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PostPosted: Thu Mar 31, 2011 7:22 pm 
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Location: Slovenia---that forest land
Is there any differnece in rolling resistance between those two tires?

Veloflex is 20g lighter...but is faster than conti? Veloflex Corsa 22

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PostPosted: Thu Mar 31, 2011 8:54 pm 
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Hi

Here's the hook-up for this kind of query:

http://www.biketechreview.com/tires/rol ... oller-data

Endless fun. Seriously :thumbup:


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Posted: Thu Mar 31, 2011 8:54 pm 


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PostPosted: Thu Mar 31, 2011 9:36 pm 
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Location: San Diego California
I've ridden multiples of both of these tires for some years. The veloflex is a better handling tire but wears faster and is more puncture prone. I use the 4000S as a training tire and usually get them down to the wear indicators. They do have one sorta wierd characteristic. The rear especially doesn't wear down overall like many tires. The center gets a rather drastic flat cross section usually.

The Crr values are relatively close between both tires.


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PostPosted: Fri Apr 01, 2011 1:46 am 
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Location: Belgium
Hi,

Quote:
The Crr values are relatively close between both tires.


As in nowhere near, right?

Guess puncture resistance also falls in favour of Veloflex given proper ageing and care at installation but what do I know...?

Marketing kids... :roll:

To paraphrase the inglorious glorious: no brains no glory. :mrgreen:

Aaarghhh, ;)

P.S. I'll explain if you twist my arm hard enough.

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PostPosted: Fri Apr 01, 2011 2:14 am 
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Location: San Diego California
The Crr for Veloflex Pave (same as Corsa 22) w/butyl is .00317, 15.6 watts/tire. The GP4000S w/butyl is .00307, 15.1 watts/tire. I'd call that pretty darn close.


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PostPosted: Fri Apr 01, 2011 9:22 am 
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Whatever about any rolling resistance or weight difference, I can tell you IMO the Veloflex w/latex tube feels waaaaaaaay better than the Conti, smoother, faster ... just better !!

Yes I find the Veloflex do wear more quickly, but maybe thats because I throw the bike around a lot more with Veloflex on, just makes the bike feel like its planted when cornering, makes me far more confident ( stupid ? ) than the Contis do.

I cant comment on puncture resistance as I haven't has that particular 'pleasure' yet with either ( cue multiple flats :roll: )


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PostPosted: Fri Apr 01, 2011 9:39 am 
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Hi,

wasfast wrote:
The Crr for Veloflex Pave (same as Corsa 22) w/butyl is .00317, 15.6 watts/tire. The GP4000S w/butyl is .00307, 15.1 watts/tire. I'd call that pretty darn close.


Where do those figures come from?
To my mind that's way too close to be true. Is it the butyl inner tube messing up the CRR of the Veloflex?

Ciao, ;)

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PostPosted: Fri Apr 01, 2011 10:49 am 
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Location: San Diego California
fdegrove wrote:
Hi,

wasfast wrote:
The Crr for Veloflex Pave (same as Corsa 22) w/butyl is .00317, 15.6 watts/tire. The GP4000S w/butyl is .00307, 15.1 watts/tire. I'd call that pretty darn close.


Where do those figures come from?
To my mind that's way too close to be true. Is it the butyl inner tube messing up the CRR of the Veloflex?

Ciao, ;)


They're from the Crr data in the biketechreview.com link above, managed by Al Morrison. A latex will have nearly the same improvement in either tire. There's a separate section at the end the shows the buytl vs latex difference overall.

The feel of the tires in handling etc gives the impression that the Veloflex is a faster tire. Not sure why that is. I had a set of the 320tpi Vittoria's on this last fall and they gave a similar feel as the Veloflex. Where I'm living now, the Veloflex and Vittoria's are just to cut/flat prone unfortunately as they're both preferred overall to the 4000S.


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PostPosted: Fri Apr 01, 2011 12:11 pm 
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Joined: Tue Oct 28, 2008 9:00 pm
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Location: London, United Kingdom
Here's my 2 cents. I have no instruments to support my statements. Just pure racing.

I'll omit the bike frame, groupset and wheelset because they are in common to both tests, hence not relevant.

The bike with GP4000s feels spongy, it lacks feedback, kind of uncomfy too. Feels like a hybrid!
The same bike with the Veloflex feels ALIVE, fast, grippier, angrier, very dynamic. It corners like a Ducati.

I don't believe the Marketing of the CRRs and tests done in lab. How do they account for 'real speed' and 'real performance' in a lab? the real world of racing does take into account features like grip, responsiviness, feedback and comfort. A tyre that significantly performs better in these 4 parameters will result in a faster tyre overall because the bike-wheel-tyre set-up will result in a more confident, comfy and reactive cyclist.

A tyre with a better CRR (done in lab) will be probably marginally faster than a tyre with a worse CRR if you put a robot on it and let it race in a place without gravity and air resistance! Kind of perpetual motion.

Ah, the magic of marketing and those 'tests'.

For the record, I used the GP4000s for 3 years in a row, then I switched to Veloflex Corsa. The best year so far!

Just my 2 cents. No formulae or scientific data to support any of my statements. Just my 'feeling'.


Last edited by parajba on Fri Apr 01, 2011 12:44 pm, edited 1 time in total.

