Solution for a Creak

Purl

Purl

Well-Known Member
I found the creak in my bike. It’s repeatable and isolated. My trek has a pivot bolt that is squared off round (see pic below). It calls for grease essentially everywhere but the threads where it gets loctite and tightened to 8 nm. (Other pic below bolt #7). Now the issue that happens is the bolt head is smaller than the recess it fits into and gets a bit kitty wompass in the hole and the corners of the head create the sound.

Now I’m unsure how to, if I even do fix this. I can easily grease reassemble and go but this lasts 5-10 ish miles only. I have loctite 620 (park tool RC-1) which I can apply in there. I could go back to the LBS but I have doubts anything there aside from a new linkage could do anything.

Looking for any other ideas or solutions before I attempt anything. I don’t want to anything that is non reversible or destructive.
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Brass shim stock, if you want to sit there and put in piece after piece. You can cut it with regular scissors, though you want to take care to make sure it is either flush/below the surface so you don't slice yourself on it.

You could also use large-gap retaining compound between the head and the socket, though it will be significantly harder to remove it later.

I would be surprised, personally, if that was the source of the sound by itself. Check the main pivot below.
 
Karate Monkey said:
I would be surprised, personally, if that was the source of the sound by itself. Check the main pivot below.
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99 percent sure it is the bolt I have isolated because I am able to remove, regrease, recenter and reassemble and the creak goes away.
 
Purl said:
99 percent sure it is the bolt I have isolated because I am able to remove, regrease, recenter and reassemble and the creak goes away.
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In that case, traditional method would be brass shim stock.

Maybe you could get away with rubber isolating tape if you can actually fit it in there.

Clearances should be fairly tight, so I wouldn't think you would be able to use more than one piece of shim all the way around.

You can get shim assortments from some hobby shops--there's a large one in Tom's River/Brick, if I recall correctly.

Cut a long strip the height of the bolt head, lay it out along the circumference, and then trim the excess. Install it in the socket in the frame first, rather than trying to slip it into place after.
 
Thanks @Karate Monkey i can aquire shim stock without a problem. I just didn’t know it would work with such small depth. Worth a try as a non destructive
 
Hey, may I suggest something that I went through with my Sentinel. I had a creak I thought sure was in the frame. I greased the bb, then each pivot….. still had a creak, finally i greased the headset and the creak was gone. What i learned was sounds can travel through the tubes of the frame and confuse me on where the actual noise comes from…… just a fyi.
 
scott62 said:
Hey, may I suggest something that I went through with my Sentinel. I had a creak I thought sure was in the frame. I greased the bb, then each pivot….. still had a creak, finally i greased the headset and the creak was gone. What i learned was sounds can travel through the tubes of the frame and confuse me on where the actual noise comes from…… just an fyi.
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Oh yea, I been on a hunt for this. I’ve fully torn and rebuilt this bike including fork and shock a minimum of once, two or three times for some things. It was frustrating cause it would go away, then come back and I finally realized it was only when I played with the linkage pivot. I’ve now successfully been able to get rid of it 4-5 times for like 5-10 miles till it came back. So I’m convinced it’s fully identified.
 
i guess the only other question to ask is what kind of grease are you using? are you using a real grease(think marine or wheel bearing type) or the park tool crap which washes out like water?
 
shrpshtr325 said:
i guess the only other question to ask is what kind of grease are you using? are you using a real grease(think marine or wheel bearing type) or the park tool crap which washes out like water?
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Juice lube bearing grease. It white and a very tacky grease that’s very close to teflon grease. It’s a gut feeling that it seems good but have no actual data or reviews to back that up. Thoughts?
 
Purl said:
Juice lube bearing grease. It white and a very tacky grease that’s very close to teflon grease. It’s a gut feeling that it seems good but have no actual data or reviews to back that up. Thoughts?
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Never heard of it. And anecdotal evidence but my suspension bearings last alot longer (at least 2x) since I stated useing heavy duty wheel bearing grease in them and on the pivots. The bicycle specific grease just washes out too easily ime. Especially if you hose off your bike to clean it.

That said if you have a tube of wheel bearing grease in the garage it's free to try a heavier (I'm assuming since most bicycle specific lubes are pretty thin) grease to see if it helps.
 
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There is a technique called epoxy bedding where you use a high strength epoxy filler to fill such voids and create a tighter interface. Research the process but in this case you would clean the frame recess in the area where you want to take up the void. You apply a small amount in there (mostly in the outer perimeter where you pointed out the excess play) and then apply release agent to the bolt head so epoxy sticks only to the frame, not the bolt. When dry the fitment will be much more precise. Not sure if the suspension forces would cause the epoxy bedding to break free eventually though.
 
When grease gets pushed out of the way, adding some vinyl tape can close some gaps. Just completely clean the surface before applying.
 
If you are the original owner, I would reach out to MFGER via your lbs. It is often the case that your issue is not isolated to your specific bike. If a problem like this is widespread, it is likely that they have devised a remedy.

Creaking sucks. Nothing is better than a completely silent ride.
 
Looking at that also make some wonder which side is the bearing? Seat tube or rocker link? It doesn't look to me (from these pictures) like there should be much rotational force on that bolt if the bearings are good.
 
shrpshtr325 said:
Looking at that also make some wonder which side is the bearing? Seat tube or rocker link? It doesn't look to me (from these pictures) like there should be much rotational force on that bolt if the bearings are good.
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Agreed in perfect world, but with the summer we have it seems like dust is creeping into everything therefore creating a whole new scenario I can’t understand with my electrical brain.

@jdog you’re right. I’m just always in the “how can I fix it” kind of mindset
 
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