Headset Bearings

muymuygordo Posts: 11
edited November 2008 in Workshop
In a normal/old style 1 inch threaded headset, is there a "correct " orientation for the bearing races? or does it not really matter?

I have checked the Park Tool website and got a little confused as they seem to use the term cups sometimes and talk about four "races".

When I tried to install some forks in an old frame earlier this evening, it seemed to work best with the open side of the bearings facing upwards in both upper/lower instances. When I tried things the other way I was unable to eliminate a small wobble on the forks without over-tightening the upper race/locknut.

Can someone who is familiar with this sort of setup help?


  • yeah, always have the bearings open side facing each other. Even better, use free bearings as theres no chance of a cage collapsing and bollocksing the bearing surface up. might be that the forks are very slightly too long?

    Did you change the crown race over too (the small ring fixed onto the bottom of the streerer tube)? these are specific to pretty much every headset and must be put on the new forks.

    The cups are the things pressed into the frame.
    yep, my letter 0 key is bust
  • nicklouse
    nicklouse Posts: 50,675
    races are the surfaces that the bearing run on. Not much you can do to get them wrong as one sits on the fork and the other is pressed in the frame.
    Now i guess you are asking about the cages that the bearings are held in?
    yes there is a right and a wrong way for them. BUT the position is opposite at each end.
    the pictures on park show it quite well.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • Thank you for both of the above replies.

    In answer to the queries, I think the forks are the right length as the top of the steerer tube is about 2-3mm below the top of the lock nut at the top.

    I am actuallly using the crown race that came with the forks, so there is a potential mis-match? Looking at the Park website the specification for the crown race differs for JIS and ISO, but I assumed this refers to the inside diameter, i.e. the race on both is the same?

    I have re-read the Park information again and think I now understand it.

    In the upper/top part the bearing cage sits in the cup open side up (the opposite of the picture on Park).


    In the lower/bottom part, fork crown race, the bearing sit the other way round with the open side facing down (as shown in the picture on Park)

    In conclusion, it appears the closed/retainer side face each other and that in my own example, I have put in the lower bearings upside down with the open bearings facing up into the cup and not down into the race.

    I will now go and check and try it the "correct " way round.

    What will happen if I just leave it as it is?
  • nicklouse
    nicklouse Posts: 50,675
    the races are specific to the bearings that they come with. you should swap the old one that has been run with the headset onto the forks.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown