Mauna Kea: THE hardest bike climb in the world.
Ride 42.5 miles gaining 13,850’ at 6.2% average grade to 13,800’
Photo: Mauna Loa across “the saddle” in background
Climb summary by PJAMM Cycling’s John Johnson.
We have climbed Mauna Kea five times: 2011, 2013, 2014, 2018 and 2022.
Mauna Kea is the most difficult bike climb in the world and one of the most epic. Adjectives do not do justice in describing this climb. Distinguished by the highest Fiets Index in the world, Mauna Kea is a monstrous, nearly impossible ascent. In addition to the daunting climb, cyclists must be mentally and physically prepared for changing weather conditions, altitude sickness, and varying terrain on this extremely challenging 42 mile climb.
Not much vegetation on a volcano.
Before heading to Hawaii for your Mauna Kea cycling adventure, be sure to rely on our list of Things to Bring on a Cycling Trip, and use our interactive checklist to ensure you don't forget anything.
What Makes This the World’s Hardest Road Bike Climb: The sheer elevation ascended (13,800’/4200m), the average grade (9.9% for the last half of the ride), dealing with the gravel for 4.7 miles, the altitude (be prepared for the possibility of altitude sickness, as it commonly occurs above 8,000 feet; Wikipedia), and dramatically changing weather (for example, rain and 80 degree weather in Hilo, followed by wind, snow, and sub 40 degrees at the top, depending on the season). On one climb up the volcano in December, it was 73 degrees in Hilo when we started, and we endured as low as 34 degrees and blustery snow towards the summit.
Well . . . you can’t say they didn’t warn you . . . 😨
When to Climb Mauna Kea: We have taken on Mauna Kea twice in May, twice in June, and once (foolishly) in December. We recommend going in May or June, as these are the lowest rainfall months for the start of the climb in Hilo. The highest rainfall months there are March, April, and November. The temperature throughout the year always averages in the 70s so it will be warm in Hilo when you start, but often cold to extremely cold (it was in the 30s and snowing in December 2013 when we rode to the top).
PJAMM’s Brad Butterfield on Mauna Kea summit, December 20, 2013.
Checking Road and Weather Conditions on Mauna Kea: The best resource for Mauna Kea road conditions and status is the Mauna Kea Weather Center. For example, when I originally typed this entry on January 14, 2020 from my hotel in Kona, I had just checked the MKWC site and the road from the VC to the summit was closed due to snow and ice - good to know! Additionally, each PJAMM Cycling climb page has current and forecasted weather for the start and finish of each climb.
How to Climb Mauna Kea by Bike: There are more tips below, but in a nutshell:
End of the gravel. May 2018.
40mm gravel tires on a Specialized Crux cross bike.
Photo: Riding up Mauna Loa - Mauna Kea is in the background.
Chris, John, and Jen after our May 24, 2022 Mauna Kea climb.
What Gear to Bring to Climb Mauna Kea by Bike:
We have always done the paved portion of the climb with a compact disk and in 2011 (27t cassette at age 55), 2013 (30t age 57), 2014 (32t age 58), 2018 and 2022 (30t chainring and 42t cassette - age 61 & 65 - see a trend here . . . ). In 2018 and 2022 I used a specially fitted Roubaix Crux cross bike that I used 30mm tires for pavement and 38mm knobby tires for the gravel. Note that for all but exceptional riders, I recommend swapping to a mountain bike for the gravel - I am not an exceptional rider at age 65 and would have been much better served with a mountain rather than gravel bike in 2022. As noted above, bring very warm clothes for the top. You may also wish to bring breathable rain gear because there is a good chance of rain in Hilo, regardless of the month you pick to tackle the climb.
Micah Ling’s Input: Bike - Moots Routt RSL -- same bike all the way up. I started with about 55 psi, lowered to about 30 for the gravel, did not reinflate. Maxxis Rambler tubeless tires, size 38. I'd ride this setup again, just because I'm so used to it. The bike did me well even though I had to walk a couple sections. I might go up to 42 for the tires.
MAUNA KEA FROM A DISTANCE
As seen from Mauna Loa.
Mauna Kea as seen from Waikoloa Road (55 miles)
Other four photos are Mauna Kea as seen from Mauna Loa.
Mauna Kea left, Mauna Loa right.
Top photo: From the air leaving Kona
Bottom Photo: From Waikoloa Road (55 miles)
Statistics for the four segments of this climb.
PJAMM’s interactive profile tool (exit this summary to access profile tool)
The steepest segments are on the gravel and last paved section
Quarter-mile at 15.3%; 2.5 miles at 12.4%.
