"What is the difference? Benefits? Hard to change a flat? Reason being: Renting a pair of Zipp 404's, and they are asking what I want, Tubular or Clincher? How does a tubular attach and what does sew-up refer to? It seems that high end equipment tends to be tubular - what are the benefits?
The tire that most of us are familiar with is the clincher which consists of an inner tube and a tire. I won't go into how that works because I'm pretty sure everyone understands this. The tubular, or sew up, is glued directly to a rim that is specifically for tubular tires. The glue is basically a contact cement. The tube is sewn up inside the tire making it a single piece system. You can get to the tube if necessary but it is time consuming and many simply discard it and replace the whole tubular...costly.
Most manufacturers recommend that you let the glue dry for 24 hours before riding on the newly mounted tire, though the tire can usually be ridden lightly immediately. Note that the wheels and tires for clinchers and tubulars are not interchangeable. Which is better?
It depends on your preference and what's important to you. I'll list some of the beliefs that are out there and comment on a few. Tubulars
Those who prefer tubulars often note that the tires have lower rolling resistance due to a higher inflation limit. They often have a higher tread count and can wear extremely well and ride better than a standard clincher. Some claim it's faster and easier to change a tubular than a clincher and you get fewer flats because you don't get pinch flats. These could all be great reasons for choosing tubulars. I can't disagree with any of these except the changing part.
While a tubular might be easier and faster to mount on a rim, there's a couple small problems. First is that the tough part of changing a tubular is getting it off of the rim. Because tubulars might not flat as often, and you might only use the wheel set with the tubulars for racing, there's a good chance that when you do flat, it'll be during a race.
Ironman AZ was an excellent example of this. I asked one of our sponsored athletes prior to the race if he was fast at changing his tubular on the course. He said he was but didn't want to brag. He also added that he hadn't had a flat on his race wheels in an awful long time. Jinx. Needless to say he flatted on the 3rd loop. When we finally saw him again he had fallen from the top ten to hundreds behind. He was out for 45 minutes trying to get the tire off of the rim. The glue had cured and would not release. His thumbs had dime-sized blisters on them from working on the tire for so long. Many of the pros do ride tubulars so maybe there's something to it.Now for clinchers
Most of the guys who read this have changed a clincher tire. Even if it was on a BMX bike in middle school or Jr. High. Nothing has changed. If you did it then, you can do it now. Local bike shops often offer flat tire clinics to show tips for a fast change. If you are worried about speed, you can practice over and over and get fast unlike with a tubular where the glue is a factor. Why shouldn't this be part of your training? You will flat eventually.
Clinchers have a wider range as far as price and level. You can get a decent clincher for $35. Not so with a tubular. If you spend the same amount of money on a high end clincher as you would a tubular, you should be able to get a comparable tire ($100++) rolling resistance, wear and all. Probably not true ten years ago.
You can always find a clincher tire where ever you are and have several choices. Not so with tubulars. Most shops only carry a couple choices. In some small towns you might be out of luck all together. Same with tubular replacement rims. There are far more choices for clincher wheels and tires. Tubular wheel/tire combos are lighter, but this is BeginnerTriathlete.com, not Tour de France.com. You're probably not climbing huge mountains. Weight should not be your number one concern. Final thoughtsIt's not that the higher-end equipment seems to be for tubulars, it's that there aren't any, or very few, less expensive wheels for tubulars. Nearly all of the high-end wheels are also available as clinchers. If you train for a race for 6 months and then rent a set of wheels, then flat, is your race over? Have you learned how to change your tire whether it's a tubular or a clincher? Use what you are comfortable with. Borrow a friends tubulars, experiment if you are interested. This is the first step in helping you make an educated decision by giving you a few things to think about.