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I'm pretty sure I could tell you more about torque than you'd want to hear. "Tell me the difference between horsepower and torque" was one of my test questions when hiring fresh out of univ engineers.

But yeah, you are confused. A tractor can do a wheelie and torque is a factor in that but it is mostly a matter of gearing. That tractor is going to have a top speed of about 20 mph.

A quick run down on how torque affects going fast:

Engineers have a choice when designing an engine to provide a smooth power band - which is a basically flat, horizontal torque curve across the entire usable rpm range or making a torque curve that maximizes in a narrow range. The first is the type of engine (and torque curve) that you get when you are designing a daily driver to take grandma back and forth to the bingo hall twice a week, a flat torque curve so she can change gears at almost any rpm without stalling the engine.

To make a go-fast engine you maximize the engine's output in a narrower band - say 4000 - 5500 rpm instead of from 1000 - 6000 rpm like you would with grannies car. This gives you much more power between 4000 and 5500 rpm but your design constraints will force you to drop the torque curve at the lower rpms when you maximize them in the upper range. This is why the proper gearing is important - the proper gearing allows the rider to keep the engine in the "power band."

If you want to tell me that going fast is all about torque and tractors doing wheelies I really would suggest that you read up a bit more on the subject. That and get a Jap bike instead of a Harley if you really do want to go fast. Top end 102 mph ** snicker **

“If you want to tell me that going fast is all about torque and tractors doing wheelies I really would suggest that you read up a bit more on the subject.”

Clearly not my words, don’t even suggest such. What’s your point. What, are you going to school me now. I have a college education too, lol. In fact, I’m an accomplished jet engine designer among other things. I never said the Sportster was the fastest bike in the world now did I. The Sportster’s torque curve is significantly higher than horsepower approaching inversely proportional until you hit around 5800rpm. There is a reason why they have ruled the flat track for decades. http://www.baggersmag.com/horsepower-vs-torque-horsepower-rules-torque-king