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For the effect of knobs on otherwise identical tires, see this comparison on BRR. Less than 10% RR and no grip penalty for 1.3mm knobs vs a slick tire on the exact same casing. Lower-end tires might show a bigger discrepancy, but not by much. I'm not surprised by these results.

1. I wouldn't expect ultimate grip to differ much on gravel-type knobbies. Although the Getaway is particularly well-behaved on asphalt for an all-condition tire, its lateral profile is essentially round. It feels pretty much like a slick to corner hard on asphalt.
2. When talking about gravel-type tires, the knobs are under 2mm and just don't flex that much, so they don't have a very large contribution to rolling resistance.

The knobs are just one factor, in the end. We often think they make the biggest difference because we are used to comparing cheap 26x2.1 MTBs with expensive road bikes flying past us from back before we seriously got into bikes, I think. I also fervently follow BRR, and my impression has been that the factors that affect RR are, in order:

1. Casing construction and thickness
2. Then tread thickness and compound
3. Then knobs

And if you can't or won't run tubeless, get latex tubes. It's the cheapest way to improve your rolling resistance and in fact the most speed per dollar you can buy short of a gym membership.

For the effect of knobs on otherwise identical tires, see this comparison on BRR. Less than 10% RR and no grip penalty for 1.3mm knobs vs a slick tire on the exact same casing. Lower-end tires might show a bigger discrepancy, but not by much. I'm not surprised by these results.

1. I wouldn't expect ultimate grip to differ much on gravel-type knobbies. Although the knobby in the linked comparison, the Challenge Getaway, is particularly well-behaved on asphalt for an all-condition tire, since its lateral profile is essentially round. It feels pretty much like a slick to corner hard on asphalt.
2. When talking about gravel-type tires, the knobs are under 2mm and just don't flex that much, so they don't have a very large contribution to rolling resistance.

The knobs are just one factor, in the end. We often think they make the biggest difference because we are used to comparing cheap 26x2.1 MTBs with expensive road bikes flying past us from back before we seriously got into bikes, I think. I also fervently follow BRR, and my impression has been that the factors that affect RR are, in order:

1. Casing construction and thickness
2. Then tread thickness and compound
3. Then knobs

And if you can't or won't run tubeless, get latex tubes. It's the cheapest way to improve your rolling resistance and in fact the most speed per dollar you can buy short of a gym membership.

For the effect of knobs on otherwise identical tires, see this comparison on BRR. Less than 10% RR and no grip penalty for 1.3mm knobs vs a slick tire on the exact same casing. Lower-end tires might show a bigger discrepancy, but not by much.

  I'm not surprised by these results - first, I wouldn't expect ultimate grip to differ much on gravel-type knobbies, although the Getaway is particularly well-behaved on asphalt for an all-condition tire, its lateral profile is essentially round. It feels pretty much like a slick to corner hard on asphalt. Second, when talking about gravel-type tires, the knobs are under 2mm and just don't flex that much, so they don't have a very large contribution to rolling resistance.

The knobs are just one factor, in the end. We often think they make the biggest difference because we are used to comparing cheap 26x2.1 MTBs with expensive road bikes flying past us from back before we seriously got into bikes, I think. I am also fervently following BRR, and my impression has been that it's casing construction and thickness, then tread thickness and compound, then knobs that affect RR. And if you can't or won't run tubeless, get latex tubes, it's the cheapest way to improve your rolling resistance and in fact the most speed per dollar you can buy short of a gym membership.

For the effect of knobs on otherwise identical tires, see this comparison on BRR. Less than 10% RR and no grip penalty for 1.3mm knobs vs a slick tire on the exact same casing. Lower-end tires might show a bigger discrepancy, but not by much. I'm not surprised by these results.

1. I wouldn't expect ultimate grip to differ much on gravel-type knobbies. Although the Getaway is particularly well-behaved on asphalt for an all-condition tire, its lateral profile is essentially round. It feels pretty much like a slick to corner hard on asphalt.
2. When talking about gravel-type tires, the knobs are under 2mm and just don't flex that much, so they don't have a very large contribution to rolling resistance.

The knobs are just one factor, in the end. We often think they make the biggest difference because we are used to comparing cheap 26x2.1 MTBs with expensive road bikes flying past us from back before we seriously got into bikes, I think. I also fervently follow BRR, and my impression has been that the factors that affect RR are, in order:

1. Casing construction and thickness
2. Then tread thickness and compound
3. Then knobs

And if you can't or won't run tubeless, get latex tubes. It's the cheapest way to improve your rolling resistance and in fact the most speed per dollar you can buy short of a gym membership.

For the effect of knobs on otherwise identical tires, see this comparison on BRR. Less than 10% RR and no grip penalty for 1.3mm knobs vs a slick tire on the exact same casing. Lower-end tires might show a bigger discrepancy, but not by much.

I'm not surprised by these results - first, I wouldn't expect ultimate grip to differ much on gravel-type knobbies, although the Getaway is particularly well-behaved on asphalt for an all-condition tire, its lateral profile is essentially round. It feels pretty much like a slick to corner hard on asphalt. Second, when talking about gravel-type tires, the knobs are under 2mm and just don't flex that much, so they don't have a very large contribution to rolling resistance.

The knobs are just one factor, in the end. We often think they make the biggest difference because we are used to comparing cheap 26x2.1 MTBs with expensive road bike tires from before we seriously got into bikes, I think. I am also fervently following BRR, and my impression has been that it's casing construction and thickness, then tread thickness and compound, then knobs that affect RR. And if you can't or won't run tubeless, get latex tubes, it's the cheapest way to improve your rolling resistance and in fact the most speed per dollar you can buy short of a gym membership.

For the effect of knobs on otherwise identical tires, see this comparison on BRR. Less than 10% RR and no grip penalty for 1.3mm knobs vs a slick tire on the exact same casing. Lower-end tires might show a bigger discrepancy, but not by much.

I'm not surprised by these results - first, I wouldn't expect ultimate grip to differ much on gravel-type knobbies, although the Getaway is particularly well-behaved on asphalt for an all-condition tire, its lateral profile is essentially round. It feels pretty much like a slick to corner hard on asphalt. Second, when talking about gravel-type tires, the knobs are under 2mm and just don't flex that much, so they don't have a very large contribution to rolling resistance.

The knobs are just one factor, in the end. We often think they make the biggest difference because we are used to comparing cheap 26x2.1 MTBs with expensive road bikes flying past us from back before we seriously got into bikes, I think. I am also fervently following BRR, and my impression has been that it's casing construction and thickness, then tread thickness and compound, then knobs that affect RR. And if you can't or won't run tubeless, get latex tubes, it's the cheapest way to improve your rolling resistance and in fact the most speed per dollar you can buy short of a gym membership.