Where to Start: The traditional start for Mauna Kea, and the location that ranks Mauna Kea as the highest rated bike climb in the world, is Hilo, Hawaii. It is best to stay in Hilo so you needn’t get up at an insane time to drive from the west side of the Island (Kona side) to the east side (Hilo). Twice we have made the early morning trek across the island to start the climb and do not recommend it. In 2022, we stayed in Waikoloa but also rented a hotel in Hilo the night before our climb so we could get up 1.5 hours later (still up at 4 a.m. for sunrise start).
Dipping our bike wheels in the Pacific just across the road from the start of the climb.
Photos with the Pacific in the background just across from the start of the climb.
Climb begins at mile 0 on Waianuenue Avenue (we just call it W Avenue).
We start early.
The alternate route from the west side of the Island (Mauna Kea West; commonly known as the “Kona side”) is 59 miles (15 miles longer than from Hilo) and thus necessarily ranks lower on the Fiets scale (21.82 v. 28.9 from Hilo). The comparative statistics for the western approach are: Miles: 59 v. 42.6, average grade 4.6% v. 6.1%. The first 44 miles from the west are at 3.3%. The final 14.8 miles from the start of Mauna Kea Access Road to Summit are at 9.2% and go from 6,579’ to 13,767’; that stretch alone is a 23.4 Fiets which would rank the final leg of Mauna Kea at #11 in the world if we only rated that fraction of the entire climb. What does that tell us? Save your energy for the last 14 miles of the climb.
Alternate start - Anaehoomalu Point, Waikoloa
Profile Gradients from our friend Erwan Treguier of Brittany, France
SEGMENT ONE: Hilo to Mauna Kea Access Road
Ride 27.6 miles gaining 6,595’ at 4.5% average grade.
The first leg of this journey is the "easiest" part of the ascent. With a Fiets score of 10 for this segment alone, it would rank #37 in the U.S. Top 100 (equal to Mt. Lemmon in Arizona).
You will often encounter rain on this segment, but
. . . with rain in Hawaii can also come the beautiful rainbows!
The final 16 miles of this segment are on Saddle Road (Highway 200).
Traffic on Saddle Road - note the safety rumble strips.
Highway 200 is a main connector from west and east Island of Hawaii.
The 16 miles on Saddle Road are fairly easy (not too steep and not yet at elevation), but traffic makes this segment a bit unpleasant as vehicles do whiz by at 60 mph.
You may get some drizzle or rain on Saddle Road.
On a clear day you will see Mauna Kea as you ride west on Saddle Road.
SECOND LEG: Mauna Kea Access Road to Visitor Center
Ride 6.5 miles gaining 2,808’ at 8.2% average grade from 6,613’ to 9,421’.
Top photo: Mauna Loa in background.
While the climb from Hilo to Mauna Kea Access Road is challenging, the section of this climb that makes it the most difficult in the world starts just after you begin your climb up the Access Road. The Access Road part of the climb is broken into three parts and includes segments 2-4 of the full climb.
A couple of interesting signs along this segment.
For the most part, the hillside is bare but for two pockets of conifers along the way.
You know the road’s steep when it’s got a Runaway Truck Ramp . . .
. . .and when the sign at the top says 17%. 😓
Note: As of May 2022 the Visitor Center was being renovated and had only tap water available - no food or other drink.
Fill out your information sheet and give it to the ranger before continuing above the VC.
THIRD LEG: Gravel Section:
This segment of the ride is two-tenths of a mile after Visitor Center; you must have four-wheel drive.
Beginning of the gravel - 300 yards up from the Visitor Center.
Ride 4.6 miles gaining 2,472’ at 10.2% average grade from 9,421’ to 11,877’.
There are five switchbacks that are murderous -- they are generally steeper than the straight road and at the steepest sections cause your rear wheel to slide towards the inside of the turn.
It’s a long, lonely grind up this segment.
Sorry for the shaky video, but . . . I was a bit shaky at the time.
Back to the pavement at mile 38.9.
FOURTH AND FINAL LEG: End of Gravel to the Summit:
Ride 3.7 miles gaining 1,980’ at 10.3% average grade from 11,877’ to 13,857’.
Last 3.7 miles.
At the end of the gravel, you may wish to swap back to the road bike, or continue on the mountain bike with its lower gears. The final stretch presents a serious challenge to climbers with its altitude and extreme gradient in places.
You’ll not see that elevation outside Colorado and Mauna Kea in the US.
Mt. Evans (14,125’), Pikes Peak (14,110’) and Mauna Kea (13,767’)
are the only paved roads topping 13,000’ in the U.S.
Approaching the hairpins.
