Are All Mountain Bike Pedals The Same Size? | By Thread

Shopping for MTB pedals looks simple at first glance, then the details start piling up. Threads, cleats, platform area, axle length, stack height, even the stance width between your feet—each one changes fit and feel. This guide clears up which parts are standard and which parts differ so you can pick pedals that bolt on cleanly and ride the way you like.

The short version: most current mountain bikes use the same threaded mounting (9/16″ x 20 TPI). That said, pedal bodies, cleats, and axles differ a lot. Those differences affect shoe compatibility, cornering clearance, grip, and comfort on long rides. Let’s break it down, part by part.

Are All Mountain Bike Pedals The Same Size? Rules And Exceptions

If you’re asking “are all mountain bike pedals the same size?” because you want to know whether they’ll screw into your crank, the answer is nearly always yes for modern MTBs: 9/16″ threads. Edge cases exist—older bikes and one-piece cranks use 1/2″, and rare vintage standards pop up—but trail bikes from the past couple of decades stick with 9/16″. Beyond the threads, the “size” that affects ride feel varies a lot.

What Actually Varies On MTB Pedals

What Varies	Typical Range / Options	Why It Matters
Thread Size	9/16″ x 20 TPI (most MTBs); 1/2″ x 20 TPI on some one-piece cranks	Must match your crank threads to install safely
Platform Area	85–115 mm wide flats; smaller dual-sided clipless bodies	Foot support, grip, and rock strike risk
Cleat Standard	2-bolt SPD-style, Crankbrothers, Time; each needs matching cleats	Shoe interface, release feel, and mud shedding
Spindle Length	Standard to +2–5 mm options on some models	Fine-tunes stance width and heel/frame clearance
Q-Factor / Stance	Driven by crank design; pedals add or subtract a few mm	Knee tracking, comfort, and handling feel
Stack Height	~10–20 mm clipless; lower is common on flats	Center of gravity and cornering clearance
Weight	~250–450 g/pair clipless; ~300–500 g/pair flats	Spin-up feel and bike mass

Pedal Threads: What Fits A Mountain Crank

The near-universal mountain standard is 9/16″ x 20 threads. Pedals for one-piece “Ashtabula” cranks—common on kids’ bikes and some BMX—use 1/2″ x 20. Mixing them won’t work, and forcing a mismatch ruins the crank. A classic reference confirms the sizes and also lists rare vintage patterns you might meet on old French frames and oddball systems.

There’s one more thread detail that saves headaches: the right pedal tightens clockwise; the left pedal uses a reverse thread. That’s by design, and it prevents the pedal from loosening during riding due to precession. A respected bicycle tech resource documents both the size standards and the left-hand thread on the non-drive side, so if you’ve fought a stuck pedal, you’re not alone. See the section on pedal threading and thread sizes for the full rundown.

Install Basics That Prevent Creaks

Clean the threads on both sides, add a thin smear of grease or anti-seize, and start each pedal by hand a few turns before using a wrench. Tighten to a solid, positive stop—many mechanics land around the mid-30s to low-40s newton-meters depending on brand guidance. A widely shared torque table sourced from Park Tool lists a minimum of ~35 Nm for some models.

Tools And Orientation

Most pedals take a 15 mm pedal wrench on the flats or a 6/8 mm hex from the back of the crank. Think “toward the front wheel to tighten” on both sides: forward on the right is clockwise; forward on the left is counter-clockwise. That mental shortcut reduces cross-threading risk.

Cleat Standards And Shoe Interfaces

Clipless mountain pedals aren’t interchangeable across brands at the shoe level. You need cleats that match the pedal’s binding. The most common is SPD-style 2-bolt. Shimano’s SM-SH51 is the workhorse single-release cleat that ships with many SPD pedals; it works with nearly all SPD models. The official product page confirms the match.

Shimano also introduced a newer CL-MT001 cleat that aims to make clipping in easier from more angles while staying backward-compatible with SPD systems, which recent cycling coverage notes. That’s handy when you miss the first stab clipping back in on a rough descent.

When Flats Make More Sense

Flat pedals avoid cleats entirely. Pick based on shoe rubber and terrain. Bigger platforms spread load on long rides and reduce hot spots; taller pins boost grip in wet roots and off-camber rock. If you smash pedals on ledges, a thinner body with chamfered edges resists strikes better.

Release Feel, Float, And Mud

Release angle and float vary by system and cleat. SPD-style cleats often offer 4–6° of float with a defined exit angle; alternative designs can feel looser or more linear. Riders in sticky clay or deep slop often prefer mechanisms with open bodies that shed mud fast.

