strowler is not designed for street or park.
(some people might ride though without problems,but it is not the same strong as a street designed frame.
i guess the downtube that is oval doesnt let you ride harder types of riding as it will bend or even crack near the welds.)
Hoffman will not guarantee you a cracked strowler from riding street,thats what i was told from hoffman bikes when i emailed them to ask if the frame is strong for street riding.
but yeah it must be superstrong for flat and can take some street punishment i guess since it has thicker tubes.
i guess there will not be a problem from grinding rails since you will not hop very high