Gravel Cyclist's Tire Dilemma: Knobbies or Slicks? 1/8

Read this, if you are a critical thinking gravel or allroad cyclist

Majority VS Minority

A segment of gravel cycling tires is growing rapidly during last years. More and more tire producers all over the world offer more and more different gravel specific tires. A look at these reveals that they typically have a knobby pattern, which makes them similar to MTB tires. However, in comparison to MTB tires, gravel tires often have smaller knobs which are sometimes even further reduced to an (almost) semi slick pattern in the center of the tread.

As the supply and the demand tend to correspond to each other, it doesn't surprise that a majority of cyclists choose knobbies for their gravel rides.

So far, the picture is clear. Yet at the same time there are some tire producers who also offer slick tires for gravel cycling (Panaracer, Compass, Soma, WTB etc). Correspondingly, there seem to be some gravel cyclists out there who swear on slicks.

Should we take the idea of riding gravel on slicks as a caprice practiced by minority alone? Doesn't such a deviant behaviour only prove the well established general rule that a cyclist should use knobbies on all surfaces but hardpack?

A knobby or a slick for riding gravel? Schwalbe Racing Ralph 700x33 mm on the left, and Compass Snoqualmie Pass 700x44 mm on the right.

The Turn in Our Heads

It is hard for an individual to step out of long-trodden patterns, in particular if the patterns are shared by the majority. For in this case the patterns not only seem to be true for the individual but also are presented as the established general truth valid for all. Unfortunately, every general truth makes its followers see facts affirming it, and disregard or misinterpret facts opposing it.

For example, majority of cyclists are convinced and feel that narrower and more inflated tires role faster than wider and less inflated ones. What majority doesn't know is that both its conviction and feeling are based on the assumption that all vibrations are indicative of speed. The logic behind the assumption can be illustrated like this: »When I stand beside my bicycle, my speed is zero, and there is no vibrations coming from my bicycle. The faster I cycle, the more vibrations come from my bicycle. Thus, more vibrations mean more spead«. This sounds simple and clean at the first sight. Yet as we bring some other parameters into the equasion, its simplistic logic turns to be wrong. Namely, it totally disregards the huge influence of tire width and tire pressure on the vibrations. The narrower the tires, the higher pressure is required for their optimal operation. The higher pressure inevitably means harder tires. And harder tires inevitably generate more vibrations. This means that at a given speed, narrower and more inflated tires vibrate more, due to which they only feel faster, while in fact they are not.

Cycling through a short cobblestone section of Gravelest's Great Larch S-route might give the final push in understanding that more vibrations don't always mean higher speed.


Credibility of the Article

The author of the article is Matej Goršič [Matey Gorshich], 41, male, PhD, who has been an active sportive cyclist for 28 years. In his youth, he trained, and competed in, road cycling and athletics. Once finally out of the competitive waters, he started consciously re-defining his understanding and practice of cycling. Today, he feels most at home in a creative mixture of non-competitive, electronic-devices-free, self-exploring, adventurous allroad cycling.During last 3 years, he spent over 25.000 km mostly on tiny gravel roads of South Estonia.

The tires tested for the article were bought by its author at normal market prices from different cycling shops in Europe. There have been no sponsors or donations for writing the article nor for mentioning brands and items in the article and showing them in its photos.

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