On the Cervelo S5 + 808. Read that it’s marginally quicker than the Tron concept bike.
You want a climbing bike for the Alpe. Especially if you get the Lightweight Meilensteins with the Specialized Tarmac Pro. Enve SES 3.4s are the next best hoops.
That said, I did 58:33 yesterday, and I was level 6. So the standard Zwift Carbon and 32 mm wheels.
259W average, 77 kg, so 3.36W/kg, 1062 VAM. My pacing wasn’t ideal - from bend 10 to the finish was 28:32, 274W, 1108 VAM. Last 6 hairpins, 15:24, 283W, 1129 VAM.
My general strategy isn’t, as some have said, to push harder on the hairpins. Instead, pushing harder on the steep bits gets them over quickly, relax on the lighter bits a bit. Of course, drafting might change things, but I don’t think the speeds are high enough to compensate for losing power on the ramps.
ZwiftPower compiled some nice data for L’Alpe de Zwift for different powers / mass. There’s a surprising amount of scatter in the data, but there’s a clear trend, and it provides a nice reference:
Here’s a regression on those data I did, along with a dashed line showing a formula suggested by Robert Chung: