Something going "bunk" in the front end

[Veloo]

Recently I've noticed when I put weight on the bars, I hear a quiet "bunk" sound and feel a click like something is loose and shifting/ snapping into place.
Thought it was the stem clamp coming loose so I tightened it up and even put new bolts on it. I also took the top cap off and gave the bolt a 1/8 of a turn. Thought it went away after that but I'm still hearing/ feeling it.
It's not the hoods cuz I hear it when I put weight on the drops and tops of the bars.
Haven't taken the fork out just yet. I find that Chris King o-ring to be a bit of a PITA when reinstalling the fork.

Any thoughts?

[oldpotatoe]

Recently I've noticed when I put weight on the bars, I hear a quiet "bunk" sound and feel a click like something is loose and shifting/ snapping into place.
Thought it was the stem clamp coming loose so I tightened it up and even put new bolts on it. I also took the top cap off and gave the bolt a 1/8 of a turn.(??) Thought it went away after that but I'm still hearing/ feeling it.
It's not the hoods cuz I hear it when I put weight on the drops and tops of the bars.
Haven't taken the fork out just yet. I find that Chris King o-ring to be a bit of a PITA when reinstalling the fork.

Any thoughts?

Sounds like your headset is loose(threadless??). Taking off the top cap and tightening that won't do anything if the stem bolts are tight.

Adjust properly..loosen the stem pinch bolts that hand onto the steerer, tighten that top cap bolt a little, straighten stwm and tighten bolts. If this sounds daunting, go to decent LBS.

[Veloo]

Yup, 1 1/8 threadless and I did loosen the two steerer tube bolts when I gave the top cap bolt a 1/8 tightening but it was a rushed quick and dirty before a ride so I'll give it a proper once over.

Thanks OP.

[Cicli]

Yup, 1 1/8 threadless and I did loosen the two steerer tube bolts when I gave the top cap bolt a 1/8 tightening but it was a rushed quick and dirty before a ride so I'll give it a proper once over.

Thanks OP.

And make sure the top cap isnt hitting the steer tube when you set it. If it does you can tighten all you want, nothing will happen.

[OtayBW]

....I gave the top cap bolt a 1/8 tightening but it was a rushed quick and dirty before a ride so I'll give it a proper once over.
Of all the things you DO NOT want a 'quick and dirty' adjustment on, the headset is at the top of the list!

[CiclistiCliff]

If carbon, make sure the expander plug is not loose and pulling up as you 'tighten' the top cap, effective accomplishing nothing.

Check QR and hub and brake pivot bolt tightness.

[tumbler]

I had the same issue and it was my Chris King headset. The click happened under hard braking so I assumed the headset needed to be tightened down. I tightened it several times (a little each time) and it never went away. A short while later, I was swapping some other bits and removed/reinstalled the fork. The clicking disappeared entirely. I'm guessing something wasn't seated properly inside the headset the first time around. You might try disassembling, wiping everything down, applying a little grease, and reassembling carefully to make sure everything is seated well.

Aside from that, also make sure the top cap isn't contacting the steerer tube and that the expander plug is secure and not moving up as you tighten.

[Mark McM]

I use this quick test to see if the headset is loose: Stand in front of the bike (facing backwards) and grab the fork tips in each hand. Lift the front of the bike up until it is "standing up", balanced on the rear wheel. "Chock" the rear wheel so it can't roll (I use my foot) and pull up and down on the fork tips, to feel if there is any play, or if there any noises. If the headset is loose, you'll feel some motion as you pull up and down.

[bkw]

Throw a spacer on top of the stem and wiggle the fork as you tighten the cap. Sounds like it's not seated correctly or something is wrong with the bearing housing.

[nicrump]

not that uncommon. especially with a light carbon steerer and that king top cap. the steerer flexes a tad and upon return "bonks" when the cap re-seats into its place.

it was endless on my last king equipped 44mm HT bike. seems to never happen since switched to IS and canecreek in my frames.

if all else checks out, i deem it ok.

[Veloo]

CK 1 1/8 threadless headset and spacers
Enve 2.0 fork
Deda expander bung
Ritchey stem

Top cap isn't contacting the steerer tube.

I'll disassemble and give it a bit of an overhaul. Have a bit of breathing room to do so this weekend.

Thanks all.

[David Kirk]

Check that the fork crown race isn't loose on the fork crown.......if this is at all loose is will shift and make a 'bonk' and act like poorly adjusted headset.

dave

[Ryun]

Had a similar issue, turned out the king front hub needed an 1/8 turn adjustment. Just for something different...

[drewellison]

I had a very similar problem with my plastic bike, solved just this week. I swore it was the BB and had it chased and faced. Didn't solve the problem. In addition to the chronic rhythmic creaking when I would pedal (more on one side than the other) I would occasional stop very hard and get a clunk coming from the HS. There was no play in the headset and it was smooth. But I tightened the preload a bunch, and the clunk went away, the headset still spun smoothly, but then I'd still get some clicking when pedaling, even easily, and sometimes when I'd turn the handlebars about 30 degrees (stopped, off the bike), I'd get a good click.

Bought some new (inexpensive) bearings from Wheels Mfg, installed with grease for the contact surfaces, and it's nice and smooth and beautiful and quiet now (with not much pre-load on the bearings). I'm happy.

[Veloo]

Bringing this back up.
I opened up the headset, cleaned it up a bit an put it all back together.
No "bunking" at this point.
One thing I noticed when I first got the bike was that the gap between the upper cup and the bearing cap wasn't consistent. When viewed from the side, the gap at the front is just a tad tighter than the gap at the back. You can see it in the pic. Never could get it seated level.
Can't recall if I ever asked the shop about it but it never seemed to be a problem. Wonder if this is the case of the "bunk".

