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Campagnolo brake drop bolt: incompatible?

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Campagnolo brake drop bolt: incompatible?

Old 03-29-23, 07:44 AM
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Campagnolo brake drop bolt: incompatible?

Well, I was OK with the rear brake being a wee bit short; I knew drop bolts existed. So, I ordered one from a parts seller (NOT eBay), the price was OK and "near mint". It arrived last night and i just started assembly of the brake and ? Brake arms won't go on. The micrometer says shaft is 6.04mm, hole in brake arms 5.95mm. Yeah, "Campagnolo compatible" no markings. Anyone run into this? Perhaps later brakes than the Record used a different diameter, and this bolt is for that? Goes to show, "universal application" is relative; perhaps it fits Dura-Ace brakes?

Tempted to bore out the brake arms but I presume I'd never get it right.
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Old 03-29-23, 08:10 AM
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I have not had that experience. The campy been compatible with all the standard pieces.

I just picked up the Shimano 7200 series calipers with the drop bolt. I haven't pulled it apart but it's not what you have.
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Old 03-29-23, 10:18 AM
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-----

both shaft and hole likely to be 6mm nominal

.09mm quite a small difference

possible bolt may have been compatible diameter prior to plating

would definitely take some emery cloth to shaft before enlarging hole in caliper arms
removal of some plating should be eno'

it is available in strip form on rolls; used by plumbers to dress copper pipe ends prior to soldering

prior to rendering any alteration check to verify that thread is the correct 6.0mm X 1.0
-----

Last edited by juvela; 03-29-23 at 10:35 AM. Reason: addition
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Old 03-29-23, 10:55 AM
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Originally Posted by juvela View Post
.09mm quite a small difference

possible bolt may have been compatible diameter prior to plating

would definitely take some emery cloth to shaft before enlarging hole in caliper arms
removal of some plating should be eno'
Typical decorative chrome plating is at most 0.015mm.
But yes. 0.09 would still be quick with emery cloth.
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Old 03-29-23, 11:04 AM
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Originally Posted by Mr. 66 View Post
I have not had that experience. The campy been compatible with all the standard pieces.
This might simply become a PSA advising folks that not all will work.

Originally Posted by juvela View Post
----- both shaft and hole likely to be 6mm nominal .09mm quite a small difference possible bolt may have been compatible diameter prior to plating would definitely take some emery cloth to shaft before enlarging hole in caliper arms removal of some plating should be eno' it is available in strip form on rolls; used by plumbers to dress copper pipe ends prior to soldering prior to rendering any alteration check to verify that thread is the correct 6.0mm X 1.0 -----
(a) yeah, the nuts thread onto the offset bolt correctly; indeed, the brake arms slide readily onto the threaded part of the bolt -- then stop once past that.
(b) pretty sure I have emery cloth; once, long ago, I replumbed the entire house, in copper, including all the radiators.

Originally Posted by oneclick View Post
Typical decorative chrome plating is at most 0.015mm. But yes. 0.09 would still be quick with emery cloth.
OK, I am considering it. I have found ONE genuine Campagnolo bolt, in OK but not great shape so this might be a solution. I just tried putting the threaded end in an electric drill's chuck and it actually spins without oscillating out of control due to the offset. I would have thought the chrome would wear out the emery cloth rather than the other way around.
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Old 03-29-23, 05:46 PM
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I had this exact problem. I ordered a "Campagnolo" drop bolt from an eBay seller in Europe and it turned out to be a Modolo bolt that had too large a diameter. I had difficulty sourcing a proper bolt and eventually bought one from an eBay seller in the US (southern California I think) who makes them out of titanium. That one worked perfectly, though it was a bit pricey. I bet I saved a whole 1/2 oz of weight too!
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Old 03-30-23, 07:41 AM
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Originally Posted by davester View Post
I had this exact problem. I ordered a "Campagnolo" drop bolt from an eBay seller in Europe and it turned out to be a Modolo bolt that had too large a diameter. I had difficulty sourcing a proper bolt and eventually bought one from an eBay seller in the US (southern California I think) who makes them out of titanium. That one worked perfectly, though it was a bit pricey. I bet I saved a whole 1/2 oz of weight too!
probably Jim Merz out of Big Sur.
At one point he was in the CR Google group, probably still is.
he did have an eBay presence, might find him by searching for an Italian titanium bottom bracket lock ring.
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Old 03-30-23, 07:51 AM
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I heard from the seller late last night. She was surprised and offered that I could (a) return it, (b) modify the bolt, or (c) perhaps the brake arms were not to spec and could be modified . Uh, the non-drop bolt has been in there for almost 50 years, so (c) is a non-starter IMHO.

