Distance: 68.6 km
Average Gradient: 6%
Elevation gained: 4,186 metres
Surface: Mainly sealed (part gravel)
Here is a link to the Strava segment here:
Mauna Kea is an active volcano which last erupted in 1984. It is situated on Big Island of Hawaii and is technically the tallest mountain in the world (if you include it starts from 5,000 meters below sea level). This is one of the most extreme paved climbs that you can do in the world. Not one that you can take lightly or to attempt without planning. There are very few services available on the climb. If you don’t have a support vehicle following you then be prepared. You may need to carry a large amount of food and water with you.
The climb starts from Hilo on the East coast and stretches over 68 kilometers and 4,200 meters of climbing to its peak on top of Mauna Kea. This is considered to be one of the world’s longest climbs. What makes it extra challenging are the weather conditions. There can be much different weather conditions at the top of this volcano than at the base in Hilo.
The first half of this climb out of Hilo takes you along Saddle Road, and has really long straight sections of road with a pretty consistent gradient of around 5%. You probably won’t see too much traffic, but drivers have been known to drive at excessive speeds along this road, and thankfully there is a shoulder that you can cycle in.
Once you reach the middle of the island, turn right into the Mauna Kea Access Road. From here there is a further 22km of undulating climbing with an average gradient of 10% to the peak (this includes 7km of gravel climbing). Most will probably avoid climbing the dirt section, although I’m always a firm believer that you haven’t truly climbed a mountain until you’ve gone as high as you possibly can. This last section is truly brutal and expect to encounter some very nasty pinches up to 20% in gradient along the way.
You will need to stop off at the Visitor Center. You’re encouraged to stop for a minimum of 30 minutes in order to help acclimatize to the high altitude. It is also the only place where you can get water on this climb.
If you plan on attempting this climb, there is a list of safety precautions at the Mauna Kea Visitor Website that you should read here:
Most choose to stop at the Visitor centre. If you choose to continue riding, the road turns to gravel. The vegetation disappears and cinder cones rise from the earth to make everything appear to look like a moonscape. The next 7 km is very steep and unpaved and in bad shape. The surface consists of rocks mixed with volcanic ash, which offers little in the way of traction, and is a very bumpy ride as the road is rutted and you will experience hell getting to the top.
When you reach the top you are rewarded with a 360 degree view of the world. Mauna Kea offers some truly spectacular Mars-like scenery. On a clear day you should be able to see most of the Big Island below you, and see the Mauna Loa Volcano across from the south of the island, and Haleakelo on Maui to the north.
A ride like this isn’t about getting to the top as quickly as you can. It’s a journey and an adventure with the goal to get to the top in one piece. When you climb Mauna Kea, it is important that you ride within your abilities and take regular rests where necessary. Altitude sickness can be common for altitudes above 2,400 where the oxygen level is greatly reduced which can lead to shortness of breath and/or impaired judgement. Your body will need time to acclimatise.
Mauna Kea tips to survive:
- A very high level of fitness would be required to even attempt a climb like this
- Be prepared for the possibility of rapidly changing weather conditions (extreme heat, strong winds, rain and even snow). Check the observatory websites for wind and weather reports. (you can also call the visitors information station at 808-961-2180) before starting the ride to check summit weather conditions and to get information about possible road closures.
- Have a support vehicle and bring plenty of food and water to survive the ride
- Allow your body regular rests to help acclimatize to the thinner air