From my experience I have observed that 4000s don't have the biggest market penetration among all consumers because of the price, let's face, not everyone who rides a bike is a racer or appreciates a supple tire. Many triathletes and ultra endurance cyclist seem to stick to slightly cheaper Gatorskins or Vittoria Rubinos, although once the budget oriented rider tries a Conti 4000 they might not go back.
You might wonder what exactly is the big deal? How much of this is marketing BS along the lines of "laterally stiff, vertically compliant"
There are two main things that set this tire apart.
1.Black Chili Compound:
26% lower rolling resistance, 30% higher grip, and even 5% longer mileage compared to the previous generation GP3000.
Black Chili is only made at the Conti factory in Korbach, Germany.
These are 'nano' sized soot particles, who's surface properties are optimized for use in bicycle tyres. These smaller particles enable the tyre tread to deform around surface objects more quickly, improving grip. They also form a tighter bond with each other thus improving compound strength for improved tread life and less chance for lugs to rip and tear on MTB tyres. The way in which these particles interact with each other also lowers rolling resistance.
2. Vectran puncture protection belt:
The specs and info on this are ridiculous! If you want to learn more check out this great page on Conti's site about Vectran:
for you techies:
"Vectran is based on polyester (PET) chemistry rather than nylon and it offers advantages over aramids similar to PET over nylon. (Just as "aramid" is an abbreviation of "aromatic polyamide", Vectran is an "arester" (ar-omatic poly-ester). Advantages include near-zero moisture absorption, excellent fatigue performance, and improved dimensional stability. Vectran also has much better resiatance to flex/fold/buckling - essential for relaibility in low-tension flexing or induced twist in fabric, rope, or cable applications."
Here is a glowing review from Cycling weekly:
Cycling Weekly - GP4000 Tubular - Highly Recommended - 10/10
"After the love affair I had with the GP3000, I was gutted when Continental brought out the GP4000 and I just didn't get on with it. So it was with much trepidation that I stuck a set of the new GP4000 tubulars on my favourite race wheels during the summer.
Now the magic is back in our relationship - these tyres are absolutely brilliant!
Like the 3000's, the wear rate is on the high side but the performance is ample compensation. Wet or dry, they stick to the road and you never find yourself having those random moments when your bike is doing something you didn't expect it to.
The Black Chili rubber compound gives excellent grip and the casing is certainly up to the job. Though not the most supple tyre on the market, the Contis offer a great compromise and appear to have a low rolling resistance.
Superb puncture protection, graet grip in the wet or dry and excellent build quality; these are the best road race tubulars yet." Score 10/10