Power to weight Ratio

[sideslider]

Well I have been trying to learn about Power to weight ratios and I did not find anything off hand in the search.

here is where I got my info from

Power-to-weight ratio - Wikipedia, the free encyclopedia

So if I did this right the ratio for an fz6 (I used rounded numbers 90bhp and 450 lbs) the fz has around 204 W/kg Power to weight ratio.

I know this is a rough estimate but that would put the fz up there with Lotus Exige GT3 2006 and Artega GT.

After reading the specs for the Lotus it looks like the fz is a much better purchase for performance...

any thoughts?

 

[reiobard]

seems like you got the gist of it.

 

[GConn]

A bike generaly has better specs on paper. In reality though you only have a small contact patch with the ground to apply that power efficiently. A car has 2 large contact patches, or in the case of an EVO or Carrera4S for example, 4 of them.

So, using the power to weight ratio on the bike is more difficult than in a all-wheel-drive car. Not an expert in physics but this is the way I think of it...

 

[Chaosratt]

A bike generaly has better specs on paper. In reality though you only have a small contact patch with the ground to apply that power efficiently. A car has 2 large contact patches, or in the case of an EVO or Carrera4S for example, 4 of them.

So, using the power to weight ratio on the bike is more difficult than in a all-wheel-drive car. Not an expert in physics but this is the way I think of it...

Motorcycles tend to have a higher PtW Ratio, but a harder time getting that power to the pavement.
Sound about right?

 

[SovietRobot]

Still, not many cars can beat motorcycles off the line, and even then, those cars cost 10+ times more.

 

[abner]

In regards to the contact patch, is it better to have a larger contact patch or smaller?

IMO, a larger patch means a larger wheel and tire to try and turn, using up valuable torque ft/lbs. Also, it means less pressure on the contact patch (lbs/sq inch) which equates to less friction between the tire and pavement, meaning it has more ability to slip. On the other hand the more rubber gripping the pavement means more traction. Therefore, I think there is a fine line between too much contact and not enough.

I think the real issues are that the FZ can flip over backwards, and the disadvantage of the Lotus is that it can lose traction and burn the tires off.

In my experieces, the FZ walks that fine line very well. When I am accelerating hard I can feel the front tire barely making contact on the road, meaning it is using all its horsepower efficiently, and not wasting it to wheelie the bike.

 

[opds9091]

this sounds like a old thread, i think it was F=MxA in the search type ......force equals

 

[notjohndavid]

In regards to the contact patch, is it better to have a larger contact patch or smaller?

IMO, a larger patch means a larger wheel and tire to try and turn, using up valuable torque ft/lbs. Also, it means less pressure on the contact patch (lbs/sq inch) which equates to less friction between the tire and pavement, meaning it has more ability to slip. On the other hand the more rubber gripping the pavement means more traction. Therefore, I think there is a fine line between too much contact and not enough.

I think the real issues are that the FZ can flip over backwards, and the disadvantage of the Lotus is that it can lose traction and burn the tires off.

In my experieces, the FZ walks that fine line very well. When I am accelerating hard I can feel the front tire barely making contact on the road, meaning it is using all its horsepower efficiently, and not wasting it to wheelie the bike.

Look at top fuel dragsters. They've got a lot of rubber on the back. The fine line is once you get a contact big enough where you aren't breaking traction, there's no reason to get bigger.

Also, a bigger contact patch means that you are more likely to hydroplane in the rain.

 

[FZyLarry]

Another part of the equation is how much the rider adds to the vehicle. Not sure what a lotus weighs but lets say 3000#. If the driver is 200# he is 6.6% added weight. If the bike rider is 200# he is 44% added weight. That knocks the old power to weight ratio in a pretty big way. (I'm not a math whiz so there may be some fuzzy logic here but you get the idea)

 

[Kent Soignier]

fzylarry is right, you have to figur3e in the weight of the bike and rioder combined, since the bike can't launch itself.
The size of the contact patch only factors in where wheel spin limits the forward acceleration of the bike(and rider).
then suspension and geometry affects that too.
Total weight divided by horsepwer, it is that simple
chow