Singlespeed & Fixed Gear - Thudding sound at front end--loose headset?

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chicagoamdream
10-19-05, 10:25 AM
I think this is a headset problem, but I don't know much about headsets, so maybe you guys can help me out.
What I've got is this dull, reverberating thudding noise when I go over bumps that seems to be coming from the headset. I can replicate it if I lift the front of the bike up by the stem about six inches and let the front wheel drop and bounce on the ground. The thudding noise will be loudest on the first (initial) bounce and will successively get quieter.
I've got the stem clamped in all the way and nothing feels loose, and if I just shake the fork nothing seems to be shaking. What gives?
Definitely loose headset. Get a headset wrench and tighten the cups. It's not the stem and fork, just the headset. Or if you're not into spending money on a headset wrench, most LBS's will charge you a fiver if that at all.
fixedpip
10-19-05, 10:29 AM
Second the call on a loose headset.
Check also that your wheel is properly mounted.
drac_vamp
10-19-05, 10:35 AM
thirded on the headset tightening. easy as pie, just dont overtighten.
if you turn the bike upside down, or put it on a bike stand, grab both of the fork blades and try push/pull on them see if there is movement. this was my first question on bikeforums, oddly enough, and i had that same reverberating noise and thudding sound. it was the headset. i had some play in my forks, like the steerer tube of the forks seemed to be free to move a micro-mm inside the headtube, and was worried that riding on it would ovalize the tubes. so yeah, give the headset a tighten, test ride and make sure it worked and the sound is gone.
drac_vamp
10-19-05, 10:38 AM
another thought, if the headset ends up being fine and the sound still persists, it could possibly be the hub's cup/cones are loose? my rear hub was loose and there was some side to side play between the hub body and the axle... anyhow, it made the same noise as the headset problem, almost exactly, when i do the 6 inch drop test. but, if you feel movement when steering or hear the noise when going over bumps and such, chances are its the headset. but i'd give the hubs a once over too to check.
chicagoamdream
10-19-05, 10:40 AM
Sweet. Thanks for the help, guys. While I'm asking about the front end, how hard are quill stems supposed to be to get out? I just can't, it seems really stuck, and I remember reading somewhere that it's not a good idea to really wrestle with it, lest you bend/strip something.
I know there's nothing rare about a stuck stem in a 25-year-old bike...probably another something to bring to the LBS, eh?
drac_vamp
10-19-05, 10:41 AM
oh and i dont know how you are on tools and stuff, but get the proper headset wrench. for awhile i would use just a big adjustable crescent on my headset and it chewed it all up.
Nat - I have a couple of headset wrenches if you need to come over and use them. What size is yours? I have 2 32mm wrenches.
chicagoamdream
10-19-05, 11:05 AM
Nat - I have a couple of headset wrenches if you need to come over and use them. What size is yours? I have 2 32mm wrenches.
Sean-thanks for the offer. I'm not really sure what size I need...this is the part of the bike that I haven't had to do anything with until now, but maybe I'll come over and try this weekend.
Catch the Canadiens game last night?
slopvehicle
10-19-05, 11:09 AM
my bike's been doing this in the last week or so. usually the "dull thud" happens when I first mount the bike and get rolling. "DUNK!"
I knew it had to be the headset, but I hadn't gotten around to fixing it.
isotopesope
10-19-05, 11:13 AM
i second checking your front hub if it's not your headset. when i first built my iro up, a noise developed. i went freaking nuts trying to adjust my headset. after much headset headachce, i realized i had a locknut on my front surly hub break a few threads out, which made it appear to be tightened enough rotationally, but the locknut could rock a little bit laterally due to the threads. i replaced the locknut and the noise went away.
You should go to track wars this weekend! I'll bring my wrenches.
Of course I caught the Canadiens game! It was effing beautiful.
bostontrevor
10-19-05, 11:44 AM
Catch the Canadiens game last night?
F you, man! I go to dinner at 2 - 0 end of the first and by the time I get home it's over at 3 - 4. I think one thing we can agree on, and that's that the B's have to work harder if they want to win. I just haven't seen good effort so far this season.
Anyhow, to try to remain topical, make sure that when you try to remove the stem, you knock the bolt down to unwedge the wedge. If that doesn't work, do some searching, this has been discussed pretty thoroughly pretty recently. Given the age, I suspect that the grease is long gone and the stem has corroded to the steel.
baxtefer
10-19-05, 12:00 PM
Bruins suck!
so do the blackhawks.
/Go Canucks!
//it's your headset
///get the stem out with some ammonia and a BFH
chicagoamdream
10-21-05, 10:13 AM
Ohh, okay. Now I can admit this: the more I looked at my headset, the less I could figure out where headset wrenches would have gone; and all of the tutorials I was looking at online didn't make any sense. I have a quill stem, so I thought I had a threaded headset, and none of the threaded headsets looked like mine, with the external cups.
