Conti UltraRace or GP4000S?

My 2 favorite tires (durability, speed, price, etc) are Conti 4000S and Schwalbe Ultermo DD.

I've ridden on Michelin and Vittos before and they just don't do it for me...although they're nice tires in their own right.

I believe you.

I've been racing the GP4000S tires for the last couple of years.

Johnny - what's your choice? 

I've been using the Vittoria Open Corso CX or SL.  I used Michelin Pro3 before that, which are very similar to the GP4000S.

I also use the Vittoria Open Corsas.  But what's interesting is the aero data that's coming out now...and how the Vittoria may roll faster, but may not be as aero as some other tires.

But anytime you're going to consider aero data, it's important to know how your tire pairs with the wheel.  A 23mm GP4000S will likely have different aero data paired with a 23 mm rim than it would a 19mm rim.

Yeah, I have heard about that but haven't looked into it much yet.  Might have to consider if they are still the best choice for me (at least on the front).

i have both, and the GP4000s is the better of the two.

they are on sale for $35 at probikekit.com right now... look around online and you can easily find a few additional coupon codes to throw on their too.

Ultremo DDs are a great tyre, but they are really only for race day in my experience, mine got so cut up in regular usage I had to give up on them after about 2000km!

Man, I feel like a loser. The used tri bike I bought came with Ultra Race.

Mine did too.  They're not bad tires. 

Were your previous tires gatorskin +K's with slime, thorn liner, and filled with rocks?

the UltraRace is an inexpensive training tire that you'll find comes stock on many bikes.

the GP4000S is one (if not the) best all-around racing/training tire.  there are a few tires out there that are 'faster' for TT's and race day, but there is probably none faster that has a reasonable amount of protection for regular use.

I was using Serfas Survivor Series tires...somewhat similar to Gatorskins...probably slower.  No slime, no liner, no rocks.  Roughly 1 mph speed difference at 250 watts on the flats.  Previous testing on rolling resistance and calculations based on those tests in analytic cycling tend to back that up as well.