Para los que les interesa saber mas del tema, les dejo el link
http://www.expeditionswest.com/resea...tion_rev1.html
y un pequeño resumen para los que no tenga tiempo que tambien aparece en el link.
The impact of tire width on traction
Position: A tall, narrow tire is a superior choice for all off-highway surface conditions with the exception of deep, soft sand or mud.
Summary:
This is an empirical summary of my position. The supporting details of this argument are contained in the body of the document. The start of my study came as a result of asking the critical question. What is better for most trail surfaces; a wide or narrow tire?
This initially led me to research the physics of tire traction, which is mostly related to dynamic friction as the vehicles are not just parked on a surface trying to maintain a static state. There has been some research on the subject related to performance vehicles and race cars, operating on highly tactile surfaces, and running at high speeds (and subsequent heat generation), but there was no significant research done for off-highway vehicle operation. So I spent several months researching the subject, testing the logic and formulating a position. Why a position, and not a conclusion or "law" of tire performance? For me to proclaim a conclusion would require much greater testing volume, samples, variables etc., which time does not allow. So, the following is my position.
When driving off-highway, the performance of a vehicles tires is influenced by the elements of friction as related to the following items: Adhesion, momentary molecular bonding, deformation and mechanical keying (Haney, 2003). Where a race car operates on a highly tactile surface, which allows wide, even smooth tires to perform exceptionally (due to adhesion and bonding), an off-highway vehicle operates in the exact opposite environment, with minimally tactile surfaces. Rocks, dirt ledges, dusty boulders, highly irregular surfaces, sandy washes, etc. occupy the fourwheeler's environment. Surfaces that do not provide high adhesion rates or momentary bonding. However, these surfaces are highly irregular, which does provide the opportunity to take advantage of mechanical keying and deformation. These traction elements require high contact pressure, coupled with low air pressure to get the tire to flex with the terrain. A wide tire distributes the vehicles weight over too large of a surface, preventing deformation from occurring at the same rate as a narrow tire with the same pressure (force). A narrow tire will hold better than a wide one by keying to the surface aggregate due to the greater vertical force.
It is important for me to note that this document is NOT about reducing tire air pressure "airing down". Airing down provides its own performance benefits which are not covered in detail in this paper. For all examples assume that the wide and narrow tire are both at 15psi for the trail.
Abstract:
While the coefficient of friction (Ff = Cf x Fv) is linear and not affected by width (on a perfectly smooth surface, traction is consistent despite width), it is the variability of the road surface conditions off-highway that improves traction for a narrow tire. The greater the contact pressure, the greater of effectiveness of the friction elements of Deformation and Mechanical Keying. A narrow tire also presents less rotating resistance on a soft surface, like shallow mud, snow and sand. Additional performance is gained by the assumption that most vehicles can fit a taller tire if it is narrower, which provides greater axle clearance. Final arguments are made for the benefits related to reduced rotating mass and unsprung weight.
Saludos
CAXTROL