try them out. |
| What Does Your Wet Footprint Look Like? | Describe Your Arch | Your Best Tread Labs Insole Height |
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My arch is flat when I stand or sit. | Low |
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My arch is flat when I stand but appears when I sit. | Medium |
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My arch is close to but doesn't touch the ground. | Medium |
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My arch is high off the ground when I stand. | High |
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My mid-foot barely touches the ground, if at all. Sometimes, my footprint is two pieces. |
Extra high |
Wet Foot Test
Quickly and easily find your arch height with this simple test.
What Do High Arches Mean?
People with high arches can often experience foot pain because of the extra stress high arches put on your metatarsal bones. The stress ends up shifting your weight to the ball of your foot.
With high arches, underpronation (also called supination) is common. This can put too much pressure on the joints and muscles of the foot, ankle, and leg.
What Are The Best Insoles for High Arches?
People with high arches need insoles that offer full support across the entire arch so as to eliminate excessive pressure on the ball and heel of the foot. The arch support of the insole should mimic the height of the arch of your foot and the insoles should be firm and durable so they keep their shape during use and over time.
What Do Flat Feet Mean?
Many people with flat feet don't experience any difficulties, but some suffer from pain in the heel or arch (plantar fasciitis), swelling along the inside of the ankles, and knee and hip problems.People with flat can experience overpronation, which is when the foot rolls too far inward before you push off to move forward. When this inward rolling motion goes too far, the alignment of the foot is compromised and there is a loss of efficiency in every step you take. Negative effects of overpronation include arch collapse, plantar fasciitis, inefficiency and pain in your feet, knees, hips and back.
Rigid vs. Flexible Flat Feet
If your wet footprint indicates you have flat feet or low arches, you'll need to determine if you have rigid flat feet or flexible flat feet because it will change the arch height your feet need for maximum comfort and support. To figure out which type of flat feet you have:
- Sit with one leg over the opposite knee. Look at where your arch should be. If your foot looks more arched than your wet test footprint, you have flexible feet. This means your low arches are brought on by weight-bearing and a medium arch insole will work best for you.
- Stand on tip toes. Have a friend look at where your arch should be. Like the example above, if your arches show themselves, your feet are flexible.
- If an arch doesn't appear in either of the tests, you have rigid, low arches and should choose an insole with a low arch. A higher arch support will probably be very uncomfortable on your arch and feel like you have a golf ball in your shoe.
People with flat feet often ask if they should get insoles for high or extra high arches to try and "fix" their flat feet. While low arches aren't anything that need to be fixed, they do still need to be properly supported.
Using a high or extra high arch on low arches could cause discomfort, and the feeling like something is digging into your arch. A low or medium arch (depending on the flexibility of your foot) is the best place to start.
What Are The Best Insoles For Flat Feet?
The best insoles for flat feet support your arch and stabilize your heel, preventing overpronation. Typically, the best insoles for flat feet will offer a low, but supportive arch. Finding one that matches the contours of your foot is key.
While soft, cushioned insoles might seem like the best choice, what your feet really need is structural support. All of Tread Labs semi-custom insoles come in four arch heights to accommodate arch heights from low to extra high.
What Makes Tread Labs Insoles Better
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Four Arch Heights
Low, medium, high, and extra high. Support that matches the natural shape of your foot.
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Firm Arch Support
Clinical-grade arch support designed to hold its shape and provide consistent stability step after step.
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Precision Heel Cushion
Targeted heel cushioning softens and reduces harsh impact where your foot takes the most load, without compromising support.
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Guaranteed to Last
Our molded arch supports are built to last a lifetime. If the arch support ever breaks or loses shape, we’ll replace it.
The Support of Custom Orthotics, Simplified.
We support all 26 bones and 33 joints in the human foot with our 26-33 ARCHitecture—the technology behind our semi-custom orthotics. With 4 arch heights to choose from, you get personalized support without the hassle or cost of custom orthotics.
Perfect for Common Foot Conditions
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Plantar Fasciitis
⭐⭐⭐⭐⭐
"I bought these for plantar fasciitis relief and found it almost immediately."
- Matthew M, Verified Buyer
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Supination & High Arches
⭐⭐⭐⭐⭐
"I’ve tried other insoles to help with my high arches but none have been as impactful."
- Chad P, Verified Buyer
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Flat Feet & Fallen Arches
⭐⭐⭐⭐⭐
"I have flat feet and these are the only insoles that work! Love them!"
- Shannon H, Verified Buyer
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Morton's Toe
⭐⭐⭐⭐⭐
"Has worked much better for my Morton's neuroma pain than custom orthotics from podiatrist"
- Patrick K, Verified Buyer
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Tendonitis
⭐⭐⭐⭐⭐
"Great support for my Achilles Tendinosis."
- Eileen K, Verified Buyer
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Metatarsalgia
⭐⭐⭐⭐⭐
"I have high arches and metatarsalgia, and Pace (with a met pad) is the only insole I've found that relieves the pain."
- Melissa U, Verified Buyer
Compare with Other Insoles
Our insoles are available in 3 levels of support so you can customize to your needs.
 Carbon Fiber SL Insoles$ 120.00 |  Pace SL Insoles$ 75.00 |  Carbon Fiber Insoles$ 125.00 | |
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Best For |
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Fits In |
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Firmness |
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Arch Support Material |
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Available Arch Heights |
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Top Cover Thickness |
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Met Pad Compatible |
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Million Mile Guarantee |
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Meet the Carbon Fiber Family
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Carbon Fiber
Our firmest insole, reinforced with a carbon fiber arch support, and a 5mm moisture-resistant top cover for added cushion.
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Carbon Fiber SL
A low-profile version of Carbon Fiber, with a thinner 3 mm moisture-resistant top cover for close-fitting footwear and maximum control.
