Boulder Critical Mass
Boulder's monthly last-Friday bike takeover. Hundreds of cyclists flood the streets in a joyful, slow-rolling celebration of bikes over cars.
The vibe
Streets belong to bikes tonight
Once a month on the last Friday, Boulder cyclists of every stripe — commuters, cruisers, fixie riders, cargo bike parents, and the occasional unicyclist — converge and take to the streets together. It’s not a race, not a tour, and nobody’s timing you. Critical Mass is the city riding itself, a rolling reminder that bikes belong here too.
The ride winds through Boulder’s neighborhoods at a pace anyone can keep up with. Expect corking at intersections, a lot of noise from bells and horns, and that particular energy that comes from being in a crowd of people all doing something they love. Kids and dogs are welcome. So are decorated bikes, costumes, and whatever playlist you’re blasting from that speaker you strapped to your rack.
Boulder’s version of Critical Mass tends to stay accessible and welcoming — this is a university town with a deep cycling culture, so the crowd is genuinely diverse. Show up at Pearl Street around 5:30 PM on the last Friday of the month, look for the bikes, and you’ll find it. No RSVP, no registration, no fee. Just show up and ride.