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-   -   HP and power-to-weight (https://www.motorcycle.com/forum/motorcycle-general-discussion/12543-hp-power-weight.html)

nicholasm 07-15-2009 11:07 AM

HP and power-to-weight
 
Ok, HP = torque in ft/lbs x rpm. Power-to-weight is the total wgt of the bike divided by HP. So a 2008 Dukati 1098 V2 is 377 lbs dry and 180 HP and a 2008 R6 is 366 lbs dry and 110 HP. By my calculations the Dukati and Yamaha R6 have power-to-weight calculations of 2 and 3 hp per lb respectively, so how do you interpret that? I know the rider's weight is a major factor and this was not factored in.

sarnali2 07-15-2009 01:11 PM

I interpret that as being basically irrelevent. Unless you are racing, any modern sportbike is going to have more than enought torque and horsepower to get out of it's own way.

If in fact you truly want an objective opinion then when you're talking about bikes in this classification, IE Very high performance streetbike then the numbers alone don't tell the story, you can't ride these bikes anywhere near their full potential anywhere but on the track and there, as a general rule, rider skill will have more effect on the outcome than pure performance numbers at anything but the top levels of amature and proffesional level competition.

For a street enviroment things like braking and suspension and tire choice become more important than outright performance because that's whats keeping the wheels on the ground in acceleration and stopping.

Comfort is also an issue (for me at least) because if your scrunched up sitting on a narrow plank of a seat your discomfort will effect your ability to concentrate much the same as if you have to piss. If you're riding these types of bikes anywhere near their potential on the street then you dam* sure better be focused on the task at hand, so........

That's why I say power to weight ratios and outright performance figures are irrelevent in street riding, other than to bag on your buddies about how weak their bikes are compared to yours.

longride 07-15-2009 01:24 PM

"That's why I say power to weight ratios and outright performance figures are irrelevent in street riding, other than to bag on your buddies about how weak their bikes are compared to yours."

If you aren't going to bag your buds about their weak bike, what else is there to do at the Burger Barn?

seruzawa 07-15-2009 01:49 PM

If power to weight is your concern then you apparently are concerned about pure acceleration. If you want serious power-to-weight and the ability to shred just about any other bike out there do the following:

Find an older GSXR-750. Remove all the body work. Replace the clip-ons with a new crown that accepts regular handlebars. Lower the footpegs. Alter the countershaft and drive sprockets until the bike's calculated top speed is near 130mph. You don't need the fairing because drag is not a factor at any speed that won't get you arrested and impounded. Now you can easily lean over the handlebars to get a good launch that will keep your front wheel on the ground. Go out and practice your launches.

Now you will be able to stomp any other bike out there regardless of what the magazine stats say. Actually, if you took a totally stock bike and just practiced your launches a lot you'd still be able to stomp most anyone else since virtually no one else except me and MOKE practice this skill. Most people think that just having more power means they will be faster. This is a common but entirely false concept.

pushrod 07-15-2009 01:50 PM

The other issue is the application of torque. The 1098 will have a lot more 'motivation' to accelerate, since the engine can turn the wheel harder.

But as Snarly says, it's mostly an academic exercise on the street.

However, if you use the bike around town, and delight in grunting around in the first three gears and on one tire, you want torque and you want it in the rpm range you will be using.

The simplified statement is: Torque is acceleration, HP is speed.

Buzglyd 07-15-2009 03:45 PM

Quote:

Originally Posted by longride (Post 218807)
"That's why I say power to weight ratios and outright performance figures are irrelevent in street riding, other than to bag on your buddies about how weak their bikes are compared to yours."

If you aren't going to bag your buds about their weak bike, what else is there to do at the Burger Barn?

True because the burgers suck.

mscuddy 07-15-2009 06:25 PM

Get an old CR500R Honda MX bike, get a license plate, run 15/45 gears and NO ONE on a street bike will ever be able to take you on a start. Take off in 2nd gear too. Really pisses off guys on crotch rockets when a smoky old MX bike cleans their clock.

It's been said a 500cc two stroke MX bike accelerates faster than a F1 car, and I believe it.

Kenneth_Moore 07-15-2009 06:35 PM

Quote:

Originally Posted by Buzglyd (Post 218821)
True because the burgers suck.

Is there actually a place called Burger Barn, or is it just an expression?

seruzawa 07-15-2009 07:11 PM

Quote:

Originally Posted by Kenneth_Moore (Post 218831)
Is there actually a place called Burger Barn, or is it just an expression?

Well, yes. and here it is:

http://i495.photobucket.com/albums/r...ger_barn-1.jpg

Empty tables just waiting for piles of bike mags. This was Saturday when I took the picture so naturally there were no sportbikers there. But Sundays it's packed full. Buz sits at the head of the table to the left.

But you must remember that the Burger Barn is far more than a physical place. It is a place of spiritual enlightenment. Devotees of the Burger Barn (Blessed Be It!) achieve a state of spiritual consciousness where physical reality is suspended. At the Burger Barn (Blessed Be It!) motorcyclists are transformed from wobbling squids into MotoGP world Champions. They achieve such superiority in their unique spiritual state that there is no need to spend many hours practicing the skill of motorcycling. They ascend to the Nirvana of Squidly-Godhood where simply proving through logic skills and stat sheets that they are Uber-Motorcyclemenschen.

The_AirHawk 07-15-2009 08:25 PM

Looks like a good place to go to pick a fight you know you'll win...........


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