Bike pedals can become damaged and stripped over time due to repeated stress, improper installation, or from impacts. When a bike pedal is stripped, it means the pedal threads have become worn down or damaged, preventing the pedal from properly threading into the crank arm. This can cause the pedal to wiggle, spin loosely, or even detach from the bike – making pedaling difficult or impossible.
While a stripped bike pedal may seem like a complex repair, there are actually several easy methods to fix it with basic tools. This guide will provide a step-by-step overview of how to diagnose and repair a stripped bicycle pedal using a thread repair kit, helicoil, or even just by adding shims.
Common Causes of a Stripped Bike Pedal
Before learning how to fix a stripped pedal, it helps to understand what may have caused the issue in the first place. Here are some of the most common causes of a stripped bike pedal:
- Over-tightening – Installing pedals too tightly can damage the threads over time, especially if using a narrow pedal wrench which applies focused pressure. Always tighten just to the recommended torque specs.
- Poor maintenance – Neglecting to periodically check and tighten loose pedals can allow them to wiggle, slowly wearing down the threads.
- Using the wrong tools – Don’t use a cone wrench or vice grips which can easily round-off pedal bolts. Use a proper thin pedal wrench.
- Repeated stress – Frequent pedaling miles over time naturally wears down pedal threads gradually. Heavy-footed riders can accelerate wear.
- Sudden impacts – Striking pedals on rocks or drops can damage threads suddenly rather than through gradual wear.
- Cross-threading – Forcing in pedals crooked initially damages threads making them prone to stripping.
- Low quality pedals – Cheaper pedals often have softer, lower grade threads more prone to stripping. Invest in quality pedals.
Knowing what may have caused the issue provides insight into preventing it in the future through proper installation, maintenance, and avoiding damage. Next, let’s explore the methods for repairing a stripped pedal.
Diagnosing a Stripped Bike Pedal
Before attempting to fix a stripped pedal, you’ll want to properly diagnose the issue. Here are the signs that indicate a pedal is stripped:
- Pedal has excessive wobble or looseness when pedaling
- Unusual clicking, creaking or popping sounds when pedaling
- Pedal does not thread smoothly into crank arm
- Pedal spins independently within crank arm
- Pedal falls out of crank arm suddenly
First, try tightening the pedal with a pedal wrench to the proper torque specifications (usually around 33-35 Nm). If the pedal still wiggles or doesn’t hold tight, it likely has stripped threads.
Visually inspect the pedal threads for damage – worn, rounded, or crossed threads indicate a stripped pedal. Finally, attempt to thread the pedal into the crank arm by hand. If the pedal does not thread smoothly or pulls out without being unthreaded, it is certainly stripped.
Thread Repair Kit Method
One of the quickest and easiest ways to fix a stripped bike pedal is using a thread repair kit. These inexpensive kits contain adhesives and inserts to fill damaged threads and restore grip. Here is how to use a thread repair kit to fix a stripped pedal:
Materials Needed
- Bike thread repair kit
- Bike degreaser
- Torque wrench
- Pedal wrench
- Shop rag
Steps to Repair:
- Remove the stripped pedal from the crank arm using a pedal wrench. Inspect the threads on the pedal and crank arm for any debris or damage.
- Use a degreaser to thoroughly clean any oil, grease or grime from the pedal threads. This allows the adhesive to bind properly. Wipe clean and dry the threads completely with a rag.
- Select the thread insert from the kit that best matches your pedal’s thread size. Common sizes are 9/16” or 1/2″ for road bikes and 1/2” for most mountain bikes.
- Apply a thin layer of the adhesive resin from the kit around the pedal threads. Follow the kit instructions for proper curing time.
- Insert the thread insert into the stripped pedal hole and turn clockwise until it stops. Allow the adhesive to fully cure.
- Apply another thin coat of adhesive around the insert and pedal threads.
- Reinstall the pedal into the crank arm slowly, being careful not to cross-thread it. Tighten to torque specs using a torque wrench.
- Allow the adhesive to fully cure for at least 24 hours before riding on the pedal. Retighten as needed.
Pro Tip: If the pedal still loosens, apply more adhesive and try a slightly larger insert. The adhesive hardens like a metal insert to prevent loosening.
Thread repair kits offer an quick, easy fix that can salvage stripped pedals. The adhesive permanently fills any damaged threads to restore a solid hold. Just be sure to prep the area properly and allow adequate curing time.
Helicoil Method
While thread repair kits provide a solid temporary fix, helicoils offer a more heavy duty, permanent solution for badly stripped pedals. Helicoils are stainless steel threaded inserts that screw into the stripped pedal hole to restore the threads. Here is how to install them:
Materials Needed:
- Helicoil thread repair kit (with correct pedal insert size)
- Cutting fluid or oil
- Shop rag
- Pedal wrench
- Torque wrench
- Bench vise
- Tap handle
- Helicoil installation tool
Steps to Repair:
- Clamp the crank arm with the stripped pedal hole securely in a vise to prevent spinning.
