Stills taken from our Headset set up and maintenance DVD which is available for £3.97 from our ebay store
This guide is intended to be a basic introduction to road bike headsets.
For the past 100 years bikes have used threaded headsets, that was untill Dia-Compe came up with the lighter and easier to adjust threadless type. These names simply relates to whether the fork steerer tube is threaded or not. As most headsets are now threadless – that is what this guide is going to concentrate on (although our step by step DVD guide does cover threaded headsets as well)
Just to confuse you Dia-Compe called their new invention the 'Aheadset' and this term is still sometimes used – so just remember that 'threadless' and 'Aheadset' both mean the same thing.
Road headsets were traditionally all 1 inch in diameter, but the standard is now 1 1/8 inch.. All this measurement relates to is the diameter of the fork steerer tube.
Finally, you can also get intergrated (sometimes called hidden headsets) or non-intergrated ones. The only difference is that intergrated headsets have the bearings hidden inside the head tube to give a nice flush look, whilst non-intergrated ones have the bearing in cups on the outside of the headtube.
Checking adjustment is a simple operation. If the headset is too loose it will clunk when you are riding and there may also be play in the fork. If it's too tight the bars will simply feel tight (and possibly notchy).
To check for looseness have the bike on the ground and rock it back and forth (holding the bars) with the front brake on – do this with the bars at 90 degrees as well – feel for play where the fork enters the headtube – if there is any play the headset is too loose.
To check for tightness have the bike off the ground and turn the bars through 180 degress - if it feels tight, rough, or notchy then the headset is set too tight, additionallly a rough or notchy feel may indicate that the bearings need replacing.
So to summerise a correctly adjusted headset will have smooth and free turning bars, but crucially there should be no play where the fork enters the headtube.
Adjusting the headset is easier when you understand two things. Firstly, the top compression bolt adjusts the amount of play in the headset only. Secondly, all the stem bolts do is clamp the steerer tube in place and thus stop the headset going out of adjustment. To make adjustments you will need either a 5 or 6 mm allen key. Simply loosen the stem bolts right off then adjust the top compression bolt (situated on the top of the headset) to tighten or loosen the headset. As a starting point the bolt should be just lightly finger tight - IT IS IMPORTANT THAT THIS BOLT IS NOT OVERTIGHTNED!. Check for correct adjustment as you go along (turning the compression bolt 1/8th of a turn only, between checking) . Once it is adjusted correctly, line up your bars and front wheel and tighten the stem bolts alternately to get an even pressure on the steerer tube. To get the correct tightness of the stem bolts tighten them as hard as you can - but do this with a small allen key to prevent overtightening.
Before removing the headset you can make life easier for yourself my taking off the front brake first. Then, loosen the stem bolts and completely undo the top compression bolt (if your bike is off the ground at this point be prepared to hold the fork in place to stop it falling to the ground). Remove the compression bolt and top cap then slide the stem off the steerer tube.The fork should then drop out of the head tube. Remove all bearing, seals, and spacers MAKING A NOTE OF THEIR POSITION AND ORIENTATION TO MAKE REFITTING EASIER. If you have none cartridge bearings be careful that the bearings dont go walkabout all over your garage floor.
Essentially the only thing that wears on a headset is the bearings. If your bearings are the cartirdge type that will not come apart check to see if they run smoothly - if they don't then there is no other option but to buy new ones. If you have standard / loose bearings then these can be cleaned up and inspected. Pitting in the bearing cups (or ball races) is the type of wear that causes rough and notchy operation and indicates that the headset needs replacing.
Fitting (as they say in Haynes manuals) is the same as removal, but in reverse. Bearing surfaces should be greased first, and this will also help to keep the bearings in place - thus negating the need to have four pairs of hands. Once all back together adjust the headset as above.
I hope you found this guide a useful introduction to headsets. If you did, please take a couple of seconds to vote below. thanks!
You can also see exactly how it's done in close-up detail with our easy to follow step by step DVD which is available from our ebay store - just click on the link below.