Mauna Kea Bike Climb - PJAMM Cycling






Mauna Kea

HI, USA

The hardest road bike climb in the world - for real!

Page Contributor(s): Ron Hawks, USA; Ties Arts, Netherlands; Mark Manner, Nashville, TN, USA

Explore this Climb

Featured Video

PJAMM Cycling LogoDark Sky logo
LOCAL WEATHER

Start
Finish

PJAMM’S CLIMB REPORT

If you love climbing by bike and would like more detailed information on the world’s top bike climbs, join our PJAMM Cycling group and receive our Special Edition Climb Report.
  • Receive a monthly report.
  • Get detailed and entertaining information on the greatest bike climbs and climbing areas throughout the world.
  • Discover beautiful landscapes with drone video and professional photos of remote and exotic places.
  • Gain insider knowledge on where to stay and how to conquer some of the most difficult climbs.

Climb Summary

Riding bike at the top of Mauna Kea above the clouds.

Mauna Kea -- THE hardest bike climb in the world.

We have climbed Mauna Kea 4 times - 2011, 2013, 2014, 2018.

Mauna Kea is the most difficult bike climb in the world and one of the most epic.  Adjectives do not describe 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.  

Cycling Mauna Kea - view of clouds, road and volcano near top

Not much vegetation on a volcano.

PJAMM May 2018 Great Hawaiian Adventure Blog and Trip Page.

Tips from cycling adventurer Helmuth Dekkers, Netherlands.

What Makes This the World’s Hardest Road Bike Climb:  The sheer elevation ascended (13,000+ feet), 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).  We climbed the volcano December 20; 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 once 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 always be warm in Hilo when you start but often extremely cold (in the 30’s and snowing in December, 2013 when we rode to the top).

Note on road closure beginning July 15, 2019:  The road is closed to vehicles and bikes for an unstated period of time beginning July 15, 2019 (Article 1; Article 2) to build another giant telescope at the summit.

Warning signs at Mauna Kea Visitor Center with bicycle. 

Mauna Kea summit, December 20, 2013.

How to Climb Mauna Kea by Bike:  There are more tips below, but in a nutshell--

  • Train, train, train.  Be in the absolute best shape you can be before even thinking about this climb;
  • Choose the right time to try the climb, we suggest May or June;
  • We finish at about 13,800’.  To the extent possible, altitude train, either using an altitude tent or riding up Mauna Loa or to the Mauna Kea Visitor Center.  Perhaps that’s just psychological because the studies indicate it takes at least three weeks to “fully acclimate” to altitude, but we recommend it anyway.  Regardless of what studies say, we have always ridden Haleakala (Maui) and Mauna Loa on the same trip before riding Mauna Kea and that seemed to help us.  One of our cyclists used an altitude tent in preparation and he felt that was an advantage;
  • Be prepared to swap out to a mountain bike or at least change tires on your cross bike to 38-40mm at the Visitor Center (mile 34) for the 4.7 miles of sand/gravel beginning at mile 34.2 (the pavement begins again at about mile 39 and the last three miles are paved);

Warning signs at Mauna Kea Visitor Center with bicycle. 

End of the gravel. May 2018.

40mm gravel tires on a Specialized Crux cross bike.


  • Make absolutely certain you have warm clothes for the trip above the visitor center.  The temperature will be between 25-40 degrees lower at the top than in Hilo at the start.

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 (28t cassette at age 55), 2013 (30t age 57), 2014 (32t age 58), 2018 (28t chainring and 42t cassette - age 61 - see a trend here . . )  In 2018 i used a specially fitted Roubaix Crux cross bike that I used 30mm tires for pavement and 40mm knobby tires for the gravel.  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.

View of Mauna Kea Summit from Mauna Loa as framed by cyclist.

Mauna Kea as seen from across the saddle (and through JJ) from Mauna Loa.

RIDE SEGMENTS

PJAMM at the start of the Mauna Kea bike climb leaving from Hilo, HI.