Originally Posted by juvela View Post
would definitely take some emery cloth to shaft before enlarging hole in caliper arms -----
Originally Posted by oneclick View Post
But yes. 0.09 would still be quick with emery cloth.
SUCCESS! I chucked up the bolt in my cordless drill, laid it on its side so kinda a mini-pseudo-lathe. I cut 15mm strips of emery and it really did not seem to be cutting much. But I had a fine file of the right width, that did "get me there". Arms go on and actuate smoothly now (I worried about taking a couple of 1000'ths too much off and having permanent brake chatter).

Originally Posted by davester View Post
I had this exact problem. I ordered a "Campagnolo" drop bolt from an eBay seller in Europe and it turned out to be a Modolo bolt that had too large a diameter.
Very interesting. Drop-bolt has no markings at all. I was online shopping and seeing various sellers, some on eBay, all using the exact same photo where there are no markings on the bolt but a Campagnolo box in the background. What I bought looks identical to my eye. Hmm, a quick search for "Modolo drop bolt" gets no specific hits/photos. Could this be that bolt? I do not know.

Originally Posted by davester View Post
I had difficulty sourcing a proper bolt and eventually bought one from an eBay seller in the US (southern California I think) who makes them out of titanium. That one worked perfectly, though it was a bit pricey. I bet I saved a whole 1/2 oz of weight too!
Titanium would be cool but I'm already spending plenty on this project -- and the resultant bike is going to be 24LB+ anyway. I think.

Hopefully, future readers looking to install a drop bolt will find this interesting/useful.

UPDATE: The brake assembled well, but when I went to install it the bolt was too tight for the rear brake bridge! A few minutes with a rat-tail file fixed that, but another data point on this bolt.
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Last edited by tiger1964; 03-30-23 at 09:55 AM. Reason: Additional information
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Old 03-30-23, 12:20 PM
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Can you post a pic of your drop bolt that didnít work?

in my random box o parts I got from my deaf/blind bike shop owner was a bunch of drop bolts. It would be good to know what works and what doesnít.
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Old 03-30-23, 01:36 PM
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Originally Posted by Robvolz View Post
Can you post a pic of your drop bolt that didnít work? in my random box o parts I got from my deaf/blind bike shop owner was a bunch of drop bolts. It would be good to know what works and what doesnít.
From the website of the place where I ordered mine:


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Old 03-30-23, 06:07 PM
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Well, that is Justyne.

She is honorable.

If you were to explain your circumstance, Iím sure your money would be refunded.

She lives less than a mile from me. Many of us on the site have bought incredible pieces from her at good prices.
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Old 03-31-23, 05:25 AM
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Originally Posted by Robvolz View Post
Well, that is Justyne. She is honorable. If you were to explain your circumstance, Iím sure your money would be refunded. She lives less than a mile from me. Many of us on the site have bought incredible pieces from her at good prices.
She seemed concerned; and she did offer return/credit. One could presume she was told it was compatible, and thus why would anyone check?
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Old 04-01-23, 04:19 AM
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tiger1964 Exactly what brakes are we talking about? You mention brakes "newer then Record" but which ones?

I tried to use a drop bolt on a pair of Mono Planer brakes but while the hole is OK the bolt isn't long enough for the wiser arms.
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Old 04-01-23, 05:54 AM
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Originally Posted by Bianchigirll View Post
tiger1964 Exactly what brakes are we talking about? You mention brakes "newer then Record" but which ones?
For me, that would be anything newer than mid-1970's but I am not familiar with the various versions. I had a set of what I understood might be "Super Record" with script on the arms instead of block letters -- but I think I threw them away. All of my sets here are identical Records. For me, it's conceivable that Campagnolo changed the diameter of the shaft by .1mm for later brake systems... but why would they do that? More likely, this drop bolt is simply not Campy, not designed to fit Campy, but can be modified to fit. YMMV.
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