The few things you should know
-The faster you pedal, the less quickly your legs will tire.
-You are more stable moving forward, pedaling, than you are moving forward, without pedaling.
-Bicycling is an all-body sport.

Why those things are important
The bicycling leg is your best chance to refuel. It’s also where you will spend the bulk of your time on race day, and where you will spend the bulk of your time training. It’s where you stand the most chance of improving your time, so you do *not* want to do like I did this season and willy-nilly skip bicycle workouts all over the place and then pay no attention to things like heart rate and cadence when you do finally get to your bike workout.
Although the advantages of training by heart rate are well documented, some folks still overlook the importance of cadence. It’s really important to keep your cadence somewhere between 80 and 90 rotations a minute. It’ll mean easier pedaling, and you’ll get stronger, faster.
You’ll be able to sustain a longer ride if you can keep your legs from tiring, and cadence is the key to that. Remember, you still have a run to do after your ride, so ride smart, maintaining a good speed, and let it carry you up hills where you can.
Learn to ride smart on the downhills. Know which speeds you can maintain without feeling unstable; a crash at a high speed wouldn’t be much fun at all.
Be sure to spend a fair amount of time on your bike, practicing things like eating and drinking. You won’t be able to stop every time you want to take a drink or eat something, so learn how to do that on the fly, and get comfortable doing it.
You are going to experience a few uncomfortable things your first couple of weeks on your bike. First, there’s a little spot between the shoulder blades that’s bound to cramp from holding yourself up (c.f. “all-body sport” above). And, your butt will hurt. Don’t worry; these things will go away with time, but there are things you can do to immediately alleviate some of the pain.

Things to buy
Triathlon is an expensive sort, and while there are things you don’t need to spend money on, I do think that buying a good pair of cycling shoes and pedals is one of the best things I’ve ever done in my cycling career. A proper cycling stroke means that you use the muscles in your legs on the upstroke as well as the downstroke (think of the motion you make with your foot when scraping a piece of gum off the sole of your shoe). Being clipped in to your pedals means you can use that stroke without worrying that you’ll lose contact with your pedal. If you’re worried about getting your money’s worth, don’t: I’ve had the pair I’m using in this weekend’s triathlon for 13 years, and they’re my only pair of road riding shoes.

Beat up, ratty shoes. These are SIDI Genius 2s. For reference, SIDI is now making Genius 6s.

Cleats are the key to staying attached to your bike, and uber-efficient

Buy a couple pairs of cycling shorts. These are padded in all the right places, for all the important reasons.

I’d also invest in a Bento Box for your top tube. It velcroes right to your bike frame and allows you to access things like…food. It’s likely the best $14 you’ll ever spend.

Get a computer that will measure your cadence and speed for you. Some of the fancier models will connect wirelessly to a heart rate monitor so you can keep track of everyone right on your bike, but…I’m not that cool.

Also, spend the money and get some Body Glide. It’s an allatonin-based product that will keep your clothes rubbing from rubbing against your skin, and prevent chafing. Put it on your butt, and anywhere your skin meets fabric. Do it. It’ll help.
Finally, *do* get a road bike, even an inexpensive one. There’s nothing quite like flying over the course on one of these sleek, silent machines. I’ve hit a top speed of 38 miles an hour on my road bike, and although that’s not nearly as fast as the pros on a good downhill, it is really an unbeatable, unmatchable feeling.
More important, though, you’ll be on a machine that’s engineered to go long distance over an asphalt surface. If you ride a triathlon course on a mountain or a hybrid bike, you run the risk of wasting a lot of energy for no good reason.
Right, that’s it for now. Tomorrow, the run course.

Swim
Legend goes that triathlon organizers built triathlon to be in the order it is now because the swim is the area that’s the most dangerous. You don’t want tired, zoned-out people flailing around in deep water. It’s bad juju, and bad liability, to boot. So they put the swim first, which means you get on your bike cold and wet. Well, that can’t be helped, and you dry off pretty fast, anyway.
The swim leg is most difficult for many people. Many triathlon organizers, if they make use of cut-offs (times requiring you to be done with specific legs, or the race itself, at a given time) give you the most time to do the swim, proportionately. For instance, I’ll probably finish the swim time in about an hour and a half, if I’m lucky and do everything right. The pros will finish in under an hour. But the swim cutoff time is still a whopping 2 hours and 20 minutes.

(This is what a swim start looks like. Messy, splashy, and fun. Also, confusing.)

Some things to learn
There’s actually not too much to say about the swim; really, it’s just something you have to get through.
More and more sprint race directors have cut the swim to 400 meters, or about a quarter of a mile, a distance that even only a fairly decent swimmer can get through in 10 minutes. I know people who have done that distance entirely on their backs, or using the breast stroke. Heck, I know folks who have done 800 meters in a sprint race on their backs. The point is, learn to do the crawl. It’s much more efficient, and you’ll be able to see.
Another skill you’ll need to learn is sighting. It’s the art of looking up every once in awhile to see where you’re going. In a pool, you’ve got the lap lines and the pool wall to guide you. In a murky lake, no such luck. You only need to sight every six or so strokes, but make sure you learn to do it. Getting lost in the swim portion of a triathlon is fodder for a lot of bad jokes at your expense.
Learn, as well, to breathe bilaterally. The theory is that it will help to keep you going in a straight line if you’re not just breathing to one side all the time, but I’ve found that it also keeps my neck muscles loose in a long swim. At the very least, it’s something else to focus on, which helps me to get through the time better.

Some things to expect
When you do get to your first triathlon, be sure to spend some time in the water before the race starts. A lot of people freeze up when they get into the open water. I’m not saying that this is going to happen to *you*, but you might as well prevent it if you can.
Then there’s the actual start of the race.
It feels like this:
Clif Bar on YouTube
No, I’m not kidding. Just be ready for it. There’s a lot of people, all vying for their spot to swim in, and you need to expect that you might be kicked.
You might experience some vertigo coming out of the water. This is normal. Once you get out of the water, start unzipping your wetsuit and struggling out of it. I’ve seen racers apply Body Glide to their lower arms and legs, both under the wetsuit and on the outer of the wetsuit itself, so it’ll slide against itself better and be easier to remove. Do practice taking your wetsuit off a couple of times, at least, in a hurry. You don’t want to be struggling in the transition area and losing valuable time. Don’t forget to pull off your goggles and swim cap.

That’s about it for the swim. Tomorrow, the bike leg.