Can someone explain torque to me?

[Bren]

I understand Horsepower, but I just dont understand torque.

Can someone give me an explanation in laymens terms (for the dumbass I am).

Cheers,
Bren

[Steam]

Okay, how to explain Torque...
Well, it was a crap movie with quite a lot of sportsbikes. Britney Spears made a song "Toxic" that had nothing to do with the film, but they somehow managed to connect the two.
The main characters were... etc etc.:2thumbsup


But seriously, here's an easy-ish explanation, not mine...


Torque is a twisting force applied to an object, like a wheel or a crankshaft. Note that motion is not required for torque to exist! If you stand on a lug wrench that is on a frozen lug bolt, you are applying a torque to that bolt even though there may be no movement. For our purposes, we will consider that torque is measured in pounds-force feet (lbf-ft) meaning the equivalent of a given force, in pounds, acting on the end of a lever of length in feet. For example, standing with 180 pounds body weight on a lug wrench one foot long yields 180 lbf-ft of torque. A child of 90 pounds standing on a two-foot lug wrench applies the same torque.

Work is the application of force over a distance. Unfortunately, the units used are the same (pounds times feet) but we write this as ft-lb just to distinguish it. The real difference is that in this case, the "feet" part means feet of movement. If you push on a car with 100 pounds of force and maintain that for 30 feet, you have done 3000 ft-lb of work. An easier example is lifting a weight (in pounds) a given distance (in feet). If you use some sort of mechanical advantage, like a winch, you will do the same amount of work because by halving the effort required, you will have to double the distance through which you apply the force to achive the same objective.

Power is the application of work within a finite time. 550 ft-lb of work in one second is one horsepower.

Mr Watt made this famous calculation to define the relationship between TOrque and Horsepower.
Hp = rpm x torque
...........5,252

But I don't... really understand it properly.

Someone said this, which sums it up quite nicely...
I'd like to think that torque is an intuitively easier concept to understand. If that were true, though, then more people would understand the relationship between torque, horsepower, and vehicle acceleration. In reality, none of it is intuitive. If it were, Newton wouldn't be considered the Really Great Guy that he is.

[Jantar]

Think of Horsepower as being the source of the push, but Torque as amount of force available to do the pushing.

[PrincessBandit]

Power is what comes out of the engine, torque is what is applied at the wheels. Most often demonstrated on race track - power moves the drive shaft and the vehicle forward, torque is what makes the tyres spin and the front end rise.
Torque = position of fulcrum x force acting on the lever.
Think of turning a bolt with your fingers: you don't have much twisting force there, but add a wrench and you multiply the torque applied to the bolt. The longer the wrench handle (lever) the greater the torque.
compliments of my husband.

p.s. (this is the edit) torque is what's required to 'get it going or to accelerate', horse power is what is needed to 'keep it going'. (again, compliments of Rik)

[Pussy]

Torque... it's when you've got a woody, and you bend it down to take a pee, and your feet leave the floor :blink:

[NordieBoy]

Power (hp) = Torque (ft-lb) * RPM / 5252

- Maximum acceleration at any speed occurs at the HP peak.
- Maximum acceleration in any gear occurs at the torque peak
- HP = torque * RPM / 5252
- torque = HP * 5252 / RPM
- torque = HP at 5252 RPM

[ital916]

Torque is twisting force, also described as a moment. In enigneering applications, moments are summed and balanced to determine forces acting on object *along with other equilibrium equations...but we won't talk about those*. To find torque, most people use a basic formula which force applied multiplied by perpendicular distance from the point of rotation is used to find torque. Thus when the motorbikes rear wheel is spinning there is a torque/twisting force. If the force from the torque *which can be found from the torque and perp distance* is greater than the maximum force that can be applied to the tarmac ,thus exceeding the coefficient of static friction means you get a nice burnout *there is a formula for this where f=mus*N, argh no scientific symbols. :D

*note: I do not have my eng textbooks at hand, and have not thought bout eng for a few months now, so if there is a mis-wording i'm sorry. Really should get my brain back in uni mode*

[twinkle]

torque is the work done, power is the rate the work is done. Do the work faster you have more power.
what NordieBoy said in other words.

