I like to think of myself as a runner. It's what I do. It makes me happy. When I don't run, I'm a grumpy SOB. Just ask the wife or the boys. (Hell, I've even been called out by the guys I run with) So, I ride my bike instead or lift weights or even walk (shudder). Thankfully, most of the times when I'm not able to run, I can ride. Not always.
Cool things about the bike.
Coasting has got to be at the top of the list of the best things about riding a bike. Nothing better than coasting down a steep hill at 90 mph. (least it feels like it) Or even to stop peddling on the flat, just 'cause your legs need a rest for a little while. Can't do that on the run.
You can cover roughly twice as much distance in the same amount of time as running. So instead of a easy eight mile run, I can get in close to twenty miles. The distance isn't the driving factor, its the variation in scenery. A four mile out in back from the house is pretty boring. Ten miles out into the country is a completely different feeling. Even doing the entire greenway on the bike is ok, the first time out for the season.
Cycling is low impact versus the pounding of running. You name and I've had it at one time or another from running. Great thing about the bike is the ability to ride while suffering a running injury. But, any injury from the bike is usually pretty traumatic. Been there, done that.
Gears, bikes have them, runners have to run harder. Nice to change gears to increase the speed or maintain speed and increase turnover. Think it really complements the running. Though it is just as fun to ride a single speed bike and not have to shift. Plus, the single speed is great to make a quick trip to the store.
Hot, sunny and 110 degrees, no big deal on the bike. Not so much fun to run in those kind of conditions. Great thing about the bike is the air moving past you. Even if it does feel like you're standing in front of a giant hair dryer. The bike gives you the ability to carry a couple of frozen bottles of water, without having to hold on to them. (carrying a water bottle isn't really that big of deal, only limit is volume)
Speed, on the bike is a blast. Running fast is hard work, though sometimes it just feels like your flying. Going fast on the bike isn't as hard as running. The effort is different. Either the gravity of the downhill or tucking in behind someone and drafting at a quicker than normal pace.
Not so cool things about the bike
The gear/clothing/kit, you don't have to wear it, but it makes things easier/better. Worst is probably the shorts, only they aren't like runners shorts, nope these are tights spandex/lycra which show all your glory or lack thereof. But, the chamois in the rear end area make it all worthwhile. Shoes with toe clips are only annoying when you are off the bike trying to walk. Like the stop at the convenience store to get something to drink. The jersey isn't necessary but it does ride in the wind better and has pockets in the back. Gloves keep your sweaty hands from slipping on the bars, or more importantly keep the gravel out of your palm should you hit the ground. Helment, no brainer.
Cold and the bike just don't go together. Props to those who bike year round. Not me. If' it's below 40 degrees, my interest is non-existent. Like this morning, low 40's and a cold north wind. Great weather for a long run, not so much fun on the bike. I did the ride, but a run would have been more enjoyable.
Cars, just as dangerous for a runner, but I feel more vulnerable on the bike. At least when I'm running, it's usually facing the traffic, so I can see the cars coming. On the bike, its the cars that I can't see that worry me. Though I can stack the odds in my favor by running or biking with others, easier to see a bunch of bikes or runners versus just one.