Fastest & Grippiest Tires?

[tylercheung]

With hysteresis, a couple of questions come to mind...

-if a tire has poor rolling resistance due to hysteresis, can that be improved by more inflation pressure? (i.e. increase hardness by more PSI?)

-why doesn't a stiffer tire, i.e. a Gatorskin, have amazing rolling resistance?

[MikeD]

Originally Posted by Mark McM

The diamond plate doesn't have to be representative of real pavement to provide useful data. As you say, rolling resistance of any given tire will vary with pavement surface, so the data from the diamond plate test may not correspond with the actual rolling resistance experienced on some particular road. But the rolling resistances of all tires vary with pavement roughness, increasing as the roughness increases. Testing of tires on a variety of surfaces has shown that a tire that has less rolling resistance than a second tire on one surface will consistently have less rolling resistance than the second tire on other surfaces as well, even if the absolute rolling resistances of both tires change with different surfaces.

What it boils down to is that the purpose of these tests isn't necessary to find the absolute magnitude of tire rolling resistance, but to find the comparative differences between tires. When people consult the data, they typically aren't trying to find the exact Watts of resistance, they just want to know which tires are better than others. And for this purpose, the tests are useful.

In this article, Jan Heine rails against drum testing https://www.renehersecycles.com/tire...-vs-real-road/

He even states that supple tires, which inherently have lower rolling resistance, don't do as well on drum tests. YMMV. There's a sticker out there that says "Jan Heine is wrong." But, in this case, he's probably right.

There’s another problem with lab tests on drums: The drum is convex, and it digs into the tire more than a flat road surface. This flexes the tire more, and it increases its rolling resistance. That alone wouldn’t be a huge problem, if it affected all tires the same. But it doesn’t: Supple tires deflect more than stiff tires. That means they have a disadvantage on the steel drum that doesn’t exist in the real world. Even if drum tests show supple tires being faster, they won’t show the full advantage you get from running supple tires.

[Mark McM]

Originally Posted by tylercheung

With hysteresis, a couple of questions come to mind...

-if a tire has poor rolling resistance due to hysteresis, can that be improved by more inflation pressure? (i.e. increase hardness by more PSI?)

The answer is both Yes and No. There are two components to rolling resistance - the hysteresis losses in the tire, and losses int the system due to vibration passed through by the tires. In terms of just the hysteresis losses, tire rolling resistance does indeed decrease as pressure increases. But harder tires pass through more vibration, and the increased vibration losses (also called suspension losses) can overwhelm the lower hysteresis losses.

Silca has a good discussion of tire rolling resistance here. Here's a chart from the Silca web page, showing how the hysteresis losses (called "casing losses" on the chart) combine with the suspension losses for total rolling resistance:



In the end the pressure that mimimizes rolling resistance is dependent on both the tire and the riding surface.

Originally Posted by tylercheung

-why doesn't a stiffer tire, i.e. a Gatorskin, have amazing rolling resistance?

The Gatorskin may be less compliant (less flex), but the hysteresis in it's dense casing and thick tread is so high that it will still lose more energy, even with a little less flex. The Gatorskin has often been likened to riding a garden hose. If you flex a garden hose in your hands, and compare it to flexing a TT tire, you can feel the extra losses in the garden hose.

[dddd]

The Gatorskin tire is relatively stiff and has high hysteresis losses compared to the better performance tires, but is far from the worst out there in this regard.

At the expense of perhaps 20 watts for both tires at higher speeds, these tires provide a good compromise in terms of their suppleness and puncture resistance.
It's why they are so popular.
Even running them at lower pressures, it takes competitive-level riding to really feel the speed difference, and the lower pressure brings their ride quality into the civilized range.
In hilly terrain, where climbing at low speeds imposes less wattage losses, and descents involve braking, one might never feel that their ride is being compromised.

