# Mountain Biking - How much Horsepower do people make?

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DonValley
10-05-06, 07:29 PM
Just wondering if cyclist's output has often been measured in Horsepower? It seems we gotta be the equivalent of a 35CC motor or so on a good day for a few seconds? DO any of you know typical output? Or perhaps measured in Thrust ?

Dannihilator
10-05-06, 07:30 PM
Depends on the person.

jiiiim
10-05-06, 07:38 PM
fyi - 1lb of thrust = 2hp
thought maybe some of you might wanted to know

Flak
10-05-06, 07:39 PM
The roadie forum might be useful to ask in. They seem concerned with wattage and the likes.

DonValley
10-05-06, 07:52 PM
I know small trolling motors claim 40 poundes of thrust, so that would make them 80 HP. Your formula must be off by a decimal or something.

trevor
10-05-06, 07:57 PM
I would think a horse in real life has more power than a person.. but thats different. I think? lol horses run and pull way more than humans thatns for sure.

thatguy
10-05-06, 08:01 PM
43.

jiiiim
10-05-06, 08:13 PM
sorry for my mistake. i'm a mythbuster fan and i was watching one of their episoda where they were mounting rockets on the roof of the car. adam said the rocket produce x amount of thrust which means the car has 2x of horsepower. i just googled a bit and the formula to convert such forces needs the factor of speed. at low speed, the ratio is about 1:.9 (thrust to HP), at a moderate high speed it's about 1:1 and at the speed of sound it's 1:2.
plz do correct me before i sink myself further with incorrect info.

mcoine
10-05-06, 08:21 PM

womble
10-05-06, 08:32 PM
43.

I think that if you revist your calculations, you'll find it's 42 ;)

idleuser
10-05-06, 08:35 PM
Humans don't measure in HP but instead in watts. If I remember my basic physics class, 1HP is 743 watts of power. Personally I have no idea how to measure human power output because I have no desire to do so, but I know that PowerTap makes hubs for road bikes which can measure this.

--Oh yeah, my guess is that average power output is around 200 - 300 watts? so that divided by 743 watts gives you HP.

I stand corrected, I read the stuff on google and it's 746 watts :rolleyes: and it's probably less than 200 watts *shrugs*

^*^BATMAN^*^
10-05-06, 10:29 PM
Well on my road bike, I have a power tap on my race wheels. On a 100-150km ride, I will average about 300w. The most I have seen myself put down, was in a sprint, I maxed out at 1235w(that was a 100m standing sprint).

Siu Blue Wind
10-05-06, 10:30 PM
Depends on the person.

Or the horse.

idleuser
10-05-06, 10:50 PM
The most I have seen myself put down, was in a sprint, I maxed out at 1235w(that was a 100m standing sprint).

Was that the average for the whole 100m or THE max.

Dannihilator
10-05-06, 10:53 PM
Or the horse.

A horse is easy.

1 horsepower.

Siu Blue Wind
10-05-06, 10:55 PM
Not if the horse has been working out....Hmphh! (flips head and tosses hair in the air)

Dannihilator
10-05-06, 10:58 PM
Miniature horse equals 1/2 horsepower.

A dead horse equals 0 horsepower.

Siu Blue Wind
10-05-06, 11:00 PM
:lol:

gcl8a
10-05-06, 11:01 PM
fyi - 1lb of thrust = 2hp
thought maybe some of you might wanted to know

Only if you're going 1100 feet per second.

You have two different types of units. Thrust is force, while power is force times speed (energy per time, really).

wompwomp
10-06-06, 06:49 AM
roughly .1, if you're a 'baseline' active/athletic person, depending on how long of a period of time you're measuring over.

darkmother
10-06-06, 07:18 AM
1 hp = 745 W If you are in good shape you might be able to put out 1000 W for a couple of seconds.

free_pizza
10-06-06, 07:48 AM

^*^BATMAN^*^
10-06-06, 08:18 AM
Was that the average for the whole 100m or THE max.

Max, in a sprint like that, we spanned two lanes wide with people sprinting, you dont really watch your computer...so all I saw was the max after the sprint was done and I looked at the computer. I have had sustained efforts at about 800w for about a km. It was a race up a hill, my legs hurt after that, so ya, about 1hp.

RIC0
10-06-06, 08:58 AM
I"m crankin out like 35 RWHP on a good day.... DOH

rockrates
10-06-06, 09:13 AM
I think that if you revist your calculations, you'll find it's 42 ;)

OF COURSE it's 42. maybe you don't know what the question is?

Sincerely, Deep Thought

junkyard
10-06-06, 10:17 AM
43.

incorrect, the answer is 8. 8 is the answer to most of life's difficult questions.

recursive
10-06-06, 10:21 AM
I can do 0.5HP (380W) for maybe 3 or 4 minutes.

dminor
10-06-06, 10:53 AM
That's about right. According to this quote from the HPVA: "A computer model of the HPV hour race, indicates it will take a combination of a national caliber racing cyclist, riding a World class HPV such as the Varna, along with an excellent course and ideal conditions to claim the Dempsey - MacCready Prize. It will be difficult, but it can be done. The required human power is formidable. Only top competitive cyclists can manage the more than 400 watts necessary to cover 90 km in one hour (0.54 horsepower)." (boldface mine)

idleuser
10-06-06, 02:30 PM
Number 6 is my favorite number. So it's not 42 or 8, it's 6 ;)

thatguy
10-06-06, 03:50 PM
I think that if you revist your calculations, you'll find it's 42 ;)

It is 42. You passed the test.

