Mauna Kea Base via Hilo

This route is considered one of the world's most difficult cycling climbs due to its immense altitude gain of nearly 14,000 feet (4,200 meters) from sea level, sustained steep gradients (up to 20% in sections), significantly reduced oxygen levels at higher altitudes, and a challenging 7 km (4.7 to 5 miles) section of gravel and volcanic ash that is very difficult to traverse.

Due to the prolonged gravel and sandy sections, a mountain bike or a gravel bike with appropriate wide, knobby tires is highly recommended. Road bikes will struggle significantly, especially on the unpaved portions, and may become unrideable.

The best time to attempt this climb is typically during the drier months, generally from late spring to early fall. However, weather on Mauna Kea can be highly unpredictable, with temperatures ranging from warm in Hilo to freezing at the summit, and strong winds or even snow possible year-round. Always check the latest weather forecast before you go.

Services are extremely limited. There are no water or services for a significant portion of the climb after about 10 miles from the start. The Mauna Kea Base Start (Visitor Information Station) offers some amenities before the gravel section, but it's crucial to carry ample water and supplies, and a support vehicle is highly recommended.

The route typically starts from Hilo, where various public parking options are available. Specific trailhead parking for the start of the climb itself is not explicitly designated, but cyclists often begin from sea level in Hilo. Plan your start point with consideration for safe parking and easy access to the initial climb.

Given the extreme difficulty, high altitude, lack of services, and challenging terrain, this cycling route is not suitable for dogs. The conditions at higher elevations can be dangerous for pets.

There are no specific permits or entrance fees required to cycle the Mauna Kea Access Road itself. However, be aware of any regulations or closures, especially for the summit area, which is a sacred site and home to observatories. Always respect local guidelines and cultural significance.

The route offers incredibly diverse scenery, ascending through five distinct climate zones. You'll start in the lush rainforests of Hilo, transition through native high-elevation dry forests, and eventually reach a dramatic, almost lunar landscape above the clouds. The panoramic views from the upper slopes and summit are stunning.

While the Komoot tour data suggests a moving time of around 5.5 hours for the 'Base' section, completing the full climb from Hilo to the summit (approximately 42 miles and 14,000 feet of gain) is a monumental undertaking. For most experienced cyclists, this can take anywhere from 8 to 12 hours or more, depending on fitness, conditions, and stops. It's often planned as an all-day endeavor.

Yes, while primarily a road cycling route, the path does briefly intersect with other trails. You'll find it crosses sections of the Kaumana Trail (2% of the route) and the Pu‘u ‘O‘o Horse Trail (1% of the route).

Due to the dramatic temperature changes from sea level to the summit, layering is crucial. Start with light, breathable cycling gear for Hilo's warmth, and pack insulated layers, a windproof and waterproof jacket, gloves, and a warm hat for the higher elevations. Temperatures at the summit can be near freezing.