[Mark McM]

Originally Posted by MikeD

In this article, Jan Heine rails against drum testing https://www.renehersecycles.com/tire...-vs-real-road/

He even states that supple tires, which inherently have lower rolling resistance, don't do as well on drum tests. YMMV. There's a sticker out there that says "Jan Heine is wrong." But, in this case, he's probably right.

There’s another problem with lab tests on drums: The drum is convex, and it digs into the tire more than a flat road surface. This flexes the tire more, and it increases its rolling resistance. That alone wouldn’t be a huge problem, if it affected all tires the same. But it doesn’t: Supple tires deflect more than stiff tires. That means they have a disadvantage on the steel drum that doesn’t exist in the real world. Even if drum tests show supple tires being faster, they won’t show the full advantage you get from running supple tires.

Jan Heine is starting from incorrect statements, and then trying to come up with explanations to support the incorrect statements. Let's start with the premise in his first paragraph:

In discussions of supple tires, you sometimes hear comments along the lines of: “If wide tires are so great, why don’t they score at the very top in lab tests?” That’s a good question, and it goes to the root of how to test things: If tests don’t replicate the real world, they aren’t of much use.

The observations of wide tires being slower than narrow tires is most common in apples/oranges comparisons. In the past, narrow tires were generally designed for performance, and had thin casings and treads, whereas as wider tires were built for utility and ruggeness, and had thick casings and treads. But when testing tires with identical construction in different widths, the wider tires score better in lab testing. Here is a test on
BicycleRollingResistance in which the rolling resistances of the Continental GP 5000 S TR tire in 4 different widths are compared, which shows the wider the tire, the lower the rolling resistance.

Later in the article Jan Heine says:

Testing supple tires on real roads, with a rider on the bike, shows that higher pressures do not roll faster—as long as you keep the tires inflated enough that the bike can be ridden and steered normally. Above you see data for 42 mm tires: They roll at the same speed at 30 psi (2.1 bar) and at 40 psi (2.8 bar). Why aren’t the tires faster at ‘Firm’ pressure than at ‘Soft’ pressure?

This is again an apples/oranges comparison. Drum testing measures only hysteresis losses, not suspension losses. When tires are tested on roads, it includes both hysteresis and suspension losses. Does this mean that drum testing is useless? Of course not. Suspension losses have been found to be mostly governed by tire width and pressure, while hysteresis losses are governed not only by width and pressure, but also by tire construction. What this means is that although the drum test may be less than the rolling resistance on the road, the tire will less rolling resistance on the drum will be the one with less rolling resistance on the road. In other words, the drum test is not for absolute values, but for comparitive testing between tires.

There’s another problem with lab tests on drums: The drum is convex, and it digs into the tire more than a flat road surface. This flexes the tire more, and it increases its rolling resistance. That alone wouldn’t be a huge problem, if it affected all tires the same. But it doesn’t: Supple tires deflect more than stiff tires. That means they have a disadvantage on the steel drum that doesn’t exist in the real world. Even if drum tests show supple tires being faster, they won’t show the full advantage you get from running supple tires.

The above goes against published data, which shows more supple tires (tires with thinner and lighter treads and casings) do better on drums that non-supple tires. And no data is presented to back up what is "the full advantage you get from running supple tires," at least in terms of rolling resistance.

In my reading of the article, what Jan Heine is really saying is that he doesn't understand how to apply drum test data, so he just assumes it is useless.

[AngryScientist]

I didnt read any of the previous responses, but the fastest tires I have used in recent history are Specialized S-Works Turbo Cotton tires. Zoom zoom!

[RoosterCogset]

Originally Posted by Mark McM

I'd like to see some actual evidence of tread pattern improving traction (wet or dry). There's been plenty of anecdotes and theorizing, but I've seen no hard, repeatable evidence.

Came across this quote in the article linked. I wonder if the miniscule chevron tread you get on Vittoria Corsas (just one example) is related to the idea that there's evidently some ways in which some tires can have less drag vs other tires (eg. golfball dimples rationale)? Moreso than being just about grip. I assume the below referenced tests were for the same width tires on the wheelset (otherwise this would be a 'no kidding' statement).

