Nuts ‘n’ Bolts – Headset Replacement Tools and Tips

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Hardcore bike mechanics sooner or later will want to replace a worn headset. If turning your handlebar feels gritty or notchy and you can’t get smooth motion with no perceptible shake after cleaning, lubricating, reassembly and adjustment, it is time to replace the whole set.

Published December 17, 2007 by C.I.C.L.E.
Story and Photos by Harv

Hardcore bike mechanics sooner or later will want to replace a worn headset. If turning your handlebar feels gritty or notchy and you can’t get smooth motion with no perceptible shake after cleaning, lubricating, reassembly and adjustment, it is time to replace the whole set. Most of the headset pieces can be removed by unthreading the lock nut and adjustable cup and catching all the balls and spacers as they fall out (along with the fork). However the cups are an interference fit into the frame and must be removed with considerable force. Traditionally, the home mechanic has resorted to a hammer and punch to get the cups out. This is bad for several reasons. You risk damage to the frame and/or the cups, which you may want to reuse. Uneven pressure is applied to the cup because you are hitting only a single point, which may tend to push one side of the cup out of the frame more than the other.

Meeting the challenge, the bicycle tool industry has devised various better ways to approach this problem. For about $30 you can buy a simple flared tool (a ‘Rocket’ tool) to hammer out the cups. Or you can make one for about a dollar’s worth of material. Get a one-foot long piece of one-inch diameter steel electrical conduit. This is sold in ten-foot lengths at hardware stores, but maybe you can grab a scrap piece from a construction site, if you hang around such sites as I do. After installing the electrical wiring for a residential house, there should be some valuable bits left behind by the electricians.
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Just hacksaw slots in the conduit as shown. Flare the sawed sections slightly outward with a long-nose pliers and that completes the fabrication. To use the tool, insert it into the frame so that the flared end snaps into place behind the cup to be removed. Hit the other (non-flared) end with, preferably, a copper or brass hammer and the cup should pop out. Flip the tool around and knock out the other cup.

Crown races can be removed and replaced without special tools. Open the jaws of your bench vise just enough to clear the fork legs, but not enough to allow the crown race to drop through. Put a wooden block on top of the steerer tube and tap the wood block with a hammer until the fork drops down and leaves the crown race sitting atop the vise jaws. Knock the new crown race on with a piece of metal tubing which will slip over the steerer tube, I use a chunk of chain-link fencepost. Keep in mind that there are two standards for crown race inside diameters – JIS (Japanese Industrial Standard) and the rest of the world. If your crown race seems too tight, it just may be the wrong size. If too small, it is possible to machine out with a bit of emery cloth, being careful to measure frequently to avoid removing too much material.
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For replacing the cups with new ones, press them in with a piece of half-inch allthread (standard hardware store item), two nuts, and several washers. Assemble as shown and tighten the nuts slowly, making sure the cups are going in straight and even. If not, knock them out and start over. If necessary, remove any paint and excess material from the frame, with a half-round file, until the cups go in without cocking to one side. Be careful to not remove too much material from the frame, especially an aluminum frame. Work slowly and check the fit frequently.

Alternately, if you don’t want to make up a headset press, knock the cups into the frame with a chunk of wood pounded with a hammer. Again, take care to drive the cups straight and even. When the cups are fully seated into the frame, remove the blocks or headset press. Grease and assemble the remaining pieces to complete the headset replacement. Adjust for no shake, yet allow for smooth movement of handlebar. You’re done.

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