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tinman

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Reply with quote  #1 
http://www.bicyclerollingresistance.com/mtb-reviews/continental-race-king-racesport-tubeless-2014



Thats about as scientific & professional as I have ever seen.  

Pretty impressed with the Conti Race King 29er.  When they took it up to 55psi it had as little resistance as some of the 25mm road slicks !  

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Slim

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Reply with quote  #2 
It's a huge effort, so thanks to Jarno for doing that!
Unfortunately for gravel riders, he hasn't tested very many gravel tires.
The other issue is that while rolling resistance on a drum has been fairly well correlated to actual rolling resistance on a smooth road, soft surfaces or very rough ones are very different.

It is very possible that a tire which performs well on a drum(/smooth road) at high pressure, does not do well at much lower pressure in soft sand/gravel or over rocks.

You see in his tests that some tires 'flip' position at the different pressures he tests at.
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Barrettscv

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Reply with quote  #3 
I also use the Bicycle Rolling Resistance website often. I have some expectation that a few popular gravel tires will be tested.

Back at the end of 2015, I sent a PM to Jarno suggesting that he test the Vittoria Voyager Hyper as a fast rolling touring bike tire. Within a few months he posted a review.

I expect that if Jarno has multiple requests for reviews of the Schwalbe G-One or Panaracer Gravel King, that some of the more popular gravel tires will be tested.
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bobknh

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Reply with quote  #4 
Thanks for the post and link. The results seem to confirm my subjective observations about the benefit of latex tubes --- which seem very hard to find in the size tires I ride. The other advantage of latex tubes is they are less susceptible to pinch flats at lower pressures. Of course, rolling resistance is not the only factor to consider when evaluating a tires relative performance, the other factor is suspension loss, which is a function of tire width, suppleness, and pressure. Here again, performance will favor both tubeless and latex as they favor wider tires at lower pressure. I just ordered a pair of 35 mm Compass Bon Jon's. When I return to my NH dirt and gravel roads, I'll set them up tubeless; but for now, I'm anxious to see how well they perform on high speed group rides in South Carolina vs, my 28 mm Conti 4000 II s's. The Conti's have Vittoria latex, but for convenience I will set up the Bon Jon's with Schwalbe light butyl tubes.
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dangle

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Reply with quote  #5 
Quote:
Originally Posted by Barrettscv
I expect that if Jarno has multiple requests for reviews of the Schwalbe G-One or Panaracer Gravel King, that some of the more popular gravel tires will be tested.


The G-One Allround is the same rubber, casing and construction as the "Big One" that he already tested. It's safe to assume it has wicked low rolling resistance compared to similar size tires. Not as low since it's more narrow, but probably not too far off.

Jarno's results (along with other RR testers) seems to find trends with most brands. Schwalbe's high end stuff is always fast. Continental black chili is always fast.  The new Vittoria stuff looks promising. I don't know if Specialized has their off-road tires made under the same roof as their road tires yet, but their road tires are fast. Clement tires seem to do just 'okay' in rolling resistance tests, but they seem to prioritize ride feel, grip, longevity and easy setup. There's barely any rolling resistance info (in general) out there on Maxxis, WTB or Panaracer tires. It would be hard to believe they aren't testing that stuff and it would be hard to believe they wouldn't advertise it if it wasn't fast. I have seen rumbling that Maxxis off-road tires do pretty well in rolling resistance, but nothing published. Kenda has the worst rolling resistance in the business for road, mountain and fat bikes, so it's foolish to believe their new tires treads with the same rubber are any faster.
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bobknh

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Reply with quote  #6 
Quote:
Originally Posted by bobknh
Thanks for the post and link. The results seem to confirm my subjective observations about the benefit of latex tubes --- which seem very hard to find in the size tires I ride. The other advantage of latex tubes is they are less susceptible to pinch flats at lower pressures. Of course, rolling resistance is not the only factor to consider when evaluating a tires relative performance, the other factor is suspension loss, which is a function of tire width, suppleness, and pressure. Here again, performance will favor both tubeless and latex as they favor wider tires at lower pressure. I just ordered a pair of 35 mm Compass Bon Jon's. When I return to my NH dirt and gravel roads, I'll set them up tubeless; but for now, I'm anxious to see how well they perform on high speed group rides in South Carolina vs, my 28 mm Conti 4000 II s's. The Conti's have Vittoria latex, but for convenience I will set up the Bon Jon's with Schwalbe light butyl tubes.

One other thought about tire performance. The boys from Bicycle Quarterly claim that tires run at higher pressure subjectively feel faster because they are more likely to transmit high frequency road vibration, than tires run at lower pressure which dampen these vibrations. The vibrations make you think that you are going faster. Of course, Bicycle Quarterly is a sister company of Compass tires whose main sales angle is softer wider and more supple tires. None the less, I've read thier reports and field tests. While not exactly scientific or unbiased, they seem to be at least trying to be impartial. Any way, I'll be doing my own subjective tests on the Bon Jon's in a few weeks.
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Slim

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Reply with quote  #7 
Quote:
Originally Posted by dangle
I don't know if Specialized has their off-road tires made under the same roof as their road tires yet, but their road tires are fast.


The rubber guy who works at Specialized now, used to work at Conti, obviously he's very good at his job!

Specialized have started to make some off-road tires with the new compounds he develops, but it's hard to know which ones they are for sure.

Interestingly, the new Michelin road tire performs very well at the Velones test. In the past they have not done well.

My conclusion from BRR, Velonews and Slowtwitch tests is this:
At high (road) pressures, once you have a decent casing, fastest compound has the most effect on rolling resistance of a tire.
Specialized, Schwalbe, Conti and Vittoria Graphene+ seem to be the leaders in compound.
The casing deforms a tiny bit, and the rubber compresses and bounces back (high rebound).

But, at low (gravel) pressures, casing deformation is much larger. Compass, followed by Challenge in some sizes, seems to have the most supple casing.

My hypothesis is:
As you keep dropping pressure, and you test a faster compound tire against a more supple casing tire,
at a certain point the more supple tire will take over, regardless of compound.

I have asked Jarno to test this, hopefully he can!
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