In days of yore cyclists who wore Lycra shorts were viewed with deep suspicion. In these more enlightened days Lycra is de rigeur on bicycles (and in gyms) - but togging up for a bike ride is much more than just donning your tightest spandex shorts.
First of all, cycling shorts. When the weather is warm these are what you need. They are available in varying qualities (commonly described according to the number of panels of material from which they are constructed - 8-panel shorts tend to fit better than 6-panel and cost more). Proper cycling shorts will have a padded seat, originally made of chamois but these days usually a bacteria-retardant synthetic material. They also commonly have textured elastic around the bottoms of the legs, of a type which will feel familiar to any woman who has worn self-supporting stockings. This keeps the legs in place but tends to make the waist creep downwards (but see 'bib shorts' below). Cycling shorts are usually black, although some people do wear replica team colours as seen on the bottoms of Tour de France riders.
Why use shorts which come almost to the knee? They keep the thigh muscles warm, helping to prevent cramp.
On cooler days you need a bit more warmth, and long cycling trousers are available; they tend to be tight all the way down, especially around the ankle to keep out of the way of the chainset, hence they generally have zipped cuffs at the bottom. You might wear 'longs' over padded shorts, and it's common to take the long trousers off and stuff them in your saddlebag when you get warmed up.
Better than ordinary shorts (and trousers) are the bib variety. These have built-in shoulder straps so they don't slip down while you are riding. Since a cold lumbar spine is the curse of all cyclists this is a benefit not lightly to be passed over.
Mountain bike (ATB) riders will sometimes wear expedition-style shorts with pockets everywhere, while tourists may wear longish versions of the classic Fred Perry type short, with a reinforced seat. But in the end padded Lycra shorts are the most common coverings for a cyclist's nether regions. As with all Lycra the question of taste is not always fully addressed by the wearer, although in the case of cyclists it is more likely that offending legs will be spindly rather than fat.
Some female cyclists prefer skirts. These can come in two varieties: the short (sometimes excessively so) and the modest. In order to wear modest skirts the cycle should be equipped with the traditional fully enclosed chainguard, and an arrangement to prevent the skirt from catching in the rear wheel (which usually involves a series of cords running between the drop-outs and the mudguard, or something similar). This Researcher has seen one young lady wearing a very short, very tight skirt. Quite aside from the questionable advisability of presenting your underwear to the world's vulgar gaze in this way, it did seem that this arrangement made pedalling unnecessarily difficult - although the Researcher freely admits to having no first-hand knowledge of such problems.
Cycling jerseys are long, covering your bottom when standing upright, so even when they ride up they keep your back covered. They usually have pockets at the bottom at the back; three pockets across is typical. These are often the only usable pockets a cyclist has - things fall out of any others - so may be stuffed with waterproofs, puncture kit, spare inner tube, bananas, energy bars, maps, tools and a quite improbable array of other cycling impedimenta.
Jerseys come in many colours. In racing these denote team membership and - most importantly - position on the leader board; in the racing fraternity only the leader gets to wear a solid yellow jersey. On the road, of course, anyone can - which is just as well given the myopia of some drivers.
In warm weather cyclists will wear a short-sleeved jersey, maybe with a vest underneath on cool mornings. As the weather chills the sleeves get longer and the material changes from breathable fabrics to knitted acrylic or wool.
All cycling jerseys share one attribute: they are tight. Cyclists tend to have massive legs and skinny bodies and arms - and for some reason they seem intent on showing this to the world by wearing tight clothing on their upper bodies.
Gone are the days when cyclists all wore black leather shoes with toes reinforced against the wear inflicted by toe-clips. Now road cyclists will most often wear special shoes with cleats on the bottoms, which clip into the pedals and greatly increase pedalling efficiency. ATB riders will tend to wear specialised (or Specialised, a maker of cycle equipment) trainers. Tourists may wear road-bike shoes or perhaps a hybrid shoe in which walking is still possible but which still cleats into the pedal.
The two most common form of clipless pedal are the Shimano SPD (or 'Spud') pattern and the Look pattern. Look are slightly better for touring, but the cleats make walking in the shoes nearly impossible. Spuds are less intrusive but more inclined to give ankle and knee problems on long tours (note: this is a personal view; many people swear by Spuds, and others always use toe clips because it's easier to get your foot out of clips rather than cleats in traffic).
Bike shoes often have a hole or two in the sole. This is because waterproof trousers divert every drop of water straight into your shoes. The holes let some of the water drain out, leaving just enough to make horrible squidging sounds as you pedal.
Here's what to do if you want to stay dry while riding a bike in the rain: forget it. What with wind chill, sweat, condensation, and water forced into the seams by 20mph+ riding speeds, you are going to get wet. But that doesn't stop the attempt.
Cycle capes are still popular. They keep the cyclist (including hands) and the bike tolerably dry, stop your saddle from getting soggy (leather saddles are rapidly destroyed by water), and don't impede the movement of the legs. They are also amusing in falling snow, but that's another story.
More common are waterproof jackets, trousers, overshoes and other odds and ends. Here the breathable Gore-Tex fabric is unquestionably the best, otherwise the moisture and sweat generated by cycling efforts render the waterproofing futile. Overshoes mitigate the drainpipe effect discussed above, but waterproof trousers are almost always a waste of time.
Many cyclists will use a thin waterproof jacket to cut down wind-chill on dry days. This tends to result in excessive heating and sweat, so most cycling waterproofs have long double-ended zips, zips under the arms, and vents down the back to help you maintain airflow during the few minutes of the year when it isn't actually raining.
Opinion is divided over the wearing of helmets. Some cyclists believe that wearing a helmet is an intolerable restriction, and argue that the improved safety they provide is irrelevant - that drivers should be more careful. Others, the majority, see helmets as a necessary and wise precaution to protect the head in the event of an accident. Given the poor state of the roads a spill can happen any time.
Helmets must fit and be adjusted properly, so they don't slip about on the head (which would prevent them from working properly). You should also note that helmets are designed to protect by controlled destruction. In other words, if you fall off and hit your head, the helmet will have absorbed some or all of the impact by collapsing. A helmet which has been involved in an accident should be replaced.
Cycle clothing has changed comparatively little over time, give or take a reduction in modesty and the advent of modern materials. You can still see Victorian cycling dress at veteran cycle runs where riders of Ordinaries1, hobby-horses and other ancient machinery display their prized mounts.
Flat-soled leather shoes, as mentioned above, calf-length moleskin trousers, caps and occasionally bowler hats (an intriguing forerunner of the cycle helmet) may look old-fashioned, but look closer and you see the familiar themes: legs either short or tight to keep out of the way of pedals, jackets and jerseys long to keep the back warm, and a preponderance of black to hide the inevitable oilstains.
Motorists are generally incapable of seeing anything less substantial than a white van, so many cyclists will festoon themselves with a variety of high-visibility accoutrements such as the iniquitous reflective Sam Browne belt, and numerous flashing LEDs (lights fixed to a bike must be steady, white in front and red at the rear, but you can light your person up like a Christmas tree).