[Bren]

okay then...thats all the technical stuff...but for a dumbass like me a bike with lower HP but higher torque is better in the twisties than one with higher HP and lower torque??? The reason I ask this is there are 2 bikes on my mind that keep on popping up as possibilities for later.
One of my criteria is a low seat height (wife suffers from ducks disease)

So here are the specs (hp and Torque) of both. On those details which one is better?
Bike 1: 34HP 40.68 NM @ 3200 RPM
Bike 2: 31HP 45.5 NM @3400 RPM

Both have seat heights at 27 inches...

I know the figures are not flash but I am not a speed freak and dont plan to be going at 150kmh

[idleidolidyll]

think of torque as a measure of the ability to accelerate.

it aint horsepower that makes for acceleration, horsepower is merely a measure of work done.

torque is more real world: the higher the torque at any given rev, the more the acceleration available

[martybabe]

:laugh:
Think of Horsepower as being the source of the push, but Torque as amount of force available to do the pushing.

Well said.

Torque is a twisting/rotational force,generaly speaking Car engines and trucks have large toquey engines to move large heavy loads,5 people plus luggage plus trailers whereas bikes,generaly speaking have high horse power and lower torque to move a lighter object faster.

So a 1000cc two stroke bike with five passengers and a trailer aint gonna move but a 1000cc car will pull that load fairly easily .

A large capacity Harley will pull up a tree stump,torque.A two fifty two stroke racing bike attempting the same feat would disintegrate.:scratch:

I apologise for the above,it wasn't till I came to write this that I realised how hard it is to explain.:laugh:

Anyway if you can get a bike with large torque and large power that peaks at similar revs youre on to a winner. I've got a headache now,easier Questions please. :msn-wink:

[ital916]

Sorry :confused: you meant in terms of motorcycles...yeah basically what the others said lol..can a harley really pull up a tree stump?

[FzerozeroT]

mate, a "tourquey" bike has say a twenty litre bucket of "force" and a "Revvy" bike has a ten litre bucket of "force"

at 3,000 buckets per minute the tourquey bike is moving twice as much as the revvy bike, but by 5,000 buckets per minute it hits the wall, moving approximately 100,000 litres per minute

the revvy bike can move 15,000 buckets per minute at it's fastest so it can actually move 150,000 litres per minute

tourque being the size of your bucket
power is the work per minute
more buckets per minute = more power!

[idleidolidyll]

that's a bloody excellent description FzerozeroT: humour and intelligence in one post, a rare thing

[Jantar]

So here are the specs (hp and Torque) of both. On those details which one is better?
Bike 1: 34HP 40.68 NM @ 3200 RPM
Bike 2: 31HP 45.5 NM @3400 RPM...

On first instincts I would be inclined to say that bike 2 would be better for the twisties and Bike 1 for outright performance. However looking at where the peak torque comes compared to Revs, it appears that Bike 1 may have the smoother delivery. This is where a dyno chart will give more infomation than raw claims from the manufacturer.

Don't make the mistake of selcting a bike based on HP and torque alone.

[MSTRS]

I've always thought of it as -

High torque = high acceleration
High HP = high top speed

It is why I claimed in another thread that a big v-twin will usually see to an equivalent capacity IL4 in the twisties.

[El Dopa]

okay then...thats all the technical stuff...but for a dumbass like me a bike with lower HP but higher torque is better in the twisties than one with higher HP and lower torque???

Very, very crudely, and leaving out the technical stuff:

If you want a bike that can go through twisties well (accelerate out of a corner) - get a higher-torque bike.

If you want a bike with a higher top speed in a straight line - get a higher HP bike.

simple? :)

Edit: beaten to it by MSTRS.

[cowpoos]

mate, a "tourquey" bike has say a twenty litre bucket of "force" and a "Revvy" bike has a ten litre bucket of "force"

at 3,000 buckets per minute the tourquey bike is moving twice as much as the revvy bike, but by 5,000 buckets per minute it hits the wall, moving approximately 100,000 litres per minute

the revvy bike can move 15,000 buckets per minute at it's fastest so it can actually move 150,000 litres per minute

tourque being the size of your bucket
power is the work per minute
more buckets per minute = more power!
Thats a fucking excellent discription!!! I was about to explain it in air pump terms...

