Bicycle Rolling Resistance is one of the most reputed sources online for rating tires, but some results are still a bit counter-intuitive, especially when tires have knobs.

I understand that the rolling resistance test is done on a hard surface (a steel metal plate with some safety), but how representative is this surface from surface in the real world? My impression is that the presence of knobs tend to underestimate the rolling resistance on hard surfaces on BRR. But are there other observations/measurement in their dataset that would allow to differentiate/nuance the rolling resistance number tires with very different thread patterns?

To give some context, I've seen that they added recently a semi-slick tire, that I'm using on a gravel bike for road rides (Michelin Power Adventure 48mm, but I'm using the 42mm). However, this tire has more rolling resistance than the "pure gravel tire" from Michelin in 40mm (Power Gravel). So if I accept the compromise of the lesser grip due to the little knobs, I may in fact be better off keeping the Power Gravel for road rides and gravel, and avoid having to swap wheels/tires. But other combinations can be found where the knobby tire performs similarly in BRR than a semi-slick tire, but probably not in real situation (for example: Specialized Pathfinder Pro vs Schwalbe Hans Dampf Pacestar).

EDIT: clarified the question to be closer to the original intent

Bicycle Rolling Resistance is one of the most reputed sources online for rating tires, but some results are still a bit counter-intuitive, especially when tires have knobs.

I understand that the rolling resistance test is done on a hard surface (a steel metal plate with some safety), but how representative is this surface from surface in the real world? My impression is that the presence of knobs tend to underestimate the rolling resistance on hard surfaces on BRR. But are there other observations/measurement in their dataset that would allow to differentiate/nuance the rolling resistance number tires with very different tread patterns?

To give some context, I've seen that they added recently a semi-slick tire, that I'm using on a gravel bike for road rides (Michelin Power Adventure 48mm, but I'm using the 42mm). However, this tire has more rolling resistance than the "pure gravel tire" from Michelin in 40mm (Power Gravel). So if I accept the compromise of the lesser grip due to the little knobs, I may in fact be better off keeping the Power Gravel for road rides and gravel, and avoid having to swap wheels/tires. But other combinations can be found where the knobby tire performs similarly in BRR than a semi-slick tire, but probably not in real situation (for example: Specialized Pathfinder Pro vs Schwalbe Hans Dampf Pacestar).

EDIT: clarified the question to be closer to the original intent

Bicycle Rolling Resistance is one of the most reputed sources online for rating tires, but some results are still a bit counter-intuitive, especially when tires have knobs.

I understand that the rolling resistance test is done on a hard surface (a steel metal plate with some safety), but how representative is this surface from surface in the real world? My impression is that the presence of knobs tend to underestimate the rolling resistance on hard surfaces on BRR. But are there other observations/measurement in their dataset that would allow to differentiate better tires with very different thread patterns?

To give some context, I've seen that they added recently a semi-slick tire, that I'm using on a gravel bike for road rides (Michelin Power Adventure 48mm, but I'm using the 42mm). However, this tire has more rolling resistance than the "pure gravel tire" from Michelin in 40mm (Power Gravel). So if I accept the compromise of the lesser grip due to the little knobs, I may in fact be better off keeping the Power Gravel for road rides and gravel, and avoid having to swap wheels/tires. But other combinations can be found where the knobby tire performs similarly in BRR than a semi-slick tire, but probably not in real situation (for example: Specialized Pathfinder Pro vs Schwalbe Hans Dampf Pacestar).

EDIT: clarified the question to be closer to the original intent

Bicycle Rolling Resistance is one of the most reputed sources online for rating tires, but some results are still a bit counter-intuitive, especially when tires have knobs.

I understand that the rolling resistance test is done on a hard surface (a steel metal plate with some safety), but how representative is this surface from surface in the real world? My impression is that the presence of knobs tend to underestimate the rolling resistance on hard surfaces on BRR. But are there other observations/measurement in their dataset that would allow to differentiate/nuance the rolling resistance number tires with very different thread patterns?

To give some context, I've seen that they added recently a semi-slick tire, that I'm using on a gravel bike for road rides (Michelin Power Adventure 48mm, but I'm using the 42mm). However, this tire has more rolling resistance than the "pure gravel tire" from Michelin in 40mm (Power Gravel). So if I accept the compromise of the lesser grip due to the little knobs, I may in fact be better off keeping the Power Gravel for road rides and gravel, and avoid having to swap wheels/tires. But other combinations can be found where the knobby tire performs similarly in BRR than a semi-slick tire, but probably not in real situation (for example: Specialized Pathfinder Pro vs Schwalbe Hans Dampf Pacestar).

EDIT: clarified the question to be closer to the original intent

Bicycle Rolling Resistance is one of the most reputed sources online for rating tires, but some results are still a bit counter-intuitive, especially when tires have knobs.

I understand that the rolling resistance test is done on a hard surface (a steel metal plate with some safety), but how representative is this surface from surface in the real world? My impression is that the presence of knobs tend to underestimate the rolling resistance on hard surfaces on BRR. But are there other observations in that sense?

To give some context, I've seen that they added recently a semi-slick tire, that I'm using on a gravel bike for road rides (Michelin Power Adventure 48mm, but I'm using the 42mm). However, this tire has more rolling resistance than the "pure gravel tire" from Michelin in 40mm (Power Gravel). So if I accept the compromise of the lesser grip due to the little knobs, I may in fact be better off keeping the Power Gravel for road rides and gravel, and avoid having to swap wheels/tires.

Bicycle Rolling Resistance is one of the most reputed sources online for rating tires, but some results are still a bit counter-intuitive, especially when tires have knobs.

I understand that the rolling resistance test is done on a hard surface (a steel metal plate with some safety), but how representative is this surface from surface in the real world? My impression is that the presence of knobs tend to underestimate the rolling resistance on hard surfaces on BRR. But are there other observations/measurement in their dataset that would allow to differentiate better tires with very different thread patterns?

To give some context, I've seen that they added recently a semi-slick tire, that I'm using on a gravel bike for road rides (Michelin Power Adventure 48mm, but I'm using the 42mm). However, this tire has more rolling resistance than the "pure gravel tire" from Michelin in 40mm (Power Gravel). So if I accept the compromise of the lesser grip due to the little knobs, I may in fact be better off keeping the Power Gravel for road rides and gravel, and avoid having to swap wheels/tires. But other combinations can be found where the knobby tire performs similarly in BRR than a semi-slick tire, but probably not in real situation (for example: Specialized Pathfinder Pro vs Schwalbe Hans Dampf Pacestar).

EDIT: clarified the question to be closer to the original intent