Our Nightmare… Noises

Our Nightmare… Noises
Nasty Bearing

Its a dark and gloomy night, I find myself manning the shop alone, well after normal office hours. Strange vagrants wonder past the shop front, as the dim store lights flicker and hum. In walks a customer wheeling in their beautiful carbon 29er hard tail, the flowing lines and elegant form contrasts strongly against the anguish on the owners face. He leans his machine on the workshop bench and announces that he is getting an indeterminable creak from somewhere around his BB. “Nnnnoooo!!!!” I am jolted awake by my own screams and my wife calming me down, “shhh love, you’re at home safe in bed, there is no creak, try go back to sleep.”

When a customer brings a bicycle into the our workshop complaining of a strange noise, our usual response is a sigh, a wry smile and then an interrogation of the bicycle owner. Why? Simply because trying to diagnose the cause of the sound can often lead to the biggest mystery in a professional bicycle workshop. Fixing the noise is usually a straight forward matter, but diagnosing the source of the sound is the tricky and time consuming bit, so here are our tips on where to start, but always know that when it comes to creaks & squeaks, it is a matter of trial-and-error and there are no guarantees.

Things to know:
1. The noise on your bicycle might be generated in one place but the sound escapes from another part of the frame often resulting in a misdiagnosis. For example your rear hub bearings might be worn and creating a rough sound, but the noise is escaping at the BB often resulting in the BB or crank taking the blame.
2. Some noises are normal on a Mountain Bike. If the bike is old and is making noises, don’t spend unnecessary money trying to fix all the sounds, unless it is unbearable or obviously catastrophic.
3. Using the correct bicycle specific tools, torques and greases/lubes are important and critical to resolving noises! 4 types of grease are common in any bike mechanic’s workshop. And remember, always clean and dry an area before you lube it. Chain Lube – obviously. Meant for the chain! The only other possible application for chain lube is on creaky saddles where he saddle rails and saddle plastic underside are joined. Bearing Grease – thick, water resistant, clear, smooth with a multitude of applications on a bicycle. Anti-Seize Grease – most commonly copper paste is used where there are threads or where surfaces join. Penetrating Multi-Purpose Spray – WD40 is good off the shelf stuff (much better than crappy Q20), and is useful for cleaning and lubing, especially old bikes, seized bolts, stuck parts, quick-release levers, and sticky cables. We use mainly the Wurth lube and cleaning products in our workshop.

Diagnosing the cause or area of the noise… the COMPREHENSIVE guide!

Step 1: Let’s get the easy stuff out the way. Is it your Saddle or Seatpost?  The Sound: Creak from somewhere under your bum. The Source: Creaking emanating from the contact between the seatpost and the frame, from the contact between the saddle rails and the seat post, or from the contact between the saddle rails and the saddle top. The Diagnosis: Typically the sound happens repetitively when pedalling with your bum in the saddle. Get out of the saddle and if the noise disappears, it is most likely the saddle/seatpost. The Remedy: Take the seatpost out of the frame, clean the inside of the frame seat tube and the outside of the seatpost. Grease the seatpost with an Anti-Seize grease like copper slip, or if the frame or seatpost is carbon, use a Carbon fibre anti-slip  grease. Take the saddle off the seatpost, thoroughly clean both area’s and again grease both the seatpost and the rails with a light layer of Anti-Seize grease. Finally, spray some penetrating lube (e.g. Wurth WS5 or WD40) into the area where the saddle rails and saddle plastic underside are joined. Additional Notes: If the sound is more of a click, that a creak, or if you can make the creak sound occur by flexing the saddle in your hands (even after attempting the above), it is probably time to buy a new saddle.

Step 2: Noisy brakes, even when it is in dry conditions. Lift your front and rear wheel of the ground, spin the wheels and make sure that the Brakes are not rubbing the discs/rims. The Sound: Squeal… sounds like a pig being branded. The Source: The brake pads or brake disc/rim. The Diagnosis: This one is simple… squealing noise under normal braking. The Remedy: This is less simple, and is a matter of trial-and-error. First of all remove the pads.  If they come out oily, replace them. If they are a bit shiny, give them a light sand with some low grit sandpaper until any shiny parts are removed leaving a dull finish. If the pads are worn out, or worn unevenly, replace them. The pad compound and quality also makes a difference. Metallic pads are noisier but wear longer – good for winter.  Resin Pads bight harder and are less noisy but wear out quicker – better for summer. And Semi-Metallic or Multi-Compound pads are usually the best of both worlds suitable for all riding conditions. They are usually our favourites and the brands include the cheaper pad from Quaxar, mid level pad from Ashima and the expensive pad from Swisstop. Next up, if the rotor is discoloured, burnt or warped, replace it. If you want to try save it, give the rotor a light sand, a good clean with a solvent like Alcohol or a Disc Brake Cleaner, and try patiently bend it straight with a shifting spanner. If this does not work, buy new rotors, with plain rotors costing about R200 each, and the best on the market Shimano Ice-Tec rotors costing around R600. Heat build up between the pads and disc can cause brake fade, brake failure and brake noise. This is best resolved by changing both the rotors and pads to Shimano Ice-Tec rotors and Resin Pads or Multi-Compound pads. Finally, also make sure that the brake callipers are very clean, and the pistons are lubed before reinserting the brake pads. If you want to, use a very small amount of copper grease between the brake calliper piston and the back plate of the brake pad. The risk is that some of that copper grease gets onto the brake pad surface. Additional Notes: Vibration from braking is different to squealing. It is usually caused by incorrect brake set-up or contaminated pads and rotors. Use the methods above to try fix this. On the very rare occasion  it is a symptom of the particular bicycle frame and brake combination (the frequencies at which the brake resonates and the bicycle frame resonates interfere compounding the vibration effect), and the only way to resolve this is to buy completely new brakes, preferably a different brand.

Step 3: Hold your handlebar, lift your front wheel off the ground, and turn left and right… if it is not perfectly smooth, it means that you need new headset bearings, even if there is no sound. The Sound: Creak, Rattle or Grinding from the front-end of bike. The Source: Cables and housings,  Headset bearings (top & bottom), The Diagnosis: If there is a rattle, check that your cable housing is isn’t bouncing into each other or the frame, causing the rattle. And check that your headset is tight enough. A creak or some grinding could be the headset bearings or front wheel bearings. Roughness when turning the handlebar means headset; spinning the front wheel and feeling vibrations through the fork means front hub bearings. The Remedy: Shorten or redirect cables and housings so that they don’t touch & rattle, and clean & lube (with a penetrating spray) where the cables & housings make contact with the frame. Open up the headset, clean & lube (with a bearing grease) the whole headset area. Make sure the bearings are not rough otherwise replace them. And finally repack your headset so that all the internals are in the perfect order and are correctly tightened. Finally, a front hub service to be performed by a professionally mechanic is needed when roughness & vibrations are felt through the fork when spinning the front wheel. Additional Notes:The sounds could also be coming from the bicycles fork itself. Check for cracks in carbon forks, or for wear, dryness & dirt on suspension forks.

To be continued:

BB Noises

Crank Noises

Other Drivetrain Noises

Pedal Noises

Rear Hub Noises – the hub or the freewheelbody