But one thing I would add to you post Matt...is at a point where your maximum torque [maximum buckets of water per minute without spillage??] the torque drops off [water starts to spill]...so efficency drops off...but the higher work rate counters that and you still get the higher work rate [more litres per min]

:)

[HDTboy]

The way I see it, Torque will get you out of a tight corner quicker, while horsepower will help you pass someone in a straight line.

People ride torque, and talk horsepower. The bigger and flatter an engine's torque curve is, the easier, and faster it will feel to ride.

The dyno charts attached are for two bikes with similar power, but massively different torque curves, which do you think would keep it's front wheel off the ground more? Which do you think would feel faster?

[idleidolidyll]

I've always thought of it as -

High torque = high acceleration
High HP = high top speed

It is why I claimed in another thread that a big v-twin will usually see to an equivalent capacity IL4 in the twisties.

only sorta: the world's fastest indian had bugger all horsepower but managed over 300kph.
instead it had good torque, low weight and a great shape.

torque is a measure of available power (at any specific revs) and HP is a measure of work done over time.

[martybabe]

okay then...thats all the technical stuff...but for a dumbass like me a bike with lower HP but higher torque is better in the twisties than one with higher HP and lower torque??? The reason I ask this is there are 2 bikes on my mind that keep on popping up as possibilities for later.
One of my criteria is a low seat height (wife suffers from ducks disease)

So here are the specs (hp and Torque) of both. On those details which one is better?
Bike 1: 34HP 40.68 NM @ 3200 RPM
Bike 2: 31HP 45.5 NM @3400 RPM

Both have seat heights at 27 inches...

I know the figures are not flash but I am not a speed freak and dont plan to be going at 150kmh


OK,thats a bit easier.You want to take the wife and her handbag but don't go that fast.Bike two is the bike for you theoreticaly...in reality those figuers are so close I doubt you'd notice much difference. Bike two :first:;)

[jrandom]

I claimed in another thread that a big v-twin will usually see to an equivalent capacity IL4 in the twisties.

Bike: 10%

Rider: 90%

[cowpoos]

Bike: 10%

Rider: 90%
I'd go IMHO...rider 70% setup 20% bike 10%

[jrandom]

I'd go IMHO...rider 70% setup 20% bike 10%

Yes, true. Good point.

[cowpoos]

Yes, true. Good point.
and in saying that...Rider is the key to good setup anyway.

[Ixion]

If you have to shovel a big pile of dirt from A to B, is it better to use a big shovel and chuck a big shovelfull every so often, or a smaller shovel and thow the dirt faster.

Torque is the size of the shovel, horsepower is the size of the pile of dirt. Smaller shovel, you need to shovel faster (more revs). Bigger shovel, you can fling the dirt less often, but it's going to be harder work each time. In the end the pile of dirt is the same size when the foreman comes round, whichever way you do it.

[NordieBoy]

Don't make the mistake of selcting a bike based on HP and torque alone.

It has to be the right colour too.

[Ocean1]

They're onto it, unless you're chasing ultimate top speeds concentrate on the torque numbers, and how well spread it is across the rev range.

Hint: 86ft lbs on a 178kg bike makes for great acceleration out of the hole.

This explains it well: http://www.msgroup.org/Tip.aspx?Num=221

[idleidolidyll]

Can someone explain torque to me?

it's what those who 'can't' do

[idleidolidyll]

Hint: 86ft lbs on a 178kg bike makes for great acceleration out of the hole.



hell yes!
that's nearly as much as my yammy 1300 had.

on a bike under 180kg, that's great acceleration

'course, on say a buell, that acceleration only lasts for a few thousand revs and then you'll need to hook a new gear; the yammy was way wider

[Ocean1]

it's what those who 'can't' do

Teach, dude, is the word you're groping for I believe.

[jonbuoy]

I think of torque as being how the bike "pulls" at the low/mid RPM range, and HP as top end near redline power. Hence why torquie bikes are nice on the road. Not that many sports bikes are lacking in midrange these days either. I think this has been proven several times - there was a shoot out in a magazine a while ago between the Triumph rocket 3 and a blade', even in top gear roll ons the blade kicked its arse as I recall.

