Disclaimer: Climb AT YOUR OWN RISK! Many of these will be difficult, strenuous, with dangerous descents. Do your own research and make sure you are prepared for the terrain. You are responsible for yourself!
Arapahoe Basin – From Keystone, a little beyond the halfway-point to the top of Loveland Pass. It is approximately 5 miles, but has a consistent 6% grade for most of the time. There are not too many curves on this climb, although that will change if you keep riding beyond the basin. I passed through Arapahoe on my way to Loveland Pass.
Battle Mountain Pass – This was my favorite climb on the Copper Triangle ride. It was short and not too steep, about two miles and 4% grade, but it was very scenic. You climb along a cliff ledge, cross an alpine bridge, while overlooking a lush valley below.
Copper Mountain – This is an easy, scenic climb from Frisco, with light grades and a little bit of rolling. It can be done on a bike path from Main Street, Frisco. I climbed this on my way to Vail Pass.
Fremont Pass – From Copper Mountain, this is a long climb of around 10 miles, with a few difficult sections of around 6%, where you gain a total of 1,500 feet in elevation. The smooth roads make this a pleasant climb, which starts out the Copper Triangle ride.
Hoosier Pass – This is a decent climb from Breckenridge or Alma. I did the climb from Breckenridge, which is roughly 4-miles with an average 5% grade. There are some rolling hills before-hand, so you could measure it from Breckenridge as nearly a 10-mile climb that gains about 1,700 feet. There are a handful of tight switchbacks, and a little bit of traffic to ride with.
Independence Pass – A lengthy, twisting climb. It starts out at an easy, gradual grade with some flat sections, and then becomes more twisty the closer you get to the top. The summit is gorgeous and it makes for a hair-raising descent. It can be climbed either from Aspen, or Twin Lakes, which is where I started my climb.
Lookout Mountain – This is a busy climb that begins right outside of Golden. Expect lots of traffic from road and mountain bikes. It is a scenic climb, with a view of Golden visible throughout much of the climb. It ends just beyond Buffalo Bill’s gravesite, after turning right on Colorow Rd. It is a steady climb, with around a 5-6% grade, with the occasional steeper section. I rode it up to the gravesite here.
Loveland Pass – This is a lengthy, 8+ mile climb from Keystone. The grade is consistently in the 5-6% range. The bottom portion up to Arapahoe Basin in relatively straight, while the upper section above the treeline has a number of tight curves. Watch out for hazardous chemical trucks that use the pass as a bypass to get to I-70. I climbed it from Keystone.
Mount Evans – The highest paved road in the USA makes for a challenging climb. It is rarely steep, averaging around 4-5% from Idaho Springs. What hurts is the elevation, as you end up above 14,000 feet at the summit. Despite the difficulty, it is one of the more scenic and rewarding climbs that I’ve ever done.
Swan Mountain – This is a short climb of around 300 feet that can be climbed on the road from Frisco or Breckenridge, or on the bike path from Dillon or Keystone. I took the bike path after climbing Loveland Pass, and found it to be a pleasant climb.
Tennessee Pass – This was an easy climb from Leadville, where I climbed it on the Copper Triangle ride. It was about 3-miles long and you gain just over 400 feet. I understand that it’s a lot more difficult coming the other way.
Vail Pass, East – This is a lengthy climb of over 20 miles, depending on where you start. It passes by the Village of Vail and Lionshead Village, before it takes a bike path most of the way up. The last several miles are the toughest, which are on a recpath parallel to I-70. There are some sections with double digit grades. I climbed it to finish the Copper Triangle ride.
Vail Pass, West – This is the easier and shorter version of the climb. It is approximately 4-miles from Copper Mountain at a moderate grade, all on a bike path that follows I-70. There are some steeper sections and some switchbacks as you get closer to the top of the pass, which ends at a rest area. I climbed this with some friends as a tune-up for Copper Triangle.