Metrics: > Entire Nate Harrison Rd from Hwy 76 to end at intersection with Boucher Hill Rd and Hwy S7: 9.4 mi; 4,223'; 9.1% avg grade; 15.2% max > Mixed terrain portion of Nate Harrison Grade, from pavement's end until return to continuous pavement: 7.0 mi; 3462'; 9.7% avg grade Cole Grade: The real work of Cole Grade starts 0.4 mi. past Old Cole Grade for 1.7 mi with 743' of elevation gain, an average grade of 8.4% (max. 12.2%). Ride description: Started with the OCWSatCentury group from Oceanside towards Palomar Mountain. It was a big turnout, included Chuck Bramwell, of course, Pete, Judy & Carl, Allison, Steve Meitry & Teresa Back on tandem, George Vargas and Lori on tandem, Stefan, and many others. While at Mother's, I was surprised and happy to see Hector from the High Country 1200k earlier this year. Anyway, when the others turned right onto Hwy 76 to head up S. Grade, I turned left and took Nate Harrison Grade up. (I also did a little .7 mi bonus, stupidly thinking I was making the left at Valley Center Rd.) A significant amount of Nate Harrison Rd is asphalt, and a lot of the rest of it was apparently paved at one time, but is now covered with gravel and/or dirt; regardless, the surface was more difficult for, maybe, 90% or more of the climb than what would be the case with regularly maintained pavement; traction was compromised and my wheel slipped a few times due to some soft dirt or sand (nothing nearly as bad as Santa Clara Divide from Bear Divide towards Mt. Gleason/Mill Creek Summit, though). The switchbacks are very exposed to the sun, and I was happy it was generally a cool day; still, it was nice to get up to the alpine area with trees where it was considerably cooler. I was riding the SL4 with the stock tires, racing 26mm, and they were fine; the easiest gearing I had was 34-28 and, if I had an 11-32 cassette, I would have used that 32 cog as there were a lot of pitches of a double digit grade. The views of Pauma Valley are great on this ride, and you can also see the Boucher Hill Fire Lookout Tower during much of the climb. As you start up through the orchards, you can see the switchbacks which are impressive, if not of the scale of Horseshoe Meadow. I caught many of the riders at Mother's, but heard I had just missed Pete who had started back down the S. Grade to get to Jeff's birthday party in the late afternoon. I caught Judy and her group on the way back from the observatory, and turned around and rode with them back to Mother's (so I only put in 3 mi/410' RT from Mother's towards the observatory, a 10 mi out-and-back), had warmed apple pie with vanilla ice cream, and - having gotten chilled while sitting around all that time - I bundled up for the descent like I was in the snow, only to have to strip everything off and pack it up again before climbing Cole Grade. Stopping and sitting down at rest stops makes staying warm much more complicated and costs me a lot more time than just the original stop when I have to put all that stuff on and take it off again a short while later. After Cole Grade, the rest of the ride back was pretty fast.