54.5
PDI
62.2 mi
DISTANCE
11,874 ft
GAINED
3.4 %
AVG. GRADE
FULL CLIMB STATS
Page Contributor(s): Ron Hawks, Las Vegas, NV, USA Ties Arts, Bussum, Netherlands; Luke Hise, Phoenix, AZ, USA
INTRO
Mauna Loa is one of the only bike climbs in the world where you can say, "I did the __________ bike climb in the world." Mauna Loa is hands down the longest bike climb in the world and is a grueling climb from nearly sea level to 11,000' above sea level. Mauna Loa can also be accessed from the opposite side of the Island of Hawaii from our western approach, but starting from the east will not put The Longest Bike Climb in the World into your trophy case. After turning onto Mauna Loa Observatory Road at mile 45 (with 17 more miles to climb) you are surrounded by landscape like no other on any climb we have ever done - if you want to know what it would be like to ride your bike on Mars, climb Mauna Loa.
See also our Mauna Loa Hike page and our dear friend Erwan Treguier's entertaining tale of Mauna Kea + Mauna Loa . . . in the same day!
PLAN YOUR ROUTE
We've partnered with Sherpa-Map.com to bring you the best route planning tool. With a PRO Membership you can use this climb as a reference when creating your route. Do not be lulled into complacency by the mundane 3.4% average grade for the Mauna Loa bike climb. First, you are climbing for over 50 miles which is a grind like no other. Second, there are several descents which when removed increase the true average grade from 3.4% to 4.2%. Third, you are climbing at altitude, finishing at an altitude with 33% less oxygen than where you began at sea level.
The steepest quarter mile of the Mauna Loa bike climb is 11% and steepest mile is 8.8%. The final 3,000' feet of altitude gained (10 miles) is at 5.6%. The only "good" news to be gleaned from the stats is that less than 2% of the climb is 10%+.
See more details and tools regarding this climb's grade via the “Profile Tool” button.
Observatory Road is closed at Hwy 200 as of November 28, 2022 due to Mauna Loa eruption and lava.
Traffic: This is a problem. The first 19 miles on Waikoloa Road and Highway 190 have moderate to heavy traffic, including commercial trucks, traveling at 50-60 mph. However, there is a wide shoulder those first 19 miles. 11.5 miles on Old Saddle Road are a blast with minimal traffic. Onto Highway 200 (Saddle Road) for 13 miles of busy and fast moving traffic, but with a wide shoulder with rumble strips separating slow lane from shoulder. Once onto Mauna Kea Access Road (final 17 miles) vehicles are rarely encountered.
Parking: This is hard to find near the start. We park on Waikoloa Road just past Highway 19 and ride 3 miles down to the climb's start. Map; Street View.
Cothing: I have been snowed on (in December) on Mauna Loa. Consult the PJAMM Weather Tool for the forecast at the time you expect to finish your climb and bring or stash appropriate gear.
Provisions: As of May 2018, the only place after Waikoloa Village (mile 8) for provisions on this 62 mile route are the vending machines (water, Gatorade, chips, and candy bars) at the Gilbert Kahele Recreation Park at mile 38.5 - Map; Street View. I would not rely on those machines being there when you go, though. I have stashed provisions at the beginning of Mauna Loa Observatory Road (and Mauna Kea Access Road when I've done that one) in the past.
Before heading out on any cycling adventure check out our Things to Bring on a Cycling Trip and use our interactive check list to ensure you don't forget anything.
- VRBOs for cycling Mauna Loa
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We prefer staying in the Kailua-Kona (25 miles south of climb start) area as it has a more low-key (and reasonable) atmosphere which is to our preference (and, hey, Kona Brewery). The Hilton Waikoloa Village area closer to the climb start has higher-end accommodations, and we have stayed there, but we got a great deal!
Also consider climbing Mauna Kea (hardest bike climb in the world), Kaloko Dr (US #5 hardest bike climb), and Waipio Road (steepest mile road in the world).
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MEMBER REVIEWS & COMMENTS
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BOBradley
I did this climb on October 3rd, 2024. All but the last 6.6 miles are available. Staring in Waikoloa, this amount to 56 miles of riding and over 9,600 ft. of elevation. No laws were broken - the road/gate is open and it's obvious when you can go no further.
