It has all those necessary qualities you would want in your road tire. Light enough, grippy enough, sturdy enough. Just dont expect it to beat an Ultremo in a race or go thru debris like a Gatorskin or a 4 Seasons.
The key to the Grand Prix 4000s' performance is Continental's judicious inclusion of a variety of features found across its offerings.
Technical Features
For puncture resistance, Continental decided to include only one Vectran anti-puncture layer where the Conti 4 Seasons has two. This sacrifices a bit of puncture protection but yields lighter weight and improves rolling resistance.
Key to the GP 4000s' grip is the use of the Black Chili compound. First developed in 2005, Black Chili basically infuses the basic rubber base with microscopic carbon soot particles. Continental claims that this technology produces 26% less rolling resistance, 30% more grip... all while decreasing wear by 5%.
This is remarkable since rolling resistance, grip and wear are opposing requirements. Say you want to increase grip, wear is usually sacrificed. With Black Chili, resistance and grip are improved as well as wear. Amazing.
Black Chili technology is said to be so sensitive that it can only be produced out of Conti's Korbach plant in Germany.
The GP 4000s' are quite average in terms of weight. We measured our 700x25 sample at 224 grams, a good six grams below the listed 230g.
700x25 - A good 6 grams lighter than advertised
700x23 - Mysteriously overweight
MountingFor people of moderate hand strength, the tires can be mounted without levers. In our experience, initial fitting (and dismounting) requires at least one lever to get that final inch or three of bead over the brake surface. Subsequent removals and mounts required only light-moderate hand strength and no tools. These tires were meant to be mounted a certain direction. A vague direction arrow may be found somewhere in the sidewalls. Directionality aside, we have actually mistakenly ridden the tires backwards to no ill effect.
23c vs. 25c
Perhaps the bigger question is 'which tire size to go for?'. We have been using 700x23 GP4000s' for quite a while. For a week or two, we had two 700x25's mounted purely for testing.
Lacking any sort of scientific testing equipment or data, what we can report on is subjective ride feel.
With fresh legs, what size tires you're on doesn't really matter. You have enough strength to spin either tire size equally well.
But.
Over a long ride, we found that the wider tires are somewhat harder to spin as the kilometers pass along. Net effect is feeling a bit more tired after a ride on 25's than on 23's. During the course of testing, all pressures were constantly maintained at 8 bar (116 psi). Going wider, even by 2mm, would also produce a less aerodynamic wind profile compared to a thinner tire (if those things matter to you).
But.
Over rougher asphalt, the 25's are noticeably more comfortable than the 23's. This can be substantiated by the 'bounce' you feel when going over road imperfections. On 23's these can be jarring but 25's take the sting out of the same ruts and pits. If you take a look at the images below, this all makes sense as the 25's stretch out to almost 30mm (28mm to be exact) once mounted.
When mounted, 25's round out to 28mm
23's round out to 25.5mm when mounted
In the end, we decided to make the most of the situation and go staggered on the tires. 23's in front 25's at the back. We get the most support in the rear where we put the most weight. And we have a more responsive, lighter and more aerodynamically sound tire at the front.
On the Road
Getting back to the 23 vs. 25 choice. Ultimately, it's up to the rider and the road. If your'e a Clyde or frequent rough asphalt, go for the 25's; your butt will thank you for it. If you're a lighter weight rider who prioritizes weight and performance over vertical compliance, by all means go for the 25's.
.... or maybe be like us and get the best of both?
Vedrict
With so many things going for it and virtually nothing going against it, the GP4000s gets top marks and top recommendation from us.
Ultimately, it's up to the rider and the road. If your'e a Clyde or frequent rough asphalt, go for the 25's; your butt will thank you for it. If you're a lighter weight rider who prioritizes weight and performance over vertical compliance, by all means go for the 25's.
ReplyDeleteThink the latter should be 23.
Agreed, Pétur.
ReplyDeleteEverything in cycling comes down to rider preference. There's enough evidence to justify just about any cycling theory out there :)
Armand
Oh dear.
ReplyDelete25mm tyres require about 20PSI less for any comparison tests to make sense at all. Running wider tyres at the same pressure will just give you a harsher ride.
As for the lack of "...any sort of scientific testing equipment or data..." all you need it to time your rides on your usual routes.
It shouldn't take long for you to realise that you'll be typically faster on 25mm tyres (especially on bad surfaces) or at worst just as fast but much more comfortable and with better grip.
Armand Gonzales:
There's pretty enough of good research on tyres and rolling resistance available and it's funny that there's no evidence of any sort that 23mm tyre width offers any advantages for the majority of riders;-)
@Barteos,
ReplyDeleteThe point is to compare the behavior of the tires with as much factors equal as possible.
Thanks for pointing that out though.