The swim brief with 1.5 inch (4 cm) sides. Who would dare to wear one?
Normally Speedo have manufactured briefs with 2 inch sides, but more recently they've widened them. But according to Wikipedia:
http://en.wikipedia.org/wiki/Swim_briefs
'The most common racing suit styles are 1.5 inch to 3 inch paneled briefs (as measured by the height and length of the suit's side panel).'
And it's not that they're difficult to find. In the Swim Brief section of Figleaves, for example, nearly half of the suits are that width.
http://www.figleaves.com/uk/men/swim...SP3_swimbriefs
Of course, if you trawl the internet you can find much briefer suits, but who wears these? It's possible you might see this at a beach resort, but not a public indoor pool where the dress code is stricter.
It would seem that the 1.5 inch swim brief is the minimum you can wear while still maintaining respectability.