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Showing posts with label Tires. Show all posts
Showing posts with label Tires. Show all posts

Review: Continental Grand Prix 4000s 23c and 25c

Yes, there are lighter tires our there. There are grippier. There are sturdier. But, in our experience, nothing comes close to being the perfect all rounder as Continental's Grand Prix 4000s.

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

What got us dumbfounded was our used 700x23 sample. Our scales have them at 218 grams where it was only supposed to be 205! We were relieved upon measuring another used sample which went for 209 grams.  You'll have to take our word on that as we failed to photograph before mounting. Although we cannot be 100% sure, we attribute this major discrepancy to the way the tires were folded during measurement. This may have distributed the tire differently and may have affected the center of gravity putting more pressure on the scale's strain gauges. Again, only a theory. Regardless of this, the 4000s' are adequately light.

700x23 - Mysteriously overweight
Mounting

For 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

Size differences aside, Continental's Grand Prix 4000s delivers a performance worthy of several Tour Magazine comparo awards. Indeed these feel spin easily, grip extremely well and have adequate puncture resistance. That said, we did have one puncture where a safety pin (which looks awfully like the ones used on runners' race bibs) hung on to the tire and eventually penetrated the casing through to the inner tubes. Compare this to more than two years of puncture free performance we had with Conti's own 4 Seasons tire. However, we would readily trade the 4 Season's armored hide for the 4000s' slick and light rolling performance any day.

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.

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