What you can fix with what you can carry (commuting)

This seminar is designed for cyclists who want to learn the basics of on-the-road maintenance, especially as commuters. We presume no prior experience with repairing bicycles and we focus on fundamental concepts that apply to all bicycles, including road bikes, touring bikes, and mountain bikes.


The picture below labels all the main parts of a bicycle. First thing first: we need a vocabulary for talking about bicycles. We’ll be using several of these terms in our seminar.

Al2 [CC BY 3.0 (]

Parts of the bicycle

  • Wheels and Tyres
    • Wheels are made up of hubs, spokes, and rims. The tyre is technically a separate part, but sometimes when we talk about a wheel we mean the tyre too. Keep your tyres inflated!
    • Hubs
      • The hubs are the part that spins. They have bearings, which help the hub spin smoothly. If the bearings are too tight, you might feel a grind when the wheel spins. If the bearings are too loose, you might feel a wobble in the wheel.
    • Spokes
      • The spokes hold the rim to the hub. They are under a lot of tension to make the wheel strong. When a spoke loses tension, the rim will move away from the spoke and you’ll see a wobble in the wheel. This might happen if you hit a kerb, for example.
    • Rims
      • The rim spins around the hub, and the tyre attaches to it. We want the rim to be a perfect circle, and we adjust the spokes to make this happen.
      • On some bikes, the rim is where the brakes make contact with the wheel. It’s important that this part of the wheel be clean and free of grease and oils.
  • Cranks and stuff
    • Often when we talk about the pedals, we mean the whole mechanism that spins around at the bottom of the bike. But really:
      • the pedals are attached to the cranks
      • the cranks are attached to the bottom bracket.
      • If you feel grinding when you pedal the bike, this might mean there’s a problem with the bottom bracket, where there are bearings, just like in the hubs.
  • Brakes and stuff
    • Brakes work by friction. All brakes, disc or otherwise, have a brake pad that rubs against some part of the wheel to slow it down. Rim brakes rub against the rim; disc brakes rub against a rotor.
    • The brake lever tightens the brake pad against the rim or rotor. It’s important that:
      • you don’t have to pull the lever too far to get the pads to contact the brake surface
      • the brake surface doesn’t rub against the brake pads.
  • Shifters and stuff
    • When you shift, you move the chain from one size gear to another. When you tighten the shifter, you make it easier to pedal; when you loosen the shifter, you make it harder to pedal — but you can go heaps faster!
    • If your bike doesn’t shift right, it all comes down to something being too tight or too loose.
  • Tubes
    • Head tube: the one the handlebars come out of.
    • Top tube: the one that goes from the handlebars to the seat.
    • Down tube: goes from the head tube to the cranks.
    • Seat tube: has the seat sticking out of it.
    • Bottom bracket: where the down tube and seat tube meet; the cranks go through here.
    • Seat stays: go from the top of the seat tube toward the rear wheel.
    • Chain stays: go from the bottom bracket toward the rear wheel.



What you can carry:

