is my headset loose?

Discussion in 'Mountain Bikes' started by freerida93, Aug 14, 2007.

  1. freerida93

    freerida93 New Member

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    I have a couple of questions about headsets.

    1. when i spin my front wheel by lifting the bike by the frame and hold the front brake really fast, my bike kind of vibrates near the headset. also, im not sure if this is my brakes or the headset, but when i brake hard with my front brake while going fast, i feel like my headset is moving, or as if there was a rock or a bump on my brake pads. are those signs of a loose headset? BUT i tried the holding the front of my bike and rocking it and it seems pretty solid.

    2. how tight does the top bolt on the headset have to be? does it have to be as tight as you can turn it? if not, about how many turns from tightest?

    thanks in advance
     
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  2. 1id10t

    1id10t New Member

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    You could also try putting the bike up on it's rear wheel with the front wheel up in front of you. Grab the forks in one hand and the handlebars in the other and try to 'rattle' it. There should not be any play. If it's loose tighten the the bolt on the stem cap first with the stem bolts loosened. Can't tell you how many turns it's going to take. Just make sure it's tight without having to put your whole body into tightening it (you don't want to strip the thread). When you're satisfied it's tight (apply the front brake and push back and forth to feel for play) then tighten the stem bolts.
    If you are unsure whenther you are doing it right then take it to your lbs. If you have a good rapport with them they may not chanrge for the service. It's a quick and easy check anyway.
    From the description in your first point I would also check the rim for any buckles/bulges if you are using rim brakes. It could be that there is a bulge which, when the brakes are applied, is hitting the pads each rotation and causing the feeling you are experiencing.
     
  3. octagon

    octagon New Member

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    I'm asuming you've got a threadless headset and cantilever brakes.

    You may be right to think brakes, sometimes, if the brakes are loose on their pivots, you can get them twisting into the wheel and cinching, it may be worth checking the toe-in angle of the pads as well. Also, bear in mind that when the stem is clamped onto the steerer tube, there's no pressure on the star-nut, if not, then the headset will loosen, and there will be play at the intesration of the stem and steerer, so make sure the stem is properly clamped. Also, a little wobble with the wheel spinnning is normal, as the valve puts the wheel slightly out of balance. if the wobble is huge and noticeable, then it may be the wheel is out of true.

    There's no answer to the second part of your question. it is a matter of trial and error. you need to work from not-very-tight, clamp on the stem, then check with the rocking-forward-whilst-front-braking for any play in the bearings. If you feel any, then loosen the stem, tighten the headset bolt by 1/4 turn, re-tighten the stem, and check again. Repeat until play disappears, no more, no less.

    It's laborious, but if you get it right, and you headset is sealed and reasonable quality, you should not need to do this again in a hurry.

    If you're using an old-fashioned headset, my general rule is to go for fingertight plus or minus 1/4 turn.

    Dan
     
  4. MarkInNC

    MarkInNC New Member

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    Just went through this on my road bike.

    Place the bike on the ground and stand next to it holding the front brake on with one hand. Use a finger from your other hand to feel for movement of the headset as it comes out of the frame stem as you rock the bike forward and reverse against the brake.

    My bike had a little movement that indicated a problem. I took the fork assy out and checked the bearing races for signs of damage caused by the rocking and did not find anything too bad. I did find two things which were contributing to the problem. The upper bearing race was not as tight in the frame head as it should be. There was a little slop, not much I could do about that. The other thing I found was that the fork tube was cut about 1/8" too long for the spacers installed. The cap would not pull everything together as it should. I placed a temp washer in the stack and reassembled. There is no movement now which is as it should be.

    Mark


     
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