advice needed: trouble fitting Campy skeleton brake to new Moots road fork

[sfhbike]

I finally decided to install my new Moots road fork. But I have a few issues getting my front brake to fit right (1st gen Record 11-speed skeleton). I'm coming from an EDGE fork that had no issues with this brake set up. Here's what I'm running into:

1) Shoulder nut (24mm) is a few cm too long and the head sticks out. Ok, no problem, I can by a shorter one.

https://farm1.staticflickr.com/976/27086902977_92588c4b48_c.jpg

2) The bolt on the left side pivot of my brake touches the fork if installed only with the serrated washer . . . Ok, fine, I'll put another washer underneath it to get a better fit.

https://farm1.staticflickr.com/866/41056858735_5683693293_c.jpg

3) The problem is now with an extra washer in place, i only have about 4 threads holding the brake bolt to the recessed nut. My understanding is I need a minimum of 6.

Should I be having this many problems? Is my Moots fork drilled wrong? Do I have to get a new center bolt for the brake in addition to a new recessed nut? I like to work on my own bikes but little things like this can get frustrating . . . Any advice on the best way to approach this?

[cadence90]

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[Kontact]

There are several different common lengths of brake nuts in common use. Get a longer one.

[oldpotatoe]

These come in a variety of lengths(and colors too:))...get the 2 washers in there and go see a decent LBS for a proper length..many brakesets(including Campag) come with a variety of lengths.

[sfhbike]

Thanks for the feedback and suggestions on the recessed nut options. As I said, I have no problem changing the nut length and that will fix problem #1. An extra washer will easily fix #2.

But what do I do about the lack of thread engagement on the bolt? The problem here is that any size recessed nut is going to hit the shoulder inside the fork with only 4 threads engaged (because only 4 threads protrude beyond that far left shoulder). If you look at the pic below, on my fork there is no gap between the two arrow points; the shoulder in the fork leaves only 4 threads of the bolt exposed and eventually the end of the nut seats right up against it when torqued down. (There is actually plenty of room for a nut to recess as the recessed part at the far right in my fork is a lot further in the fork).

https://farm1.staticflickr.com/953/41911811982_03c3865a44_z.jpg

Hopefully I'm being clear. Is this a defect in how my fork was drilled, or is it common to replace a brake center bolt between two similar carbon forks? It just seems strange to me that a Moots fork would not easily accomodate a brake that an EDGE fork handled with no issues.

[sfhbike]

There are several different common lengths of brake nuts in common use. Get a longer one.

Actually, I think a longer nut would just stick out further and wouldn't solve anything for me. See the picture I referenced above. My nut is already hitting the furthest back shoulder in the fork and protrudes out the back. Does that make sense or am I missing something obvious?

[cadence90]

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[Kontact]

Actually, I think a longer nut would just stick out further and wouldn't solve anything for me. See the picture I referenced above. My nut is already hitting the furthest back shoulder in the fork and protrudes out the back. Does that make sense or am I missing something obvious?

It sounds like the recess for the brake nut isn't deep enough for the brake nuts you've tried. If the 4 thread nut is bottoming out inside the fork recess, then there is something dimensionally wrong with the fork, or the brake.



The "brake bolt" - threaded shaft - is a pretty standard length, so this shouldn't be a brake model specific problem. For example, a SRAM Force caliper I just measured with the bolt and star washers removed is 27mm long.


You aren't trying to mount a rear brake on the fork?

[cadence90]

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[sfhbike]

Can we make sure that the terminology is clear here first, so that at least I can be sure that I am understanding correctly?

1) by "brake nut" and "recessed brake nut", you are referring to the internally-threaded nut that slides into the fork from the rear, colored in black in your diagram above, correct?

Yup. Exactly.

2) by "brake bolt", you are referring to the externally-threaded bolt that is attached to the brake caliper, correct?

Yes.

What part of the recessed brake nut is "bottoming out" against the fork? Is it the nut head, hitting against the very back drilled shoulder, as in one of your photos, or is it inside, against the internally drilled (second) shoulder?

The nut is hitting on the end opposite the nut head, at the brake side of the fork. After threading only about 4 threads, it hits inside, against the internally drilled second/left shoulder in the fork, as pictured by the farther left arrow in the diagram.

If the problem is that the recessed brake nut is bottoming out against the internal shoulder in the fork then you will need, as I see it:
a shorter recessed brake nut, in order to allow for complete tightening,
AND
a longer threaded brake bolt, in order to allow for +6-thread engagement.
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Agreed, but I'm confused that this should be happening at all. See below.

It sounds like the recess for the brake nut isn't deep enough for the brake nuts you've tried. If the 4 thread nut is bottoming out inside the fork recess, then there is something dimensionally wrong with the fork, or the brake.
The "brake bolt" - threaded shaft - is a pretty standard length, so this shouldn't be a brake model specific problem. For example, a SRAM Force caliper I just measured with the bolt and star washers removed is 27mm long.
You aren't trying to mount a rear brake on the fork?

