Rear wheel bearings are critical components in a BMX bike. They allow the hub to spin smoothly, reduce friction, and handle the stresses of tricks, jumps, and racing. Worn or damaged bearings can cause grinding noises, poor wheel performance, and even safety risks. For BMX riders—whether street, park, or racing—knowing how to replace wheel bearings is an essential maintenance skill.
This guide will walk you through how to remove, clean, and replace your rear wheel bearings step by step.
Tools and Materials Needed
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Freewheel removal tool (specific to your cog type)
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Chain whip
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Adjustable wrench
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15mm cone wrench
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Light-colored towel or rag (to catch small parts)
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Fresh bicycle grease
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Replacement bearings (same size and quantity as original)
Disassembly: Removing the Old Bearings
Step 1: Remove the cog/freewheel
Take the rear wheel off the bike. Insert the freewheel removal tool through the center of the cog. Hold the cog in place with a chain whip and turn the tool counterclockwise using an adjustable wrench. This will loosen and remove the cog.
Step 2: Prepare your workspace
Lay a clean towel or rag underneath the wheel. This will prevent losing small bearing balls or washers during disassembly.
Step 3: Loosen the axle locknut
Using a 15mm cone wrench, hold the non-drive-side (left side) axle cone. Turn the locknut counterclockwise with a wrench. The locknut is located near the tip of the axle.
Step 4: Remove axle and cones
Unthread the locknut and cone completely. Slide the axle out from the drive side (right side).
Step 5: Remove the bearings
With the axle removed, the ball bearings inside the hub are now exposed. Carefully remove them from both sides of the hub. Count the bearings on each side—this ensures you replace them with the same number. Many BMX hubs use deep groove ball bearings because of their high load capacity and smooth rolling performance because of their high load capacity and smooth rolling performance.
Step 6: Clean the hub and axle
Wipe off old grease, dirt, and debris from the axle, cones, and hub bearing races using a rag. Avoid harsh solvents that could damage the grease-retaining surfaces.
Replacement: Installing New Bearings
Step 1: Grease the bearing races
Apply a layer of high-quality bicycle grease inside each bearing race (the smooth circular “shelf” inside the hub where the bearings sit).
Step 2: Insert new bearings
Place the new ball bearings into each race. If you ride in harsher environments (rain, dust, or dirt), consider using stainless steel bearings for better corrosion resistance. Make sure the bearings match the size and count of the originals.
Step 3: Add grease over the bearings
Coat the bearings with another layer of grease. This holds them in place and provides lubrication.
Step 4: Reinsert the axle
Carefully slide the axle back through the drive side (right side) of the hub. Do this slowly to avoid dislodging the bearings.
Step 5: Reinstall the cone and locknut
Thread the cone and locknut back onto the non-drive side of the axle. Start by tightening them with your fingers.
Step 6: Adjust hub tension
Hold the cone with the cone wrench and tighten the locknut against it with your other wrench. The wheel should spin freely without grinding or side-to-side play. Adjust carefully until smooth rotation is achieved.
Step 7: Reinstall the cog/freewheel
Fit the cog back onto the hub threads. Using the freewheel removal tool and wrench, turn clockwise to secure it firmly.
Final Check
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Spin the wheel by hand—there should be no binding or excessive play.
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Wipe off excess grease.
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Reinstall the wheel on your BMX frame.
Properly maintained bearings keep your BMX rolling smoothly and reduce the risk of hub failure during tricks or competition. Replacing your bearings when needed extends the life of your hub and keeps your ride safe.
Pro Tip: If you prefer a low-maintenance option, many modern BMX hubs also support sealed bearings
Step 3: Add grease over the bearings
Coat the bearings with another layer of grease. This holds them in place and provides lubrication.
Step 4: Reinsert the axle
Carefully slide the axle back through the drive side (right side) of the hub. Do this slowly to avoid dislodging the bearings.
Step 5: Reinstall the cone and locknut
Thread the cone and locknut back onto the non-drive side of the axle. Start by tightening them with your fingers.
Step 6: Adjust hub tension
Hold the cone with the cone wrench and tighten the locknut against it with your other wrench. The wheel should spin freely without grinding or side-to-side play. Adjust carefully until smooth rotation is achieved.
Step 7: Reinstall the cog/freewheel
Fit the cog back onto the hub threads. Using the freewheel removal tool and wrench, turn clockwise to secure it firmly.
Final Check
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Spin the wheel by hand—there should be no binding or excessive play.
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Wipe off excess grease.
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Reinstall the wheel on your BMX frame.
Properly maintained bearings keep your BMX rolling smoothly and reduce the risk of hub failure during tricks or competition. Replacing your bearings when needed extends the life of your hub and keeps your ride safe.
Pro Tip: If you prefer a low-maintenance option, many modern BMX hubs also support sealed bearings. While they can’t be serviced like loose ball bearings, they offer excellent protection against dirt and water and are replaced as a complete unit.
Where to Buy Quality Bearings
At Bearing Maker,we provide a full range of precision bearings for BMX and other cycling applications, including:
- Deep groove ball bearings for smooth performance
- Stainless steel bearings for corrosion resistance
- Sealed bearings for easy, long-lasting protection
If you need help choosing the right bearings for your BMX hub, feel free to contact us Our experts will help you find the best solution for your riding style.