[idleidolidyll]

Teach, dude, is the word you're groping for I believe.

that's sometimes true..............just like bike riding

[madandy]

And to add to all that: Torque is the grunt you feel that stretches your arms when you twist the throttle. High HP reflects an engines ability to continue making good torque at high RPM.

[Ocean1]

hell yes!
that's nearly as much as my yammy 1300 had.

on a bike under 180kg, that's great acceleration

'course, on say a buell, that acceleration only lasts for a few thousand revs and then you'll need to hook a new gear; the yammy was way wider

And weighed?

But you're right, that "top third" just ain't there on the Buell. I really don't care, I don't want to wring it out on the straights. A big slice of that torque's available from 2K through to 7K, far wider than the difference between ratios.

[idleidolidyll]

And weighed?

230kg the manual said less the bloody heavy mufflers that lasted 2000km before i wanted a nicer sound

my mate's 1200 buell could never keep up to it in a straight line drag but of course the buell would kick arse in a canyon (all other things being equal)

[*caution*]

Torque is actually a simpler concept than power i feel.

How much torque an engine has, its the amount of turning force it has available to turn the wheels, power is how quickly it can apply that force.

[martybabe]

OK, I think that about covers it.

To sum up torque is something to do with buckets,tree stumps,shovels and air pumps. Twisting pulling or pushing something with the aid of some horses.

oh and some technical jiggery pokery that's a bit magical. Hope that cleared it up for ya mate. :laugh:

[Edbear]

... good torque, low weight and a great shape.


So that's where I'm going wrong...:bye:



...in reality those figuers are so close I doubt you'd notice much difference.

Perzackery!



OK, I think that about covers it.

To sum up torque is something to do with buckets,tree stumps,shovels and air pumps. Twisting pulling or pushing something with the aid of some horses.

oh and some technical jiggery pokery that's a bit magical. Hope that cleared it up for ya mate. :laugh:


Got it in one!:first:

[Bren]

Hey thanks for your help guys....green bling on the way for some of ya...

The 2 bikes that I mentioned the specs for were as follows
Bike 1: 34HP 40.68 NM @ 3200 RPM...Buell Blast
Bike 2: 31HP 45.5 NM @3400 RPM...Suzuki LS650 Savage

[NordieBoy]

Hey thanks for your help guys....green bling on the way for some of ya...

The 2 bikes that I mentioned the specs for were as follows
Bike 1: 34HP 40.68 NM @ 3200 RPM...Buell Blast
Bike 2: 31HP 45.5 NM @3400 RPM...Suzuki LS650 Savage

On performance they're about the same but the LS will run out of puff first but be better down low.

With those two it's really down to cruiser vs more sporty style and which floats your boat.

[Bren]

On performance they're about the same but the LS will run out of puff first but be better down low.

With those two it's really down to cruiser vs more sporty style and which floats your boat.


and the buell might get me into hog rallies...:banana:

[NordieBoy]

and the buell might get me into hog rallies...:banana:

Whereas the Savage may get you lynched :D

[Bren]

Whereas the Savage may get you lynched :D....like a redneck at the Boston tea party???

[Ocean1]

and the buell might get me into hog rallies...:banana:

:laugh: What do they cost dude?

Any more than 8 or 9K and I'd be looking at one of the XB9 variants. Far more capable donk, bugger all heavier and better suspenders.

[Bren]

I dont think you can get the new ones in NZ now, but 2nd hand ones crop up from time to time. The new peice in the states is about US$4700...just a couple of hundred more than a new savage over there. last one I saw for sale over here had 10,000km and was going for $5000

What sort of seat height has the xb9 got?

[Ocean1]

I dont think you can get the new ones in NZ now, but 2nd hand ones crop up from time to time. The new peice in the states is about US$4700...just a couple of hundred more than a new savage over there. last one I saw for sale over here had 10,000km and was going for $5000

What sort of seat height has the xb9 got?

Ya got me, 30" ain't exactly short.

http://www.bikez.com/motorcycles/buell_lightning_xb9s_2004.php

XB12X is though. :niceone: But a tad more expensive. :pinch:

[McJim]

Good on ya for going for something with more torque than hp. I've found it gives real useability in the real world. One of the more important aspects I've found in the bikes that get described as "Torquey" is that it's not so much about peak torque but more about how early the torque is delivered.

