A pre-packed commuter bag makes cycling to work faff-free. Some things you might pack the night before; others can live in the bag semi-permanently. The essentials don't take up much space. A rackpack or large (7+ litres) saddlebag will swallow most of these things with room to spare, while a pannier, backpack or messenger bag will be only part-filled.
We've assumed you'll leave some things at work or fixed to your bike, but you may also need to make space in your commuter bag(s) for: a bike lock; your primary cycle lights; work clothes; toiletries; and a towel (a hand towel is sufficient for showering). Check your commuter essentials periodically, at weekends perhaps, to ensure that what you think is there actually is there.
Spare quick link
Pick up a pair of polythene gloves for free from a garage forecourt or buy some stretchy Nitrile gloves from your bike shop. They'll keep your hands clean if you have to fettle your bike. They can also be worn to help keep your hands a bit warmer if the temperature plummets.
Tools you'll commonly need include 3, 4, 5 and 6mm allen keys, a Phillips head screwdriver, and a chain splitter. But it depends on the fittings your bike has, and also on your mechanical aptitude; there's no point carrying a chain splitter if you don't know what to do with it. Lezyne's V10 covers most bases.
A pair of small LED backup lights, such as the Moon Gem models, will get you home safely if your main lights fail. If they're USB rechargeable, you can charge them at work. Make sure they're stored in your bag in such as way that they won't switch themselves on.
Puncture repair kit
If you puncture while commuting, you'll normally just fit a new innertube. If you run out of tubes, there's no option but to get out the patches, glue and sandpaper. A pen is a useful addition, for marking where the hole is.
Two tyre levers
Get the right size – and valve type. A schrader valve won't fit through a hole in the rim for a presta valve, as it's 2mm wider. To save space in your bag, unbox the tube but then wrap it (for example, using a Buff) to prevent accidental damage. If you puncture relatively often, take two tubes.
A pump can be fixed to most bike frames, but in your bag is better when theft is a possibility. The pump head must be compatible with your bike's valves, and the pump must not be so awkward to use that you can't reach the tyres' minimum pressure rating.
Whether it's a smartphone or a cheap PAYG phone, make sure you've stored numbers for work, home, an ICE number (http://en.wikipedia.org/wiki/In_case_of_emergency), a couple of taxi firms, and your cycle roadside recovery provider, if you have one. And don't forget to keep it charged.
Spare pants and socks
If you don't have a locker at work, carry spare pants and socks in your commuter bag. If you commute in bike gear, you'll forget them at least once otherwise and be forced to spend the rest of the day commando. And if you commute in normal clothes, you then don't have to worry about getting uncomfortably sweaty, being caught in a downpour, etc.
A wet wipe wash (face, arm pits, groin) will spruce you up if there's no shower at work. Travel packs are more compact, but big unscented wipes meant for babies can be decanted a handful a time into a ziplock plastic bag. Or you can carry a flannel in a plastic bag.
Two plastic bags
Mostly they'll be used to separate items in your commuter bag, keeping your lunch away from your laptop. They can also be used as extra protection for you in bad weather. A flattened out plastic bag will help keep the cold off your chest if you put it under a cycling jersey. Or you can use both as shoe liners if it's wet and cold. Remove shoe, put foot in bag, and put your bagged foot in the shoe, taking care not to tear the bag. Tuck in or cut off any excess. Your feet will get damp with sweat but won't get nearly as cold.
Regular cycling isn’t just good for your physical health: it also benefits your mental wellbeing.
When your bike folds to the size of a suitcase, your cycle-to-work strategies will be different. Here are some tips.
Tyres come in a range of sizes and tread patterns. Here's how to choose the right ones for your bike.