Sunshine Canyon to Fourmile Canyon loop via Poorman Hill Road

While there isn't a single designated trailhead parking lot for the entire loop, many cyclists start from central Boulder. You can often find street parking near the beginning of Sunshine Canyon or utilize public parking garages in downtown Boulder, such as those near East Pearl Street. Ensure you check local parking regulations.

This loop features a diverse mix of paved and unpaved sections, including dirt roads that can be washboarded and loose. A gravel bike or mountain bike is highly recommended for comfort and capability on the varied terrain. While some paved sections are manageable on a road bike, the dirt portions, especially on Poorman Road and upper Sunshine Canyon, are challenging for narrower tires.

The best time to cycle this loop is generally from late spring through early fall (May to October) when the weather is mild and the roads are clear of snow and ice. Wildflowers are abundant in the summertime, adding to the scenic beauty. Be aware that conditions can change rapidly in the mountains, so always check the forecast before heading out.

No, you do not need specific permits or to pay entrance fees to cycle this route. Much of the area falls within Boulder Open Space and Mountain Parks, which generally does not require permits for cycling on designated trails and roads. However, always respect local regulations and trail etiquette.

This route is primarily on roads and some multi-use paths, making it less ideal for dogs to accompany cyclists directly on the bike. If you plan to bring a dog, they must be on a leash at all times in Boulder Open Space and Mountain Parks areas, and you should be aware of traffic on the road sections. Consider shorter, dedicated hiking trails if your primary goal is to exercise your dog.

The most challenging sections are the climbs on Poorman Road and Sunshine Canyon. Poorman Road is known for its steep, well-graded dirt, often requiring cyclists to stand. Upper Sunshine Canyon also turns to dirt, featuring washboarded and loose surfaces with steep switchbacks and grades reaching nearly 12%. These sections require good fitness and appropriate bike handling skills.

You can expect beautiful and varied scenery, including views of the Indian Peaks, rugged rock outcroppings, and tree-lined streams. In summer, wildflowers bloom. You'll also see areas affected by the 2010 Fourmile Canyon fire, with dead trees. The descent into Lefthand Canyon is particularly scenic, and you'll get views of Mount Sanitas as you head back towards Boulder.

Yes, the route offers several points of interest. You'll pass through Fourmile Canyon, known for its rugged beauty. Near the start or end, you can explore East Pearl Street in Boulder, which offers various shops and eateries. For a coffee or pastry stop, Spruce Confections is a popular local cafe.

Yes, this loop is a classic Boulder ride and often forms a crucial part of longer, iconic routes like the Gold Hill Loop. It also utilizes sections of the Boulder Creek Path and the Sunshine Canyon Trail, integrating into the broader network of Boulder's cycling infrastructure.

Absolutely. This loop is considered to be of moderate to hard difficulty, requiring good to very good fitness. Its significant climbing, varied terrain, and challenging sections make it a serious workout and a popular choice for advanced cyclists looking for a demanding ride. It has even hosted the annual Sunshine Hill Climb race.

Given the mixed terrain and elevation changes, bring a well-maintained gravel or mountain bike, plenty of water, snacks, and appropriate layers of clothing. A helmet, repair kit, and navigation device are essential. Sunscreen and sunglasses are also recommended due to exposure. Be prepared for steep climbs and potentially loose surfaces.