FORM BIKE FITTING SPD LEG LENGTH SHIMS (EACH)
Precision Alignment for Perfect Symmetry.
The Form Bike Fitting SPD Leg Length Shim is a professional-grade medical and ergonomic tool designed to address leg length discrepancies (LLD) on the bike. Unlike "one-size-fits-all" solutions, these shims allow for precise, incremental adjustments to your stack height, ensuring that both legs can reach the bottom of the pedal stroke with equal extension. By leveling the pelvis and equalizing muscle engagement, these shims help eliminate the "rocking" motion on the saddle that often leads to lower back pain, saddle sores, and premature fatigue.
Specifically designed for 2-bolt SPD-style cleats (commonly used for Mountain Biking, Gravel, and Commuting), these shims are sold individually, allowing you to stack them to the exact height required for your unique biomechanics. Crafted from high-density, lightweight polymer, they provide a rock-solid interface that won't compress or "squish" under heavy pedaling loads.
Key Features
Biomechanical Correction: Designed to compensate for leg length discrepancies, helping to stabilize the pelvis and reduce strain on the lower back and hips.
SPD 2-Bolt Compatibility: Specifically molded to fit the profile of standard 2-bolt MTB/Gravel cleats, ensuring a seamless and secure fit.
High-Density Construction: Made from a non-compressible technical polymer that maintains its shape and transfer of power even during high-torque efforts.
Stackable Design: Each shim is designed to be used alone or stacked with additional shims to reach the exact height required by your bike fitter.
Symmetry Restoration: Helps to equalize muscle recruitment between the left and right legs, improving overall efficiency and comfort on long rides.
Minimalist & Lightweight: Engineered to add height without adding significant rotating mass to your footwear.
Technical Specifications
| Feature | Specification |
| Material | High-Density Technical Polymer |
| Cleat Compatibility | 2-Bolt SPD (MTB / Gravel / Commuter) |
| Thickness | ~3mm (Per Shim) |
| Quantity | Sold Individually (Each) |
| Color | Stealth Black |
| Included | Shim Only (Longer bolts may be required) |
✅ Why This IS For You
Riders with Known LLD: If a professional bike fitter or medical practitioner has identified a functional or structural leg length difference.
Lower Back Pain Sufferers: Perfect for cyclists who experience persistent one-sided back or hip pain that hasn't been solved by standard saddle adjustments.
Gravel & MTB Adventurers: Ideal for those using 2-bolt walking-friendly shoes who want the same level of ergonomic precision usually reserved for road racing setups.
❌ Why This May NOT be for you
Road 3-Bolt Users: These are strictly for 2-bolt SPD systems. If you use Shimano SPD-SL or Look Keo (3-bolt), you will need the Form Road Leg Length Shims.
Self-Diagnosis Risks: We strongly recommend getting a professional bike fit before adding shims; guessing your leg length discrepancy can sometimes create new alignment issues if not measured correctly.
BFC Pro Tip
The Form SPD Shims are a "game-changer" for comfort, but the most important thing to remember is bolt length. When you add a shim, you are moving the cleat further away from the sole of the shoe; you MUST ensure your mounting bolts have enough "thread engagement" (at least 4-5 full turns) to be safe. If your standard bolts are too short, come see us for a set of extended SPD bolts! Also, because these shims sit between the cleat and the shoe, they can slightly affect the "tread clearance" on some MTB shoes—always test your clipping in and out on a stationary trainer before heading out to the trails!