December 2014 Start - 79 degrees (35 at the top when we finished).

 Starting the Mauna Kea bike climb in Hilo at sunrise.

                                                     May 2018 start.  Lucky again, a rare dry morning in Hilo.

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.  We have always used Airbnb or VRBO for our rental accomodations.  In 2018 we stayed in Hilo within one mile of the start which was perfect for the Mauna Kea climb.

The alternate route from the west side of the Island (Waikoloa; 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 13,771’; that stretch alone is a 23.4 Fiets which would rank the final leg of Mauna Kea at #4 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.  

View of Mauna Kea Summit from Mauna Loa as framed by cyclist.

Alternate start - Anaehoomalu Point, Waikoloa

First Leg, Hilo to Mauna Kea Access Road:  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 #29 in the U.S. Top 100.

Warning signs at Mauna Kea Visitor Center with bicycle.

Amazing banyan tree on Waianuenue Ave ½ mile up from the start.

Warning signs at Mauna Kea Visitor Center with bicycle.

Just turning onto Saddle Road from Kaumana Dr.

Mile 8.5 - 34 miles, 11,690’ at 6.4% to go

Mauna Kea in the distance.

  • Beginning elevation is nearly sea level, ending elevation for first segment is 6,584';
  • 4.5% average grade over 28.8 miles;
  • Includes the only two turns on this epic 42 mile adventure;    
  • The first three miles of the climb take us along the only urban portion of the route (along Waianuenue Avenue). Make sure to bend left at about mile 1.3 onto Kaumana Dr. which merges into Saddle Road (Highway 200) about five miles further up the volcano.​

Warning signs at Mauna Kea Visitor Center with bicycle.

Saddle Road

Aerial photo looking back east along Saddle Road towards Hilo.

Stacy Topping riding her bike on the Mauna Kea gravel.

Traffic flies by, but there is a very wide shoulder.

Mauna Kea from . . . you guessed it . . . mile 16.

26.7 miles, 9,730’ at 6.9% to go.

Second Leg, Mauna Kea Access Road to Visitor Center:  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 segment of the ride can be divided into 3 parts:

The grueling segment from Saddle Road to Visitor Center

Riding our bike up Mauna Kea Access Road - Steep Curves

30 mile mark - 6,950’ - Mauna Loa is in the background.

12.6 miles, 6,765’ at 10.1% average grade to go.

Climbing to just short of 13,800’

   Riding by bike up Mauna Kea Access Road from Saddle Road.

Just about to rise above the clouds -- 8,000’.

  • 6.3 miles;
  • 8.5% average grade (some sections are 16%);
  • 2,586' gained;      
  • Begin 6,577', end 9,163';
  • 0' descended.

Visitor Center - Swap out to a mountain bike here (these can be rented in Kailua at the Bike Works), or swap from road to cross bike tires. 

PJAMM at the Mauna Kea VC changing from road bike to mountain bike for gravel section.

 Visitor Center at 9,200’ and 34 miles into the climb.

Rest at Mauna Kea Visitor Center on our bike climb up the volcano.

Some decent provisions at the Visitor Center: pre-made sandwiches, drinks, etc.

Warning signs at the Mauna Kea VC for altitude sickness, headaches etc.

Warning Signs, they don’t give you much incentive to continue past the Visitor Center.

   

Third Leg, Gravel Section: 2/10th mile after Visitor Center - you must have 4 wheel drive (Harpers Rentals in Kona and Hilo are great!).


Warning sign while riding bike up Mauna Kea  just before the gravel section.

If the first set of warnings weren’t enough . . .

    Signs on the gravel section of the Mauna Kea cycling route

. .  . here are a few more to chew on!

           

  • 4.7 miles;
  • 11.1% average grade;
  • 2,408' gained;      
  • Begin 9,348’, end 11,756'’
  • 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.

     View down at Mauna Kea Visitor Center while cycling on the gravel section.

 View of the Visitor Center from the gravel road about a mile up.

Stacy Topping riding her bike on the Mauna Kea gravel.

