The first hint that something might not be quite right with a headset bearing is often a slight clicking or knocking noise, which might be accompanied by the development of free play. In the case of the headset in my Roberts PBP, it was instead a detectable deterioration in what was originally as sweet and neutral a steering as that of any road bike I have ridden.
In place of effortless stability and millimetre-perfect positioning mid-bend came the kind of uncertain wander more readily associated with a softening front tyre. When this proved not to be the culprit, off came the stem, spacers and headset top cap to reveal an upper cartridge bearing looking very rusty. Once I prised off the “seal”, the extent of the deterioration inside became clear; most of the original grease had been washed out and replaced by a near-solid combination of rust and what little grease was left.
Odd, this, since it is the lower head bearing that usually takes more punishment. The Roberts, however, almost always wears mudguards, which keep muck off the lower race. The bike also has upper and lower bearing sets from different manufacturers and the Shimano Ultegra threaded type lower would appear to last better than the nondescript PRO threadless-style upper.
The correct course of action, of course, would have been to throw away the bearing and press out the cups before installing a replacement. Something about the ease of access to the balls, however, persuaded me to take the quick and easy route. I packed in a load of grease, pressed the seal back into place, reassembled the top cap, spacers and stem and, with the whole lot tightened up, waggled the bars around to check that all rotated freely.
Which it duly did. So that’s a job saved for another day; I reckon there’s another 1,000 miles in that upper bearing. If not, the next look at it will come as it lies in the bin – promise.