If you’ve spent any time looking into skate insoles, you’ve probably run into two heavyweights: Remind Insoles and FP (Footprint) Insoles. Both claim to save your knees, heels, and lower back from the harsh vibrations and heavy impacts of skateboarding.

But when you strip away the marketing, how do they actually compare in a controlled test?

Below, we dive deep into the lab numbers, the science of their materials, and how common “cinder block” tests are often manipulated to mislead skate consumers.

1. The Infamous Cinder Block Test: Legit or Lab-Tricked?

You’ve likely seen pros drop bowling balls or bricks onto insoles placed over cinder blocks to demonstrate shock absorption. When Tommy Sandoval famously showcased FP’s performance, it became an iconic piece of skate marketing.

However, in a revealing look behind the scenes, Sandoval demonstrated exactly how brands can “fake” or easily mislead viewers using these tests:

• The Profile Trick: A brand might compare their thickest, highest-profile insole against a competitor’s thinnest, low-profile model without naming the competitor.
• The Drop Zone: Dropping the weight onto the thinnest edge of the arch on the competitor’s insole (where there is almost no padding) rather than the heel, ensuring it shatters the block underneath.
• The Pre-Cracked Block: Relying on the cumulative damage of a previous drop to ensure the competitor’s block breaks easily, while using a completely fresh block for their own test.

To see the breakdown of how these visual tests are manipulated, check out the demonstration:

Watch Tommy Sandoval expose the cinder block test

In a truly fair head-to-head drop test using identical profiles, the difference remains substantial. When dropping a bowling ball from height on comparable 7mm profiles, the Remind Cush allows the block to shatter, whereas FP’s Kingfoam structure absorbs enough kinetic force to keep the block intact.

Watch the raw 7mm bowling ball impact test

2. The Lab Data: Impact Force Transmission

While visual stunts are great for social media, impact testing on calibrated laboratory equipment provides the real, unvarnished truth. Lab impact testers measure force transmission in Newtons (N) where a lower number means less impact force passes through the insole to your foot.

What’s more, these tests must be conducted at realistic temperatures. Insoles don’t operate in a vacuum; they sit inside hot shoes warmed by body heat and friction.

Summer & Body Temperature Performance (45°C / 113°F)

When tested in an oven calibrated to a typical summer shoe environment of 45°C, the materials behave very differently under heavy impact:

• Remind Medic 7mm: Let a massive 41,000 N of force transfer straight through.
• FP Kingfoam Elite Quantum: Transferred only 13,000 N under the exact same impact load.

At real-world operating temperatures, FP’s formulation absorbs nearly 4x more shock than Remind’s standard foam structure.

Watch the 45°C body temperature lab test

Standard Heated Performance (40°C / 104°F)

Even under slightly milder heat testing conditions (40°C), the performance gap remains highly visible:

• Remind Cush 7mm ($60): Transferred 14,000 N of force.
• FP Kingfoam Elite Sport ($34): Transferred only 7,000 N of force—performing twice as well at nearly half the price. Watch the 40°C impact lab test

3. Materials Science: Traditional Foam vs. FluidX Non-Newtonian Technology

The massive performance gap in the lab comes down to the underlying chemistry of the materials.

Remind Insoles (Traditional Polyurethane Blend)

Remind uses high-quality, dense polyurethane (PU) foam blends. It provides excellent structural support, retains its shape well over time, and feels incredibly comfortable right out of the box. However, traditional foams are elastic. When you hit the ground hard, the foam compresses rapidly, and once it bottoms out, the remaining kinetic energy is transferred straight up into your skeletal system.

FP Insoles (Non-Newtonian FluidX / Artificial Cartilage)

FP uses a proprietary molecular structure called FluidX (frequently referred to as “artificial cartilage”). This is a non-Newtonian material.

• When you walk, the molecules flow past each other easily, keeping the insole soft, flexible, and comfortable.
• The millisecond an impact occurs, the molecules instantly lock together, forming a solid barrier that chemically dampens and scatters up to 90% of the shockwave energy before it can hit your heel.

Head-to-Head Comparison

Feature	Remind Insoles	FP Insoles
Primary Technology	High-density memory/PU foam blend	Non-Newtonian FluidX (Kingfoam)
Force Transmitted (at 45°C)	~41,000 N (Higher impact transmission)	~13,000 N (Up to 4x better absorption)
Best For	Arch support, rigid structure, durability	Maximum raw impact protection, heavy drops
Price Range	~$50 – $65	~$30 – $55

The Verdict: Which Should You Buy?

Choose FP Insoles if your primary goal is preventing heel bruises, protecting your joints from high-impact skate drops, and getting the absolute highest level of scientifically proven shock absorption.