Rarely do we have the good fortune of exclaiming “This is the _________climb in the world.” There is only one hardest (Mauna Kea), one highest (Uturuncu), one most deadly (Death Road), and one LONGEST (Mauna Loa) in the entire world.
What good fortune we have that the hardest AND longest roads in the world are on the same Island (Hawaii’s Big Island). At 62.2 miles, Mauna Loa is a good distance in front of the world’s second longest climb, Alto de Letras in Colombia (52.1 miles).
World’s #2 longest bike climb - Alto de Letras, Colombia.
Surprisingly, of the two routes to the top of Mauna Loa, the longest route is also the lower ranked, coming in at #7 US/#60 World, versus the shorter at 44.8 miles, #4 US/#28 World (MAP).
When to Climb Mauna Loa
PJAMM Cycling has taken on Mauna Loa once in May, twice in June, and once in December (we had to call in for help on that one as we got caught in a snowstorm at the top). The lowest rainfall months on the Big Island on the eastern side (Hilo) are May and June and the highest rainfall months are March, April, and November. Thus, we recommend cycling the Hilo side in May and June. The lowest rainfall totals on the western side (Kona) are February and December. We have no data for the top of the volcano and in our experience it is best to climb in May and June. The temperature throughout the year consistently averages in the 70s at sea level, meaning it’ll always be warm in Waikoloa when you start, but often cold at the top (it was in the 30s and snowing in December 2013 when we rode to the top).
The weather can change in an instant on the volcano.
How to Climb Mauna Loa by Bike
While this climb is not as “hard” as its neighbor Mauna Kea, it is by far the longest bike climb in the world -- 124 miles round trip. Train very seriously for this climb. The climb begins in Waikoloa Hilton Village by riding east (and yes, uphill) on Waikoloa Beach Drive, across Queen Ka’ahumanu Highway (mile three) then on up Waikoloa Road. We rise to 11,000’ so it is best to altitude train if at all possible. Our training has only consisted of cycling up 10,000’ to Haleakala in Maui, before flying to the Big Island to climb Mauna Loa in preparation for Mauna Kea. Since studies suggest it takes three weeks to become fully acclimated, unless you’re planning on an extended vacation, you’ll probably just have to suck it up and go for it without much altitude preparation.
Mauna Kea Park -- mile 38.5.
The only spot on the climb where provisions can be had.
The first segment from start to the right turn onto Mauna Loa Observatory Road is 44.6 miles, 3.2% average grade and gains 7,318’ over that distance.
Start of climb -- Hilton Waikoloa Village (elevation is two feet here).
We are on Waikoloa Road for the first 15 miles.
Ride on Highway 190 for five miles to Highway 200 (Old Saddle Road).
Climb Old Saddle Road for 11 miles (gain 3,095’/descend 191’).
14 miles on new Highway 200 (Saddle Road) at 1.5% average grade.
At the 44.8 mile mark, turn right onto Mauna Loa Access Road and climb the final stretch to the Mauna Loa Observatory -- 17.5 miles, 4,457' climb, 17' descent with a 5.2% average grade. This stretch of road is desolate, with very little traffic.
Road ends at the observatory -- not a through road.
Stacy and Bruce at the finish -- Mauna Loa Observatory in the background.
The one lane Observatory Road has been resurfaced as of 2013 and is in much better condition than its former decrepit state. Of all the climbs you will ever do, this one will give you the feeling of being on the moon more than any other. The lava fields range from smooth lava to basalt-looking rock that stretch for thousands of acres. There is little to no vegetation along this route -- it is all lava with not only no green, but also not a bit of vegetation anywhere to be seen for miles.
Roadway in 2011 before it was repaved.
Roadway in 2018 (Mauna Loa in background).
Mauna Loa Observatory Road is all about rollers.
After travelling 45 miles and turning onto the final leg, we still have a ways to go.
17.5 miles, 4,457' climb, 17' descent with a 5.2% average grade.
Although the climb averages 5.2% for the final 17.5 miles . . .
There are plenty of steep pitches.
Some Trip Tips
In our experience, the weather is better earlier in the day than later. The most epic part of the climb (other than it being the longest in the world) is the last 17 miles: riding over the volcano moonscape on a narrow road with no traffic, passing by surreal telephone poles in site of the mighty Mauna Kea to the north. The descent over the 17 miles of Observatory Road is equally unique and exhilarating. Thus, if you’re short on time or don’t feel like you’ve trained enough, leaving in the early morning and just doing the 17 miles is an attractive alternative to the full ride.
The roadway from Waikoloa to the Mauna Loa Access Road is busy, particularly the start to mile 17 (turn off to Old Saddle Road/Highway 200) and then from mile 27.7 (back on main Highway 200) to the turnoff to Mauna Loa Observatory Road. The remainder of the trip is quite the opposite of the first part; in our three trips up Mauna Loa Observatory Road we have seen no more than five cars - TOTAL! Beware that there are absolutely no provisions or water available for the last 54 miles of this climb.
The road from Hilo to Mauna Loa Access Road is busy and the traffic travels at a highway clip. However, there are deep rumble strips separating the wide bike lane from the roadway for much of Saddle Road, and while the traffic can be a bit unnerving, for a highway this is a medium risk route. In my six trips up Mauna Loa and Mauna Kea, I have never experienced a close call.
The weather will be nice in Waikoloa or Hilo any time of the year you start. However, also beware that 11,400’ up the volcano, weather conditions can change dramatically. In December 2013, we left Waikoloa in 75 degree weather only to run into snow near the top of the climb.
A Bit About the Mauna Loa Observatory
Built in the 1950s, the Mauna Loa Observatory (MLO) has been “monitoring and collecting data relating to atmospheric change, and is known especially for the continuous monitoring of atmospheric carbon dioxide” since 1958 as part of the National Oceanic and Atmospheric Administration. This observatory is the oldest continuous CO2 monitoring station in the world, and is the “world's primary benchmark site for measurement of the gas” (Wikipedia). Because the conditions of “undisturbed air, remote location, and minimal influences of vegetation and human activity” the MLO is an ideal location for monitoring atmospheric factors that can cause climate change (Mauna Loa, Hawaii Observatory).
Visiting Mauna Loa
The Mauna Loa volcano is part of Hawaii Volcanoes National Park. More information about visiting and camping in the area can be found on the National Parks Service website. Note that due to the May 2018 eruption of the Kīlauea volcano, areas of this National Park are still in recovery (read more about the park’s recovery process in this article from the National Parks Service). Though it is an active shield volcano, Mauna Loa itself has not erupted since April 15, 1984.
Mauna Kea to the north, 10 miles up Observatory Road (seven miles from top; 8,000’).
Ties Arts Summary:
Mauna Loa is truly a bizarre climb. From the access to the Mauna Loa Observatory the road becomes truly mystique.
The road is constantly surrounded by Lava fields, a kind of moon landscape. The entire 27 kilometers (approximately 17 miles) up to the observatory felt like an interval training. Never did the elevation gradually increase, just 27 kilometers of straight interval training. Short sections of 18% followed by sections of 1% and 2% and then constant sections of 6%, etc. This means hard work constantly. The parking lot where the surface ends is not the most beautiful end of a climb though with good weather you can see the Mauna Kea, which we could!”