More advanced maintenance

This page provides links to videos that show you the more advanced bicycle maintenance tasks.  You may need special tools to do the job and/or there is scope to really screw things up if you get it wrong!  Remember, if you are not sure about what you are doing, get your bike checked by a local bike shop.

Current areas covered are:

  1. Adjusting a threadless headset
  2. Fixing a creaking bottom bracket or cranks
  3. Replace a threaded Shimano bottom bracket
  4. Bleeding Shimano Hydraulic Road Disc Brakes
  5. Changing the rear cassette

Adjusting a threadless headset


Headset – courtesy of Sheldon Brown

Unless you have a vintage bike, you almost certainly have a threadless headset, and a good thing too!  They rarely need adjustment, but they might if you take the forks out or need to grease the headset bearings.

Sometimes, the headset can feel loose or the front of the bike starts to ‘knock’ – check the headset for excessive play by stopping, holding the front brake on and rocking the bike back and forth.  If the headset is loose you will feel and hear a knock – you might even see the play where the forks leave the headtube.  Adjust the headset but, if the problem persists, you may have to replace the headset bearings. Cheaper bikes (and some more expensive ones) can have cheap bearings that last only a year or two, so replace them with better quality items.

Adjustment is easy, but do take care not to over or under tighten the Allen bolts – this job needs care to avoid putting too much pressure on the bearings, or to make the steering too loose, leading to an unstable ride.  Anyway, here is a helpful explanation:

How to adjust your threadless headset, by Road CC.    [TOP]

Fixing a creaking bottom bracket or cranks

Ah, the dreaded creaks…  Does your carbon fibre miracle bike make more noise than your Grandma’s dodgy knees?  First, make sure the creaking is coming from the bottom bracket or cranks – it is quite common for the noise to come from somewhere else e.g. an over-tightened wheel or a loose saddle.  Also, press-fit bottom brackets are considered more prone to this problem.  If you’re sure you know where the problem is, here is how to fix it:

Fixing a creaking bottom bracket or cranks, by GCN.  [TOP]

Replace a threaded Shimano bottom bracket


A threaded Shimano bottom bracket – reliable, easy to maintain, cheap & sensible – why mess with it?

The bottom bracket sits at the junction of the seat and down tubes with the chainstays.  It holds the crankset, allowing the pedals to turn, and resists a considerable amount of force.  If you cycle for five hours a week at an average cadence of 80 rpm, your bottom bracket goes through 1,248,000 rotations per year.

Working out what bottom bracket you have can be a bit of a ‘mare with nine or so different types and standards as manufacturers pursue ‘less weight, more stiffness, and lower manufacturing costs’.  Bikerader have written the complete guide to bottom brackets to help you out, but this section is about Shimano threaded bottom brackets (BBs).

Step one is to remove your chainset or crankset, for which we already have a link on the basic maintenance and safety page.

Step two is to remove and replace the bottom bracket, courtesy of a video from GCN.

Replacement BBs are relatively cheap, with an Ultegra/105 version costing £11 or so.  However, you can pay a lot more for something fancy from Chris King (oooh, silky…) – these will be incredibly long-lasting and lightweight, but not necessarily any better than something a lot cheaper.  There are also claims that ceramic bearings are the ‘ultimate’, but arguably they only make sense at 5,000rpm, if you can pedal that fast.

Press fit bottom brackets are a whole other ball game requiring the careful use of a BB press tool.    [TOP]

Bleeding Shimano Hydraulic Road Disc Brakes


Shimano Hydraulic Road Disc Brake

Hydraulic brakes rely on a fluid to transfer the force the rider applies at the lever to the brake caliper, in turn squeezing the pads onto the disc.  Over time, the fluid will deteriorate and air and moisture may enter the system.  The rider will notice this as increased softness at the lever, reduced braking efficiency or increased brake noise.  Either way, for your safety, you may need to ‘bleed the brakes’ by which is meant that the old fluid should be replaced with fresh fluid.

The task is fairly straightforward, but what is harder is to correctly diagnose what might be wrong if bleeding the brakes does not improve braking performance. Check the hydraulic pipes for damage, the fluid reservoir for any loose screws and the pads for wear.  If in doubt, get a bike mechanic to service the brakes – it’ll be cheaper and safer in the long run.

As long as everything else in the brake system is in good order, bleeding the brakes should bring back performance.  Here’s how:

How to Bleed Your Shimano Hydraulic Road Disc Brakes


Changing the rear cassette


A Shimano 10 speed rear cassette

Why change your cassette?  They wear out over time, perhaps every 12,000 km or so, depending on how dirty they get, leading to poor gear changes and increased wear of the chain and (expensive) crankset.  If you are struggling on the hills you might want to change to a greater range of gears e.g. from a 11T – 25T to a 12T – 30T cassette.  If your riding in a flat TT, you might want to change back!  If you want to get the cassette properly clean it is easier to take it off the wheel – pop it in the dishwasher (no responsibility accepted for the oil stains on your breakfast bowl…).  Some riders keep a spare wheel with the right cassette for the conditions they expect and just swap it into the frame.


Chain whip and various lock nuts – you will also need a large spanner

You will need a lock ring and a chain whip to do this.  Be careful of sudden movement as the lock-ring loosens leading to a painful high-energy collision of knuckles with bladed spokes…  Take care also when buying a replacement cassette to make sure you have the right number of gears for your groupset and the gear ratios that you want.

Those nice chaps at GCN have produced this video to guide you through the process:

How to change your cassette