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..)

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.

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?

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.

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.

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 UKposts 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.

A bike in its power makes more torque too, than remaining part of the rev range. So he's not wrong.

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

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.

Right, that's why mass per power (kg per kW or pounds per HP) was invented, and should be considered too.

EE Jason is brilliant👍