That's basically the gist of it. The added drag from having more weight is less than the power increase that having more weight allows. Being tall is helpful too. I believe Finian (previous record holder) is about 260lb and probaby in the 6'-3" to 6'-5" range. Antione Albeau is about 6'-1", 200 or 210lbs. Either of these riders may have been wearing weight as well.
Skill and equipment obviously have a lot to do with it too. Antoine is a very accomplished professional racer.
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