Signed up for a 6 day bike ride in Colorado in June. I have done other 6 day rides via Ride the Rockies but this ride is considerably more challenging. 435 miles with 39,000' of elevation gain with the final day being Pikes Peak summit. 8,210' over 24 miles of climbing. Calulations says only an average of 6.15% grade but tops out at over 14,000' where oxygen gets a little thinner. But these are only numbers, right? Hard spin classes 3-4 times a week are going to get me there so needed to find local hills with an average grade of 6% for a mile or more and do repeats. Today was the start. 31 degrees this morning but by 1:00 it was a balmy 45. Wanted to do only 3 repeats but did a fourth on the way home. Hill climb was 7.5% to 8.4% so steeper than planned and speed varied between 6.6 mph and 5.6 mph so a good workout. Data: Plan was to stay in Level 1 and go to level 2 on the steepest parts. After 4 repeats, used 15% of the battery or 37.5 watts and climbed 4 miles i.e. 9.4 watts per mile. If the climb is 24 miles I would use 225 watts of the 250 watts available. That is IF I can maintain this burn rate for 24 miles. Doubtful. Hill was steeper than planned 6% ie 7.5%, 7.69%, 8.36% and 8.04% and average speed was 6.62mph, 6.41 mph, 5.65 mph and 5.62 mph. Shifted to level 2 about half way up the hill and back to level 1 to finish.