Torque and Horsepower Explained! | The Shop Manual
2024 ж. 12 Қаң.
525 537 Рет қаралды
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Riders and gearheads love to talk about torque and horsepower, but the terms can be a bit confusing if you try to think of them as something more than a number. So what is torque, and what is horsepower? In this episode of The Shop Manual we give simple explanations for these often misunderstood terms that are such a fundamental part of motorcycling.
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Hey Team, thx for another awesome video :) Would it maybe possible to get a video from Ari´s Shop Manual, of him doing an upside-down fork rebuild? I know there is an video during his old MM times, but thats 8 years old and was about an right-side-up one. Greetings an have a good one folks
i’m sure y’all have muted me but this video rly needs a rewrite if u want to avoid misinformation and actually elucidate the difference btwn torque and power for bikers who don’t know.. power = acceleration torque ≠ acceleration torque = where the power band is in the rpm power tells u how fast u can accelerate torque tells u what rpm range yr power band is at.. (a 200ftlb 100hp bike had a much lower redline than a 60 ftlb 100hp bike for example,, but w the perfect transmission they’ll have the same acceleration..)
This was the explanation i was looking for. I knew the diff...but only at a surface level. The crank motion animation & explanation with the two different motorcycles really helped.
Yes - holding the piston-con rod and the crank pin made the difference for me too. Have seen many videos on hp vs torque and the force x distance equation but somehow that visual made it click.
same was very helpful!
Indeed
Torque is just a force. I think the concept of force is quite intuitive. Power is the one that is less intuitive. In layman's terms, a powerful muscle can exert a lot of force. But when you say a powerful engine can exert a lot of torque, it can get confusing because of the power and torque numbers/curves in the specs/dyno sheets. The torque can climb down while the power still goes up, but all is relative to the rpm. In describing engines, compared to describing muscles, the term Power is more technical. A force causing motion in the direction of that force, is producing work. The higher the rate that you can do that "work", the higher is your measured power. Torque is the rotational force produced by the engine's combustion, causing the crank to rotate (revolves). The rate of crank rotation is in revolutions per minute. The higher the torque that your engine is exerting at a certain rpm, then the higher the power will be at that rpm. Suddenly, the term "work" here is not specifically mentioned anymore. If your engine crank is rotating at a rate 6500 rpm with a force (torque) of 500 lb. ft. behind it, then it is producing 619 hp. The terms that are constantly there is the torque (force) and the revolutions (motion) per minute (rate). Power is kind of just a "calculated" result.
“How rapidly the torque is applied” made a lot of sense to me.
A wise man once said "Horsepower is how fast you can crash into a wall and Torque is how many walls you take with you."
Classic. Saying.
Worst analogy ever.
😂😂😂😂 what an awesome analogy.
@@doomman700how’s it wrong? I’ll wait.
@@nogginbonker76how is it wrong, start with torque is a twisting motion not push. Then the fact that momentum will be what carries that wall which means speed and Hp will push it farther. Need more?
The wrench into gear graphic was spectacular.
Of all the videos I've seen explaining torque and horsepower, this is the best one ! Way to go Revzilla, another great video!
I always knew what it was. But the analogy of the runner is a good one. The actual step pushing off the ground is the measure of torque, and HP measures the distance with multiple of those steps
It is a nice but completely useless analogy, because the torque as in the subject of this video is crankshaft torque, which is one of the most useless engine parameters, unless boasting and bragging are a virtue. Crankshaft torque cannot be compared to the runners "push-off" because bikes and cars, unlike runners, have gearboxes. Crankshaft torque is TOTALLY meaningless. At best, the SHAPE of the torque curve matters, but only a bit, and only for mediocre drivers that do not know how to use a gearbox (and I know that because I am one, hence my preference for older big twin sportsbikes like the 2-valve Duc's). The best practical example for the utter irrelevance of engine torque can be found in Moto Grand Prix racing in the 1960's and '70's: Despite fourstrokes being "torquey" and riderfriendly with a wide powerband, pulling like a freighttrain, opposed to twostrokes being peakey and high revving, narrow powerband and not all that much torque compared to the 4-strokes, without a single exception ALL manufacturers went with the 2-stroke for the simple reason that it is horsepower that wins races. Not torque. Even Soichiro Honda, who absolutely HATED twostrokes and tried to keep racing a fourstroke with the NR series, knew this (the NR was intended to extract 2-stroke horsepower from a 4-stroke engine). Honda had to cave and also changed to 2-stroke. Quite succesfully, I might add.
