Did a nominal power busting ride with the TT club group Tues night. Rode the cross bike on 38mm treaded. It cost some watts for sure. But I guess if the delta on watts and weight is big enough it doesn't matter. I still could pull away pretty easily. 280w NP for the 1:15 ride. Felt good. When they push the start time back I'll just get in a 40min workout of intervals or something before the ride, then go on the ride and play sweeper in the future. Even with those tires and the cross bike it was too much a difference.
Garmin claims bike and run VO2max are up. 63 bike and 55 run. It's still a "novelty" number, but makes you feel good for work you've put into it.