A great comparison is my wife's 750 which has around double the hp and the same peak torque as my bike BUT I find that the little Ducati feels far more aggressive because 70% of the Torque gets delivered at about 30% of the way to redline whereas the inline 4 engine doesn't deliver big torque until about 60% of the way to redline. This is just how it feels to me though and has not been scientifically tested.

[Big Dog]

Have not read whole thread because there are lot of technical answers to a question that is difficult to answer by even those who know.
I look at as such:
Horsepower wins races, Torque sells bikes.

[martybabe]

Hey thanks for your help guys....green bling on the way for some of ya...

The 2 bikes that I mentioned the specs for were as follows
Bike 1: 34HP 40.68 NM @ 3200 RPM...Buell Blast
Bike 2: 31HP 45.5 NM @3400 RPM...Suzuki LS650 Savage

I was just off to bed when I spotted the bikes names. what the hecky peck is a buell blast, Ive never heard of it in pomland and I've roasted me nuts on a few Buells. I have heard of mcsavage though,they stopped selling them in blighty years ago.

I'll just google the blast thing before I go sleepies. Have fun whatever you choose.:2thumbsup

[McJim]

I was just off to bed when I spotted the bikes names. what the hecky peck is a buell blast, Ive never heard of it in pomland and I've roasted me nuts on a few Buells. I have heard of mcsavage though,they stopped selling them in blighty years ago.

I'll just google the blast thing before I go sleepies. Have fun whatever you choose.:2thumbsup

IT's a funky little single cylinder bike

[Coyote]

I think the bikes sound so close together in hp/torque that what should really concern you over what to get is style, comfort, price, condition, etc.

[Usarka]

Saw this described as a boxing analogy somewhere recently.

Torque is how hard a boxer can punch.

HP is how fast he can punch.

[pritch]

I saw written somewhere that torque is what is produced by one engine revolution. Horse power is that figure multiplied by the number of revs.

The various analogies for buckets etc therefore seem to work.

That still doesn't really convey what the torque figure actually means in the real world. If I recall correctly, the torque figure for the Hornet 900 engine is in the same ballpark as the torque setting for the rear axle nut. Which example may provide a reference point. Although I do stand to be corrected by underemployed engineers etc :whistle:

[Ocean1]

I saw written somewhere that torque is what is produced by one engine revolution. Horse power is that figure multiplied by the number of revs.

Less, it's a static snapshot of the force available at any given time. And yes the description of HP is exactly correct, but because torque reduces at higher revs, (even though the HP initially keeps climbing) eventually HP numbers drop also.

Torque is the correct unit to describe force available to contribute to acceleration, but because your gearbox acts as a torque multiplier, (shorter levers for a higher gear) you accelerate faster by exceeding the max torque rpm a tad, to take advantage of the "longer lever". In fact maximum acceleration is achieved if you change at the rpm which drops the revs smack onto the max torque rpm after the change. Max HP revs have nothing to do with acceleration at all, it's just that that's usually about where most engines need to change to achieve the above.


That still doesn't really convey what the torque figure actually means in the real world. If I recall correctly, the torque figure for the Hornet 900 engine is in the same ballpark as the torque setting for the rear axle nut. Which example may provide a reference point. Although I do stand to be corrected by underemployed engineers etc :whistle:

Doesn't sound enough to describe the kick in your arse it produces does it? Probably about right though, and if you could keep that force going at the back wheel at a couple of hundred rpm while nonchalantly navigating said cycle you wouldn't need that fekin' great lump of metal between yer knees. :laugh:

Need a big breakfast though...

[Mikkel]

In the modern world there are a set of units called SI units - they are as follows:

Torque - measured in Newton-Meters or Nm for short.
Energy (or work if you insist) - measured in Joules or just J for short.
Power (or rate of work) - measured in Watt which is equal to Joules per second. If you got 1000 of these you call it a kilo Watt or kW for short.

As for the misunderstanding that high torque will get you out of the corner quicker... Well, if you're wringing an IL4 and got it on the cam I'm sure it'll get you out of the corner just as fast as a super torquey V-twin sitting at half the revs.
If torque was equal to acceleration then I guess tractors (e.g. MF 6499 - 7.4 litre 6 cylinder turbo diesel - 180 kW @ 2,000 RPM and 970 Nm max torque:eek: ) should be insanely quick to accelerate... However it isn't so - there's also the small matter of gearing and rotational inertia in the engine. Usually the measuring of engine characteristics are made at the flywheel - as such they don't count gearing. I'd imagine that you'll find that torquey bikes have a higher gearing than the more revvy ones.