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PostPosted: Fri Apr 01, 2011 12:36 pm 
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Location: Belgium
Hi,

Tour magazine measured the rolling resistance of the GP4000S and converted to Watts it turened out to be 34.3W at 35km/h and a 50kg load.

While I think Al Morrison does a fabulous job, I somehow have a hard time believing a tyre with what's essentially a lowish true TPI can come that close to a Veloflex Pave.

What helps it IMO is the Black Chili Compound and it's essentially slick casing.

A latex inner tube in a casing that has a low TPI count won't help it either. I doubt the difference would be measurable as it will be swamped by the lack of flex of the casing.

Not saying the GP4000S is a bad tyre, it isn't and it's probably one of Conti's best.
Yet performancewise none of their tyres come even close to what all of Veloflex tyres offer especially when combined with a fine latex inner tube a la Vredestein.
It's a totally different world. Honest. 8)

Ciao, ;)

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PostPosted: Fri Apr 01, 2011 2:08 pm 
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Location: Athens, Greece
parajba wrote:
I have no instruments to support my statements. The same bike with the Veloflex feels ALIVE, fast, grippier, angrier, very dynamic.
I don't believe the Marketing of the CRRs and tests done in lab.


+ 100

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PostPosted: Fri Apr 01, 2011 2:49 pm 
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Location: San Diego California
Let me be clear, I prefer the Vittoria Open Corsa CX 320tpi or Veloflex Pave/Master/Corsa/Record by far over the Conti for the "feel" and cornering reasons. The Conti seems more flat resistant for general riding. The Conti is a good compromise of weight, rolling resistance and durability. YMMV.

Al's data is done in a very high technology lab, his house on rollers with a power meter. His data is consistent which allows relative comparison of tire/tubes/gluing methods etc. He makes no claims that Crr is the be all,end all for tires. It's a single measurement of an important characteristic for speed and making your own personal tire selection. He'd be the first one to agree that no matter how fast a tire may be, if it punctures constantly, what good is it for that application? Certainly the tire choice for a flat, perfectly smooth road TT isn't the same as a road race with gravel sections.


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PostPosted: Fri Apr 01, 2011 3:38 pm 
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Location: Natovi Landing
Yes, Al's data bursts a few bubbles.

The Open Corsa SC seems a bit better than the standard to me. No doubt it's just because I've read it is. But it seems less sketchy in corners. Standard OC is an overrated tyre IMO.

Latex tubes and clinchers - only use in the mountains if you're auditioning as a stunt double.


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PostPosted: Fri Apr 01, 2011 4:08 pm 
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Wish I could say I've had experience with the Veloflex clinchers, but I don't. But since you're now discussing Vittoria Open Corsa CX's a bit, I will say that I used to ride those all the time. Cuts and punctures were commonplace and just a way of life with the Vittorias. So... thought I'd try some of the Conti 4000s clinchers. I never looked back. Several years of Vittorias and always fixing flats. A year and a half with the 4000s and I'm having a hard time recalling my last puncture. As for the ride quality, not enough of a difference that I even think about it... all round I'd choose the Conti's. At least they seem to last the life of the tread which is more than I can say for the Vittorias. There's been more than a few times that I've had to toss a Corsa CX after one ride due to a cut that was just too big. Looking at my Contis, they look clean of damaging cuts, etc., just normal even wear. I don't know exactly what their "black chili" compound is made of, but it seems to live up to their claims. These tires roll supremely well, and I don't find them "slick". A Vredestein tri-comp is a tire I would consider as having a slick outer casing. Rain, shine, crud whatever... the Conti 4000s is tough to beat in my book.

Of course, I've just finally entered the world of tubulars and have some veloflex carbons that I can't wait to try once my Continental Competitions need to be retired.

Oh... I would like to add that I built up a set of HED Belgiums (slighter wider rim) and mounted the Conti 4000s tires on them. Yes, I notice a difference in the ride, and it is positive (less harsh) and having ridden the same tire on both narrower rims (Campy Neutrons) and now the HEDs, I am definitely an advocate of the the slightly wider rim. The downside is if you're switching between the two sizes, it's a pain to always be adjusting your brakes to the different rim widths. Slightly off topic I know, but just thought I'd mention it.

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Posted: Fri Apr 01, 2011 4:08 pm 


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PostPosted: Fri Apr 01, 2011 4:54 pm 
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A few comments:

Al Morrison's tests are done on a small diameter roller and then converted to a flat surface, but this last part may not be completely accurate. You probably need to multiply by 1.5 or so, or add ~.00015 to the Crr numbers. The ranking is quite valid though... many corroborating tests have been done.

Crr values are important to speed. The tread compound is obviously an important part of this, since Conti tires sucked until they came out with the Black Chili stuff. And the Black Chili tread is very durable also... they last longer for me than any tire I've used, including the old Krylions... and they have great traction (measured by Tour). I think they feel great on switchback descents.

I haven't used the Veloflex tires recently, but have used the Vittoria and Challenge top clinchers which are very similar. They do ride smoother, but the puncture resistance and life are not close.

All road tires of similar size will flex about the same amount. The casing offers little resistance... it is the air pressure that is holding the tire up. The difference in feel comes mostly from the vibration damping characteristics of the tire.

The reason the tires get a flat spot eventually is because the tread is fairly thick. Thin tread will wear out before the flat spot becomes noticeable. If the flat spot bothers you, then get the Supersonics... they won't get a flat spot before they wear out either, and they are faster than any of the "open tubulars".


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