Actually, my memory just ain't what it used to be....

Minesbroken
10-06-06, 04:01 PM
It depends on how many cubic inches they are :)

bcubed
07-01-08, 07:43 AM
Here's what I did to figure out horsepower:

1. Determine the combined weight of you, bike, all acessories.
2. Find a steep hill of constant, known gradient.
3. Ride up as fast as you can; note avg. speed.
4. Convert speed from mph/kph to ft/sec (fps=mphX5280/3600)
5. Once you have fps across the road, multiply that by gradient/100 to get fps straight up.
6. Multiply fps straight up with combined weight, then divide that number by 550 to get hp. (because 1hp=550ft-lb/sec)
7. Add on something like a 15% "fudge factor" to account for rolling+wind resistance, as well as drivetrain losses.

According to this calculation, I averaged 0.54 hp for a 0.2-mi. hill, and was asking for a chair by the end. Note that 1hp=3/4kw (roughly), so multiply hp by 750 for metric enthusiasts.

EDIT: Eek, just realised how OLD this is! Yet, the calcs ARE correct and I'm inclined to leave it...

HOV
07-01-08, 07:59 AM
Ya, I did some really rough calculations a while back and figured an average person can generate 1/3-1/2 HP pushing a car, so I figure it's about the same on a bike.

Kind of gives you some respect for the amount of HP a car can generate from fossil fuels. Also kind of makes you wonder why all that power is being wasted.

Rutnick
07-01-08, 08:17 AM
That's about right. According to this quote from the HPVA: "A computer model of the HPV hour race, indicates it will take a combination of a national caliber racing cyclist, riding a World class HPV such as the Varna, along with an excellent course and ideal conditions to claim the Dempsey - MacCready Prize. It will be difficult, but it can be done. The required human power is formidable. Only top competitive cyclists can manage the more than 400 watts necessary to cover 90 km in one hour (0.54 horsepower)." (boldface mine)

Marco Pinotti AVERAGE 374 watts on stage 21 of the Giro this year. AVERAGED and that was after oh 20 other stages.

That's on a upright bike AND he was "taking it easy".

You guys really don't realize that Pro cyclists AVERAGE over 400 watts for a stage on a regular basis.

DirtPedalerB
07-01-08, 10:06 PM
You guys really don't realize that Pro cyclists AVERAGE over 400 watts for a stage on a regular basis.

yeah using horse steroids

slvoid
07-01-08, 10:13 PM

How did I become involved in this discussion???

slvoid
07-01-08, 10:14 PM
That's about right. According to this quote from the HPVA: "A computer model of the HPV hour race, indicates it will take a combination of a national caliber racing cyclist, riding a World class HPV such as the Varna, along with an excellent course and ideal conditions to claim the Dempsey - MacCready Prize. It will be difficult, but it can be done. The required human power is formidable. Only top competitive cyclists can manage the more than 400 watts necessary to cover 90 km in one hour (0.54 horsepower)." (boldface mine)

There's also someone on this forum that can produce 400 watts!!.

free_pizza
07-01-08, 10:23 PM
How did I become involved in this discussion???

jeebus, that was like 2 years ago... im having troubles remembering 2 weeks ago.

BenLi
07-01-08, 10:34 PM
jeebus, that was like 2 years ago... im having troubles remembering 2 weeks ago.

Tsk. That's what that stuff will do to ya.

07-02-08, 11:14 AM
I think it's fairly well accepted that we produce less than one horsepower.
If memory serves me, one horsepower lifts 550 pounds one foot per second.

mfennell
07-03-08, 07:57 AM
You guys really don't realize that Pro cyclists AVERAGE over 400 watts for a stage on a regular basis.400 watts for 5 hours? No. Way. In fact, the infamous Landis solo attack in '06 averaged 281 watts for 5.5 hours. His peak 30 minute was 401 watts. Reference Here. (http://www.twowheelblogs.com/2-old-2-go-slow/floyd-landis-powertap-file-for-his-tour-de-france-attack-in-stage-17)

Billy Bones
07-03-08, 09:25 AM
No reference at hand, but I recall back in the "Gossamer Condor" days the dudes they used as pilot-engine were cyclists who could output a steady 1/3 hp for the time it takes human power to fly the English Channel.

mic2377
07-04-08, 05:23 PM
The average recreational cyclist can maintain 150-175 watts for awhile, a couple hours maybe. Trained cyclists are when you start seeing 250+ watts for any appreciable time. I call BS on anyone putting out more than 300 watts for an appreciable time, even pros in long stages only average 250-270 watts unless they are attacking, in a break etc.

I did a 16-mile TT on a road bike, and averaged somewhere around ~280-290 watts based on common calculators. That was a warm-up for the peak of the season which a race several weeks later. Putting out that kind of power makes you go REALLY FAST.

Pros train with 4.5-6 hr rides at 220-240 watts. Don't even ask about their intervals, some guys put out 4 minute power outputs of 470+ watts. That is 2/3 horsepower, for an 80 kg person, and 33+ mph on flat, level ground.

Roadies are obsessed with such things... Hell, I have even seen people with powertaps and carbon tubular wheels in a Cat 5 race. The silliest friggin' thing ever.

Cheers~

scbbbc
07-06-08, 03:30 PM
clydesdale got horse power lol

pinkrobe
07-07-08, 01:14 PM
It's not about the horsepower, it's about "the look". That said, 400 HP combined with "the look" is tres formidable.

free_pizza
07-07-08, 05:06 PM
Tsk. That's what that stuff will do to ya.
what stuff? horsepower?