160 BPM

Riding with a group yesterday, trying not to go too fast that I fragment the group.  I found that if I ride at heart rate of 160, they can keep up.  When I get to 165, I lose them.  I can go for a good period of time at 160.  I can probably maintain 165 for only about 10 minutes before my legs start to feel like rubber.  My heart rate usually gets that high only when I'm climbing or pulling at the front.  I peak out at about 180-185 - I can only hold that for about 30 seconds on a steep climb out of the saddle, and then I really have to slow down to catch my breath.  It's good to know this sort of thing when you're trying to keep the group together.