Altitude riding

Closed Thread Subscribe

Thread Tools

Search this Thread

Dec 10, 2013 | 10:11 AM

#21

upflying

Seasoned HDF Member

Joined: Aug 2013

Posts: 35,824

Likes: 38,688

From: Post Falls, ID

Air at high altitudes is less dense so while the engine is down on power, you need less power to push through the thin air.

Dec 10, 2013 | 10:13 AM

#22

deano360

Road Warrior

Joined: Aug 2011

Posts: 1,991

Likes: 9

From: washington

Quote:

Originally Posted by upflying

Air at high altitudes is less dense so while the engine is down on power, you need less power to push through the thin air.

so are you saying it almost a wash, the power vs. air resistance?

Dec 10, 2013 | 10:33 AM

#23

upflying

Seasoned HDF Member

Joined: Aug 2013

Posts: 35,824

Likes: 38,688

From: Post Falls, ID

Quote:

Originally Posted by deano360

so are you saying it almost a wash, the power vs. air resistance?

In aviation, non-turbo charged piston engine aircraft reach that "wash" at about 8500'. Above that at WOT and the plane slows down due to less power. Below that and air density slows the plane down, even with more power. This is referring to true air speed and not indicated airspeed.
Besides altitude, humidity and temperature also play a factor in air density.
So no, very high altitude riding will never overcome low engine power pushing through less dense air. If the bike is turbo charged, it will scream at higher altitudes.
I'm not a Phd in physics so if someone feels I am wrong, please feel free to correct me.

Dec 10, 2013 | 10:55 AM

#24

Pumba11

Elite HDF Member

Joined: Jan 2007

Posts: 4,020

Likes: 69

From: Twin Cities, MN

Quote:

Originally Posted by Harsh1828

Pikes peak, Independence Pass, Trail Ridge, Mt Evans, all are 12k + and bike runs fine. ECM should adjust fuel air mixture so bike will work fine,

I've did these all last summer with no issues either. And my CV carb worked beautifully!
.

Dec 10, 2013 | 11:23 AM

#25

EricD10563

Outstanding HDF Member

Joined: Jan 2009

Posts: 2,480

Likes: 73

From: Florida

I've rode to the top of Mt Evans (14,230 feet) and Pikes Peak (14,115 feet) with no issues.

Dec 10, 2013 | 01:30 PM

#26

Twistnride

Ultimate HDF Member

Joined: Feb 2012

Posts: 7,855

Likes: 11

From: Oroville,Washington.

Quote:

Originally Posted by C908

Mt Evans, if my memory is right elevation is slightly under 15,000.

"Slightly under 15,000 feet"?

Yeah,by about 800 feet. To the OP's question.............been over Evans,and Pikes Peak,both a little over 14,000 feet. Trail Ridge,which stays at 11,000 to 12,000 feet,for most of it's course. No problems with an injected bike. My carbed shovels used to gasp for air over 8,000 feet in the Sierras,unless you rejetted. But who the hell wants to mess with that?

Dec 10, 2013 | 02:35 PM

#27

nm deluxe

Novice

Joined: Sep 2013

Posts: 20

Likes: 0

From: new mexico

Brought my boat from okc, to northen newmexico. Altitude on lake I work is over 8000'. Had some performance problems. After some research, found out that all combustion engines suffer from altitude. The numbers that seemed most consistant were a loss of 3% per thousand foot gained. For me, damn near 25%. Just fyi. With gears, you'll be fine. I had to re-prop... twice! Doh!