My brake bolt is also 27mm long, so definitely a front brake. The front fork recess is ~25mm in to the final "ledge," and the entire length of the hole, end to end, is ~44mm. So that leaves almost 20mm of carbon covering the brake bolt. And with an added washer and the star washer, I am losing 3-4mm more of the bolt, leaving me with only 3-4mm of threads left. I can post up more pictures soon if needed.

Basically, my question is this. Given that my bolt seems to be a "standard" length (27mm) for a front brake, does this mean I have a defective fork? The problem is aggravated by the fact that I need to use an additional washer to clear the left side dual pivot bolt on my Campy brake. I'm just stumped by why my fork won't easily fit one of the most standard brakes that is mounted to these bikes.

The fork was purchased new from Moots, so I can contact them. But first I'm just trying to figure out if this is user error, a brake problem, or a fork problem. So far I'm leaning toward fork.

[sfhbike]

My brake bolt, 27mm:
https://farm1.staticflickr.com/863/27086901577_a4101186e0_c.jpg

View of inside of my fork brake hole, for reference:
https://farm1.staticflickr.com/974/41911655332_d76b3ac94c_c.jpg

Entire length of hole measures about 44mm:
https://farm1.staticflickr.com/944/27086901557_4905759f8c_c.jpg

Length to the last/furthest front "shelf" in the fork hole is 25mm:
https://farm1.staticflickr.com/969/41056858665_dce669c9a6_c.jpg

[Kontact]

It certainly sounds like your fork's internal dimensions make a lot of sense if there is a 20mm section that is not wide enough to accept the brake nut. Using two star washers (5mm) is normal, reducing the available threads to just 2mm.

I would call them tomorrow.

[cadence90]

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[sfhbike]

I do not see any images.

Is the "Length to the last "shelf" in the fork is 25mm" from the front of the fork, or from the rear?

In other words, if the fork is 45mm deep at the drilled crown, is it 20mm + 25mm (recessed nut) from the front to the rear, or is it 25mm + 20mm (recessed nut)?
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If you have Privacy Badger or an ad blocker in Chrome, it might be blocking your images. It happened to me on this post also.

So, looking from the rear of the fork, it is 25mm in to the last shelf, then an additional 19-20mm at bolt width to the front of the fork where the brake mounts.

[cadence90]

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[yashcha]

I also had this problem on a Reynolds fork, and I had to carefully dremel 1-2mm off the lip of the the inner hole so that I could use a longer recessed nut.

[cadence90]

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[yashcha]

:eek:

I'm just going to file that under, "NOT what I would ever do, NOR would suggest that anyone else ever do."

The proper Reynolds recessed nut is $15. New. In titanium.
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What ever. It was was fine for five years.

[cadence90]

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[yashcha]

For you, apparently so, but I'm not so cavalierly "whatever" when it comes to safety issues and equipment recommendations, and certainly never when other people are concerned, sorry.

I'm not trying to be a jerk, but would you really advocate that someone drill out a carbon fork, especially in lieu of simply procuring the proper part?
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I am not sure how getting a shorter bolt is going to help. The only way to fix this problem is to take a bit off the inside of the fork and use a longer recessed nut.

[Kontact]

I am not sure how getting a shorter bolt is going to help. The only way to fix this problem is to take a bit off the inside of the fork and use a longer recessed nut.

Or find out if there is something wrong with the fork before you break out the power tools.

[cadence90]

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[yashcha]

I never suggested a shorter brake bolt.

I suggested a shorter recessed nut (for better tightening, i.e. no "bottoming out") AND a longer brake bolt (for more thread engagement).

In any case, I will reiterate in order to avoid any confusion:
I would NEVER advocate drilling out or modifying a carbon fork in any way. That is just really irresponsible "advice".
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Sorry, just reread, your post about the longer brake bolt. You are totally right, longer bolt, shorter nut.

[cadence90]

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[sfhbike]

Hmm, I don't know about that computer stuff, sorry.

In any case, if I have it correct, the situation is as per this diagram below?

I wish I could help further, but I still think you could try a shorter recessed brake nut and a longer threaded brake bolt (stud), especially if you can find access to them...LBS maybe?

http://i1360.photobucket.com/albums/r654/traghetter/Recessed%20Nut_zpsi26jbqab.jpg (http://s1360.photobucket.com/user/traghetter/media/Recessed%20Nut_zpsi26jbqab.jpg.html)
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Well done. That is exactly the situation right now. :help:

Don't worry. I'm not about to bust out the dremel. I still think it is absurd that I should have to replace two parts of my Record front brake to make this work when there is nothing out of the ordinary about the brakes. Are Campy center bolts even readily available? Searches don't seem to come up with anything very readily, and if they do they don't seem cheap.

I think I'll see what Moots has to say and if they can give me any specs on this fork. I can't imagine I would be the first to have this problem if this is just how they make them. Next step would be to go to an LBS and see what they can do for me (I had them mount the crown race already, and I cut the steerer and expected an easy install after that).

So for those who wrench more than I do, has anyone else seen an issue like this?

And thanks for all the input and for trying to get to the bottom of this.

[cadence90]

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[Kontact]

Are Campy center bolts even readily available? Searches don't seem to come up with anything very readily, and if they do they don't seem cheap.

