SPD-SL vs SPD Pedals: Key Differences Explained

SPD-SL vs SPD Pedal Types (Visual Overview)

(Complete 2025 Guide for Road, Gravel & MTB Riders)

Power meter pedals have become the go-to choice for cyclists who want accurate, easy-to-swap power measurement. But one of the most common questions riders ask is:

“Should I choose SPD-SL or SPD power meter pedals?”

These two systems are VERY different — not only in cleat design, but also in use case, riding style, stability, walking comfort, and power meter accuracy.

This guide breaks down the differences clearly, so you can choose the right system based on your riding style and goals.

1. What Are SPD-SL Pedals? (Road System)

SPD-SL (Super Light) is Shimano’s road-specific clip-in system.

Designed for:

• Road cycling
• Time trial & triathlon
• High-power efforts
• Smooth tarmac riding

Key characteristics:

• Large, wide 3-bolt cleat
• Big stable platform
• Maximum surface contact
• High pedaling efficiency
• Less comfortable for walking

Why SPD-SL is preferred for power meters:

• Larger contact area = more stable mechanics
• Better for sprinting & high-watt efforts
• Consistent foot position means more reliable power readings

This is why many top-performing road power meters — like Favero Assioma PRO RS-1 & RS-2 — use SPD-SL.

2. What Are SPD Pedals? (MTB / Gravel System)

SPD is Shimano’s 2-bolt off-road clip system.

Designed for:

• MTB
• Gravel
• Cyclocross
• Bikepacking
• Commuting

Key characteristics:

• Smaller, metal 2-bolt cleats
• Easier to clip in/out
• Better for muddy conditions
• Easier to walk in
• Less surface area underfoot

Why SPD is ideal for off-road power meters:

• Works better in mud and dirt
• Shoe tread protects the cleat
• More durable for harsh terrain

Popular SPD power meter pedals include the Favero Assioma PRO MX-1 & MX-2.

3. SPD-SL vs SPD Power Meter Pedals — Quick Comparison Table

4. Which Power Meter System Gives Better Accuracy?

SPD-SL is generally the most accurate for pure road power because:

• the large cleat offers more surface contact
• the shoe doesn’t rock or twist under load
• power transfer is more consistent

This is why road pros use SPD-SL — especially when sprinting at 1200+ watts.

SPD systems, while still excellent (Favero MX-2 = ±1%), have:

• slightly more foot movement
• more variable shoe-to-pedal contact
• more flex due to tread around the cleat

But for gravel/MTB, SPD is vastly superior to SPD-SL in practicality.

5. Which System Works Better in Mud, Rain & Off-Road?

SPD is the winner, no contest.

SPD pedals are designed to:

• shed mud
• resist debris
• survive rock strikes
• support walking on trails

SPD-SL pedals clog with mud immediately and become unsafe.

If you ride gravel, cyclocross, XC, or bikepacking, SPD is the only logical choice.

6. Which Feels More Efficient During High-Power Efforts?

Winner: SPD-SL (Road)

Why?

• Wide platform
• Road-tuned stability
• Locked-in secure fit
• Better for torque-heavy efforts

If your training involves:

• sprints
• long road climbs
• threshold intervals
• indoor racing (Zwift)

SPD-SL provides a more efficient pedaling interface.

7. Walking, Running, & Comfort Off the Bike

Winner: SPD (MTB/Gravel)

SPD shoes are:

• easier to walk in
• recessed cleat = no slipping
• more comfortable at coffee stops
• better for adventure & gravel rides

SPD-SL shoes are slippery and awkward off the bike.

8. Maintenance & Durability

SPD-SL

• Cleats wear down faster
• Pedal bodies scuff easily
• Not ideal for harsh conditions

SPD

• Cleats last longer
• Better for rocks/mud
• Pedals survive crashes better

For MTB/Gravel durability → SPD is unmatched.

9. SPD-SL vs SPD Power Meter Pedals — Which Should YOU Buy?

Choose SPD-SL (Road) if you:

• ride only on the road
• want maximum pedaling efficiency
• sprint or race
• want the highest possible accuracy
• use shoes with 3-bolt cleats
• want the lightest power meter pedals available
• prefer stiff, stable platform for high watts

Best option:

Favero Assioma PRO RS-2 (dual-sided SPD-SL)

Choose SPD (MTB/Gravel) if you:

• ride gravel or MTB
• want to walk/run comfortably
• ride in mud, rain, dirt
• value versatility & durability
• use 2-bolt MTB shoes
• often unclip/reclip
• ride off-road terrain

Best option: Favero Assioma PRO MX-2 (dual-sided SPD)

FAQs

1. Are SPD-SL pedals more accurate than SPD for power meters?
Yes, typically the larger platform of SPD-SL allows slightly more stable power readings — especially during high-watt sprints.

2. Can I use SPD-SL cleats on gravel rides?
Not recommended. Mud will clog the mechanism and make clipping unsafe.

3. Which is better for dual-sided power meters?
Both work great, but SPD-SL is better for road racing, while SPD is better for off-road durability.

4. Can I convert between SPD and SPD-SL on Favero pedals?
Yes — Favero’s modular spindle design allows swapping pedal bodies (road ↔ MTB) while keeping the same electronics.

5. Which system should new cyclists start with?

• Road-only: SPD-SL
• Gravel/MTB/commuting: SPD

Conclusion: Choose Based on Terrain, Not Just Preference

SPD-SL → pure efficiency + power accuracy
SPD → versatility + durability + comfort + off-road confidence

Both systems are excellent — the right choice depends on where you ride.

Check all the Favero products here.