On this final stretch we are fighting: altitude, gradient, and fatigue. Upper left photo is a photo of Luke Hise and Erwan Treguier paperboying it up the last 17% pitch - these are not weak cyclists! They went on to ride down Mauna Kea, up Mauna Loa and then on to Waikoloa, dipping wheels in the ocean at 2 a.m. after 19.5 hours riding, 139 miles gaining 19,000’ (Luke Hise’s Double Dip).
Two giant hairpins at the finish.
Eight miles from Visitor Center to top.
THE FINISH - HIGHEST POINT IN HAWAII
Finish at the Gemini Observatory.
Mauna Kea Summit to your right as you finish the climb.
On top of the world!
While our downloaded map reads 13,800+ elevation, our Garmin 2011 and 2022 is a bit less.
Note, the full section from Mauna Kea Access Road to the Summit: Approximately 14.8 miles, 9.9% average grade, 7,189' gained, 0' descended, 23.38 Fiets Index, by itself would rank this ride as #1 in the US, even eliminating the first 28 miles and 6,500' of climbing, that's how much of an absolute beast this part of the climb is.
Bottom right photo: View from Mauna Kea Summit back to cycling finish.
From the finish of our ride you can hike to Mauna Kea Summit which is the highest point in the Hawaiian Islands.
The Mauna Kea Summit is 13,796’ (from its base under the sea = 33,500’ - tallest mountain in the world)
I think my 65 birthday post-cancer challenge in 2022 will be my last Mauna Kea climb.
But, there’s always the challenge of my 70th coming up . . . .
A comparison of the european cycling club BIG's top climbs confirms that Mauna Kea is THE world’s BIGest bike climb.
Thank you to Helmuth Dekkers, Netherlands for providing us this BIG climb comparison.
Helmuth’s summary of the climb is located further down this page.
It does snow in Hawaii:
Top of Mauna Kea during winter 2020 with Mauna Loa in the background.
JOHN SUMMERSON SUMMARY
“Mauna Kea is another gian ascent on the Big Island of Hawaii and one of the most difficult and spectacular climbs in the world. After just over one mile in town turn left on Kaumana Road (which becomes Saddle Road). You soon leave the city over moderate grade along with a short flat. Rolling miles follow and signs of civilization (including traffic) soon end. The route becomes tree lined about 6 miles in as you continue to ride over mostly shallow grade. Laa slowly and eventually replaces trees as you ride between two massive shield volcanoes over a long section characterized by mostly shallow and rolling grade...Soon the grade eases within the magnificent saddle between the two giant mountains and just beyond mile 28 turn right for the top.
This is quite isolated and spectacular territory and the next section continues as shallow and through grassy fields (there were a few cattle hanging around this area when the author was on this hill) and then gradually gets steeper as you ride. Just over 3 miles into this upper section you encounter the first of two steep ramps. The initial one lasts for over one mile and then the slope moderates. Very soon the 3nd and steeper ramp appears and lasts for one mile and is one of the steepest paved miles in the U.S. It also provides spectacular views of the surrounding mountains and lava fields in places as you ascend. Soon the grade eases, there is a small descent, climbing resumes over moderate grade and you reach the Mauna Kea Visitor’s Center (on the right) which is an interesting place to spend some time (and fuel up for the return trip as needed). Just beyond the Visitor’s Center the pavement and listed climb mercifully ends within a lunar like landscape with long views from high points. If you reach this point you hae come a long way.
A somewhat soft (mountain bike) gravel road heads to the very top of the mountain (pavement reappears a few miles from the summit) and its high altitude and world famous observatories. Snow occasionally accumulates on top in winter which is quite a sight. If and when the unpaved section is paved this hill may well become the world’s most difficult paved road climb. It is tough enough as is so go prepared if you tackle it (there are no services onces you leave Hilo). Keep in mind Mauna Kea is a giant descent as well.” (This quote is presented with the approval of John Summerson, from his book, The Complete Guide to Climbing (by Bike), 2nd Edition, pg. 178.)
That’s a wrap!!
 Brad was 16 when he climbed Mauna Kea. Since then he has documented climbs for PJAMM in the US, Canada, Colombia, Bolivia, Chile, Australia, New Zealand, England, Wales, Scotland, Ireland, France, Italy, Spain, Switzerland, Austria, Germany, Slovenia, Slovakia, Bosnia and Herzegovina, Serbia, Montenegro, Ukraine, Poland, Bulgaria, Albania, Czechia and all the top US climbing states, including Hawaii, California, Colorado, Utah, New Mexico, Idaho and more.
 These are Helmuth’s personal comments, not as a representative of BIG.
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