ADJUSTING THE VINTAGE HEAD SET

The head set is designed to hold the bicycle's front fork assembly securely in place while allowing them full rotational movement to complete the function for which they are intended.  In other words, the head set prevents the forks from falling off of the bicycle but still allows for unimpeded movement in a defined plane.

Before the headset can be set or adjusted to working specification, the handlebars, brake levers and callipers need to be installed and working properly.  The front brake system must be functional to final adjust and lock the head set.

Adjusting the head set bearings is a simply matter of tightening the top cup which is threaded onto the fork steering stem.  With the forks inserted in the frame, thread the top cup all the way onto the stem until it gently bottoms out.  At this point there should be zero pre-load on the bearings and no play between the head set top cup and the bicycle's head tube.  Incidentally, pre-load will be felt in the form or roughness or even indexing.

Stand the bicycle on its wheels and close the front brake lever, locking the front wheel into place.  Next, sort of wrap one of your fingers around the head tube where the top head set race meets the bicycle's head tube.  Now, with the front wheel still locked into place, attempt to gently rock the bicycle back and forth.  While doing this try to feel for any movement between the head set and the bicycle's head tube.  Any play here means that the head set needs to be adjusted a bit tighter by screwing the top cup onto the fork steering tube a bit more.  Play with this for a few minutes getting a bit too loose and then a touch too tight.  Finally, attempt to get it as close to zero play as you can without preloading the bearings.  Finally, tighten the lock nut against the bearing race being careful to not disturb the adjusted position of the bearing.

Once satisfied that the head set is properly adjusted, place the bicycle back into the maintenance stand and remove the front wheel.  Rotate the forks one way and then the other several times, feeling for any indexing or roughness.  Indexing will feel like the head set is slipping from one spot to the next and that is pretty much exactly what is happening.  But the set should be rolling and the balls cannot roll well when they are preloaded.

If you do experience the indexing phenomenon, install the wheel and try again.  Do your best and even in so doing, it is possible that you will not hit the sweet spot.  If you feel that you have to make a mistake make the its too tight mistake.  Normally, I would suggest that you leave bearings a little bit loose rather than too tight but not when it comes to the head set.  A touch too tight is much better than any kind of too loose.

And that is pretty much it when it comes to installing and adjusting the vintage road bicycle's steering bearings found in the head set.  Though it takes a while to explain, the actual process of rebuilding is very straight forward and well with-in the reach of most home bicycle mechanics.