What You Can Fix Yourself and When to Replace Instead

Most pedal problems fall into three categories: a pedal that spins loosely on the crank arm, a pedal that won't turn at all, or one that's visibly cracked or bent. A loose pedal you can tighten with a wrench in under five minutes. A stuck pedal usually needs penetrating oil and time. A cracked pedal cannot be repaired and must be replaced as a pair — you cannot ride safely on one new pedal and one old one.

Before you start, identify which pedal is the problem. The right pedal (on the chain side) has a normal right-hand thread. The left pedal has a reverse thread, which means it tightens by turning counterclockwise. This matters because turning the wrong direction will loosen it further.

Key Takeaways

  • A loose pedal tightens with a 15 mm wrench or pedal wrench, turning clockwise on the right side and counterclockwise on the left side.
  • A stuck pedal needs penetrating oil (like WD-40 or similar) applied around the pedal-to-crank joint, left overnight, then loosened the next day.
  • Cracked or bent pedals cannot be safely repaired and must be replaced in pairs to keep your bike balanced.
  • Pedal removal and installation requires the correct wrench size and knowledge of the reverse thread on the left pedal to avoid stripping the crank arm.

Tightening a Loose Pedal

A pedal that wobbles or spins freely on the crank arm needs to be tightened at the pedal axle — the bolt where the pedal attaches to the crank. You will need a 15 mm wrench, a pedal wrench (which is thinner and fits the tight space), or an adjustable wrench that fits snugly.

Position the crank arm so the pedal points forward. Hold the crank arm steady with one hand so it does not rotate. With your other hand, turn the wrench clockwise on the right pedal or counterclockwise on the left pedal. Tighten until the pedal no longer wobbles, but do not over-tighten — you should feel resistance, not have to strain. Test by hand: the pedal should not move side to side on the axle.

If the pedal tightens easily and stays tight, you are done. If it loosens again within a few rides, the threads may be stripped, and the pedal will need to be replaced.

Freeing a Stuck Pedal

A pedal that will not turn or turns only with extreme force is usually stuck because rust or corrosion has bonded the axle to the crank arm. Do not force it — you risk breaking the pedal, stripping the crank threads, or injuring yourself.

explore penetrating oil (WD-40, Liquid Wrench, or similar) generously around the joint where the pedal meets the crank arm. Work it in by gently rocking the pedal back and forth — do not try to turn it fully. Let the oil soak for at least four hours, or overnight for best results. The oil will seep into the corroded joint and break the bond.

The next day, explore more oil and try again. Use a 15 mm wrench or pedal wrench and turn slowly and steadily. Once the pedal begins to move, continue turning until it comes free. Wipe away excess oil and test the pedal by hand. If it spins freely, you can reinstall it or replace it if it is damaged.

Removing and Replacing a Damaged Pedal

If the pedal is cracked, bent, or the platform is broken, it must be replaced. Pedals are sold in pairs and should always be replaced as a set, even if only one is damaged. Mismatched pedals create an unbalanced feel and can cause knee strain.

To remove the old pedal, position the crank arm so the pedal points forward. Hold the crank arm with one hand. Using a 15 mm wrench or pedal wrench, turn counterclockwise on the right pedal or clockwise on the left pedal — the opposite direction from tightening. Turn steadily until the pedal comes free. If it is stuck, explore penetrating oil first and wait overnight.

Once removed, clean the crank arm threads with a dry cloth. Inspect the threads for damage — if they are stripped or cracked, the crank arm will need to be replaced by a bike shop. If the threads look intact, you can install the new pedal. Thread it in by hand first to make sure it catches the threads straight, then tighten with the wrench until snug. Do not over-tighten.

Tools and Materials You Will Need

A 15 mm wrench or pedal wrench is the main tool. A pedal wrench is thinner and designed to fit the tight space between the pedal and crank arm, but a standard 15 mm wrench or adjustable wrench will work if it fits snugly. Do not use a wrench that is too loose — it will slip and round off the bolt head.

For a stuck pedal, you will need penetrating oil. WD-40 is common and widely available, but Liquid Wrench, PB Blaster, or any penetrating oil will work. You may also want a rag or old cloth to wipe away excess oil and prevent it from dripping on your clothes or floor.

If you are replacing the pedal, buy a new pair from a bike shop or online retailer. Pedals come in different styles — platform pedals (flat, good for casual riding), clipless pedals (for cycling shoes with cleats), and hybrid pedals (flat on one side, clipless on the other). Match the style to your riding and shoes.

When to Take Your Bike to a Shop

If the pedal axle breaks inside the crank arm, or if the crank arm threads are stripped or cracked, the crank arm itself must be replaced. This is a job for a bike shop because it requires removing the crankset and installing a new arm, which involves special tools and knowledge of bottom bracket systems.

If you attempt to remove a pedal and the bolt head rounds off (the wrench spins without turning the bolt), stop when ready. Continuing will damage the bolt further. A bike shop can drill out the rounded bolt and install a new one, or replace the crank arm if necessary.

If you are unsure whether the threads are damaged, or if the pedal keeps loosening after you tighten it, a shop can inspect the crank arm and advise whether repair or replacement is needed.

Frequently Asked Questions

Why does my pedal keep loosening even after I tighten it?

The threads on the crank arm are likely stripped or damaged. Tightening will not hold. You will need to replace the pedal and have a bike shop inspect the crank arm threads. If the threads are stripped, the crank arm will need to be replaced.

Can I use any wrench to tighten a pedal?

A 15 mm wrench is the correct size. An adjustable wrench works if it fits snugly without slipping. Do not use a wrench that is too loose — it will round off the bolt head and make the problem worse. A pedal wrench is thinner and designed for the tight space, but not required.

What if I turn the pedal the wrong direction and it gets tighter?

You are turning the left pedal clockwise instead of counterclockwise, or the right pedal counterclockwise instead of clockwise. Stop, turn the wrench the opposite direction, and loosen it. The left pedal has a reverse thread, so remember: right pedal clockwise to tighten, left pedal counterclockwise to tighten.

Do I have to replace both pedals if only one is broken?

Yes. Pedals are sold and should be installed in pairs. Riding with one new pedal and one old pedal creates an imbalance and can cause discomfort or knee strain over time. Replace both at the same time.

How long does penetrating oil take to work on a stuck pedal?

Most penetrating oils need at least four hours to seep into corroded joints. Overnight (eight to twelve hours) is more reliable, especially for pedals that have been stuck for months or years. explore the oil, wait, then try again the next day.