At 70-80 meters, I wouldn't have even tried to bridge. I would have sat near the front and watched. If the guys were really going to stay away, the gap would have gotten bigger.
I like to make sure the break is going to make it before I use up most of what I have in catching them. Its a fine line, if you let them get away too far and they stay off, then you will blow up trying to bridge or be so exhausted that you won't have anything for the final sprint. But I tend to err on going later than sooner. The vast majority of breaks get reeled in and if you bridge and then get caught, its game over for you.
But its good you are willing to try to make something happen. I just hate being at the mercy of the peleton. I'd rather try something and fail than just get swept along in the pack with no purpose.
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Il faut de l'audace, encore de l'audace, toujours de l'audace
1980 3Rensho-- 1975 Raleigh Sprite 3spd
1990s Raleigh M20 MTB--2007 Windsor Hour (track)
1988 Ducati 750 F1