Bike Wheel/Tires Question

As far as the disc is concerned. It is more aero than a spoked wheel. When you get above say 24 mph it is easier to maintain that speed. The reasons people don't buy them is:
1) the price. They run from $500 up
2) most people can't maintain 24 mph.
I have a Renn disc. I bought it under the asumption that it will just make me faster. But I found my times were actually slower, mainly because I didn't know I needed to be over 24. So even though I was going at a pretty good speed, I was just pulling a heavier wheel. I am racing this weekend, so I was going to through the disc on and try it again, this time getting up over 24. I usually ride by cadence and not speed, so this will be different for me.
As for the tubulars vs. clinchers ( I'm not a bike expert) but as I understand it the tubulars are glued to the rim therefore you have less loss of power from the tire contacting the street. With clincers the tires move a little with each turn and you lose some power. I'm probably not explaining it right, but maybe someone else could explain that better.
The best part of having a disc is the noise it makes. When sitting on the bike you can't hear it, but the people you are going to pass hear you coming. I had this guy say he heard me coming up on him slowly, then he couldn't take it any more he felt like prey being chased by a predator he finally sat up and let me pass him.
That was cool

I had never heard a disc wheel until my race this past weekend. The 3 guys that passed me that had them sounded like they were riding "Big Wheels"

-Frank

Disk wheels are solid (no spokes) and extremely aerodynamic. Only used as a rear wheel with the exception of track racing. While they are heavier then a typical spoked "race wheel", they aren't "that" heavy. My disk wheel weighs less then any of my 32 spoke training wheels.

Madcow, I'm not sure who told you that disk wheels were only effective above 24mph, but that's not true. The only time a disk wheel is not faster then a spoked wheel is when climbing. Depending on your wheel options, a spoked wheel may make more sense on a course with a lot of climbing if it's lighter then the disk, but the disk will be faster on the descents and the flats. The advantage diminishes the slower you go, but if you're going above 16 mph, you will have an advantage with a disk.

Many people think that disk wheels are unsafe in windy conditions, but this is only in severe conditions. Over 30 mph winds. Otherwise they will actually be advantageous in windy conditions, especially when paired with an aerodynamic front wheel.

Oh, and disk wheels make a really cool noise that makes people turn their heads to look at you as you go by. ;-)

Tubulars vs. clinchers:

A tubular (also called a "sew-up") is a tire that is sewn together sealing a tube inside it. A strip of fabric is then glued over the stitching. The entire tire is then fastened to the wheel with glue. Wheels designed for tubulars will be lighter then clincher wheels because there's less material needed to hold the tire in place. Tubulars fit very tightly, and in fact need to be stretched by hand and mounted dry for a couple of days before applying glue and remounting. Spares are pre stretched and then pre-glued. They used to be advantageous because you could pump the tire to higher pressures then a clincher. Also it's impossible to have a "pinch flat" with a tubular. On the downside, they're expensive; they're a pain in the butt to repair (most people don't repair them); and they're a bit of a pain to go through the stretching routine.

Clinchers are separate tubes and tires. It's what you are currently using. The new high-end clinchers can be inflated to similar levels as high-end tubulars and have equal rolling resistance. They are susceptible to pinch flats.

Most pro triathlete's and cyclists race on tubulars and train on clinchers. Therefore, most wannabes (myself included) do the same.

Hed and Zipp are manufacturers of high-end aerodynamic race wheels. Lots of carbon fibre. Both companies make disk wheels as well as deep dish spoked wheels that are incredibly light. Hed also makes a tri-spoke carbon wheel.

scott

ps: you can never own too many wheels, or too many bikes. :-)

I can't understand that "24mph" limitation either, seems completely arbitrary to say that at 24mph the wheels are effective but not at, say, 23.9mph? Drag is drag, regardless of the speed, although the effects of drag will certainly be more pronounced at higher speeds.

Here's a brief discussion and some relative drag numbers on different wheels:

http://www.analyticcycling.com/Hed/HedFeatures.html

Interesting that the H3 (trispoke wheel) comes close to the disk wheel. I've heard that the best set up is the h3 on the front and the disc on the rear, that you need nearly complete calm (no winds) to ride with a disk wheel on the front.

In the last tri, I rode with the Renn disk on my friend's tribike. He says it's worth 0.5mph. Does make you sound like a jet airplane when you're passing someone.