According to an online dictionary, torque is "something that produces or tends to produce torsion or rotation; the moment of a force or system of forces tending to cause rotation."
In your scooter's engine, it is the torque it produces that determines how well it will pull you up a hill for example. However, if you carry out your own maintenance on your scooter then it is in relation to your personal strength that you should consider purchasing a torque wrench for your toolbox. And here's why…
While there is no substitute for the expert, trained mechanic at your scooter shop being entrusted to service your vehicle, there is equally no reason why you can't carry out some of the basics yourself to both keep your scooter running smoothly and save yourself a few pennies along the way. Of course you first of all need to be aware of your own mechanical ability and responsible enough to realise that if you don't know a spanner from a set of mole grips, or a ratchet from a screwdriver, then for both your safety and your wallet, stick to cleaning your scooter only and leave everything else to the shop.
Presuming you consider yourself competent enough to do a few minor checks, then you must make sure you have the right tools for the job. An adjustable spanner or set of pliers for example may seem a shrewd, economical purchase on the face of things, however use them improperly and you can do more harm than good, which in turn is likely to cost you.
The same can be said for tightening nuts and bolts accurately, which leads us nicely to the torque wrench. A torque wrench is a tool used to apply a specific amount of torque to said nut or bolt. Apparently invented back in 1918 by an American chap named Conrad Bahr, today such a tool is usually in the form of a socket wrench with special internal mechanisms.
A torque wrench should be used where the tightness of nuts and bolts is crucial, and that applies to whether that be too much or too little. If you didn't tighten something enough, then there is a risk that the fastening will come lose after time - especially on a scooter that bounces along the road with the engine constantly vibrating - which could lead to catastrophic results.
Alternatively, if you over-tighten something you risk damaging the thread. If you spot this immediately then you simply put your head in your hands and cry at the thought of how much it might cost you to get the local scooter shop to repair your over-eagerness with a ratchet. If such an error doesn't come to light straightaway, then the damaged fastening might then come loose of its own accord and like an under-tightened nut and bolt, will often lead to something falling off unexpectedly.
Common sense suggests that not every single fastening always has to be torqued, but an overtightened spark plug that strips a cylinder head can be an expensive error to put right, while at the other end of the scale you do really want to make sure that wheel nuts are tightening as much as a manufacturer recommends.
A torque wrench allows the operator to control the amount of torque applied to the fastener so it can be tightened to the exact specifications for a particular application. The other ingredient therefore, apart from the tool, is the manufacturer's recommended torque setting for whatever task you are about to undertake. Torque settings are likely to be given in Nm (Newton metres), ft-lb (pounds feet) or kg/cm (kilograms centimetres). It doesn't matter which reading you choose as long as your torque wrench is calibrated in that scale. You then follow the manufacturer's instructions to set your torque wrench to the desired level of torque, and lock it at that point. Finally, you simply tighten the nut or bolt until the torque wrench tells you that you have tightened it enough.
How does it do that? The most common and affordable type of torque wrench is a 'click' type, which as the name suggests, clicks when the preset amount of torque is reached. To set these usually involves unlocking an adjuster at the end of the handle, then turning the handle until the numbers on the visible scale show the amount of torque you require. When tightening, the wrench will click and momentarily slip when you've reached the limit, warning you to tighten it no further. Simple, hey?
Another type of torque wrench growing in popularity is a digital one which is set by pressing numbers as you would a digital alarm clock, and it then beeps to warn you when you reach the preset limit.
So there you go. Not rocket science, but a little tip to make sure that any home maintenance you carry out on your scooter is finished securely so that you enjoy the ride!