What clears up all the confusion (to me at least) is gearing. Using gearing (both the ratios in the transmission and the sprockets), we can change the torque to whatever we want it to be. 100 hp = 100 ft lb * 5252 rpm 100 hp = 200 ft lb * 2626 rpm 100 hp = 50 ft lb * 10504 rpm So say at 50 mph, both the Harley and the Kawasaki will have their rear wheel spin at the SAME rpm. Say that speed is 525.2 rpm for simplicity. At this point it’s clear that the Kawasaki is actually putting more WHEEL TORQUE to the ground than the Harley, regardless of what the crankshaft torque is. 116 hp = 1160 ft lb * 525.2 rpm 83 hp = 830 ft lb * 525.2 rpm
I always knew the difference in terms of applicability, but the actual physics behind it never clicked until now! They aren’t 2 different measurements, Torque is a variable within horsepower. You finally helped it click, thank you!
It's like money. USD 50000 is a nice amount but meaningless without time, is it per week, per month, per annum, over a lifetime? Similarly, torque is timeless, horsepower is torque over time.
How did you know the difference in application, but not understand the physics? Cart before the horse.
Well,if you ride a v twin and a sportbike i would say its impossible not to feel the difference@@gorillamoto5329
@@gorillamoto5329easy, if someone tells you torque is strength and Horsepower is Power then you now know the difference in application but you still might not know the physics behind it. We all know what things do but don't know how many things do it.
@@paulneedham9885torque is strength, Horsepower is power? 😂 Watch the video again. In simple terms, horsepower is torque over time.
Ari does such a great job of breaking it down for the viewers! Keep these awesome videos coming Revzilla!!!
Torque is how many revs you need to go fast, accelerate fast, pull a load etc. (do work). Power is how much work you can do. For acceleration, more power yields more acceleration, nit necessarily torque. Power is energy output of the engine per unit time. To accelerate faster, you need to add more kinetic energy per unit time, thus you need more power, nit necessarily torque. Half the torque at four times the rpm accelerates the vehicle twice as fast at a given speed (i.e. adjusting gearing to maintain the same speed in both scenarios), because wheel power is double. Wheel torque is also double, as the transmission ratio differs by a factor of 4 while engine torque only differs by a factor 0,5.
I've heard this explained so many ways over the years. This has got to be one of the cleanest descriptions. Good explanation and analogies. Nice job!
Torque is just a number used to compute horsepower and is a static number, having no value in time. We exist in time so we want to know how much work will occur in time. Horsepower is what we use for that. Doesn’t have to be peak horsepower, but horsepower below the curve or wherever in the rpm range.
Yes! God, yes. I wish Ari would just say this. Torque on its own is basically a useless number that doesn't tell us anything. The whole HP curve is what matters, because it's the *power output of the engine*. Torque = strength and HP = speed works in many cases as a simple explanation but is very misleading and leads to misunderstandings.
@@Wintersdarkand make sure the hp and tq graph cross at 5252 which is used in the computation. I’ve seen graphs published where this did not occur.
Love the video, some great explanations, I do worry that some people will hear "torque equals stronger acceleration and horsepower means higher top speed" and miss the caveat that the transmission makes the torque somewhat irrelevant.
Yeah that line is not true. A bike acclrates faster in its powerband, it's weight and gear says the same. The only think it change was the amount of horsepower that was created.
@@pleasedontwatchthese9593 I get the simplification he's going for and I'm positive he knows the intricacies. It's difficult to tell a KZhead audience to integrate the horsepower chart across the range of the intended powerband to determine average acceleration. The sentence just seemed like a misleading sound bite when later people take it out of context.
@@joepelletier5381 I agree with you. My main point is it should have been left out because as you point out it will be misleading
True. Given perfect gearing, the engine that makes the most horsepower will also make the most torque. In real life though we have no perfect gearing so in many cases an engine that makes greater maximum torque is more useful.
@@LTVoyager I think my point is that this is only true (that we should compare just torques) if both bikes have the same redline and I'm afraid that wasn't clear in the video.
I think this is truly one of the best explanations on the Internet. I’ve watched a lot of videos on horsepower versus torque and I’ve never understood it until now.
I've seen several vids on youtube which trying to explain the difference between torque and horsepower... this one is by far THE BEST explanation ever! Thanks Ari!
This has got to be the clearest explanation I've ever heard. Thank you man. You are a treasure
Thank you. I have just spent 40 minutes over breakfast flicking through rubbish videos suggested by KZhead only to give up and see if my favourite channel has posted anything new. Yes! Sanity returned, I can now enjoy the rest of my day suitably educated and knowing there are some great videos on KZhead, just that most of them are from Revzilla.
That break down with the different runners is the best explanation I have seen for this. I am mad that I never made such a simple connection for explaining this to other people. lol
wow, great video, especially the last bit talking about the transmission, that was the best explanation i have ever seen
So what I'm getting from this is that the amount of torque at the crankshaft is not an important number. So why is it always talked about like it is? Because of a lack of understanding and of course marketers know this so they perpetuate the misconception.
You hit the nail on the head. Peak torque is kinda useless figure and is only talked about because of momentum. It doesn't matter if it's a useful number to the maker if it sells bikes
@pleasedontwatchthese9593 yeah, there are still a lot of dudes in comments thinking torque makes a difference in acceleration. If two bikes have the same hp then they will accelerate the same regardless of torque difference. Only difference will be bike with lower torque will have to rev lot higher.
@@currycel470 the bike has to Rev higher to create similar torque, torque is the turning force of the engine, HP is how fast the engine can work. The higher the torque the faster you take off, how fast you can go is HP. So a Harley will beat a Sport Bike off the line but the Sport Bike will then pass the Harley. Harley high Torque low RPM, Sport Bike high HP high RPM.
@@currycel470bro it does😂, not a big difference, but it makes a difference
Awesome explainer. Useful to me and I've been riding over a decade and driving cars for longer.
Watched this topic a hundred times. I still enjoyed your presentation. Nice work!
Best torque/horsepower explanation I've seen, thanks!
This is the best explanation I have heard of the difference. And how they relate to each other.
Thanks man. Cleared a lot of things for me!!
4:45 This video was close to being corrected. The acceleration with same tourqe comment is wrong. A bike in its *power* band accelerates faster than when its not and its the same bike with the same weight in the same gear.
A bike in its power makes more torque too, than remaining part of the rev range. So he's not wrong.
I love your videos they are easily understood for such complex topics don’t ever stop.
I absolutely love these knowledgable vids, keep them coming
This is by far the best explanation and showcase I've ever seen.
This was the explanation I was looking for and the best explanation so far, now I've better understanding of Power and Torque and their relation.
I can say that it's the one of the best video educating with simple and easy examples for torque and horse power, thanks 😊
This is an amazing explanation. Clear, concise, and easy understand.
I've always been a little confused about the difference so thanks for the video. Great explanation
Exemplary. Clear. Concise. Perfect. Thank you so much.
Very easy and straightforward explanation!
Well explained, Ari! LOVE the Shop Manual!
This is the best explanation video i have ever seen regarding torque and horsepower.
Another youtube torque vs. horsepower video? And yet this is a clear and entertaining explanation.
Amazing explanation, please keep such videos coming ! 😊
Thanks Ari 👍 Perfectly explained and illustrated
GREAT explanation Ari!! I am digging the Shop Manual.
Another banger from The Shop Manual, thanks for everything you do brother🫡
You answered a lot of my questions here thanks a lot for that
Hey man Great seeing you doing well i have watching ur videos for a long time and also long before you had a little accident. I don’t know if you will see this message but still felt happy seeing u do well 😊
Thank you Ary, finally someone make a video about this 🙏🙏🙏
best explanation i have ever heard or seen on the internet.
This is the best explanation available on KZhead right now!
I've seen 10+ videos on torque and hp and this has literally the best explanation.
Excellent explanation which nothing can beat. Thanks for this video
Hey, that was really good! Very clear and great examples!
The impressiveness of Harley Davidsons comes from their extreme efficiency to produce the greatest amount of noise from the least amount of power. Engineering excellence.
such a great way to explain this. im using that transmission one cause that is the hardest part about teaching someone besides the clutch.
Great explanation. Very easy to understand and always good to understand these things.
This is probably the best explanation of torque and horsepower I've ever watched. Kudos 🎉
Just an excellent explanation of a topic that seems simple but can actually be quite tricky to understand. The young man speaks clearly at a moderate speed, gives a clear explanation, and doesn’t see the need for loud, pounding music playing while he talks. And the video is not overly long. At last, I understand why an engine with a longer stroke makes more torque, other things being equal, than an engine with a shorter stroke.
Thank you for keeping teaching us great stuff.
The best explanation ever on a seemingly simple but complex concept to explain.
Good demonstration of these two very fundamental concepts.
I didn't realize I could understand this topic so clearly. I used to think I kinda got it, but with your explanation, no doubt. Thanks very much 👍
Thanks man. I was struggling to understand this but you saved me ❤
This is a great video, thank you
I need to be reminded of this every few years. Thanks Ari.
THANK YOU!! It super clear to me now
Great job, this is explained sooo well! :D
Excellent introduction to mechanical functions of power. Well done.❤
One final bit of the explanation is that a high revving low torque engine can still produce massive torque at the rear wheel due to the aforementioned gearing impact and in the end what you feel is torque at the wheel, not at the crankshaft.
That is what I "keep screaming" on all videos like this. They don't specify that "torque at the wheel" is important for acceleration, not at the engine. In a gearing calculation, power is same between input and output of a transmission (ignoring internal losses). But the torque and rpm "value" is what changes. Want more output rpm (=wheel speed)? Torque has to come down. It's why diesel engines are not used in (high-)performance cars.
But, as you gear it down for more torque you loose speed. To try and match the torque output of a large engine with a small engine you would end up needing to shift a lot as the gearing would be very short. Everything is a balance. That’s why heavier bikes do better with high torque engines that produce relatively less horsepower. You need that high input torque to get the mass moving. And, generally a heavy bike is going to be more about comfort where you don’t want an engine screaming at high rpm all the time.
@ In real life you won't find the same transmission ratios on a big and a small engine. The "design target" is a "target max speed" and spreading it between 5/6 gears based on power band (i.e.: not peak engine torque). I agree that the small engine will scream, but the wheel torque will be comparable (if the power is comparable). Edit: If you care about acceleration, then "as you gear down for more torque you loose speed" is not really logical. You downshift because you already lost speed and want to regain it asap. If you are at peak engine torque rpm, then downshifting will, most of the time, get you more wheel torque because you shift into higher power rpm. And that was my main point of "wheel torque", not "engine peak torque".
@@mateiberatco500 You have to account for input RPM and output RPM as well. At the end of the day it isn't that simple because when you gear down for more torque you loose output RPM which is the speed. Yes, if you're going up a hill you may need to downshift to maintain speed. But, when you downshift the engine RPM has to be higher to maintain that speed. At which point you would eventually need to upshift again because you will run out of engine RPM if you keep accelerating. I will argue that just wheel torque doesn't mean anything. I can gear down a tiny engine and get the same wheel torque as a semi truck. But, the output RPM will be very low. That's why you need to account for RPM and not just the torque numbers. It's also part of why a higher torque engine can pull heavy loads better than a low torque engine. You could gear the low torque engine so the wheel torque is the same, but you need the high engine torque in order to have high enough gearing to get the speed.
@@NBSV1 First of all: I'm fighting against "big torque numbers" (instead of "power") and how that number should not affect buying decisions. That's from where I say "wheel torque" makes more sense. Granted, it's not a beautiful single advertisement-friendly number like engine peak torque, but I also want to see the engine graph when I shop for a vehicle (and if they would provide "wheel torque vs speed for each gear", that would be my auto p**n). "when you gear down for more torque you loose output RPM which is the speed" please stop saying this. The rest of that paragraph I agree. But the output rpm/speed will not drop unless the vehicle is in the air (or hard braking or some catastrophic failiure). Vehicle inertia si orders of magnitude bigger than engine inertia to raise it's rpm. Also "gear down for more torque" - if you mean engine torque (cause everybody assumes that when talking about torque in cars/bikes), not true in any cases. You gear down for more engine power, which leads to more wheel power, and that is proportional to wheel torque at the same speed (again, speed change is negligible during a shift). Now, regarding your 2nd paragraph: "I can gear down a tiny engine and get the same wheel torque as a semi truck. But, the output RPM will be very low." We really need to define what we compare. In the video they compare a 80HP/110Nm Harley with a 110HP/50Nm Kawasaki (not sure if torque is in nm or ft-lbs). If the wheel torque vs speed would be overlapped, I would expect both to accelerate similarly until Harley tops out, because the Kawa has gearing spread to an, at least, extra 50% top speed for it's +50% HP. And that is my point: engine torque is meaningless for comparison. You need to get wheel torque graph and compare them. Otherwise we would see diesel engines is all car races. PS: Acceleration is defined as force / mass (from F=ma), force is torque / wheel radius (from Tq=F*len). So how can you say "wheel torque" does not mean anything?
Excellent video with both a simple explanation and easy to understand terms. Thanks!
Excellent explanation. Thanks very much 💪🏼
What a great explanation - thanks!
Great video. Awesome explanation.
perfect and simple, thank you!
Made it look easy to explain. Thank you.
Great explanation - thanks!
A very much needed video.
Never seen such a good explanation video ever.❤
Great explanation Ari! Thanks you
It was one of the best video on yt which explains everything so simply. I knew the formula, but always had a doubt between these 2 terms. And now I get it, why people say cruiser are torque master. And also that gear explanation with animation was also good, initial gears are big, large radius, hence generating more torque / power to move your vehicle. But, at higher speed your vehicle is already moving, u don't need torque, u need fast rotation, hence gears became shorter for high rpm.
Killer video, great job my dude
Good job on the explanation.
Very nicely explained. Passing it to my son. Thanks
Top-notch video. Good content and engaging graphics.
Decades searching for an explanation like that. Thanks Ari!
Decades? But this was explained in high school (at least from my part of the world). Force, motion, rate = power. Basically, power is the calculated result. Force, motion, and rate are its factors and are the ones that are quite intuitive to understand. More torque (force) at a certain revolutions (motion) per minute (rate), more calculated power.
Well done, thank you - great explanation
Engineering Explained has a great video on the units and math that derive 5250 in that equation!
EE Jason is brilliant👍
This is actually the best explanation of the difference I have yet to see. Finally, something that anyone can understand.
That was very well done!
Neat and simple! Very well explained sir
this is the best explanation I've ever seen of this
Top notch explanation. Really informative 👌🏽
WELL EXPLAINED!
Nice video👍. Now i get to know exactly about HP and Torque.
Do you know how many years I’ve been trying to figure THis out? . . . And I’m a car guy! Thank you, everyone who had a part putting this video together!
I learned physics at a university and I still enjoyed this video! Thanks.
Perfect "for laymen" explanation. Bravo!
That did help thank you. I could not imagine how you would get two different forces from one place.
4:51 And that's extremly important! A transmission can manipultate torque and rotational speed but not the power. n1 * T1 = n2 * T2. So a bike with more horsepower will always accelerate faster if the gearing is right.
this is seriously the best explanation of this I've ever seen.
That was the best explanation ever!
Best explanation I've heard.
Well-explained, thanks.