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FORM Universal Leg Length Shim | 3-hole, Modular
Designed for cyclists with leg length discrepancies, this universal 3-hole shim helps restore symmetry, reduce discomfort, and improve pedal stroke balance.
$23.00
In stock
FORM Universal Leg Length Shims are designed specifically for cyclists who have a true or functional leg length discrepancy and need to increase the effective length of one leg. These modular, stackable 3-hole cleat shims install between the shoe and cleat to help restore symmetry, reduce discomfort, and improve pedaling control when one leg consistently feels shorter or under extended.
Leg length shims are not general comfort accessories. They are a corrective tool used when a rider has been assessed to have a measurable difference in leg extension, either structural or functional. When used appropriately, they can dramatically improve balance, stability, and efficiency on the bike.
What Problem Leg Length Shims Solve
Cyclists with a leg length discrepancy often experience one or more of the following:
- Overreaching on one side at the bottom of the pedal stroke
- A tilted pelvis or a tendency to lean to one side of the saddle
- Uneven saddle wear on one side
- One leg feeling under extended while the other feels correct
When the rider’s position is otherwise sound and a discrepancy has been identified, adding lift under the cleat of the shorter leg can restore balance and improve overall function. In some cases, shims are also used to address functional leg length differences where no anatomical difference exists, but uneven extension is visible during riding. In these situations, consultation with a qualified professional bike fitter is strongly recommended before making changes.
Benefits of FORM Universal Leg Length Shims
- Creates a more equal leg extension between left and right sides
- Helps stabilize the pelvis during the pedal stroke
- Produces a smoother and more controlled pedal stroke on the shorter side
- Reduces pain, discomfort, and asymmetrical loading
- Supports long term comfort and consistency across rides
Key Features
- Modular and stackable design using 2 mm and 3 mm shims
- Curved shape for easier fitment to the shoe sole
- Chamfered front edge to improve clip in engagement, especially when stacking shims
- Integrated pinning system that allows multiple shims to be securely connected
- Small alignment pins insert through the shim holes to prevent movement
- Cleat position markers to help maintain accurate cleat alignment
- Constructed from tough, impact resistant nylon to withstand repeated clip-ins
- Designed to resist scuffing and hard impacts
- Compatible with and easily combined with FORM Cleat Wedges to fine tune alignment and comfort
Modular and Stackable Design Explained
The modular design allows riders or fitters to fine tune lift height by stacking a 2 mm and 3 mm shim together if needed. The pinning system ensures that stacked components stay aligned and stable, preventing rotation or compression over time. This approach provides flexibility without sacrificing durability or precision.
Compatibility
Universal 3-hole Leg Length Shims are compatible with all 3-holed cleats, including:
- Shimano SPD-SL
- Look style 3-hole
- Time/Mavic
What's in the Box?
- 1 x 2mm shim
- 1 x 3mm shim
- 6mm and 10mm pins for connecting shims or cleat wedges
- Longer screws
How to Find the Right Screw Length for Your Universal Leg Length Shim
See the full chart of universal screw lengths here
| Leg Length Shim Screw Size Reference Chart | ||
|---|---|---|
| Shim Stack | Shimano SPD-SL Style Cleats | Look Style Cleats |
| 2mm shim | 10mm / 12mm | 10mm / 12mm |
| 3mm shim | 12mm | 12mm |
| 4mm shim | 12mm | 12mm |
| 5mm shim | 14mm | 12mm / 14mm |
| 6mm shim | 14mm | 14mm |
| 7mm shim | 14mm / 16mm | 14mm / 16mm |
| 8mm shim | 16mm | 16mm |
| 9mm shim | 16mm / 18mm | 16mm / 18mm |
| 10mm shim | 18mm | 18mm |
| Original Screws: | Shimano = 8mm | Look = 9mm |
11 reviews for FORM Universal Leg Length Shim | 3-hole, Modular
FORM Universal Leg Length Shim | 3-hole, Modular
FAQs
A cleat wedge cants the entire foot whereas a cleat shim such as a leg length shim increases the effective leg length of a shorter leg in cases where a cyclist suffers from a leg length discrepancy.
Yes, the 3-hole shims and 3-hole wedges are compatible and can be pinned together to create a “stack.” Always remember to place the wedges closest to the cleats, and shim closest to the shoe.
Yes, they are. There are quite a few different shaped cleats on the market but the shims will work with all 3-hole systems even if the shape is slightly different.
2mm and 3mm which can combine to add up to any desired thickness in 1mm increments.
You can stack 3 in the staggered configuration, and multiples in the vertical configuration limited only by the length of the pin. An alternative is 3 staggered and any above that in the vertical position. Please see the image below:
Shipping. In stock items ship within 3 to 5 days of your order. You get a tracking email when your order ships. Shipping is calculated at checkout by box size and weight.
Returns. Free 30 day returns for US customers: 30 days from purchase on unused, undamaged items with proof of purchase. We provide the return shipping label on request and approval of your return; packaging is your responsibility. Outside the US, shipping costs both ways are your responsibility. Sale items are non-returnable.
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These are the best designed shims I have ever used, I have no problem clipping in even stacked 10mm high!
See comments above
This 3mm shim was easy to install and adjust/align, providing me the balance to pedal efficiently, powerfully and most important, painlessly! Will buy more for my other roadie shoes.