It turns out that I have what's called an integrated headset. Duh. It looks like this:
http://www.parktool.com/images_inc/repair_help/headtype216.jpg
So, does anyone know how I tighten/adjust this kind of thing up? The Park site that I got the image from just said that adjustment was "similar to threadless," which didn't really help.
InVeloVeritas
10-21-05, 10:32 AM
Well, I'm having a hard time seeing how you're running a quill stem with a threadless/IS headset. With this style of headset the stem is what keeps the whole business together by clamping onto the protuding section of steerer tube. In that type of scenerio you just loosen the stem bolts, crank down the cap bolt (so long as the cap isn't plastic and uses a star-nut in the fork) and then re-tighten the stem and voila. Variations include having to externally clamp the stem/headset together and then tighten the stem bolt (if there is no star-nut, ie: carbon steerer, or if the top cap is plastic).
Again, all this is based on a threadless (ie: non-quill) stem setup. I don't know how the heck you would preload a non-threaded headset with the stem sitting IN the fork steerer...
chicagoamdream
10-21-05, 10:45 AM
Well, I'm having a hard time seeing how you're running a quill stem with a threadless/IS headset. With this style of headset the stem is what keeps the whole business together by clamping onto the protuding section of steerer tube. In that type of scenerio you just loosen the stem bolts, crank down the cap bolt (so long as the cap isn't plastic and uses a star-nut in the fork) and then re-tighten the stem and voila. Variations include having to externally clamp the stem/headset together and then tighten the stem bolt (if there is no star-nut, ie: carbon steerer, or if the top cap is plastic).
Again, all this is based on a threadless (ie: non-quill) stem setup. I don't know how the heck you would preload a non-threaded headset with the stem sitting IN the fork steerer...
Ugh, man, I don't know. It's how I got it: it's a mid-80s Raleigh road bike converted to fixed.
This is actually how this happened in the first place: I was trying to take my stem out, so I loosened the bolt that runs through the stem. I actually loosened it all the way, and took it out. Nothing was moving, so I unscrewed the cap, and then the top cup, and then I got, basically, what's in that picture, except the stem and the fork were in the middle. Where they joined, there were a bunch of threads: now, I'm correct that these threads were the OUTSIDE of the steerer tube, and that the stem, which I really believe to be a quill, was INSIDE these threads, right?
Anyway, the stem was really stuck, so I gave up, and clamped everything back together as tightly as I could. Now, there's this thunking sound. Does this make sense, or am I making a single huge misevaluation of something?
Aeroplane
10-21-05, 11:55 AM
Okay, here's my interpretation:
You have a threaded headset. To unstick the stem, unscrew the bolt that holds the stem in place, but not all the way.
Take a hammer, and whack the bolt. This should unstick the wedge that holds your stem in place. Let us know what happens next. :)
baxtefer
10-21-05, 12:00 PM
there's no way you have an integrated headset on an 80's raleigh.
you took apart your threaded headset and didn't adjust it correctly.
get yourself a headset wrench and thighten those cups properly
drac_vamp
10-21-05, 12:00 PM
would a mid-80s raleigh have an integrated headset?
beat me to the punch. darn!
eddiebrannan
10-21-05, 12:04 PM
you don't have an integrated headset. they didn't exist in the 80s and they need dedicated headtubes (can't be retrofitted) and they only work with 1 1/8 threaded set-ups.
you need to take tis bike into a store and have the guy fix it and explain it to you at the same time. better a proper clarification and then you cn do it yourself in the future than to tyro-diy and fuxor it up, imo
eddiebrannan
10-21-05, 12:04 PM
or take a pic of your set-up and post it here
Like I said, Nat. Come over and we'll fix that ****.
Is this a joke? Anyway I will bite.
What you describe is a hack: integrated headtube + headset mated to a threaded fork + a quill stem. Preloading the headset bearings could have been accomplished by a nut threaded onto the steerer (the external threads you sort of remember seeing) and pressing against the bearing cone you have pictured. The regular setup prohibiting the nut from undoing itself is locknut and a washer with a tab moving inside the grove in the threads of the sterer - if you didn't have it that's the reason for the hreadset going loose.
On top of that it seems that your stem got stuck.
chicagoamdream
10-21-05, 12:18 PM
Thanks, guys, you rule. I'm still not entirely sure what I've got--I know that I do NOT have a cup at the bottom of the headset. When I got the top unscrewed and was able to push the stem down, the bearings came with it. There's nothing underneath for them to roll in, just the frame and steerer tube.
Here's a pic of the front, sorry this doesn't really have much detail. Those things at the top and bottom of the front tube aren't cups; they screw on to the frame, but the bearings are are completely contained within.
http://www.bikeforums.net/attachment.php?attachmentid=31697
You can see things better if you zoom in (just keep the mouse over the pic in Firefox and left-click).
Unscrewed, it looks like that earlier picture.
But, you're right, I do need to take it in. Plan on doing it this afternoon.
chicagoamdream
10-21-05, 12:23 PM
Sean: Tell me I'm not crazy...that doesn't look like everyone elses' headsets, right?
eddiebrannan
10-21-05, 12:24 PM
you are not as other men
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