All tires of a given diameter come in a variety of sizes, from “fat tires” to “pizza tires.” Wider tires are the dominant choice in terms of design, but beyond that, what are the actual advantages and disadvantages? What factors should determine the choice? –DRG
The technical details of different tires are more complex than you might think.
Width is just one aspect. Other factors include diameters, sidewall height profiles, ply and flex ratings, tread patterns, air pressures, and casing construction materials.
The performance of any framework is affected by all of these factors, whether they are separate effects and consequences of each other or interrelated.
There’s also the vehicle they’re in, the roads they mostly use, the loads they’re carrying, and the ambient speeds they’re exposed to.
There are also implications for performance, durability, and cost. The full recipe for choice can be confusing.
In any of these setups, the frame is part of your suspension cushion, enabling you to turn, brake, and accelerate.
So, the first and always answer is: “You can’t have it all.”
Anything that improves one aspect will hurt something else.
To make things simpler and clearer, let’s summarize the task in a comparison between “grip” and “comfort.”
With all of the above in mind, focus on the specific characteristics of the “fat” and “skinny” tires (assuming all other factors are equal…which is rarely the case).
Of all the pros and cons, the main result of fatter tires is that they are significantly more efficient in soft sand because they are more tolerant of lower pressures and are more likely to “float” on the surface rather than dig into it.
Skinny tires are generally better in slippery mud because they sink more, find more grippy substrates (rather than sliding or spinning on the surface) and provide more grip to keep you moving forward and more lateral grip to control steering.
Thicker tires are inherently “bigger”, so there is more air cushion (better heat dissipation), but they are heavier (performance downside) and more expensive.
Fat (sticky, greasy) tires are more efficient in soft sand because they are more tolerant of lower pressures and more likely to “float” on the surface rather than dig into it.
Image source: File | Shutterstock
Skinny tires are lighter and cheaper, with performance and fuel economy advantages but have more sidewall flex (more comfort at normal pressure but less tolerance at low pressures).
Perhaps surprisingly, at normal stresses on smooth asphalt, both have almost identical imprints, which are circular at normal stresses and therefore have similar wear life.
Weigh the pros and cons and decide what is best for your personal vehicle and usage patterns.