Wednesday, April 22, 2009

Bike Multi tool - 15mm nut

A friend of mine recently presented me with a question: What tool would you carry to remove a non quick release rear wheel of a bike? This seems like kind of an odd question with an easy answer: a wrench. But if you really ride bikes you would know this is not so. This is because most fasteners on a bike are Allen type, which require small tools. With almost all wheels being quick release the need for large wrenches have almost all but vanished. These days most cyclist carry a multi tool, a Swiss army knife of bike tools, which do not include a 15 or 14 mm wrench for removing nutted wheels.

With single speed bikes however, nutted wheels are still in demand. Some think that with the extra torque generated by only one gear, extra holding strength is also required. Thus the need for a large wrench.

-My first thought was the "Cool Tool". This was one of the first bike specific multi tools. Now the design is owned by Gerber.

It not only has a crescent wrench on one end, but a 14/15mm socket attachment. This is the tool that I carry, and have owned for over 10 years.

-Having a bunch of old tools in my bike bin, I then thought of this ol gem. It has various sizes of socket like fitting including a 15mm. But having destroyed one in the past, I am not sure that it can deliver the torque requirements of a 15mm rear axle nut (30is ft/lbs according to Park Tools).

But maybe I just had a crappy one, and one of better quality would work.

-The next tool to hit my brain was the stubby wrench. Maybe this would be a good alternative to a full size wrench. All the reliability, half the size. You wouldn't need to change up your trusty tool kit, just have a little addition. And they are so cute to boot.

-But if you are going to be caring a wrench for a single purpose, you might as well make it specific purpose, yet multi use; does that make sense at all. Introducing the Park tools single speed spanner. A 15mm stubby wrench with a six point socket, tire lever, and a bottle opener.
This little guy sells for under $15 dollars, and seems built for the job.

This is a good time to throw in a short discussion on "points" of a socket. What six point socket vs a 12 point one. It is the number of possible contact locations the tool/socket can have with the nut/bolt head. A hex head nut has six sides, and thus the true maximum contact points is 6. The stubby wrenches shown above are of the 12 point variety. This does not mean that it contact the nut in 12 points but has 12 possible contact locations. This allows more indexing possibilities if you are working in a tight spot. A 12 point wrench will slip over the nut every 30 degrees apart, whereas a 6 point will only do so every 60 degrees. A open end wrench only contacts the nut in 2 points, and like the 6 point, govern by the hex pattern, indexes every 60 degrees. So which is the best? Generally a 6 point socket provides the most "grip" on a nut. Each of the six points grab more of the corner than a 12 point would. However if working in a tight spot a 12 pt might be necessary. A open end wrench is generally the worst, and most likely to round out your hex corners, but in some applications they are necessary when you cannot slip a box end or a socket over the end, such as a sensor with a wire or a nut on an all thread. If a high torque application of this type is required a flared nut tool or a sensor socket can be used, 5 point. But we will save that discussion for another time.

-Finally a little bit of warning. I would stay away from multi tools that claim to have a 15mm wrench, such as this one. I doubt that the 15mm cut out in the piece of steel will hold up.
So good luck Rob, and let me know what you choose.


  1. So the gerber seems like the best solution, however haven't be produced since the 90s. Decided 6 inch adjustable wrench is the way to go. Got the usual 6" one. However there is this one
    trying to talk my self into $28 wrench. Thoughts?

  2. If you are going to go with a "tennesee socket set", adjustable wrench, then there isn't much reason to spend $28 bucks on one when it can be had for $5. There really is no advantage to having a slender jaw. Except in the case of the cool tool, the slender jaw is to be used as a cone wrench, don't know if the one you are looking at is actually slender enoguh to ack as a cone wrench. But the slender jaw also makes is easier to round out the axle nuts due to it's small contact patch. A open end wrench already has limited contact with the nut. The cool tools socket is to be driven by the jaws of the adjustable wrench and the 6 point socket to contact the nut. This is ok cause the socket is a hardened tool steel with larger flats. I'd jsut go with a basic adjustable, a 15mm wrench I already own, or the Park wrench.

  3. Not sure if this sites is totally valid, but I found a places that claims they are still selling the cool tool.