The first 44 miles are the dues to be paid for the majestic portion of the climb on Observatory Road. The descent is absolutely breathtaking as you see Mauna Kea across the street. This was my last of the PJAMM top 10 U.S. climbs (according to FIETS). I'll have to do a little math to see if it still lands in the top 10 missing the last 6.6 miles.
jimmymac
A truly epic ride, we parked at Cindercone carpark on the Saddle Road and then descended to the pacific shoreline in Hilo and turned round and rode back to the carpark for a feed/drink stop and then onward to the Observatory, we were working there so had access through the gate beyond the top of the official climb! The descent back to the car was as the sun went down and at that altitude it gets cold pretty quickly. The road down was like being on a kids toy racetrack! Super Kudos to my ride buddy (she has the QOM) for the day on a fairly clunky hired bike and later discovered she was pregnant!!! 💪💪💪
Of course this road is no longer passable since the recent erruption at the end of 2022!
Hegtosh
Rode unsupported from Hilo. Stashed water and energy bars every 10 miles. Hid my water at the beginning of the obervatory road so well I couldn't find it until I came back to collect the bottles. Kaumana Dr and Saddle Rd are easy going climbing. It was overcast so really didn't get much views apart from the first section of the observatory road before heading back into the clouds. It gets challenging above 9000ft on the steep pitches and altitude. Toward the end I felt disheartened to look back at what looks like a fairly long way home back over the ramps. Don't worry, the moment you turn around it's a roller coaster ride all the way back to the Saddle. Well worth the slog!
zross
This is a very challenging climb. I've done a number of the higher FIETS rated climbs and they don't come close to how tough this is. My support guy said it's generally between a 6-9 hour climb for most people. Mauna Loa is relentless and has basically no descent more than a couple minutes long over the entire climb. The whole last 15 miles or so are rollers with steep pitches touching up to 18% (as measured on my Hammerhead). Combine all that with extreme altitude and in my mind, you have an extreme climb.
Lilac
It's possible to do this ride alone if you plan ahead. There was no longer a vending machine at the Gilbert Kahele park as mentioned. 1 strategy is to “stash†drinks along the way in advance (just remember which mile marker you leave them at & don't be a jerk- take your trash with you or make sure you drive back to retrieve it). If you ride from sea level, you'll have some traffic, which gradually drops off the further you climb. When I did this ride 03/2021, I saw only 1 other cyclist & less than 5 cars on the M. Loa observatory road in all the hours it took me. The weather is unpredictable. I was met by sleet near the top. The scenery is unique, but on a cloudy day, the observatory road became quickly tedious, with nothing but lava fields and no birds or animals for hours. The constant little up & downs can be a battle as mentioned. The air is thin and myHR showed it. It's not a steady climb you can just put your head down for & zone out to. But at least the roads are smooth!
bbypy
Rode this 7/7/21 starting from Inouye Hwy. The road has been repaved and is perfect, unlike what you see in older pix and google maps. It's a perfect morning ride when you don't have time for an all-day ordeal/thing. Go early so the heat doesn't get you and 2 bottles will be enough. You may start in some fog but will climb clear by 7000ft. The views are absolutely the best: Hilo under clouds to the east, giant Mauna Loa shield that you are climbing to the south and west, Mauna Kea/Kohala/Haleakala to the north. Only traffic was a few work vehicles headed up to the observatory construction site. It's a stunningly scenic climb. Descent is fun but extra caution in the rollers where you cannot see far ahead. You are likely to encounter at least 1-2 vehicles coming up and there is no bail out - it's either into the lava field or a head-on.
jfswain
I agree with the above that this climb is much harder than the math suggests - the little dips and kickers aren't captured in the contours, but they get really draining. Very hard to get in a rhythm.
Also, important note: on 5/20/21, there are NO vending machines anymore at the rest stop on saddle road, so you'll need to carry all your food. The maintenance guy didn't know if there was a plan to bring them back. There is ample water, however. Coming from Kona-Kailua, you're looking at about 120 miles between services, R/T.
MethowBiker
This climb is much more difficult than the modest gradients suggest. The Saddle Road is smooth with even grades. But, the Mauna Loa Observatory road just follows the contours of the lava fields. There are dozens of 11-14% ramps for 10-50 pedal strokes, followed by short flat or even downhill sections. So, while the grade might be only 6-7% over 1/2 a mile, you will be expending a lot of energy on those ramps. These would be tiring at sea level, but are really felt above 8,000 feet.
That said, the downhill 17 miles back to the Saddle Road is the most exhilarating descent I can remember. You start to approach 35 mph, then go up a ramp to scrub some speed. We saw only three cars in three hours. But, it's a one lane road with some blind corners, so keep to the right so you don't get surprised (or worse).
Headwinds can be an issue on the descent as well. Check National Weather Service and do pinpoint forecasts before you set out. There are no services. Traffic rating is for MaunaLoa