I guess what's awesome about a big torquey is that you can sit at 2,000 RPM and then twist the grip and you got near maximum acceleration at your disposal immediately - whereas you'd need to down shift a bit on your sportsbike to achieve the same.

[Ocean1]

As for the misunderstanding that high torque will get you out of the corner quicker... Well, if you're wringing an IL4 and got it on the cam I'm sure it'll get you out of the corner just as fast as a super torquey V-twin sitting at half the revs.
If torque was equal to acceleration then I guess tractors (e.g. MF 6499 - 7.4 litre 6 cylinder turbo diesel - 180 kW @ 2,000 RPM and 970 Nm max torque:eek: ) should be insanely quick to accelerate... However it isn't so - there's also the small matter of gearing and rotational inertia in the engine. Usually the measuring of engine characteristics are made at the flywheel - as such they don't count gearing. I'd imagine that you'll find that torquey bikes have a higher gearing than the more revvy ones.

I guess what's awesome about a big torquey is that you can sit at 2,000 RPM and then twist the grip and you got near maximum acceleration at your disposal immediately - whereas you'd need to down shift a bit on your sportsbike to achieve the same.
I didn’t say torque equalled acceleration dude, I said:


Torque is the correct unit to describe force available to contribute to acceleration

As for the rest, perfectly correct, as far as the force available is concerned it matters not what’s producing the torque, or at what revs. The torque delivery characteristics are different though, as you say, between different flavours of machinery. The inertial mass in the tractor is just more work being done, and with bikes that’s more of an issue for high reving IL4s than anything else, because the force wasted in spooling the flywheel/crank mass up is higher. Sometimes slowing it down becomes a problem too, like when you’d really rather the back wheel was braking instead of spooling down all that inertia.

If you take acceleration data a from single-gear test run and compare that to the engine’s torque curve you’ll find the curves are near identical. Not because torque is the only characteristic contributing to acceleration, but because it’s the relevant description of the force required to do the work.

And yes, I ain’t real good at guessing what revs to dial up in which gear on a high-reving, peaky engine to produce the best launch out of a corner without lighting up the rear. You could probably have guessed that if you noticed what I ride… :laugh:

[avrflr]

Well said, Mikkel. To all the people who think torque = acceleration, just put a diesel motor in your bike and own the racetrack!

Torque has no time component, acceleration does. If you are standing on a spanner, failing to turn a nut, you are applying torque, you are not making power (because no work is being done), nor are you accelerating. Torque and acceleration are NOT DIRECTLY related.

Power has a time component (as does acceleration) so the two are directly related. But you can build a "dyno queen" motor that makes lots of horsepower but still produces crappy acceleration.

So how do you work out which bike will perform the best? Ride the fucking things. But if you really want to work it out on paper, it's complicated. You need to know (at least) the following:

Weight of the bike
Overall gearing ratios
Area under the power curve at the revs you will be using at the throttle setting you will be using. (This is very significant on a road bike because you will spend sweet fuck all time at full throttle and high revs).

Again, it is pointless to even try to guess which bike will make you happiest from their maximum HP and torque figures.

As for twins being faster in the twistys, why do the Ducatis always get their asses handed to them on the track? IL4s seem to clean up even on the twistiest of tracks.

[Usarka]

As for twins being faster in the twistys, why do the Ducatis always get their asses handed to them on the track? IL4s seem to clean up even on the twistiest of tracks.

Crikey what WSBK races have i been watching for the last 10 years (6 wins by ducati?):eek5:

ok it was rigged by the italians, but......

[johnnyflash]

I understand Horsepower, but I just dont understand torque.

Can someone give me an explanation in laymens terms (for the dumbass I am).

Cheers,
Bren


heheh, torque is what causes your pillion to end up sitting on the tarmac when you open the throttle and also what increased sales of cissy bars :clap:

[avrflr]

Crikey what WSBK races have i been watching for the last 10 years (6 wins by ducati?):eek5:

ok it was rigged by the italians, but......

