Ride to 10,000 Ft. Haleakala National Park Summit.

cbrlocal said:

That is fantastic. How did the bike cope at 10,000 feet? Seems everyone complains about a lack of power at sea level!

Click to expand...

An engine loses 2.0 to 2.5% of its sea level horsepower for every 1000 ft gain in elevation above sea level... so at 10,000 ft. the horsepower is down by at least 20%. So for the CBR250R, that's around 5 - 6 HP less at 10,000 ft. ASL.

Obviously for engines equipped with EFI, the air/fuel mixture is being adjusted as the altitude increases (or decreases on decent) and the air density changes. Whereas engines with carburetors require re-jetting for optimum performance at altitude. But regardless of the type of fuel system, the 2.0 to 2.5% loss of horsepower is still the rule.

As someone who lives at 7000+ ft. ASL, and regularly rides to altitudes of 11,000 ft. and above, I can tell you the power loss is noticeable between 7000 and 11,000 ft.

I can't say that I've ever starting from near sea level, and then ridden all the way up to 10,000 ft... I can imagine that for the OP, the sense of decrease in available horsepower would be fairly dramatic during the last few miles of ascent to the top of the mountain.

Interesting(long)story i have about this mountain

wow how funny, this mountain and i have a very special connection :grin2:, a couple years back i was in Maui vacationing with my fiancee and decided that i absolutely had to ride a bicycle from the summit to sea level (screw riding up thats for road bike crazies:wink2 it took about a week(on Hawaiian time of course) to find a small bike shop that would even rent me a nice mtb to ride down Haleakala without a tour group (Shutout to Krank cycles Maui, 'Moose' is the ********************) after renting a ~5 thousand dollar full sus bike, toolkit& extra tubes, a full face helmet & a go pro i was set, but before i left the owner of the shop asked me why i wanted to ride down crater rd when i could ride a gorgeous single track trail that started from close to the observatory. This just blew my mind, being an avid mountain biker putting hundreds of miles on my bike every week for years, of course i would rather ride a trail than on the road. So he gave me a small hand drawn map and mostly verbal directions . I spent the rest of the evening fine tuning the suspension and brakes to my preferences and mentally preparing for a hell of a ride in the morning.

The following morning we got up at like 330 to drive from Kihei to the summit of Haleakala to watch the sun rise. My fiancee was supper stressed out and worried she wouldn't find our meeting place, so i gave her the hand drawn map the shop owner had given me, confident that i would have no issues on such a small island. We parted ways and i rode the bike the remainder like 200 feet from the parking lot all the tourist come to watch the sun rise at, to the top where the observatory is and had to stop several times for a breather(and the air is thin at 10k that was the highest i had ever exercised at). I had passed one trail on the way up that i didn't see labeled but looked like it went in the opposite direction that i wanted to go so i continued on looking for another trail. upon failing to find any other trail i asked some local tour bus drivers if the trail i had seen was indeed the skyline trail and that people rode their bikes on it they assured me it was and wished me well(this was my almost fatal mistake, i should have had these things mapped out in detail) i very naively listened to these guys and geared up and set off thinking that this trail would somehow wrap around the mountain and bring me to the southwestish side like i was planning even though it pointed to the east. Long story short :grin2: i ended riding down the sliding sands trail into the crater which is fking huge and realized what i had done after about 2000 feet decent or whatever it is to crater lever. Reaching a Y in the road and a sign, looking back over my shoulder at the switchbacks crawling up this marslike landscape all the way back to the summit i realized with the little water and food i had packed it would be very difficult to lug the bike back up the trail.
So I had two options.
My first, a trail that continued down into rain forest and eventually Hana from the looks of direction, also i worried it would probably pass through some private property and some ganja growing and i might end up with an AK in my face.
My second, a trail that went into the heart of the crater. I chose the crater route thinking there would be a trail down and out on the other side... After spending some 8 hours riding my bike into,around and eventually thru the crater to run into a family of hikers at the base of the Halemau'u trail finding out that was the only way out from this side and it was the gnarliest trail i had ever seen in my life anyway, i was in such bad shape at this point one of the hikers carried the bike for me all the way up these switchbacks stopping periodically to nurture me and my muscle cramps back to health( we took it real slow because one misstep would've been imminent death)upon reaching the parking lot at the top of the Halemau'u trail the six of use shared some ice cold waters from a cooler in their trunk and they insisted upon taking me where i needed to go but i told them i came up here to do one thing and i was still gnna do it so i rode off the mountain on crater rd in the most emotional ride of my life. Finally connecting back with my fiancee 14 hours later absorbing all i had just been thru and my sheer luck running into the hikers that literally saved me from having to like be rescued on horseback and spend some time in a hospital on fluids or worse.

This mountain is beautiful, as it is deadly, enticing, and so very very diverse, it is a very special place to me and i hope to visit again. This was a huge lesson for me in so many ways and an amazing experience that i have grown from. This place is legit as it gets. i would put this mountains trails and roads on any sort of bucket list.. ride it, roll it, hike it, CBR it :grin2:. its a great mountain.
Oh but don't do what i did, you can only legally hike through the crater, i later found out it is like a serious federal offense to ride a bike through there.
Upon recalling the story to the bike shop owner he was extremely jealous and exited at the same time telling me that absolutely no one had done what i had just done and that he and some of his friends had contemplated it at some point but would never risk the confiscation of there 5 thousand dollar bikes and a hefty fine ...:grin2::grin2::grin2::grin2: .. i know that was long , and about a bicycling trip but i felt the need to share with you good folks as i have learned so much here and it is a nice resource for CBR owners ( Semi moral: always pack a little extra food and water and whatever it may be supply wise because you never know when a one hour excursion can turn into a 14 hour one):wink2: