Pedal Washers: What They Do and When to Use Them

What do pedal washers do?

A pedal washer sits between the shoulder of the pedal spindle and the outer face of the crank arm. It does three jobs:

1. Protects the crank face. The spindle shoulder clamps hard against the crank. A hard washer stops it biting into, or fretting against, the crank’s surface, which matters most on carbon arms and on soft or anodized alloy faces.
2. Spreads the load. A flat steel washer gives the shoulder an even surface to tighten against.
3. Adds a small amount of clearance. If a pedal body, end cap or cleat brushes the crank arm, a thin washer can move it just clear. It also adds a tiny amount of stance width, but only a tiny amount.

Pedal washers do not fix a damaged crank thread, and they are not a good way to make big stance changes.

How to choose pedal washers

Choose a thin, flat, hard washer that matches your pedal thread. The crank maker’s own washer is the safest choice when one exists.

Thread size: 9/16” or 1/2”

Most adult bikes use 9/16” pedal spindles (about 14.3 mm); one-piece cranks on kids’, BMX and cruiser bikes use 1/2” (about 12.7 mm). A washer’s inner hole must match. A 9/16” washer on a 1/2” spindle sits off-center and can dig in unevenly.

Material

Stainless or hardened steel is the right material. Aluminum washers can deform under pedal torque and plastic ones compress, and either can let the pedal work loose over time.

Thickness

Thinner is better. Typical pedal washers are around a millimeter or less, which is enough to protect the crank without costing meaningful thread. Thicker “spacers” exist, but they trade thread engagement for width.

Outer diameter

The washer should cover the spindle shoulder fully without overhanging the edge of the crank’s pedal boss. Some pedals have a large shoulder and need a wider washer to spread load properly.

Your crank’s instructions

Your crank manual wins. Some makers, including SRAM and Race Face, include pedal washers with their cranks; if your crank came with them, use them.

When to use a bike pedal washer (and when not to)

Use a washer when the crank maker supplies one, when the crank face is soft or carbon, or when you need a sliver of clearance. Skip it when it would cost thread you cannot spare.

Use one when:

• your crankset came with washers or the manual recommends them,
• your pedal body or end cap brushes the crank arm, or
• you want to protect the finish on a crank you plan to keep.

Avoid them when:

• you would need more than one per side to get the result you want,
• the pedal spindle’s threaded section is short and already sits well recessed inside the crank,
• the pedal maker’s instructions say not to use them, or
• you are trying to fix a stripped or worn crank thread (see the repair options in our reverse-thread guide).

How many pedal washers is too many? Thread engagement

One thin washer per side is the practical limit. Every millimeter you add pulls a millimeter of thread out of the crank, and a pedal that is not fully engaged can strip the crank thread or work loose.

A quick check after fitting a washer:

1. Tighten the pedal to the maker’s torque.
2. Look at the inside face of the crank arm, where the spindle end comes through.
3. The spindle end should be close to flush with that face. If it now sits clearly recessed compared with the same pedal without a washer, remove the washer or use a thinner one.

Pedals with long threaded sections tolerate a washer easily; some lightweight road pedals have very little thread to spare. If you are unsure, leave the washer out.

How to install pedal washers

Fit the washer over the spindle threads before you thread the pedal in, and grease everything. It takes about two minutes per side.

1. Remove the pedal with a pedal wrench or hex key. The left pedal is reverse-threaded: turn the tool toward the back of the bike to loosen.
2. Clean the crank threads and the crank face.
3. Put a thin coat of grease on the pedal threads and a smear on both faces of the washer.
4. Slide the washer onto the spindle so it sits against the shoulder.
5. Thread the pedal in by hand for several turns to avoid cross-threading.
6. Tighten to the pedal maker’s torque. Check that the washer is centered and not pinched against the edge of the crank.

Washers vs longer spindles for Q-factor

A washer adds width; a longer spindle adds width properly. If you want a wider stance for knee tracking, wide hips or heel clearance, the right fix is a pedal sold with a longer spindle, such as Shimano’s +4 mm road pedals or the Crankbrothers Mallet E LS. Moving your cleats inboard also widens your stance on clipless pedals. Our pedal spindles page compares the options and explains how spindle length affects stance width.

For flat pedals, check whether the maker offers a long-axle version before reaching for washers; browse flat pedals or clipless pedals for current models.