I've been watching the races of 916-999cc twins beating 750cc 4s. I also watched when the grand prix switched to 990cc four strokes and Ducati got utterly humiliated, leading to successive cc limit decreases for the jap bikes and increases for the Ducatis. I've also been watching bike racing in NZ, that isn't intended to be a Ducati benefit, and they lose. Badly.

Which races have you been watching again?

More to the point, on group rides on the road, I don't recall ever seeing a twin at or near the front.

[GSVR]

I've been watching the races of 916-999cc twins beating 750cc 4s. I also watched when the grand prix switched to 990cc four strokes and Ducati got utterly humiliated, leading to successive cc limit decreases for the jap bikes and increases for the Ducatis. I've also been watching bike racing in NZ, that isn't intended to be a Ducati benefit, and they lose. Badly.

Which races have you been watching again?

More to the point, on group rides on the road, I don't recall ever seeing a twin at or near the front.

If you want more info on the 750 vs Ducati years read Aaron Slights book. Same rules existed in NZ when the Britten ruled the roost. But the Britten probably still would have won.

[Badjelly]

There's a big problem with this thread, as with all discussions I see about torque: the word is used in various different ways, most of them confused.

To my mind the only useful way to use the word torque is in its technical sense, which has been given by several previous posters and also here

http://en.wikipedia.org/wiki/Torque

The torque of a force F acting at a distance d from an axis of rotation is F x d, and the ISO units are newton metres (N m). In terms of the output of an engine, connect your engine to some sort of hydraulic clutch arrangement, run the engine at whatever speed you like at full throttle, then measure the force x distance you need to hold the revs constant. Then power is torque multiplied by rotation rate. If you express torque in N m and rotation rate in radians per second (never mind) you get power in watts (W).

I won't go into all the other meanings, but you can read them on this thread. Torque determines acceleration and power determines top speed, whatever. They're kind of true and kind of untrue and too vague to be of much use in my opinion.

For an illustration of the misuse of torque figures, consider automotive diesel engines. These are normally quite low revving and develop humongous amounts of torque, which the manufacturers like to quote. The problem is, because the maximum revs are so low, the engines need to be geared very high, so all that humongous torque results in not-so-humongous forces at the back wheels.

[Badjelly]

Here's something useful I found on the WWW:

http://www.calsci.com/motorcycleinfo/Horsepower.html

[Mikkel]

I didn’t say torque equalled acceleration dude, I said:

I didn't quote you - what made you think my post was pointed at you?


Well said, Mikkel. To all the people who think torque = acceleration, just put a diesel motor in your bike and own the racetrack!

Oh you can - just take Audi at Lemans... ;)


Torque has no time component, acceleration does. If you are standing on a spanner, failing to turn a nut, you are applying torque, you are not making power (because no work is being done), nor are you accelerating. Torque and acceleration are NOT DIRECTLY related.

Power has a time component (as does acceleration) so the two are directly related. But you can build a "dyno queen" motor that makes lots of horsepower but still produces crappy acceleration.

I'd rather look at it this way:

Work, w, is equal to force, F, times distance, x. Differentiating on both sides with regards to time, t, yields power, P:

dW/dt = F * dx/dt <=> P = F * dx/dt

dx/dt is the rate of change in distance with regards to time - or speed, v, as it is commonly know. Now let's say you're sitting on your bike doing 80 km/h (or 22.22 m/s to keep the units right) in a gear where your engine is sitting at RPMs capable of putting out 100 kW. That means you could potentially have an amount of force equal to 4,500 N (or the equivalent of ~460 kg * 1 g) at your disposal. Some of this force is spent overcoming air resistance and the rest goes on to being used in Newtons 2nd law: F = m*a, Force equals mass times acceleration.

However - things are of course not that simple... Because unlike a helicopter a motorcycle is driven by an internal combustion engine operating at varying speeds. It doesn't do you any good to have a lot of power if you can't change the engine speed. And this is the part of the "equation" that is difficult to put down in an actual equation! This is where bottom-end torque "wins" in that it makes the engine easy to deal with... It's output is more easily accessible - i.e. it has a wider powerband.

Edit:
Oh, I forgot to debunk the power = top speed myth as well.

