It’s been a while, spare time has been tight, but I finally got some time today to fit this Chris King 2Nut headset. I’ve had this for about 6 months and most of the bikes I’ve built up have been period correct restorations but this time I wanted something a little different. Instead of the typical Shimano or Campagnolo, I went for Chris King. This headset is produced in lots of cool colours but I thought the classic silver would go well with the gloss black frame.
The quality and finish and durability of the sealed and integral bearings mean it should give years and years of excellent, trouble free service. But all of that will only happen if it is fitted correctly. The frame and headset are the best quality so they deserve patience, time and attention to detail when fitting. Chris King are very precise on their tolerances and measurements so some cutting and facing is going to be required. I have a great selection of Campagnolo and Park frame tools to choose from so this shouldn’t be a problem.
The forks threads will need to be clean and free from any burrs so that the aluminium nuts will fit and screw down smoothly. These forks are British threaded so I’ll be using the Park 1 x 24 tpi thread die. I won’t be cutting a new thread but the die can be used to run down the thread to clean it up. I’ll also be using a Campagnolo head tube reamer and facing tool to prepare the faces ready for the Chris King cups. A Campagnolo crown race cutter will also be used to clean and size the fork crown ready for the crown race. Lots of cutting requires lots of cutting fluid!
First things first! Lots of measuring…
Chris King have a 0.1 mm interference press fit, the cutting and facing should get the frame and forks ready without any problems. The fork crown is close, probably just a build up of paint, but the head tube internal diameter needs 0.1 mm reamed out to fit within specification.
Don’t be afraid to use plenty of cutting fluid – it will make the cutting easier and smoother and will save those very costly tools!
The surface of the tube should be a lovely even grey colour. If you aren’t sure that it is flat, cover the surface in sharpie pen and run the facing tool again until the sharpie has been removed. The tool not only faces the tube but also reams the internal diameter. The internal diameter is now 30.09 mm (previously 29.88 mm) which is just right for pressing in the headset cup.
Now that the frame and fork are prepped, the headset cups can be pressed into the frame. These cups have integral bearings so you need to be very careful not to put pressure on the bearings while you press the cups into the frame. I’ve got several head set presses so I just picked the best adapter to fit the cup. Some standard grease smeared onto the bare metal face of the head tube will protect the metal from corrosion but will also ease the press.
Pressing the crown race onto the fork crown is relatively easy with a good crown race installer. With that installed, the forks can be fitted to the frame and the top adjuster nut screwed into place. The top nut requires 5 full turns to ensure that it will grip and lock correctly.
The steerer column on my forks is 2 mm too long. Most people would simple add a washer or spacer to the headset to take up the 2 mm gap, but the 2Nut headset doesn’t come with a spacer so I decided to cut the steerer to the correct size. There are several tools available for cutting the steerer column. If you are confident enough and can cut in a straight line then there is nothing wrong with simply using a hacksaw and no guide. I normally screw the Campagnolo tool 718/6 tool onto the thread and cut against the face of the tool. But as this is a slither of thread I’m cutting, I will use the Park SG-1 tool as the guide is very accurate. Once it is cut, use a file to tidy up the end threads and then unscrew the cutting guide, which will help to clean the cut thread.
The seals on the bearings are tight so it’s important not to mistake that feeling for a tight headset. The seals will feel tight for a few miles of riding, after which the headset should be adjusted again.
Next on the list is a set of 126 mm sealed bearing hubs, possibly some Mavic 501 36H, and then ponder for a while on which chainset and BB!