Buy the disc or not?

If you want it and can afford it, buy it.  

Don't expect any significant time savings with it over what you currently have though.  You will gain the cool "whomp, whomp" sound too - also an important consideration.  

Do you have all the rest of the items you can buy speed with?  Fast tires and tubes, aero helmet, cable routing cleaned up?

What do you have for tires now?  Depending on what you have now, going to something like a Continental GP4000s with latex tubes will likely result in much bigger gains than that disc ever will.

I know you asked about a disc (more below), but this (a PM) is a great way to drop some coin on performance.  The PM, if used right, really helps in training and (for me) as a "do not exceed meter" in racing - helps me from not blowing up on the bike, which I would otherwise be happy to do!

As for the disc, I'm in the "if you can afford it and want it, go for it" camp.  It's certainly not going to be the quickest way to extra speed from where you are now, but it just FEELS  and SOUNDS so dang fast.  There's something about breaking out the race setup that just makes racing that much more fun than a training day with lots of other people around.

But that's me.  

Also agree on the GP4000s (although I run tubulars, so can't comment on latex).  They've been great tires for the past 2 seasons for me racing (I use GatorSkins for training).

Matt

Your LBS likely won't stock them but may be able to order them.  I buy them online from Probikekit or Wiggle.  They cost more (usually in the $12-15 range) and you have to be very careful installing them as they can easily be pinched during installation.  Also have to be sure your rim tape is perfect.  Your 88mm rim means you will have to deal with a valve extender as well but maybe you are already doing that?

you could use that money towards hiring a specialist coach for your weakest area and most likely see a far greater return on investment. 

I believe this is what Flo has attempted and they have done very well.  Though you get the added bonus that their wheel is NOT useless.   

I don't think you get the sound with their disc though?

Correct.  No whomp whomp whomp but they still look cool.

Wait a second here... You are riding chinese knock off wheels and want to spend that much on just a disc?

If I were you I would take that $1,600 and buy a nice set of Firecrest 404's or 404/808 combo. Zipp just came out with a new wheel (Firehawk I think) so the used market for Firecrests is going to get decent here soon. I just bought very lightly used 404's for $1,600. I'd do that and stick with the aero jacket. 

Or like others said spend it on other things that will make you faster or aid in your training. I doubt you will get much more than the sound of a disc for that $1,600. Not worth it IMO and you can only use the disc on race day. $1,600 is a lot for a cool sound on race day only. 

but you've ordered some GP4000s and latex tubes right?  

For $1600, you might as well get a set of FLO wheels or FLO disc for a fraction of the cost.

I have a rear wheel set up with a wheelcover permanently, and it works great. (Tape it to the rim with electrical tape.) Way cheaper than a disc, same aero, and looks just about as cool.

Ah, gotcha. Not sure what knock offs you have but I am really impressed with the Firecrest 404's. I dropped 300 or so grams of weight and got the better hubs by changing from the stock wheels my P2 came with. I know the weight is not supposed to be a big deal but it does feel different. They seem to spin up much faster, nice from a take off and nice when cornering and then getting back up to speed. I am very happy with my 404's for the $1,600 I paid, no regrets spending that money.

Might be worth a test ride on some firecrests to see if they are better than your current wheels. 

No. In fact they should be better.

And hey Jeff - nice to see you still getting on it!

When I 1st switched to latex, one of the local LBS told me that they're only good if you do hilly rides. I thanked them and walked out!

Want to geek out on review some tire data, take a look at this site: http://bikeblather.blogspot.com/  The new fast tire referenced isn't available yet but are soon to be.

FWIW, the Conti Attack/Force is suppose to be slightly faster than the 4000s.  Thinner tread layer though if your looking at training & racing in them.