Is there a difference?
The Competition has Crr numbers nearly as bad (.0059) as the S-Works Mondo (.0061) clinchers and worse than the Ultra GatorSkin (.0058)…
I’m trying to find how that exactly relates to the Sprinter, though. I know I’ve seen it somewhere.
The Competition has Crr numbers nearly as bad (.0059) as the S-Works Mondo (.0061) clinchers and worse than the Ultra GatorSkin (.0058)…
i ask my self how you get these number because what we measure is something else so please explain?!
http://www.rouesartisanales.com/article-1503651.html
I would guess it was the above link to the Roues Artisanales article. Those numbers match with their findings.
i understand its not a real life testing
this means not measured at the road
but on steel round drum where their is no road roughness
and a low presssure in tyres
.
I got similar numbers but it was by pushing the bike down the street and seeing how far it would go before it fell over. I then divided the distance by the speed squared and came pretty close.
Grant
i understand its not a real life testing
**
That is the classic response to people who don’t agree with the test. However, if you do a search on ST, you will dig up enough info from enough smart people with powermeters who have tested this stuff out on the road and were able to validate the results. People who don’t have an ulterior motive to sell or not sell tires and just want the fastest product.
Personally, I don’t have numbers, but isolating the Conti tubulars vs. a Michelin clincher on a similar wheelset (Zipp 909 vs. Flashpoint 60s with wheel cover), I found the Michelin clinchers faster every time. And the clinchers ride considerably smoother than the tubulars, ie much more comfortable on rough roads.
Chad
i understand its not a real life testing
**
That is the classic response to people who don’t agree with the test. However,
for your info we made a device to test roll coeff on the street ,where you ride with high accurracy with in 1 gram so i think we know where we talk about
so i think we know where we talk about
I’m pretty sure that is what the other people doing their testing think, too.
cees has a bit more credibility than most of the posts on the subject though. I don’t think he’s pushing a bike down the road, for example.
*cees has a bit more credibility than most of the posts on the subject though. I don’t think he’s pushing a bike down the road, for example. *
**
Perhaps, but I don’t know him from Adam. There is a wealth of info on this subject on ST provided by some pretty smart people, not to mention the aforementioned Roues test. I believe Conti themselves did a test and found very similar results.
I don’t know why I am arguing this–I hope everyone uses Conti tubulars and glues them on such that they can be easily removed in case of flat during their race… Please, everyone, ride Conti tubulars, please, please, please …
Chad
i understand its not a real life testing
**
That is the classic response to people who don’t agree with the test. However,
for your info we made a device to test roll coeff on the street ,where you ride with high accurracy with in 1 gram so i think we know where we talk about
How do you control or compensate for the street surface roughness?
It’s no wonder that your Crr numbers don’t match since they will vary depending on the particular street you choose, what pressure you run, the tire loading, the temperature, etc…
Not doing tire testing in “real life” conditions doesn’t, however, reduce the utility of doing comparisons on a more controlled smooth roller test fixture. The tire properties that will rank tires on a smooth surface are the same that rank them on a rougher surface. The absolute numbers will be different, but the rank order won’t change.
we do not control surface roughness ( but we are in the process to laser scan them )
also crr numbers change of course with tyre presssure but what is the more important they also will change rank certain tyre perform better on a specifc surface
also we are also now in the process of examine of what evry one thinks crr is linear with its weight ,but we think differant any way it will take lot of testing of diffrant tyres
we measure weight loading pressure ,airdensity plus air temp road temp gps data surface roughness speed tyre width and its behavoir on stress by camera
we all do that at differant pressurre loads roads temp altitude etc etc
.
You’ve made several references to superior data for rolling resistance. Any chance you’d be willing to share? Maybe what numbers you are getting for the best tires? Or just what tires you’ve found to be better?
Kevin
P.S. I’ll trade you some expertise in the areas of police tactics or DUI enforcement for the data if you want (it’s the only expertise I possess) 
well as you can understand we cannot give any numbers at this moment ,only i can say it differant of the numbers published so are better other are worse
and if i give numbers they yeah you want them to look bad ,and that not that i want because we are also in process of making ultra light and low roll coeff tyres
we use the measurement also as part of the development of this and some test are for clients hence we also test on the track
as beiijng is also coming lot of work ahead
.
we do not control surface roughness ( but we are in the process to laser scan them )
also crr numbers change of course with tyre presssure but what is the more important they also will change rank certain tyre perform better on a specifc surface
also we are also now in the process of examine of what evry one thinks crr is linear with its weight ,but we think differant any way it will take lot of testing of diffrant tyres
we measure weight loading pressure ,airdensity plus air temp road temp gps data surface roughness speed tyre width and its behavoir on stress by camera
we all do that at differant pressurre loads roads temp altitude etc etc
Interesting. Can you describe you test fixture a bit better? Is it some sort of cart or trailer, or does it somehow incorporate a real bike and a real rider?
trailer with a lot of electronics real wheel no bike reall weight
and can be used at a bike
we also can do it on reall bike with real rider
but we do not want to measure aerodynamics so that why we isolate it
but could be reall bike it would only make the aparatus bigger same results
also we busy with wifi data transfer ,hence we could do it with gprs data also i think
and if we have the display ready i think we gone display it on youtube i think
.
trailer with a lot of electronics real wheel no bike reall weight
and can be used at a bike
we also can do it on reall bike with real rider
but we do not want to measure aerodynamics so that why we isolate it
but could be reall bike it would only make the aparatus bigger same results
also we busy with wifi data transfer ,hence we could do it with gprs data also i think
OK. Do you find that for a particular tire, wheel loading, pressure, and road roughness that there’s an “optimum” pressure, above which the Crr begins to increase?
<< I hope everyone uses Conti tubulars and glues them on such that they can be easily removed in case of flat during their race… Please, everyone, ride Conti tubulars, please, please, please …
ok, you convinced me. Not that I took convincing, I’ve been riding them for about 20 years and have no plans on changing anytime soon. There are some things that all of the lab tests in the world can’t measure and it is some of those “things” that make Conti’s the fastest tires for me.
if you do a search on ST, you will dig up enough info from enough smart people with powermeters who have tested this stuff out on the road and were able to validate the results.
i’ve been reading this site thoroughly for years and have yet to see anything like this type of research done well…a few times someone with a powermeter will ride some ‘tests’ but they are so inconclusive due to sample size and uncontrolled factors that they would hardly be considered validation of anything, which of course the folllow-on posts point out…at best those posts are reasoned debated without one dominant conclusion