Fit Beyond The Threads: Stance, Axle Length, And Stack

Even with matching 9/16″ threads, two pedals can put your feet in different places relative to the frame. Three dimensions drive this: stance width (Q-factor), axle length, and stack height.

Q-Factor And Stance Width

Q-factor is the lateral distance between the outside faces of your crank arms, and it sets the base stance. Pedals can nudge that stance inward or outward by a few millimeters with short or extended axles. A reference article describes Q-factor as the distance between the pedal attachment points measured parallel to the bottom bracket—useful if knee tracking has been tricky.

Axle Length And Heel/Cage Clearance

Riders with wide shoes or inward-canted heels may clip the chainstays or crank arms on tight sections. A slightly longer spindle fixes that without changing cranks. Racers chasing narrow bikes sometimes pick shorter axles for cornering space and a centered feel.

Stack Height And Cornering

Lower stack keeps your center of mass down and gives more lean before a strike. Clipless bodies with tall cages ride higher than thin flats; within clipless, some models sit lower than others. If you toe strike in berms, look for a lower stack number.

Thread Choices By Bike Type

Here’s a quick way to confirm what you have before ordering. If the bike uses a three-piece crank with separate arms and a spindle, it almost certainly takes 9/16″ pedals. One-piece cranks—common on department-store kids’ bikes and various BMX—use 1/2″. Vintage French and odd systems are rare on MTBs but pop up in collections.

Bike / Crank Type	Thread Size	Notes
Modern MTB (3-piece crank)	9/16″ x 20 TPI	Standard on trail/enduro/XC cranks
BMX / Kids’ Bikes (one-piece crank)	1/2″ x 20 TPI	Not used on current MTB cranks
Vintage French	14 x 1.25 mm	Rare; do not force into 9/16″ cranks
Obscure Legacy (e.g., Dyna-Drive)	Non-standard	Collector territory; skip for MTB use

Sizing Choices By Riding Style

Once you’ve confirmed the thread size, match the pedal body to your riding. Trail riders who dab and remount often like a dual-sided clipless body with a small platform. Enduro riders who spend time off the bike on tech moves lean toward a wider cage for lateral support. Park and jump riders on flats choose big platforms and tall, replaceable pins.

Shoes And Cleats

Clipless shoes use a 2-bolt pattern for SPD-style cleats and many competitors. That doesn’t mean every cleat works in every pedal; always match the cleat to the pedal’s brand and model. Shimano’s SM-SH51 is designed for SPD pedals and is the baseline many riders start with before experimenting with release angle and float. The official listing spells out the intended match and use cases.

Terrain And Weather

In constant mud, choose mechanisms known for open bodies and spring design that resists packing. On rocky trails, a lower, thinner body scrapes less. In alpine sections with long carries, weight and shoe comfort matter more than a handful of grams.

Common Fit Problems And Fast Fixes

Creaks At The Crank

Noise under load often comes from dry pedal threads. Pull the pedals, clean, regrease, and reinstall. If the noise stays, check chainring bolts and crank interfaces.

Heel Rub Or Frame Scuffs

Try a pedal with a slightly longer axle or move cleats inward on the shoe. A few millimeters can stop rub without changing your cranks.

Hard To Clip In

Back off spring tension one click at a time and check cleat wear. Fresh cleats can transform entry and exit. Newer SPD-compatible cleats with multi-entry engagement aim to improve re-entry on rough ground.

Safety Notes That Save Parts

Start each pedal by hand. If it feels tight from the first turn, stop and confirm the side and thread. Drive-side is standard thread; non-drive is reverse. That pattern is documented in classic tech references and prevents mid-ride loosening.

Decision Checklist Before You Buy

• Confirm crank thread: 9/16″ on modern MTB; 1/2″ on one-piece cranks.
• Pick interface: flats for quick footwork and feel; clipless for secure power and rough climbing.
• Match cleats to pedals: SPD-style cleats for SPD-style pedals; brand-specific for others.
• Choose platform size for the terrain and shoe stiffness.
• Check axle length for heel/frame clearance and stance comfort.
• Look at stack height if you clip pedals in turns.
• Grease threads; tighten firmly to spec; recheck after the first ride.

So, Are They “All The Same Size”?

Mounting threads are standardized on modern mountain bikes, which is why most new pedals fit most new cranks. Everything else—body width, cleat interface, release feel, axle spacing, stack—varies by model and purpose. If you came here wondering “are all mountain bike pedals the same size?” for fit at the crank, you’re set with 9/16″. Pick the body and cleats that match how and where you ride, and you’ll feel the difference on the first climb and the first rocky chute.

Helpful References

For thread sizes and left/right thread directions, see the section on pedal threading. For SPD cleat compatibility details, check the official page for Shimano SM-SH51.