Riding our mountain bike up the gravel on Mauna Kea 4.7 miles.

It’s a long, lonely grind up this segment.

Warning signs at Mauna Kea Visitor Center with bicycle. 

Stacy Topping riding her bike on the Mauna Kea gravel.

Sorry for the shaky video, but . . . well . . . I was a bit shaky at the time . . .

    Stacy Topping riding her bike on the Mauna Kea gravel.  

  Stacy Topping flying off the gravel and back onto the pavement.

The end of the gravel section on Mauna Kea and change to road bike

Oh blessed pavement!

The end of the gravel section on Mauna Kea and change to road bike 

Descending the gravel.

Summit of Mauna Loa barely visible above the clouds.

4th and Final Leg, End of Gravel to the Summit:

  • 3.7 miles;
  • 9.3% average grade;
  • 2,020' gained;
  • Begin 11,756’, end 13,771';
  • 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 as the final stretch presents a serious challenge to the climber with its altitude and extreme pitch in places.

13,000' sign with bike leaning on it on Mauna Kea bike climb

Mt. Evans (14,125’), Pikes Peak (14,110’) and Mauna Kea (13,771’)

 are the only paved roads topping 13,000’ in the U.S.

Warning signs at Mauna Kea Visitor Center with bicycle.

It’s still no picnic after you return to the pavement!

Riding the bike through the clouds near the top of Mauna Kea

The last brutal three miles -- the steepest segments of the climb are here:

 ½ mile 15.9%, 1 mi 13.9%, 2.5 mi 12.6%.

Riding up through the clouds near the summit of Mauna Kea at mile 42

About a mile from the summit, riding above the clouds.

Riding the road bike at the top of Mauna Kea.

 Nearing the top and the Gemini Telescope.

Mauna Loa barely peeking above the clouds in the background.  

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. ​

A comparison of the european cycling club BIG's top climbs confirms that Mauna Kea is THE world’s BIGest bike climb.

Riding the road bike at the top of Mauna Kea.

Thank you to Helmuth Dekkers, Netherlands for providing us this BIG climb comparison[1].

Helmuth’s summary of the climb is located further down this page.

Roadway and Traffic:  The roadway surface is always from very good to excellent (except for the 4.7 mile gravel section from miles 34-39).  Traffic is another matter.  The first six miles and last fourteen are fine.  The 22 miles on Saddle Road (Highway 200) are a bit more daunting as you are on a major highway which connects the east and west sides of the Island of Hawaii (the Big Island).  There is almost always a wide shoulder, but there are plenty of vehicles that whiz by at highway speed, so beware of that (bring flashing red taillights with backups and extra batteries in case your first set run out of power).

Supplies and Provisions:  After the convenience store on the south side of Waianuenue Avenue one mile from the start, there are no supply stops until 34 miles later at the Mauna Kea Visitor Center.  The four times we have climbed Mauna Kea we have gone unsupported to the Mauna Kea Access Road (mile 27.5), then unsupported again to the Visitor Center (6.3 miles) and then had SAG support intermittently from the Visitor Center to Summit.  

​This climb has the highest Fiets Index Score (by far) of any U.S. climb.  It also ranks as the most difficult climb by bike in the world by the climbing site ClimbByBike.

PJAMM cycling by bike to Mauna Kea Summit June 2011

Summit June, 2011.

    John and Rochelle Johnson at the top of Mauna Kea in 2011.

                                               Yes, that is Snow in the background . . . in June . . . in Hawaii!!!!

PJAMM Mauna Kea Summit 2013 climb by bike with Gemini Telescope in the background.

December, 2013 -- encountered snow.

 PJAMM with Gemini telescope at Mauna Kea Summit 2014 at end of bike climb.

June, 2014. A perfect day, but still very windy and chilly -- high 40’s at top.

PJAMM cycling tour to Mauna Kea Summit 2017.

May 2018.


[1] These are Helmuth’s personal comments, not as a representative of BIG.