I just started playing this game and after about an hour and a half I've gotten up to the 4th level on hard. I had to quit after that though... That level had me press the b button (retry) a total of 166 times.
 
What's the most that you've retried on a course?

 @yeahno: Your not tried enough if you haven't hit the limit. One track I finally hit the finish line with 2 minuets to spear and 10 wipeouts left. I think it was 30min and 500 wipes max

Trying to beat Inferno II on Extreme either uses up all my faults or goes beyond the time limit.

I remember the first few times I tried the extreme tracks, I'd get up to the maximum faults and quit.

I got up to the limit on Inferno II twiiiice. In a row.
 
 Now I have 4 faults in it. B-)

A bit over 100 I believe. I now have gold on all the extreme tracks including the DLC ones. :)