- Use the helicoil tap from the kit, turning counterclockwise to cut fresh threads into the stripped hole. Apply cutting fluid for lubrication.
- Blow out the cut threads to remove any metal debris. Clean thoroughly.
- Insert the helicoil insert into the installation tool and thread the insert clockwise into the tapped hole until just below the surface.
- Break off the tang end of the insert with pliers and retract the installation tool. The insert should stay screwed into the threads.
- Thoroughly clean and dry the pedal threads. Apply grease to the threads.
- Thread the pedal by hand into the helicoil insert until tight. Use a torque wrench to tighten fully to specifications.
The stainless steel helicoil insert will remain permanently screwed into the crank arm to provide new, strong threads for the pedal indefinitely. This offers a more robust solution than temporary thread repair kits.
Pro Tip: If the insert screws in crooked, carefully back it out with the installation tool to re-align and re-install straight before tang removal.
Adding Shims
If a pedal’s threads are too damaged for effective repair, another fix is adding thin shim washers to take up space between the loose pedal and crank arm. Here’s how to install pedal shims:
Materials Needed:
- Shim washers or thin spacers
- Pedal wrench
- Torque wrench
Steps to Install:
- Remove the loose stripped pedal from the crank arm using a pedal wrench.
- Clean all grease from the pedal threads using degreaser. Wipe dry.
- Determine how much “play” is in the pedal when threaded into the crank. This will indicate how thick your shims should be – you want a snug fit without binding.
- Stack an assortment of Shim washers on the pedal spindle to match the needed thickness.
- Apply a drop of thread locker to the pedal threads to help keep the shims in place.
- Reinstall the pedal tightly into the crank arm with added shims, using a torque wrench to specifications.
The shims take up slack between the pedal and crank arm caused by the stripped threads. Monitor for loosening and add another shim if needed. Avoid overly tightening.
Pro Tip: Use discarded or damaged bearings as shims. Just match the inner diameter to your pedal spindle.
While not overly durable long-term, shims can provide a quick fix in a pinch if needed to get rolling again. But other options like helicoils offer much more permanent repairs.
Preventing Stripped Pedals in the Future
To avoid having to regularly repair stripped pedals, it’s wise to take preventative measures by:
- Always installing/removing pedals with a thin pedal wrench, not pliers.
- Greasing threads annually and periodically inspecting for loosening.
- Tightening only to torque specifications, not over tightening.
- Avoiding sudden impacts to pedals on rocks or drops.
- Replacing worn pedals promptly, not waiting until completely stripped.
- Selecting quality pedals – cheap pedals strip easier.
Proper ongoing pedal maintenance and avoiding damage will provide the best protection against frustrating stripped pedal issues occurring. But now you’re equipped to properly diagnose and fix them when they eventually do occur.
Frequently Asked Questions About Fixing Stripped Bike Pedals
What tools do I need to remove and install pedals?
You’ll need a good thin pedal wrench as well as a torque wrench. Don’t attempt using vice grips or cone wrenches which can quickly damage bolts. A quality pedal wrench with a thin profile gives proper grip and leverage.
How can I prevent my pedals from becoming stripped again?
Regularly greasing the threads, checking for tightness, and avoiding over-tightening or impacts will help pedals last much longer. But occasional stripping is sometimes inevitable through repeated use and exposure.
Will a stripped pedal eventually fall off while riding?
It’s possible if the damage is severe enough. But more often a stripped pedal will just become increasingly loose. Pay attention for wobble or play and address it promptly before it fails completely.
Should I replace a pedal or crank arm if stripped?
In most cases the threads can be repaired or restored with a kit, helicoil or shims rather than replacing components. But if damage is extreme, a new pedal or crank arm may be needed. Assess the threads carefully.
Can I ride the bike home if a pedal starts stripping mid-ride?
If loosening mid-ride but still threaded in, you can gently ride home. But monitor it closely and don’t stand or pedal hard which could cause it to release completely. Loosening indicates it needs immediate repair.
Summary
Stripped pedal threads are a common issue that can occur overtime through repeated use or suddenly from impacts. But left unaddressed, a stripped pedal can become increasingly hazardous if it loosens or falls out while riding.
Thankfully, stripped pedals can usually be repaired fairly easily using one of these methods:
- Thread repair kits – Adhesives and inserts fill damaged threads for a quick, simple fix.
- Helicoils – Stainless steel threaded inserts permanently restore threads for a lasting repair.
- Shims – Taking up space between the pedal and crank compensates for play in the damaged threads.
Diagnosing a stripped pedal involves looking for wobble, spin, or inability to tighten down fully. Always use proper thin pedal wrenches for removal and installation to avoid damaging bolts.
Prevention involves proactive maintenance, proper torquing, avoiding damage, and using quality components. But following the steps outlined here will get you back pedaling smoothly again after a stripping issue arises. Just take care to properly clean and prepare the area, use patience during repairs, allow adequate thread locking adhesive cure time, and torque to specifications.