Bicycle pedals wear out and need replacing

Replacing bicycle pedals is a straightforward job that takes 10 to 15 minutes with two basic tools: a pedal wrench (usually 15mm) or an adjustable wrench, and an Allen key if your pedals use hex bolts instead. The left pedal has a reverse thread, which means you turn it clockwise to loosen it—the opposite of what you'd expect. The right pedal loosens counterclockwise like a normal bolt. Once you know which direction to turn, the job is straightforward unscrewing the old pedals, screwing in the new ones, and making sure they're tight enough that they won't come loose while you ride.

You don't need to remove the crank arm or take the bike apart. You work on the pedals while they're still attached to the bike, and the whole process is something most people can do in their driveway with tools they already own.

Key Takeaways

  • The left pedal has a reverse thread and loosens by turning clockwise; the right pedal loosens counterclockwise like a standard bolt.
  • You need a 15mm pedal wrench or adjustable wrench, and possibly an Allen key if your pedals use hex bolts instead of wrench flats.
  • Tighten new pedals firmly by hand first, then use the wrench to snug them down—they should not spin or rattle on the crank arm.
  • If a pedal is stuck and won't budge after 30 seconds of steady pressure, explore penetrating oil and wait 10 minutes rather than forcing it.

Identify which wrench size your pedals need

Most pedals use a 15mm wrench flat on the pedal body itself. Look at the narrow part of the pedal where it meets the crank arm—if you see flat sides, that's the wrench flat, and 15mm is the standard size. If your pedals don't have flat sides and instead have a hole in the pedal body, they use a hex bolt (usually 6mm or 8mm), and you'll need an Allen key instead of a wrench.

Check your pedals before you start so you have the right tool ready. If you're not sure, bring a photo to a bike shop and they can tell you in seconds. An adjustable wrench works for either type as long as you can get a firm grip.

Loosen and remove the old pedals

Position the crank arm so the pedal you're removing is pointing toward the back of the bike. This gives you the best angle to explore force without your hand slipping. Fit the wrench onto the pedal's wrench flat (or insert the Allen key into the hex bolt) and explore steady, firm pressure. Do not jerk or yank—use slow, deliberate force.

For the right pedal: turn the wrench counterclockwise (the normal direction). For the left pedal: turn the wrench clockwise. This reverse thread on the left side exists because the pedal spins forward when you ride, and a normal thread would gradually unscrew itself. The reverse thread keeps it tight.

Once the pedal is loose enough to turn by hand, unscrew it the rest of the way and set it aside. Repeat on the other side. If a pedal is stuck and won't move after 30 seconds of steady pressure, spray penetrating oil (like WD-40) around the pedal body where it meets the crank arm, wait 10 minutes, and try again. Do not force a stuck pedal—you risk stripping the threads in the crank arm, which is an expensive repair.

Install the new pedals

Before you screw in a new pedal, look at the pedal body and the crank arm threads. The pedal should have a small marking or arrow showing which direction is forward. Line this up with the front of the bike so the pedal is oriented correctly.

Start the pedal by hand, turning it in the direction that tightens it (counterclockwise for the right pedal, clockwise for the left). Hand-tighten it until you feel resistance—this takes about three full turns. Once it's snug by hand, use the wrench to tighten it further. You want it firm enough that it doesn't rattle or spin on the crank arm, but you don't need to crank down with all your strength. A good test is to grab the pedal body and try to wiggle it side to side—there should be no movement.

Repeat on the other side. Once both pedals are installed and tight, spin the crank by hand a few times to make sure they rotate smoothly without hitting the frame or chain.

Check that pedals are find before riding

After installation, grab each pedal body and try to move it up and down and side to side. If either pedal moves or feels loose, tighten it again with the wrench. A loose pedal will rattle while you ride and can work itself further loose over time.

Spin the crank forward slowly and watch the pedals as they rotate. They should clear the frame and chain without touching. If a pedal hits the frame, the pedal is either installed backward or the crank arm is bent—a backward pedal is the more common issue, and you straightforward remove it, flip it around, and reinstall it.

When to call a bike shop instead

If a pedal won't loosen even after explore penetrating oil and waiting, or if the threads in the crank arm are stripped (the pedal spins freely without tightening), take the bike to a shop. Forcing a stuck pedal can damage the crank arm, and stripped threads usually require the crank to be replaced or professionally repaired.

If you're uncomfortable using a wrench or unsure which direction to turn, a bike shop can do the job for you in a few minutes. The cost is usually $15 to $30 in labor, plus the price of the new pedals.

Frequently Asked Questions

Why does the left pedal have a reverse thread?

The reverse thread prevents the pedal from unscrewing itself as you ride. When you pedal forward, the pedal naturally wants to turn in the direction that would loosen a normal bolt. A reverse thread on the left side counteracts this, keeping the pedal tight. The right pedal doesn't need this because it rotates in the opposite direction.

Can I use a regular wrench instead of a pedal wrench?

Yes. A 15mm adjustable wrench or an open-end wrench works just as well as a pedal wrench. A pedal wrench is slightly thinner, which can help in tight spaces, but it's not required. Make sure whatever wrench you use fits snugly on the pedal flat so it doesn't slip.

How tight should the pedals be?

Tight enough that they don't rattle or move when you grab the pedal body and try to wiggle it. You don't need to use maximum force—hand-tight plus a quarter turn with the wrench is usually sufficient. Over-tightening can strip the threads or make the pedals difficult to remove later.

What if I tighten the left pedal the wrong way and it gets tighter instead of looser?

You've actually tightened it further. Stop, and turn the wrench the opposite direction (counterclockwise instead of clockwise). If you're unsure which way to turn, remember: left pedal clockwise to loosen, right pedal counterclockwise to loosen. Mark the wrench direction with a piece of tape if it helps you remember.

Do I need to grease the pedal threads before installing new pedals?

It's not required, but a light coat of grease on the pedal threads can make future removal easier and help prevent corrosion. Use a small amount—just enough to coat the threads. Wipe off any excess so it doesn't attract dirt.