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What the what???
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Discussion Starter · #1 ·
2016 Specialized Allez

Rear brake cable runs internally through the top tube. With every bump, though, the housing rattles against the inside of the tube. Any suggestions for a fix or is it just the cost of internal routing?
 

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Take note of the Tech Tip.

Essentially they're saying take a piece of the inner sheath from housing and put some small rubber o-rings on it as bumpers. Thread it onto the cable inside of the top tube and it'll dampen the rattle.

I had to do this on my Tarmac, pretty standard procedure with Spec.
 

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Discussion Starter · #3 ·
Excellent! I'll give it a try. Thanks!
 

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Discussion Starter · #5 · (Edited)
Swing and a miss. It seems they took the easy route and ran housing all the way through the frame (which must be what's clanging on the inside of the top tube) rather than using any of the sheaths or ferrules like in the diagram.

For that, I might just take it back to the LBS and see what they can do.
 

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Discussion Starter · #6 · (Edited)

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Pipe cleaner wouldn't hold it's shape. The zip tie acts like a spring and holds the cable from bouncing up and down. It won't rattle.
 

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Discussion Starter · #8 ·
Pipe cleaner wouldn't hold it's shape. The zip tie acts like a spring and holds the cable from bouncing up and down. It won't rattle.
Thanks. I'll give the zip tie a shot. Hopefully it will save a trip to the LBS.

On a related note, I was surprised/frustrated by the number of threads about this issue on various bike sites. It's a known problem that seems like it would be an easy fix to engineer even for frames without a brazed on guide tube. A few specially sized rubber grommets on the cable housing when the bike is being built up would do the trick.
 

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Specialized has had this problem for years, ever since they went to internal top tube routing.

You can try the same idea with the full housing, just using larger o-rings. The same size you would use to act as a bumper against the paint on the frame at rub locations. Not sure you could fit those in the tube though.

Shimano uses the zip tie idea with their Di2 wires. They include little clip on zip tie things that do the same thing as pictured above, force the wire to one side and hold it there.
 

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What the what???
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Discussion Starter · #11 ·
Specialized has had this problem for years, ever since they went to internal top tube routing.

You can try the same idea with the full housing, just using larger o-rings. The same size you would use to act as a bumper against the paint on the frame at rub locations. Not sure you could fit those in the tube though.

Shimano uses the zip tie idea with their Di2 wires. They include little clip on zip tie things that do the same thing as pictured above, force the wire to one side and hold it there.
Yeah. I found threads going back 10 years that talk about this problem and most of them say learn to live with the rattle. I refuse. :)

It may take two or three to secure the cable.
Here's what I've done so far if anyone else has this problem:

1.) Where the brake cable enters the top tube near the head tube, there is only a small hole just big enough for the housing itself. I put a small zip tie zipped around the housing on the outside. I don't know if this will do anything or not, but I'm hoping it prevents the housing from at least wanting to slide backward.
2.) Next, I took off the cover/cable guide where the cable exits the top tube near the seat tube. There, I wrapped a small zip tie around the housing. Using a piece of external sheathing (split lengthwise) from an old brake cable, I slid that over the cable housing and used it to push the zip tie along the housing into the top tube. I coiled the excess zip tie inside the tube as I went.
3.) After I slid one zip tie in, I then repeated the process with another zip tie. With the second tie I didn't slide it in as far.

Initial driveway test has eliminated the rattle. Weather permitting, I'll take it for a ride tomorrow and see if it's well and truly fixed.

Thanks MMsRepBike and Migen21 for your suggestions and advice.
 

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Shoot some of that expanding insulation foam into the hole?
 

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Just silenced a Synapse.
Ran new bh90 brake hose and while sliding it up into the frame from the large hole in the bb i pierced it through the center of some 7/8 dia solid foam that i got from industrial hdw store. Had to slide on 4" lengths one at a time as that is easiest to pierce. Taped the sections together as i installed them.
Did the same w the DI2 wire but with 5/8 solid foam tubing. Even used surgical tubing from bb through chainstay to caliper.
Also taped foam around the junction box that was bouncing around in the frame.
Now the bike is transformed into silent bliss. The rider was going nuts before and was embarrassed by the amount of noise the bike used to make.
Cannot tell you how good this worked.
Sorry this approach will not help with top tube rattles as access is more of a challenge there but may help others with downtube rattles.
Good luck.
 

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What the what???
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Discussion Starter · #16 ·
I can report 28 miles of quiet riding this morning. On a separate but related note, it's amazing how much smoother the bike seems to feel when you don't have sound constantly reminding you of each little bump.
 
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