  • multi-tool
  • chain tool
  • spare tube
  • tyre levers
  • spoke wrench
  • spare spoke
  • Chains
    • Note: “ratio” refers to the number of teeth on a chainring divided by the number of teeth on a cog. Higher ratios let you go faster — big gear in front, small gear in back; lower ratios make it easier to pedal — small gear in front, big gear in back.
    • If your chain comes off:
      • the rear wheel:
        • Inspect the derailleur. Is it bent? If so, then usually it will be bent toward the wheel and you’ll have thrown your chain toward the spokes. Bend it back by hand for now, then have a shop realign the derailleur correctly.
        • If the derailleur is not bent, then your limit screws might be mis-adjusted. For now, try not to use the the largest gear on the cassette (the lowest ratio). Or, you can tighten the L limit screw a quarter turn.
        • In any case, service the rear derailleur soon!
      • the chainrings:
        • This is usually a problem with limiters. If the chain has come off the inside, then tighten the L limit screw. If the chain has come off the outside, then tighten the H limit screw.
    • Chain suck:
      • If you shift from a lower to a higher gear on the front derailleur, the chain can sometimes get tangled on itself. This happens when the teeth on the gear you started in are worn. When they are worn, the chain will not “derail” correctly and get wrapped up on itself. The solution is to replace the worn chainring. However, if this starts happening on your ride, don’t panic:
        • Stop pedalling.
        • Shift back to the lower gear.
        • Pedal slightly backwards, as necessary to untangle the chain.
        • Pedal forwards.
        • Try again.
    • If a link breaks, you will need a chain tool to replace the link, or shorten the chain temporarily. Shortening the chain will affect shifting, but you might not even notice.
    • If a quick link breaks and you cannot find the parts, then remove links as necessary and rejoin the shortened chain with a chain tool.
    • If a quick link breaks and you have the pieces, then reattach the quick link.
      • If the link is a KMC-style, then simply reassemble and crank until it clicks into place.
  • Tyres
    • A few notes to start:
      • Keep your tyres inflated to at least the minimum pressure indicated on the sidewall. This will improve your efficiency, and will prolong the life of the tyres — especially the sidewalls.
      • Inspect your tyres regularly for cracks in the sidewalls. When cracks develop, replace the tyre; tubes can blow out through breaches in the sidewall.
      • Do not rotate your tyres. Always use the best of your tyres on the front.
    • Punctures when you have tubes:
      • Your tyre went flat for a reason: you need to determine the reason and fix it before repairing or replacing the tyre or tube.
      • Remove the tyre from the rim. Note the orientation of the label on the tyre with the valve stem. Ideally, when your tyre was installed, the label and valve stem will have been lined up. If you find debris in the tyre, this will help you find the hole in your tube.
      • Feel around inside the tyre for sharp objects, such as thorns or nails. Using a small piece of cotton, if available, helps. Drag it, or something like it, along the inner surface of the tyre and it will snag on any road hazards.
        • If you find a pointy thing, pull it out.
          • Find the corresponding point on tube.
          • Inflate the tube slightly and listen for air coming out.
          • Patch the hole.
        • If you don’t find a pointy thing, then
          • Inflate the tube slightly and listen for air.
          • Inspect the area where air is coming out. If it is two small cuts, which we call “snakebites”, then you likely hit a kerb. This is a pinch flat. Repair as possible, and inspect the rim for damage. Also inspect for loose spokes.
          • If there is a slice in the tube, then it may have been installed improperly. Discard and replace.
    • Tubeless punctures:
      • If the puncture hasn’t sealed itself, then use a tubeless puncture repair kit to fix the tyre. Reinflate as necessary.
      • If you don’t have a puncture repair kit, then install a tube.
      • If the bead has broken off the rim, it can be tricky to reseat the tyre. Use a cartridge, or pump extremely fast, or give up and install a tube.
  • Broken spokes
    • If you break a spoke and have no spare spokes:
      • Wrap the broken spoke around an adjacent spoke so that it doesn’t interfere with the rest of the wheel or brakes or stays.
      • The wheel will have lost tension on that side, so tighten each adjacent spoke on either side of the broken spoke on the same side of the wheel. On a bicycle with rim brakes, use the brake pads as a guide.
    • If you have a spare spoke:
      • If the broken spoke is on the drive side of the rear wheel, you might struggle to get the new spoke into the hole. Be careful not to bend the new spoke.
      • Remove tyre and rim tape and remove the broken spoke.
      • Replace the broken spoke and lace following the pattern.
      • True the wheel by tightening the nipple appropriately. On a bicycle with rim brakes, use the brake pads as a guide.


What you can carry:
• multi-tool
• adjustable wrench

  • Derailleur
    • If your gears are not switching correctly, adjust cable tension at the barrel adjuster:
      • If you are having trouble switching into a lower gear, then add tension by loosening the barrel adjuster.
      • If you are having trouble switching into a higher gear, then release tension by tightening the barrel adjuster.
  • Brakes
    • If you have hydraulic brakes, there’s nothing you can do.
    • If you have cable pull disc brakes, then check the connection at the brake housing. Is it dirty? Is something preventing the cable from moving the arm? Tidy things up as appropriate.
    • If you have rim brakes, then:
      • check for dirt or debris preventing the cable from moving freely
      • check the lever itself
      • check that the brake mechanism is not damaged; this will vary with the kind of brakes you have – cantilever, V-brake, or caliper brake.
  • Bent rotor / brakes rubbing / brakes squealing
    • If your brakes are squealing, then clean the rotor. In extreme cases, clean the pads.
    • If your brakes are rubbing, then check whether the rotor is bent by watching it spin in the brake caliper; use one side of the caliper as a guide.
      • If your rotor is bent, note where the bend is and use an adjustable wrench to bend it back. This might take more force than you expect.
    • To re-align the brake caliper:
      • loosen the mounting bolts so that the brake caliper floats freely
      • squeeze the corresponding brake lever
      • while continuing to squeeze, retorque the mounting bolts


What you can carry: D-Lock

The OnGuard Bull-Dog Mini


Cable locks can be defeated by clipping them with simple cutters, as available at any hardware shop. The cable thickness is irrelevant. A 2mm cable is essentially equally as effective as a 8mm cable, as the same swift motion with the same sharp tool cuts right through either in a blink.

The D-Lock, as with any lock, can be defeated, but it requires either significant leverage or an angle grinder. Neither of these are in the toolkit of the opportunistic bicycle thief.

To reduce the risk of a leverage attack, use the smallest D-Lock that will fit around your rear wheel and an ordinary size bicycle rack.

Note: you do not have to lock your frame to a bicycle rack. Lock the rear wheel inside the rear triangle and the wheel cannot be removed — without destroying it that is. This is known as the Sheldon Brown method.

Note also: you can use a thin cable to secure other parts, such as the saddle or the front wheel. And note that the cable needn’t be thick, since, again, the same tool cuts the thinnest and the thickest cables.

Do not lock to objects that can be cut easily, as a thief can simply cut what you’ve locked to and then take your bike. Example: if you lock the top tube to an aluminium hand rail, a thief can cut the rail and ride off on the bike then grind the lock off later. On the other hand, of your D-Lock is around the rear wheel, as in the Sheldon Brown method, the bike still cannot roll — even if it is disconnected from the object it is locked to.

This concludes “What you can fix with what you can carry (commuting)”. Please feel free to ask questions about your particular bike or about anything else relevant to the topic.

Our goal is to keep you rolling!