If you have a carbon fiber bicycle, or any carbon fiber parts on your bike like a seatpost, handlebar, stem or anything else, you’re going to need a torque wrench.
And the frustrating part is that you’re going to need to either buy an expensive adjustable torque wrench, or you’re going to have to scout out a bunch of different torque specific wrenches, because your seatpost might need to be tightened to one specification, and your handlebars to another.
It is extremely important to use a torque wrench because with carbon fiber components, if you overtighten, you can ruin the component (or your whole bike!) or put your life in danger where a component fails while you are riding.
I started out by buying a couple of simple torque allen wrenches that were specific to my seatpost tightening needs for my carbon fiber road bike. But when I bought a carbon fiber cyclocross bike and eventually a carbon fiber 29er mountain bike, I ended up needed wrenches in a whole range of Nm (Newton Meters of torque, or how tight something is).
I finally broke down and bought this rather expensive Topeak set because it is digital and easy to read, and because it is also really simple to adjust, simple to use, and includes a gigantic range of attachments so that you can use it on just about anything that requires a torque wrench. (Although the low Nm limits don’t make it suitable for something like automotive repair, from what I understand. It ranges from 4-80 Nm.)
You can set the wrench for different units of measurement, including N•m, in•lb,ft•lb, or kg•cm. It is a ratchet style of wrench that you can set for tighten or loosen.
When you have it turned on and you have the wrench set to a certain unit of measurement like 8 Nm, you will hear the wrench make a BEEEP! noise when you hit that level of force, and you know to stop tightening. You can also see on the digital readout how much force you are applying as you get close to the limit you have set. It’s pretty cool.
As you can see from my set, here’s what it comes with:
Allen bits that include 3/4/5/6/8/10 mm.
Torx bits that include T25/T30/T40.
Standard and Phillips screwdriver bits.
Sockets that include 8/9/10/11/12/13/14/15 mm.
A 3/8” Square Drive Adapter that lets you attach all the bits.
It runs off of easily obtainable AAA batteries. I’m still using my first set of batteries after more than a year, although I don’t use the wrench very often.
When it comes to bike repair, this is the best torque wrench out there that I have found. Park Tools also makes a torque wrench for bicycle repair, but it is also expensive and doesn’t come with the same kind of cool kit that zips up and keeps everything together in one spot.
If you want to save a little money, Topeak makes a version that doesn’t have DX on the end that does not include the sockets and costs less. But you don’t get the sockets.