24

From TrialsWiki

There are a few 24" trials bikes available, including the Onza Zoot, Inspired Fourplay, Ciguena, Reset, Curtis, Frest Products FPTwentyFour and Leeson fluid 609.

24" trials bikes are considered more 'streety' than either stock or mod with riders tending to be more creative in their riding, mixing street and BMX moves with traditional trials.

As of yet they are unable to compete, due to them not being catogorised in either 20" or 26" which disallow their use in existing competitions. There are also currently no 24" competitions.