Hello Guest

pounds and horsepower

  • 68 Replies
  • 7769 Views

0 Members and 1 Guest are viewing this topic.

*

tzracer

  • ******
  • 1413
    +64/-61
  • 2 stroke snob
pounds and horsepower
« on: February 28, 2006, 11:17:59 am »
For years I have heard the old adage that losing 6 or 7 pounds is the same as gaining 1 hp.

I never thought the relationship should be a constant.

I finally put pen to paper and did some calculations (physicists do that sort of thing). The result I came up with after a couple different approaches turned out to be rather simple and after a couple minutes made sense.

Take the weigh of bike and rider (in full gear). Divide by the power of the bike.

That number is the amount of weight you would have to lose to free up one horsepower.

Bikes with lower weight to power ratios have to lose less weight to gain a horsepower. That is high power bikes have more to gain by losing weight than do lower power bikes (modern liter bikes do not weigh much more than say an SV).
Like
0
Dislike
0
Agree
0
Disagree
0
No reactions
No reactions
No reactions
No reactions
Brian McLaughlin
http://www.redflagfund.org
Donate at http://www.donate.redflagfund.org
  
2 strokes smoke, 4 strokes choke

*

Scotty Ryan

  • *
  • 757
    +131/-111
  • Working toward the end result
    • Trackside Suspension & Engineering
Re: pounds and horsepower
« Reply #1 on: February 28, 2006, 11:42:23 am »
Sweet, so my new bike is up about 5 hp over last years bike and I am about 10pounds lighter then last year so I can add about 2 extra HP to the 5HP for a 7 HP gain..... Bring on the Salads.......
Like
0
Dislike
0
Agree
0
Disagree
0
No reactions
No reactions
No reactions
No reactions
"MMMM - Fork Oil For Breakfast"

61 or 61 X - Which will it be??

*

spyderchick

  • *
  • 5204
    +402/-270
  • Love what you live, and live like you mean it!
    • Spyder Leatherworks
Re: pounds and horsepower
« Reply #2 on: February 28, 2006, 11:44:26 am »
Brian, you make my head hurt. So what's the fomula you came up with? Give 3 examples and show your work... ;)
Like
0
Dislike
0
Agree
0
Disagree
0
No reactions
No reactions
No reactions
No reactions
Alexa Krueger
Spyder Leatherworks
414.327.0967
www.spyderleatherworks.com
www.redflagfund.org
Do or do not, there is no "try".

*

Scotty Ryan

  • *
  • 757
    +131/-111
  • Working toward the end result
    • Trackside Suspension & Engineering
Re: pounds and horsepower
« Reply #3 on: February 28, 2006, 11:52:47 am »
Let's say that my bike weighs 380 pounds, I weigh 170 in gear..So you add the two together and get 550 pounds. Now divide the 550 by 119hp and you get 4.621848739. I am assuming that is how many pounds I would have to lose to gain 1hp...If that is the case and I am 10 pounds lighter then last year(saying that the bikes weigh the same then I would have a gain of 2.16 hp over my last years weight. Did I do something wring here Brian? Please correct me if I did...
Like
0
Dislike
0
Agree
0
Disagree
0
No reactions
No reactions
No reactions
No reactions
"MMMM - Fork Oil For Breakfast"

61 or 61 X - Which will it be??

*

grasshopper

Re: pounds and horsepower
« Reply #4 on: February 28, 2006, 11:56:15 am »
Interesting....

That number you get by adding up the weight of the rider and bike divided by the horsepower is the amount of weight you and/or the bike would have to loose to gain 1 HP correct?

it doesn't necessarily have to be the rider loosing weight it can be your machine too?
« Last Edit: February 28, 2006, 12:02:47 pm by grasshopper »
Like
0
Dislike
0
Agree
0
Disagree
0
No reactions
No reactions
No reactions
No reactions

*

spyderchick

  • *
  • 5204
    +402/-270
  • Love what you live, and live like you mean it!
    • Spyder Leatherworks
Re: pounds and horsepower
« Reply #5 on: February 28, 2006, 12:13:08 pm »
Quote
Interesting....



it doesn't necessarily have to be the rider loosing weight it can be your machine too?


