What's the reason for wearing biking clothes made of Spandex (Lycra)? They sure look pretty strange.
I thought spandex shorts looked weird too, until my wife bought me a pair with the padding. Now, I can't ride in regular shorts at all!
The shorts with padding help protect your sensitive groin parts, as well help keep you cooler and drier (preventing nasty sores) by wicking the moisture (sweat) away from your body. There's no binding or rubbing in the wrong areas, and all your jiggly parts are held securely in place.
And a big, important point about bike shorts - you wear them without underwear.
Jerseys also come in tight and loose fitting material - I personally prefer the loose-fitting jerseys (I'm not exactly skinny enough to wear the tight jerseys). Other than the moisture-wicking they provide, they also come in extremely visible colors, which is nice when you're out riding by yourself, especially if visibility is low.
There are a few good reasons for it.
- More aerodynamic, we humans don't put out much power so every little bit helps
- Padded shorts. You want these for anything longer than a short ride. Most shorts with pads happen to be spandex.
- Moisture wicking
- Read some things a few years ago about muscle fatigue when jiggling (rough road/mountain biking) is greater than if you can compress the muscles a bit so they don't move as much
Depends on whether you want respect at the LBS or every other place you go into. I'm cut-offs, T-shirts, and tennies. I like going past the dudes that spent more on their clothes than I spent on my bike. Sure, I look like a construction worker that's lost his driver's license but I don't wear 420/tie-dyed either. Misdirection and a contrarian streak. As soon as someone says 'you gotta...' I'm gone, and it is cheaper. Clothes might make THE man but they don't make a man. Go to a ski resort and look at the people coming off of the ends of the 'bunny runs', they've got all the fancy stuff. "Just do it."
Because sweaty, crumpled cotton a) chafes and b) is pretty unhygienic. Lycra ("spandex") doesn't bunch up, shifts sweat more effectively and (if padded) takes a bit of the road buzz away. I'm so used to wearing it the idea of looking strange doesn't even cross my mind.
Whatever you wear, make sure you wash it often.
The first few years of bike commuting, I was all about cotton shorts and shirts. I thought lycra looked stupid, and was a waste of money. Then I tried some lycra shorts. What a difference. My stuff didn't get chafed or squished on the 15km ride to work. I kept cooler and drier. Totally worth it. I always wear lycra bike shorts now (the padding and hold-stuff-in-place ability are essential for comfort).
For those who aren't thrilled at dropping a bunch of money on expensive lycra shorts that look weird and make you uncomfortable, there is an alternative! You can buy liners that do all that same amazing stuff (moistore wicking, bottom-padding, gonad-compressing) at a fraction of the price. For example these: Men's Cycling Liners I'm sure there are other alternatives, from other sources. These will let you keep your baggies and have 90% of the benefits of $100 lycra shorts :)