If you take a hayabusa and chuck a turbo on it, remove the limiter, etc. The top speed will not change unless you change the gearing to utilise the new power. The red line in top gear will still be at the same RPMs - which will equal a certain speed. (This is of course assuming that the haya would be able to redline in top gear before).
Mind you - you'll get there a whole lot quicker.

Mind you - if a major manufacturer makes a vehicle they'll design the gearbox to match the power of the engine... Sometimes they make a gearbox that doesn't aim for top-speed but in stead aims at enabling the operator to keep the engine in the powerband at all times - that's a close-ratio gearbox.

[Virago]

:laugh: What do they cost dude?

Any more than 8 or 9K and I'd be looking at one of the XB9 variants. Far more capable donk, bugger all heavier and better suspenders.

The Savage is definitely cheaper, proving that torque is cheap...



(Badum tish)

[Ocean1]

The Savage is definitely cheaper, proving that torque is cheap...



(Badum tish)

OK, I'll pay it.

But dayum dude, I've just eaten. :sick:

[Ocean1]

I've been watching the races of 916-999cc twins beating 750cc 4s. I also watched when the grand prix switched to 990cc four strokes and Ducati got utterly humiliated, leading to successive cc limit decreases for the jap bikes and increases for the Ducatis. I've also been watching bike racing in NZ, that isn't intended to be a Ducati benefit, and they lose. Badly.

Which races have you been watching again?

More to the point, on group rides on the road, I don't recall ever seeing a twin at or near the front.

You need to get out more dude.

Some of us don't care a jot about capacity, we're not racing. If you wanted to compare different configurations you might more usefully ask what work is done from the same fuel, but to be honest I don't much care about efficiencies either, I just find torquey donks more suited to what I do with bikes.

[twotyred]

Torque... it's when you've got a woody, and you bend it down to take a pee, and your feet leave the floor :blink:

aww man you made my beer come out my nose!!!:laugh:

[Morcs]

The simple way to remember it is:

Torque X engine speed = Horsepower.


You cannot have heaps of horsepower without a lotta torque.
And 'torquey' bikes tend to be low revving.

[Hitcher]

I have been told that I am a bit of a torque wench.

[sidecar bob]

More to the point, on group rides on the road, I don't recall ever seeing a twin at or near the front.[/QUOTE]



The reason for that, is that people with incredibly small penises & an overwhelming need to prove themselves usually dont buy twins, or race sidecars.

[Edbear]

I have been told that I am a bit of a torque wench.


I thought that was "talk wrench"...:msn-wink:

[Edbear]

The reason for that, is that people with incredibly small penises & an overwhelming need to prove themselves usually dont buy twins, or race sidecars.



Whew!!!:2thumbsup

[McJim]

I always thought that that in laymans terms torque is a measure of how inexorable the engine is. Lots of torque very inexorable, iddy biddy torque - easy to stall.:rofl:

[YellowDog]

I didn't think it was that tough a question.

The engine with more torque will give you greater pulling power at low revs right through to high revs (rather than having to change down or hold the gears to high revs.)

High torque = An all round effortless ride with greater range to the gears.

[cowpoos]

I thought that was "talk wrench"...:msn-wink:

wench??????????????????????

[Edbear]

wench??????????????????????


Wrench, as in one who tries to fix people's talk...:shifty:

Not actually having met Mr. Hitcher in person, I can't say if he's a wench and neither having met Mrs. Hitcher, I can't say whether he HAS a wench...:shutup:

[FzerozeroT]

ya, you don't see many v-twins leading group rides, and you don't see RWU forks leading group rides either. I see the connection. SV will stay at the back then like a naughty bike. But RWU forks must be lighter as my front wheel always seems to be in the air?

[pritch]

I didn't think it was that tough a question.

The engine with more torque will give you greater pulling power at low revs right through to high revs

Too simple.

The GSXR1000 produces more torque than most but it is developed at relatively high RPM. It isn't just how much torque there is, but also where it is in the rev range.

Most vee twins and the "detuned" in-line fours like the Hornet, the CB1300, and the other big nakeds, can all pull tree stumps from low revs

[howdamnhard]

Torque is turning force.Think of it as how hard a punch your motor can throw.Power is the number of punches your motor can throw.:laugh: