The stans notubes flow s1 29er wheelset burly enough to handle the toughest of trails yet light enough to pedal all day the flow s1 is up for any challenge developed from rims ridden in red bull rampage and raced on the world cup dh circuit for years the s1 is now ready for action with a 16mm deeper profile and reinforced rim walls the new flow s1 offers greater impact strength for an even wider range of use with only a minor weight gain strong and light 6061 alloy rims stainless steel