Yes.
Like
0
Dislike
0
Agree
0
Disagree
0
No reactions
No reactions
No reactions
No reactions
Alexa Krueger
Spyder Leatherworks
414.327.0967
www.spyderleatherworks.com
www.redflagfund.org
Do or do not, there is no "try".

*

rfoan27

Re: pounds and horsepower
« Reply #6 on: February 28, 2006, 12:38:30 pm »
WOW, now my head hurts.  Come on guys and gals can't we just open the throttle all the way, hold on and ok put some skill in there and win some races... ::)  As everyone says life begins at 150 and at 180 fear just can't catch up :-X
Like
0
Dislike
0
Agree
0
Disagree
0
No reactions
No reactions
No reactions
No reactions

*

throttle

  • ***
  • 145
    +2/-0
    • BGV-Racing
Re: pounds and horsepower
« Reply #7 on: February 28, 2006, 01:09:03 pm »
But what if you were to take, say, 12lbs off the wheels?
Like
0
Dislike
0
Agree
0
Disagree
0
No reactions
No reactions
No reactions
No reactions

*

Fat_Nate

  • ***
  • 218
    +1/-0
  • Ducs ducs ducs
Re: pounds and horsepower
« Reply #8 on: February 28, 2006, 01:23:55 pm »
Lemme see if I got this right:

My SV weighs, what, about 350 lbs?  I weigh 180, plus gear -- figure 200?  That's 550lbs, and 70hp . . . 7.8 lb/hp.  

Good grief -- so I need to lose about 40 pounds.  Between now and Friday.  This is going to be difficult.

Like
0
Dislike
0
Agree
0
Disagree
0
No reactions
No reactions
No reactions
No reactions

*

ecumike

Re: pounds and horsepower
« Reply #9 on: February 28, 2006, 02:21:56 pm »
Quote
But what if you were to take, say, 12lbs off the wheels?


Yup, don't forget that equation.  Rotational mass is a better place to reduce weight, but comes at probably the steepest price.

It seems to be that you can reduce weight either cheap, or easily, but not both.
Losing rider weight is very cheap, but not easy.
Buying carbon fiber rims is easy, but not cheap.  :)
« Last Edit: February 28, 2006, 02:23:26 pm by ecumike »
Like
0
Dislike
0
Agree
0
Disagree
0
No reactions
No reactions
No reactions
No reactions

*

d_dog

Re: pounds and horsepower
« Reply #10 on: February 28, 2006, 03:45:33 pm »
Pauly: I need a few more ponies. What are the odds of you getting a salad bar in the Polar-Optics trailer. (race weekend).......... Or how about just a bar.    ;D
« Last Edit: February 28, 2006, 04:00:25 pm by d_dog »
Like
0
Dislike
0
Agree
0
Disagree
0
No reactions
No reactions
No reactions
No reactions

*

cardzilla

  • *
  • 451
    +6/-4
  • First time 500 ... ees ... FACK !!!
Re: pounds and horsepower
« Reply #11 on: February 28, 2006, 04:20:29 pm »
I have to disagree a bit here... let's see if I have what you're saying right.

For example... I've been a lazy fat a$$ during the off season and I weigh 180 pounds.  Let's say that in addition to my R1 superbike I also have a RS125.  You're saying that I will proportionally go faster on the R1 if I lost, say, 15 pounds?  I know there are a lot of little people that race 125s that when they move up to a bigger bike don't do as well because they lose their advantage.  It seems like you have more to gain by losing weight the smaller the bike you ride is.  I mean, that's half the reason I bought a rocketship... so I wouldn't have to starve myself... are you telling me that I may have to start eating Broccoli again?  ;D
Like
0
Dislike
0
Agree
0
Disagree
0
No reactions
No reactions
No reactions
No reactions
Larry Dodson
CCS # 22
2004 Yamaha R1 Superbike