Are mountain bike tyres actually faster than gravel tyres? Recent trends suggest they might be, with top gravel pros maxing out tyre clearance and opting for wider MTB tyres in major races. But do the claims hold up in real-world conditions?

In this episode, we dive deep into the numbers with John Karrasch, a bike fitter, physiotherapist, performance tester, and Escape Collective member who has been conducting his own field testing using the Chung Method.

Unlike traditional drum tests, which measure rolling resistance in controlled lab conditions, John’s testing focuses on real-world gravel surfaces, combining rolling resistance, aerodynamics, and surface effects.

We explore:

• The surprising results that challenge long-held assumptions about gravel tyre performance
• Why traditional rolling resistance tests might not tell the full story
• How real-world testing methods like the Chung Method work
• The impact of tyre width, casing compliance, and aerodynamics on speed
• What these findings mean for your own gravel bike setup

If you’re serious about tyre selection for gravel, or just want to know if you can enjoy the grip and puncture resistance of a wider tyre without the speed penalty you might expect this episode (paired with our earlier deep dive with Robert Chung) is essential listening.

Timestamps:

0:00 - 3:30: Introduction

• Ronan introduces the episode and guest, John Karrasch.
• Overview of the episode’s focus: real-world gravel tyre testing.
• Karrasch’s background as a bike fitter, physiotherapist, and coach.

3:30 - 8:00: The inspiration for tyre testing

• Karrasch shares his initial surprise at how fast MTB tyres felt on gravel.
• The influence of pro riders like Keegan Swenson and Payson McElveen running MTB tyres in gravel races.
• Questioning whether wider MTB tyres are genuinely faster or if perception plays a role.

8:00 - 13:45: The testing method: Why use the Chung Method?

• Introduction to the Chung Method (Virtual Elevation Testing) for real-world tyre testing.
• How the method isolates rolling resistance and aerodynamics.
• Why drum tests don’t fully capture real-world tyre performance.
• Karrasch’s approach to controlling variables like rider position, kit, and environmental factors.

13:45 - 20:20: The tyre lineup and test surfaces

• Tyres tested:
  • Continental Terra Speed 45 mm
  • Continental Terra Hard Pack 50 mm
  • Continental Race King 2.2”
  • Vittoria Peyote XC Race 2.4”
  • Maxxis Aspen 2.4”
  • Schwalbe Thunder Burt 2.1”
• Explanation of the three gravel categories used for testing.

20:20 - 30:00: Results: What’s actually fastest?

• The Continental Race King 2.2” outperforms traditional gravel tyres on Category 2 gravel.
• The Vittoria Peyote 2.4” performs best on rougher Category 3 terrain.
• Schwalbe Thunder Burt 2.1” initially strong, but Peyote overtakes it on chunkier surfaces.
• Discussion on why wider tyres reduce rolling resistance more than expected.

30:00 - 38:00: Surprising findings & key takeaways

• Rolling resistance matters more than weight or aerodynamics in gravel racing.
• MTB tyres outperform gravel tyres more consistently than expected.
• The role of tyre casing compliance in real-world conditions.

38:00 - 45:00: Challenging traditional tyre rankings

• How lab-based rolling resistance tests fail to predict real-world performance.
• The disconnect between drum test rankings and on-road results.
• The impact of tyre pressure, terrain variability, and casing flex.

45:00 - 54:30: Why Chung Method testing is challenging

• The importance of controlling for variables like body position, wind, and road surface.
• Common mistakes testers make when interpreting results.
• Why Karrasch doesn't use a baseline tyre for each test session.

54:30 - 1:05:00: What this means for gravel riders

• Should gravel riders reconsider tyre width?
• How to apply this data to race-day tyre selection.
• The importance of personal testing and adaptation.

1:12:30 - End: Final reflections

• Closing thoughts on why real-world testing matters.
• The importance of nuanced discussions in gravel tyre selection.