Effetto Mariposa Giustaforza II 2-16 Torque Wrench
You just turn the lever until it goes 'click.' So easy, foolproof, almost. Just about any owner of any bike can use one. Just about every owner of expensive bike gear should use one. This is why the Effeto Mariposa Giustaforza II 2-16 Torque Wrench is worth serious consideration. Avoiding just one stripped bolt could save you more than the price of the wrench.
Torque is a pretty easy concept. It's a "moment of force" or rotational pressure. Wikipedia reports, "torque is defined mathematically as the rate of change of angular momentum of an object." In other words, a torque number corresponds to a certain amount of twisting force applied to a bolt. Ever turned an Allen wrench so hard you stripped a bolt, be it the wrench flats in the head or the threads on the bolt, or cracked the component that bolt is attached to, or even tore the head of the bolt off? Too much force, or torque, is the culprit.
A good torque wrench can prevent you from overtightening bolts. In our past, we were pretty good at not overtightening, with one exception. Crank bolts on square-taper bottom brackets. After we had one come loose on a long ride, we started paying more attention to the bolts. And overtightening them. After we effectively destroyed a crankarm this way, we then started under-tightening. Finally, we got the big torque wrench and our days of fear and paranoia were over.
It was only a matter of time before we got a smaller wrench to take care of the rest of the bike. Our first dalliance with a click-style torque wrench was the Syntace 1-20nM click-style. It quickly became, and remains, our go-to wrench when working on our bikes. It's always out and near the bike stand. The Y-wrench is still great, but with all the super-light bolts and carbon-fiber components these days, a torque wrench is indispensible.
The Giustaforza II is similar to the Syntace. It's a click-style wrench that is easy to adjust. The main differences are the size and the head. The Mariposa is smaller in both length and diameter: only 16cm from the head to the end of the adjusting knob. The diameter of the handle is 1.8cm. The head doesn't ratchet. The smaller size is a plus, as it is lighter, at 158g, and travels better. It also feels more like a precision instrument, while the Syntace feels more like a heavy-duty shop tool.
As you can see from the pictures, the Giustaforza comes in padded metal tin. This is good for protecting the wrench and keeping all the bits in place. Dropping the wrench could affect calibration. At the same time, the ceremony, space, and time investment of keeping it in the box are things most of us could do without.
The lack of a ratcheting head strikes us as a bit of a limiter. Because of this, we got bolts snug with a regular wrench and then bring out the Mariposa for final tightening. It adds a little time to the process, but it might also help us focus on what's important. Some folks tell us that the smaller head fits into tight places better, but we've never had an occasion where we couldn't fit in our much-larger Syntace.
On the plus side, the head is magnetic, which helps suck the bits into it. And because you don't need to put an adapter on it as you would with a ratcheting head, you gain a bit of time back.
The wrench comes with a wide assortment of bits. You get the following hexes: 2, 2.5, 3, 4, 5, 6. You get the following Torx: T10, T15, T20, T25, T30. You also get a 3/16 slotted screwdriver head and a #1 Philips head. The 4, 5, and T25 come on the end of long 100mm shafts. The rest are 25mm long and all fit into a 100mm long adapter.
The longer shafts are allegedly at the behest of pro mechanics that prefer long shafts for those three sizes. Initially, we were worried that the twisting shafts could affect torque values, but haven't had an issue of over-tightening thus far. We can see where they can help with tightening various stem, seat post, and brake bolts.
The torque range for this wrench is 2-16nM. NM is Newton-meters, and is the metric equivalent of inch-pounds and foot-pounds. NM values are appearing more and more on bike components next to places where bolts are inserted. Don't worry too much about foot-pounds, as inch-pounds will be the unit of measure for bike components if nM isn't. Because most bike parts are pretty small, 2-16 covers most everything, save bottom bracket cups and square-taper and Octalink cranks.
The wrench comes with the spring backed down to zero. Effeto Mariposa recommends dialing in the torque, using the wrench and then dialing back down to zero. This unloads the spring that the wrench fights against to make the click. In so doing, you're decreasing the likelihood that prolonged loading of the spring will slightly deform the spring and make the actual torque value diverge from the marked value on the wrench. Luckily, dialing in the torque and taking it back to zero take only a few seconds.
If you're tightening bolts that have known values because they're printed on the components, go with those numbers. Otherwise, they should be in the owner's manuals you received with the parts. In lieu of that, here is a chart . There's one on the Park Tool website as well available in a PDF, though it is in inch-pounds, so you'll need to do conversions before using the Mariposa.
The wrench is supposed to manage about 5,000 clicks before the torque values change slightly. The current values are supposed to be accurate +/- 4%. After that, perhaps, another few percent off. 5,000 clicks, assuming five clicks a week, is 1,000 weeks, means that after 19 years, you'd need to have it recalibrated. Cantitoe Road can do the recalibrating, but for those who are interested in testing their wrenches before sending in, there are videos on YouTube teaching you how to check at home.
While we like having a ratcheting head, the small size of the Effeto Mariposa Giustaforza II 2-16 Torque Wrench makes it a useful travel companion. And when the good bike is going on the road, the convenience of it fitting in with other tools is a huge plus.