For cyclists, there will always be rain rides and dusty and gritty roads. Over time, the bicycle will always produce some abnormal noise, especially the mountain bike enthusiast who likes to go off-road. Even while riding, you don’t know where these noises are coming from, especially carbon fiber frames can also amplify the noise.

If there is abnormal noise on the bicycle, they usually think about solving it. For riders with strong hands-on ability, they will choose to do it by themselves, while novices can find a professional bicycle technician to deal with it. So, in the process of eliminating abnormal noise, we often encounter several sources of abnormal noise and solutions. There are several common sources of abnormal noise for your reference.

Abnormal noise source:

1. Abnormal noise when stepping on
2. Abnormal sound from the seat post when sitting and stepping
3. Abnormal sound from the steering of the handlebar
4. Abnormal noise from the brakes

Tools for repairing:

1. Bike Repair Rack
2. A clean rag
3. Waste rags
4. Alcohol/Brake Cleaner
5. Chain lubricating oil
6. Grease
7. Center axis tool
8. Fine sandpaper / wet and dry
9. Allen key
10. Flywheel Tool
11. Torque wrench
12. Air compressor
13. Abnormal noise when stepping on

Symptoms: Intermittent noise from pedaling under load

Abnormal noise source: bottom bracket, crankset, sprocket rivet, hub, pedal, tail hook, spoke nipple

Bottom bracket

1. Remove the crank and bottom bracket
2. Thoroughly clean the inside of the central axle and the bearing, and check whether the bearing is rusted
3. After cleaning, check whether the bearing is worn, refill the grease or replace the bearing
4. When installing, remember to apply grease to the thread position of the central shaft, and remember to apply grease to the installation position of the press-in type central shaft.

Flywheel

1. Check whether the lock cover is locked (usually around 40Nm)
2. Abnormal noise still exists, remove the flywheel and clean it thoroughly
3. Put a drop of oil on each rivet and let it penetrate overnight before removing excess oil
4. Lubricate the lock cap (Shimano) or the driver body thread (SRAM XD)

The abnormal sound of the flywheel is very likely to be the abnormal sound of the rivets on the flywheel when the high power is applied, or the looseness of the flywheel lock cover causes the gap between the flywheels to move left and right. Most locking cassettes require around 40Nm or more of torque when locking the cover. Before installing the cassette, XD cassette installation requires applying grease to the freehub body threads. Cassette sprockets need to be greased on the lock cap threads.

Hub

1. Open the hub bushing/quick release bushing
2. Remove dust and old grease
3. Check the degree of bearing or ball wear
4. Re-grease after cleaning
5. Tighten the barrel bushing to fix the wheel without any clearance

The torque generated by the leg force exerts a lot of pressure through the hub, and the grit between the different contact points can cause abnormal noise under load. A thorough cleaning and relubrication is required, but many hubs require a specified grease to function properly, so be sure to check what grease your brand of hub needs.

Pedals/cleats

1. Remove the pedals
2. Clean crank threads and threads on pedals and re-oil
3. Check if there is any clearance between pedal body and shaft, tighten/repair/replace bearings, balls as needed.
4. Clean and re-grease the pedal shaft
5. If there is any abnormal sound from the cleat, you can try to spray a little dry lubricant on the cleat, and then polish it with sandpaper.
6. Check whether the lock plate is locked

Tail hook

1. Remove the tail hook from the frame
2. Thoroughly clean all contact points with the frame
3. Apply grease to the contact position between the frame and the tail hook
4. When installing the tail hook, apply appropriate screw glue on the screws to prevent loosening

Spokes/Spoke nipples

1. Check for loose spokes
2. Clean the spokes, especially where they cross each other
3. Apply a small drop of oil to each spoke nipple and spoke intersection
4. Abnormal sound from the seat post when sitting and stepping

Symptoms: Abnormal sound when the seatpost rail and the seat bow are not locked when seated

Abnormal noise source: seatpost clamp, seatpost clamp, seat cushion

Seat cushion

1. Blow off the dust with an air compressor
2. Apply appropriate lubricating oil to the connection position between the seat arch and the bottom plate
3. Try twisting the bottom plate of the seat cushion to allow the lubricating oil to penetrate fully
4. Wipe off excess grease to prevent dust

Seatpost collet

1. Remove the seat cushion and clean the rails and chuck parts
2. Clean the seat arch, you can use a cloth with lubricating oil to wipe the seat arch
3. Reinstall and tighten
4. Abnormal sound from the steering of the head tube

Symptoms: Abnormal noise when the rocker is working and the front fork is working

The source of abnormal noise: headset, stem

Bowl set

1. Remove the stem, spacer and fork (Note: the bottom bearing of the fork may fall off)
2. Remove the upper and lower bearings
3. Thoroughly clean all headset parts and frame headset mounting locations to remove dust and old grease
4. Grease the headset bearings, headset cups and frame headset mounting locations
5. Reinstall the parts in the order they were removed
6. When installing the front fork and the stem, you must first tighten the screws on the stem cover to ensure that there is no gap between the headsets
7. Tighten the screws on both sides of the stem

Stem

1. Remove the handlebar from the stem
2. Clean all contact points, including screws, washers
3. Carbon fiber handlebars need to be coated with anti-slip agent
4. When locking, follow the torque specified on the stem (usually 6Nm)
5. Abnormal noise from the brakes

Symptoms: Squealing or intermittent rubbing when braking

The source of abnormal noise: pads, brake discs, calipers

Brake pad:

1. Remove the pad to check the thickness
2. To make the instant noodles stained with oil, resulting in screaming and insufficient braking force, you can try to sand it with sandpaper first.
3. After polishing, use brake cleaner or alcohol to clean the pads and brake discs
4. Wipe the disc with a clean cloth, pay attention to whether the color change on the cloth is clean
5. Reinstall the pads and try to brake repeatedly if there is enough braking force
6. If it still does not return to the best state after several brakings, you need to replace the pads
7. Remember to re-clean the brake disc when installing new pads

Disc/caliper

1. Check whether the position of the incoming pad and the disc is centered
2. Whether the brake disc is shaking or deformed
3. If deformed, try to correct it with a disc repair tool or a small open end wrench
4. Those with strong hands-on ability can also do it by hand, but please make sure that there are no oil stains on your hands and tools
5. If the disc is completely off-center, loosen the two caliper screws, then press the brake lever to brake so that the caliper is centered, and the disc is not in contact with the pad
6. Alternately tighten the caliper screws, do not tighten one of them alone
7. Rotate the wheel again to check if there is still a disc rubbing problem