“Several years ago, we tested the same aero front wheel with tires manufactured by five different manufacturers. We were astounded to learn that wheel drag could vary by up to nine percent depending upon tire selection."

https://www.bicycling.com/skills-tip...on-in-cycling/

[yinzerniner]

Originally Posted by Mark McM

Drum testing measures only hysteresis losses, not suspension losses. When tires are tested on roads, it includes both hysteresis and suspension losses.

Great point. That's why I like the tests that Zinn has outsourced to Wheel Energy where they account for suspension losses (all behind paywall, but reader view is your friend):
https://zinncycles.com/15-paris-roub...rough-surface/
https://zinncycles.com/technical-faq...ng-resistance/
https://www.velonews.com/gear/techni...g-methodology/
https://www.velonews.com/gear/techni...-verification/
https://www.velonews.com/gear/gravel...ted-for-speed/

Originally Posted by Mark McM

In my reading of the article, what Jan Heine is really saying is that he doesn't understand how to apply drum test data, so he just assumes it is useless.

Pretty much that. Or you can take the more cynical tone, and state that some of his very high priced, yet more durable tires test like crap on drums vs competitors so he's trying to invalidate the data with word soup.

Originally Posted by AngryScientist

I didnt read any of the previous responses, but the fastest tires I have used in recent history are Specialized S-Works Turbo Cotton tires. Zoom zoom!

It's not just you: That tire with a latex tube tested fastest from the Zinn Roubaix article.

[MikeD]

Originally Posted by Mark McM

But when testing tires with identical construction in different widths, the wider tires score better in lab testing. Here is a test on
BicycleRollingResistance in which the rolling resistances of the Continental GP 5000 S TR tire in 4 different widths are compared, which shows the wider the tire, the lower the rolling resistance.

This article says "at the recommended pressures." What's the source for the recommended pressures? It doesn't say.

This article says something different https://www.bicyclerollingresistance...000-comparison

At the 15% tire drop air pressures, which are very close to the recommended air pressures for a given size, the tables are turned and a bigger road bike tire will have a higher rolling resistance. The higher rolling resistance of the bigger tire is because it provides more comfort at the 15% tire drop air pressure.

We feel the ultimate test is adjusting all tires to the same comfort level. When all tires are adjusted to the same comfort level, rolling resistance is nearly the same (0.2 watts max) for all sizes of the GP 5000.

This is suspect as well because I'd want to run a wider tire at an even lower pressure, not to equal the same comfort level as a narrower tire. Otherwise, what's the point of even running a wider tire?

The above goes against published data, which shows more supple tires (tires with thinner and lighter treads and casings) do better on drums that non-supple tires. And no data is presented to back up what is "the full advantage you get from running supple tires," at least in terms of rolling resistance.

In my reading of the article, what Jan Heine is really saying is that he doesn't understand how to apply drum test data, so he just assumes it is useless.

Well, JH says the opposite and I haven't seen test results that show that supple tires do better or not on drum tests.

[reuben]

Originally Posted by AngryScientist

I didnt read any of the previous responses, but the fastest tires I have used in recent history are Specialized S-Works Turbo Cotton tires. Zoom zoom!

I don't know if mine are S Works or not, but they're fast for sure. Maybe S Works is the only kind, I dunno.

Oh. And they're clinchers with butyl tubes. 24mm.

[glepore]

Originally Posted by AngryScientist

I didnt read any of the previous responses, but the fastest tires I have used in recent history are Specialized S-Works Turbo Cotton tires. Zoom zoom!

That's cause only one or two address the question asked, the rest is a debate about method and rolling resistance.
And yeah, I mentioned those earlier. Good enough for Tony Martin, good enough for me. But fragile.

