All tyres of any particular diameter are offered in several different widths ranging from “fat tackies” to “pizza cutters”. Wider tyres are conspicuously the predominant choice for style but, other than that, what are the actual advantages and disadvantages? What factors should determine choice? --DRG
The technicalities of different tyres are much more complicated than you might think.
Width is just one aspect. Others include diameters, tyre-wall height profiles, ply ratings and flexion, tread patterns, air pressures, and casing construction materials.
So, the first and abiding answer is “You can’t have it all.”
Anything which improves one aspect will compromise something else.
To keep things simpler and hopefully clearer, let’s summarise the quest as comparative “grip” and “comfort”.
And with all the foregoing aspects in mind, focus on the particular attributes of “fat” and “skinny” tyres (assuming all other factors are equal…which they rarely are).
Amid all the pros and cons, a primary consequence of fatter tyres is that they are markedly more competent in soft sand because they are more tolerant of low pressures and are likely to “float” on the top instead of digging in.
Skinny tyres are usually better in slippery mud because they do dig in more, find grippier substrates (instead of sliding or spinning on the surface) and give more grip to keep you moving forward and more sideways grip for steering control.
Fatter tyres are intrinsically “bigger”, so there is more air cushion (better heat dissipation), but they are heavier (performance downside) and more expensive.
Fat tyres (fat-tackies) are more competent in soft sand because they are more tolerant of low pressures and are more likely to 'float' on the surface rather than dig in.
Photo credit: File| Shutterstock
Skinny tyres are lighter and cheaper, with advantages to performance and fuel consumption but have more sidewall flexion (more comfort at normal pressure but less tolerance of lower pressures).
Perhaps surprisingly, at normal pressures on smooth tarmac, both have almost identical footprints, which are circular at normal pressures so have similar wear life.
Weigh the pros and cons and decide which is better for your personal vehicle and usage patterns.