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Posted April 14, 2012 by Adam in mountain bike maintenance
 
 

Mountain Bike Repair – The 6 Most Common Problems Fixed


There are lots of annoying little things that can go wrong, resulting in the need for bike repair. Here are the fixes you need for the 6 most common bike ‘annoyances’.

Of course not everyone has the same components and setup as the fixes described here, however they can still be applied to your equipment and bike setup.

Each of the 6 problems is first described by its most characteristic symptom. The solutions are then presented in order of severity. So, try the bike repair tips at the top first and then work your way down the list until the problem is fixed. If symptoms persist consult your doctor… I mean… bike shop.

01 :: A Flat Tyre

Symptom – You have no control of steering, braking or balance. There will also be a lot of noise from one or both of the tyres.

Cause – There is very little or no air in the tyre. Due to some sort of puncture or pinch flat.

Solution – When you replace the punctured tube…

    1. Use a higher pressure than before. You have to try and balance the control achieved with lower pressure and the puncture resistance of higher pressure.
  • Cut a slit all the way around the inside of your old tube. Put this around the new tube before you install it and you will have twice the rubber protecting it.

 

  • Buy better quality tubes or latex tubes. This will cost more but they don’t puncture as easily. Another alternative is to try Stan’s No Tubes (do a Google search)

 

02 :: A Strange ‘Clicking’ Noise

Symptom – Whenever you pedal, or maybe every 2nd pedal stroke, a loud ‘click’ or ‘crack’ come from… well somewhere. It’s annoying when you are going up a hill and seems to disappear when you show your local bike repair mechanic.

Cause – Loose crank, pedal, pedal spindle, chainring bolt, bottom bracket cup or bottom bracket bearing.

Solution – Start by tightening the cranks. This is the most expensive option to ignore but the easiest to fix. If the noise is still there, then…

    1. Tighten the chainring bolts.
  • Tighten the pedal in the crank arm.

 

  • Remove, lube and tighten the left-hand bottom bracket cup.

 

  • Remove, lube and tighten the right-hand bottom bracket cup.

 

  • Disassemble, grease and rebuild the pedals.

 

  • Replace the bottom bracket.

 

  • Replace the cranks.

 

03 :: A Stranger ‘Creaking’ Noise

Symptom – When you shift your weight, or when you are pedaling hard going uphill in the saddle, you can hear a weird metallic creak. You don’t know where it is coming from and it’s not in time with pedaling

Cause – Often a misdiagnosed bike repair problem, the ‘creaking’ noise is caused by dry or dirty seatpost bolts, rails, seatpost insertion point or seat collar.

Solution – Lube, grease, and tighten everything under you bum…

    1. Remove the seatpost from the frame. Clean the seatpost and the inside of the frame. Grease and reinstall.
  • WD40 the points where the seatrails contact the post clamp.
  • WD40 and tighten the seatpost clamp bolts.

 

  • WD40 and tighten then seatpost collar, and bolt/quick release.

 

  • Check thoroughly for cracks in the frame near the seat tube.

 

04 :: The Steering ‘Knocks’

Symptom – Going along a quick corrugated fireroad, or through bumpy singletrack, a ‘knocking’ sound comes from somewhere up front. You may also experience a single loud ‘knock’ when you hit the brakes.

Cause – Loose headset adjustment, damaged bearings or ball race, deformed bearing cup.

Solution – More than likely you need to tighten the headset. The most common design requires you to undo the stem bolts, and lightly tighten the top cap bolt. For this bike repair, rock the bike with the front brake on, and keep tightening until the knock goes away. Check that steering is not rough. (This is not a bolt, it is an adjuster. It should never go as tight as a bolt). If this doesn’t work then…

    1. Remove the headset and inspect bearings for damage. Also inspect the ball race surface for pitting, scoring and tears. Replace, grease and reinstall.
  • Look at the shape of the disassembled cup. It should be round, not oval in a front – back fashion. Replace headset cups if not round.

 

  • Check the fit of the cups in the frame, there should be no movement at all. Replace headset if cups not solid in frame.

 

05 :: The Steering is Just ‘Wrong’

Symptom – There is a strange feeling in the steering. Slow, unreliable and unnerving when trying to turn otherwise smooth corners

Cause – Loose crown fork, brake arch or wheel axle. Loose hub bearings.

Solution – Tighten everything. Start with…

    1. Fork crown bolts.
  • Fork brake arch bolts (if fitted).
  • Axle quick release or nuts.

 

  • Grease and adjust hub bearings.

 

  • Check 1 piece brake arches for cracks.

 

06 :: A Rubbing Disc

Symptom – Annoying rubbing sounds from the rotor whilst riding.

Cause – Incorrect caliper mounting, warped or bent disc, sticky piston, dodgy master cylinder.

Solution – Start with checking the caliper mounting…

    1. Loosen the mounting bolts, apply the brakes at the lever, and re tighten whilst still gripping the lever hard.
  • Check that the rotor is true. Get rid of it and replace it if not.
  • (For cable brakes) Adjust pad depth to give reasonable clearance to rotor.

 

  • (For hydraulic brakes) Check that both pistons retract when the lever is released. Remove the wheel and pads and press the pistons into the cylinder bore with a 10mm ring spanner. Reinstall everything, apply the brakes and see if it is still rubbing.

 

  • (For hydraulic brakes) Master cylinder repairs are not for the home mechanic, visit your local bike repair shop if none of the above have worked.

 

I hope some of these bike repair tips will be helpful to you.


Adam