[Mark McM]

Originally Posted by RoosterCogset

Came across this quote in the article linked. I wonder if the miniscule chevron tread you get on Vittoria Corsas (just one example) is related to the idea that there's evidently some ways in which some tires can have less drag vs other tires (eg. golfball dimples rationale)? Moreso than being just about grip. I assume the below referenced tests were for the same width tires on the wheelset (otherwise this would be a 'no kidding' statement).

“Several years ago, we tested the same aero front wheel with tires manufactured by five different manufacturers. We were astounded to learn that wheel drag could vary by up to nine percent depending upon tire selection."

https://www.bicycling.com/skills-tip...on-in-cycling/

In wind tunnel testing, the Continental GP 4000 tire was found to have lower air resistance than just about any other tire. It has been theorized that this is due to the pattern imprinted on the sides of the tread tripping the boundary layer (much like dimples on a golf ball). The Continental tire designers have admitted that they hadn't done this on purpose, it was just a lucky accident. But since then, designers of road racing tires have been purposely designing their treads to improve aerodynamics.

SwissSide has tested a variety of tires in the wind tunnel. They even tested the Continental Grand Prix mounted both forward and backward (according to the arrows printed on the casing), and found that it had less aero drag when mounted backwards.

[Mark McM]

Originally Posted by MikeD

This article says "at the recommended pressures." What's the source for the recommended pressures? It doesn't say.

This article says something different https://www.bicyclerollingresistance...000-comparison

At the 15% tire drop air pressures, which are very close to the recommended air pressures for a given size, the tables are turned and a bigger road bike tire will have a higher rolling resistance. The higher rolling resistance of the bigger tire is because it provides more comfort at the 15% tire drop air pressure.

We feel the ultimate test is adjusting all tires to the same comfort level. When all tires are adjusted to the same comfort level, rolling resistance is nearly the same (0.2 watts max) for all sizes of the GP 5000.

This is suspect as well because I'd want to run a wider tire at an even lower pressure, not to equal the same comfort level as a narrower tire. Otherwise, what's the point of even running a wider tire?

As above, it is not really valid to compare the rolling resistances of tires of different widths at the same pressure, when you'd normally be using less pressure in a wider tire. So if tests show that tires of different widths have roughly the same rolling resistance when inflated to equal comfort pressure, then why use wider tires? Because the roller tests only measure hysteresis losses, not suspension losses. Wider tires at lower pressure have less suspension loss than narrow tires at higher pressures, so depending on the pavement surface, wider tires can have lower total rolling resistance.

Even while roadies were convinced that narrower, higher pressure tires were always faster, MTBers already knew that on rougher surfaces, wide low pressure tires actually were faster. Cyclocross racers knew this too. It is only recently that roadies have been catching on. On super smooth surfaces like indoor velodromes, narrow high pressure tires (and their lower aero drag) may still rule the day, but out in the wild, where surfaces can be rougher, wider tires can be faster.

[RoosterCogset]

Originally Posted by Mark McM

In wind tunnel testing, the Continental GP 4000 tire was found to have lower air resistance than just about any other tire. It has been theorized that this is due to the pattern imprinted on the sides of the tread tripping the boundary layer (much like dimples on a golf ball). The Continental tire designers have admitted that they hadn't done this on purpose, it was just a lucky accident. But since then, designers of road racing tires have been purposely designing their treads to improve aerodynamics.

SwissSide has tested a variety of tires in the wind tunnel. They even tested the Continental Grand Prix mounted both forward and backward (according to the arrows printed on the casing), and found that it had less aero drag when mounted backwards.

Interesting. Are any of these tests publicly posted showing comparisons? Thought this was a different take on the grippy/fast discussion, which has mostly focused on rolling resistance, but not considering possibility that little things that might be related to tread/grip, could have a positive (or negative?) impact on drag and hence the fast aspect.

This recent article seems somewhat relevant to this side discussion:

https://bikerumor.com/dt-swiss-swiss...d-tire-patent/

[Louis]

Seems to me there's only one possible answer to the OP's question: