Blowout flat on left front tire just entering Milford on prior ride. Called Laurie to SAG me 2 of the four GoCycle tires I had received from my purchase order with Wim Schermer a few days earlier. Replaced left front tube and tire and right front tire and headed back home instead of looping up around the Milford YMCA and library. These buggers are fast! I was spinning out a lot sooner on the downhills and otherwise holding speed easier. Speed threw me off coming up the little steep hill on Larkins and I threw the chain downshifting the crank rings. Had to walk it up the hill to a flat spot since rolling back like this is what led to replacing my rear derailleur the last time I did that - at this same spot. With my left leg clipped in and helping guide with my right hand on the chain tube and my right foot out the footwell pushing me forward I was able to reseat the chain and continue. LIKE these tires. Quiet. Fast. Turn radius doesn’t feel worse but I wasn’t pushing it on the u-turn at Pleasant Valley and Brandywine. The are 50-406 up from 42-406.