Birzman Torque Driver 5Nm

The Birzman Torque Driver 5Nm is a rock-solid choice for working on bikes of any sort. Essentially the same as a Prestacycle TorqKey, with four of the most useful-sized cycling bits added, it's a good choice for accurate home and workshop use. Most of the options in our best torque wrenches buyer’s guide offer a range of torque values rather than just one, as you get here, but I think a single setting can be a bonus.

They say that imitation is the sincerest form of flattery, and this Birzman Torque Driver is the spitting image of Prestacycle's excellent TorqKey, with the addition of a four-piece bit set to make it more practical for first time users.

The stubby T-handle tool has a standard quarter-inch drive bit socket with a strong magnetic retainer at the back, so that it doesn't drop any bits. Insert bit into fastener, turn to tighten, click, stop turning. Included are four bits: 3, 4 and 5mm hex, plus a T25 Torx.

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As well as the 5Nm on test, there are two other value options, 4 and 6Nm. This differentiates it from the Prestacycle offering in that Prestacycle's go all the way up to 12Nm; the 4Nm version is Prestacycle's 'mini' tool and is physically smaller.

But 8, 10 and 12Nm are rather esoteric values for most cyclist's daily use, so I understand why Birzman has stuck with offering just 4, 5 and 6Nm.

The party piece of the Birzman (and Prestacycle TorqKey) is that you can undo fasteners quite safely with the tool still attached to the bit. For almost every other torque tool on the market that's a huge no-no as undoing against the direction in which torque is applied could invalidate and possibly damage irreparably the torque mechanism. Specifically, Birzman told us: "If it is to undo a bolt just tightened with the Torque Driver then yes it does have the ability to do so. However, the Torque Driver should not be the primary tool used to remove any bolt that was tightened by another tool to begin with." 

The only other tool on the market I can think of with this functionality is Feedback Sports' Torque Ratchet, where, by holding the tool by the handle and not by the torque indication knob, you can undo without damaging the mechanism. But you need to remember to flick the ratchet mechanism into reverse.

I've been using the Prestacycle version of this Birzman tool for many years and have found it to be repeatedly accurate and reliable over thousands of uses in a commercial workshop.

The ability to immediately undo, readjust and retighten a fitting, for example a stem or seatpost, is invaluable and saves an awful lot of time swapping between a torque tool and a standard hex wrench.

Single settings

The fact that these devices are single-setting only is a real bonus in my eyes, as adjustable torque wrenches mean you are constantly fiddling with a very small scale to try to work out exactly what setting to use, and if you get it wrong the results could be catastrophic. No such chance of that happening here.

One drawback of the Birzman offering is that there is no colour coding or significant branding on the outside or the top of the tool to show you exactly what the setting is, just a small figure printed on the side in rather small white letters.

This means if you have two or three of them sat on your workshop bench or slotted into holders on the wall, it can be challenging to work out which one to grab.

Cam-over

In use you get a very accurate and distinct cam-over once you've hit the required torque setting, which is extremely gratifying and safety conscious. It means there is no risk of missing the fact that you've hit the required torque setting and continuing to overtighten an already maxed-out fitting.

The movement of the cam-over action is around 20 degrees, and there is a fairly audible click as well when this happens.

I cannot overstate how wonderfully practical these tools are in real life. The fact that you can throw them into a bag or pocket, or have them hung up on a tool wall or sat on a bench without fear of damaging them, and yet get them into action very quickly without dropping any bits due to the strong magnetic retention, is an absolute winner in my view.

At 74g the tool feels robust, especially when you consider you only get a single torque value out of it. I wouldn't really recommend it as a tool to take in a pocket or gear bag out on the road, unless you were adjusting the setup of a newly installed component.

Value and conclusion

Which brings us to value. Birzman charges £24 for this set comprising the tool and four bits, whereas you can buy the original Prestacycle version for £20 without the bits. If you were going to buy multiple of these tools, obviously the extra bits will be superfluous, so you could save yourself a few quid.

However, if you're happy sticking with the Birzman brand and you like the idea of having some spare bit sets sitting around, it's not a bad shout.

Verdict

Useful tool that speeds up adjustments in the workshop of torque-sensitive components