Watch: This Fun Video Explains Tractability And How It Makes Your Riding Experience Effortless

A detailed explanation of what 'tractability' actually means and the advantages of a tractable engine

You must have read the word 'tractability' in most of our news stories and reviews. While comparing one bike to another, we often say that this particular motor is more/less tractable than the other. But what does tractability actually mean? Let us explain. 

Tractability is a character of an engine that allows the rider to ride the bike at low speeds in a higher gear (say 50kmph in 4th gear) very easily without the bike juddering or stalling. Let’s take the example of the KTM 390 Duke vs the Triumph Speed 400. On paper, both bikes produce similar peak torque outputs at 6,500rpm (39Nm in the 390 Duke, 37.5Nm in the Speed 400). It's only when you ride both bikes do you realize that if you are riding at 50kmph in the city, the 390 Duke’s motor would prefer to do that speed in 2nd gear as it is a rev-happy engine. Whereas, the Triumph Speed 400 will easily do 50kmph in 3rd gear or 4th gear, allowing you to go about your daily commute without stressing too much about gear changes. That is what we mean when we say that the Speed 400’s motor is more tractable than that of the 390 Duke.   

Having said that, a torquey engine does not always translate to good tractability. For example, the KTM RC 390, with its 373.27cc, single-cylinder engine produces more power and torque output than the Yamaha R3’s 321cc, twin-cylinder engine. So, does that mean that the RC 390 is more tractable than the R3? No, because the RC 390’s torque output is produced by a single piston while the R3’s torque output is produced by two lighter pistons. Because the pistons in a twin-cylinder engine are lighter than one single cylinder in the RC 390’s engine, they have a more prompt reaction to any throttle input and can move up and down the cylinders at a more rapid pace as well. This is why the R3 pulls more easily in a higher gear than the RC 390.  

Advantages of a bike with a tractable engine:

- One can easily ride the bike at lower speeds in a higher gear quite comfortably

- No sudden gear changes required, especially in the city, as you can ride around in a single gear with varying speeds for longer distances. This ultimately leads to a more comfortable riding experience

- In situations when you arrive at a corner and feel like you are in a higher gear than you should be, you won’t need to shift down a gear in a hurry. Instead, the motor will have enough power to let you complete the corner quite easily

- It makes it easier for beginner riders to go through the motions of developing his/her riding skills as they won’t have to constantly worry about the engine’s characteristics and the optimum time to shift to a particular gear

 

 

 

 

 

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Recently, while testing the Kawasaki Ninja 500, we saw that you can actually start the bike from 0kmph in 6th gear and the bike can pull away without any complaints. Now while that’s not advisable to do, it is a testament to its engine’s tractable nature! Also, in performance bikes like the Ninja 500, which has really great mid-range and top-end performance as well, the tractable nature adds a lot of flexibility to the engine as you can use the bike for all kinds of scenarios: in the city, for highway cruising, for some spirited riding during the weekend and if you are interested, for your track days as well.