It’s a bit silly to bail on tomorrow if it’s raining- it will be your best chance of hanging on Saturday by getting some pointers and practicing your bike handling.
Your tyres will be fine- again, you should use tomorrow to play with pressures.
As I said before- it’s a fine line between contesting the sprint and getting dropped. And that line won’t be decided by how many watts you put out but by how few you have needed and how low your HR has been thus far.
It was amazing how strong the draft of 80 riders was and even if your ftp was 400w- you ain’t going to be catching back on to a 24mph bunch in a 17mph headwind 😉
It literally took me 550-600w to maintain the gap to them last week.
If you go back to the beginning of this thread and read TiRed’s pointers (and others) it’s all there- it just may take a few goes to realise he was right 😉
The opening couple of laps were crazily slow last week- you’ll hang no problem. But if you’re hanging in the wind, riding solo effectively, you won’t have the reserves when the pace inevitably ramps up.
Also, take the pressure off mentally by having a clear plan. If this happens- I’ll do that etc etc
It’s chess on wheels and thinking straight at max HR is more than half of the battle.