Axle rows, now that is funny...
Thinking about one grip exercise since I don't have a fat bar I guess it would have to be have towel P/U's. I just really don't know which grip exercise has the most carry over. I love pinch grip training and rolling thunder DL's. Rolling thunder DL's smoke my entire forearm and grip so I am guessing that is similar to the axle lifts.
What we think, or what we know, or what we believe, is in the end, of little consequence. The only thing of consequence is what we do. -John Ruskin