The size of a cigar affects many things for sure, and not just the time it takes a cigar to burn. There are two main reasons why, as a general rule of thumb, smaller sized cigars of the same blend are different than their larger counterparts. Even though many people seem to believe they are simply bigger versions of the same brand.
The most obvious difference between a smaller ring gauge cigar and a larger one is the amount of filler. Even though the smaller cigar will also use slightly less wrapper, as a little math shows, when the cigar gets fatter, the amount of filler gets (literally) exponentially larger.
Take a 60 ring gauge cigar versus a 40 ring gauge smoke. Using some basic middle school geometry, you can see that while about 50% more wrapper is required to go around the 60 ring gauge cigar, it will also use roughly 125% more filler.
Because wrapper tobacco is generally the most expensive component, the smaller cigar will be cheaper.
Higher Burn Temperature
The second, possibly more important, and certainly more often overlooked reason that smaller ring gauge cigars are fuller flavoured is that they tend to burn hotter and more quickly. If you think about a cigar as a straw through which air is pulled, this makes plenty of sense.
Cigar smokers generally take similarly sized draws no matter the thickness of the cigar. This means that air is drawn through the foot of a smaller cigar at a faster rate than through a larger cigar, creating more air flow, more oxygen, and a higher combustion temperature.
Drew Estate President, and encyclopaedia of cigar knowledge, Steve Saka estimates the difference in temperature can be 10 degrees or possibly more between a smaller (40 or 42 ring gauge) cigar and a larger one.