[dave thompson]

If the upper cup and bearing cap are uneven as in the pic, it would indicate to me the head tube wasn't faced 'square'. I would pursue this as a strong candidate for your recurring noise.

[Black Dog]

If the upper cup and bearing cap are uneven as in the pic, it would indicate to me the head tube wasn't faced 'square'. I would pursue this as a strong candidate for your recurring noise.

This or the cup has not been pressed fully and is not completely seated. Is there an even line between the cup and top of the head tube? Veloo, is this bike your Linskey Helix?

[Veloo]

The cups look to be in the right position with no space. I'll run some shims to see if it's consistent.
Yup BD, it's on my Helix.

[Black Dog]

The cups look to be in the right position with no space. I'll run some shims to see if it's consistent.
Yup BD, it's on my Helix.

Check the gap for sure. If it is consistent then it is a facing issue and on a Ti frame not super easy to face with conventional tools due to the hardness of the Ti. A lot of shops will not want to subject their tools to Ti surfaces. However, Truenorth Cycles makes Ti bikes and they are just down the road from me and my be willing to face the head tube for you, if needed. Non, he less if the fork spins freely and there is no binding when the bearing preload is set then you should be ok. I have a King headset that has an uneven gap like yours and it spins freely and I just ride it as is and have had zero issues for years. Did you check the spacers to make sure that they are parallel? A bad spacer could also cause this.

[Tony T]

One thing I noticed when I first got the bike was that the gap between the upper cup and the bearing cap wasn't consistent. When viewed from the side, the gap at the front is just a tad tighter than the gap at the back. You can see it in the pic. Never could get it seated level.

I have the same "gap" issue (see: http://forums.thepaceline.net/showthread.php?t=122661).
Re-faced the tube, fixed the gap a bit , but still have a very small uneven gap. (No "bunking" though).
I would be surprised if the gap is causing the problem if the headset is moving freely …but it could still be the headset causing the "bunk". Not cheap, but installing a new headset is a relatively easy task.

Check that there is no movement. With the from brake engaged, move the bike back and forth — there should be no movement in the headset. — As Tihsepa suggested, make sure that there is enough space between the top-cap and stem. Easiest way to check is to put a 1/8" larger spacer between the stem and headset.
CK says to tighten only btwn 4-10 in lbs (15 in lbs max) — don't overtigten

[Veloo]

Fixed.

Leveled and no more "bunk" sound.
Had to reface the head tube. I could feel a sharp spot as soon as we took the top portion off. You'd think you spent a few thousand on a Ti frame they'd do it properly at the factory.

[oldpotatoe]

Fixed.

Leveled and no more "bunk" sound.
Had to reface the head tube. I could feel a sharp spot as soon as we took the top portion off. You'd think you spent a few thousand on a Ti frame they'd do it properly at the factory.

yup:hello:

[Mikej]

I've found that greasing the top split wedge device thing inside and out helped. It actually stated to do that in the instructions-degrease stem clamp area after.

[Ken Robb]

When I bought my Rambouillet frame I had it built with Ultegra 9 speed group including headset. Everything was brand new. There was a wee bit of drag when turning the fork. Shop owner/tech removed fork and headset, faced the head tube at both ends and installed Chris King headset. Absolutely perfect ever since. This was a quill stem fork.

While you are trying different cures I think it would be wise to make sure HT is perfectly faced/aligned.

[seanile]

wow. 2 year old follow-up.

[Veloo]

Yeah, the bunk noise was getting louder and more frequent.
ie it annoyed me enough to fix it.

wow. 2 year old follow-up.

[dddd]

I had a case where there was a plastic wedge washer that had worn/distorted to the point where it's conical outer face had become very convex, and replacing this part solved an identical-sounding problem.

On yet another bike, the Aheadset had come loose during a very rough ride, and the bearing actually had sort of hogged out the lower cup enough that the headset could no longer be adjusted to a click-free state.

The King headsets I've used (and acquired used) have been super-durable, some even enduring severe over-tightening before being re-adjusted to perfection.

[dustyrider]

Yeah, the bunk noise was getting louder and more frequent.
ie it annoyed me enough to fix it.

I love it! :beer:

[bitpuddle]

You'd think you spent a few thousand on a Ti frame they'd do it properly at the factory.

No, I wouldn’t think that, ever. Always face surfaces and chase threads.

[fignon's barber]

Yeah, the bunk noise was getting louder and more frequent.
ie it annoyed me enough to fix it.



I'm glad you did. One of my bikes has had this same problem for a year and a half. Drives me crazy. The only thing I haven't tried is refacing the headtube.

[Veloo]

The mechanic had the same issue on his own Ti frame with a CK headset which is why he had a facing tool.
The Lynskey head tubes are longish too so lots of excess material to play with.
Very simple process. Dunno why shops shy away from it. Quick search came up with the tool for $200 CAD.

http://www.canadabicycleparts.com/park-tool-htr-1-head-tube-reaming-facing-cutter-6765.html

I'm glad you did. One of my bikes has had this same problem for a year and a half. Drives me crazy. The only thing I haven't tried is refacing the headtube.

[fignon's barber]

Very simple process. Dunno why shops shy away from it. Quick search came up with the tool for $200 CAD.

http://www.canadabicycleparts.com/park-tool-htr-1-head-tube-reaming-facing-cutter-6765.html


Shops don't want to do it for liability reasons. They don't want to risk damaging
a $3000 frame for a $35 service fee.