Reigning UK National Hill Climb champion Harry MacFarlane has taken the joint Strava KOM on what is claimed to be San Francisco’s steepest street, matching a time that hasn't been bested since 2011.
The British rider tackled Green Street – a frighteningly vertiginous ascent with gradients reported to average around 41% – matching a long-standing time set in December 2011 by Brooks Sizemore.
According to his uploaded data, MacFarlane hit a peak power of 1,252W, averaging 878W for the 21-second effort.
Commenting on Strava, he summed up the ride: “41% is fu*king wild.”
San Francisco is no stranger to extreme gradients. A commonly cited 2016 article claims the top 10 steepest streets have an average gradient of at least 31%.
MacFarlane retained his UK National Hill Climb Championship titles in 2025 with a record-breaking run up Matlock’s Bank Road, producing an extraordinary 707W average and a peak power-to-weight ratio of 9.9W/kg.