I think I'll see what Moots has to say and if they can give me any specs on this fork. I can't imagine I would be the first to have this problem if this is just how they make them. Next step would be to go to an LBS and see what they can do for me (I had them mount the crown race already, and I cut the steerer and expected an easy install after that).

So for those who wrench more than I do, has anyone else seen an issue like this?

And thanks for all the input and for trying to get to the bottom of this.

I wrenched for a living and never saw this kind of problem. I think it is a fork issue and there isn't going to be a longer brake bolt to switch to.

Tell Moots that brake nut bottoms out inside the fork when you only get 4 turns on a standard front brake with two washers. They should know if that is right or wrong and how to make it work.

[cgolvin]

2) I see you are in Santa Monica. If you get no help from Moots, maybe take the fork and brake and go see Wilbur at Helen's Santa Monica on Broadway? He is nice, friendly, good. Or the (only) mechanic (older, thin gent; I don't remember his name) at Bike Effect (he used to work at TriAthlete Zombies for many years)?

Seconded on Wilbur, and I believe the Bike Effect mechanic you're referring to is Scott. I have encountered another mechanic there, younger, so if he doesn't have graying hair you've got the wrong guy.

[cadence90]

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[glepore]

FWIW, I think cadence90 had the answer in his earlier post. Its a thinwall nut that he needs.

[sfhbike]

Hi guys, moved from Santa Monica to Ventura in November, so those bike shops (both of which are great) are no longer an option (just updated my location now). I sent an email to Moots over the weekend and will try to follow up with them in the next day or two. The website doesn't show 45 rake forks as in stock anymore, so worst case scenario they take this one back and I continue using my previous fork (I was switching out for pure vanity).

FWIW, I think cadence90 had the answer in his earlier post. Its a thinwall nut that he needs.

I think if you read through the rest of this thread, I'm not sure how that solution would fix the issue. But I'm all ears if you want to explain how it would.

[glepore]

I think if you read through the rest of this thread, I'm not sure how that solution would fix the issue. But I'm all ears if you want to explain how it would.

If the diagram in post 15 is accurate, I think that what's happening is that the inner face of the nut is bottoming out on the inner shoulder. I can't see the photos for whatever reason, except for the one that appears with the thread title in tapatalk, but given how far the head sticks out, the od of the nut is contacting something. If you dig around a bit, you'll see that the Reynolds nut is .765 od and almost everyone else's is an even 8mm. Search Reynolds brake nut with google and there are a ton of threads here on this. Some folks even have sanded down the oem Campy nut. I had to do that years ago in a similar situation.
Also not the slight taper on the end of the reynolds nut.

[GOTHBROOKS]

if youre in ventura and want to go to a shop i would try metal mtn on main st or shiggys on the avenue. or drive a lil further north up the 33 to see ron at bicycles of ojai.

actually i think the mob shop in ojai is a moots dealer? they have at least one on the floor. maybe try them.

[sfhbike]

If the diagram in post 15 is accurate, I think that what's happening is that the inner face of the nut is bottoming out on the inner shoulder. I can't see the photos for whatever reason, except for the one that appears with the thread title in tapatalk, but given how far the head sticks out, the od of the nut is contacting something. If you dig around a bit, you'll see that the Reynolds nut is .765 od and almost everyone else's is an even 8mm. Search Reynolds brake nut with google and there are a ton of threads here on this. Some folks even have sanded down the oem Campy nut. I had to do that years ago in a similar situation.
Also not the slight taper on the end of the reynolds nut.

The space it would have to go into is bolt width. There's no way any nut is going to fit past that shoulder in the carbon.

I'm going to repost all pictures from flickr. Something about google photos links is not working. Sorry about that.

Edit: I misunderstood you the first time around. It's a good theory that the OD of the nut is what is getting jammed, but having measured everything, it seems like it is going all the way in to where the shelf is, so I don't think that is the problem.

[sfhbike]

All pics reposted and should be working now. Let me know if you can't see them or if there are any new epiphanies as a result. Thanks again for all the inputs.

[sfhbike]

An update. I emailed a bit with Jeremiah at Moots. This part of the response was most relevant:

The nut that we recommend is the 12mm (length from under the head to end of nut) The Shimano brakes have the same ~27mm ‘bolt’ but only require one washer so it is possible to get more than the 5mm of thread engagement Shimano recommends. Unfortunately sometimes with Campagnolo we have weird issues like this come up because their dimensions can fall outside of the industry standard (shimano). If it was my fork I would try a 12mm nut, the minimum width of washers required to not have the brake contact the fork and see if I was sufficed with the amount of thread engagement.

He confirmed that the forks they have there are similar or the same as what I'm seeing (his drawing below, 12mm to first shelf, 25mm to second shelf -although the critical measurement for me is actually the last piece to the left where I had a red "x"):

https://farm1.staticflickr.com/827/41077347345_a2165f29ae.jpg

He offered to take it back for store credit if I can't get it to work. Still a little surprised that the fork is drilled with so little tolerance for an issue like this (especially given how many people will install Campy on a Moots). Not really sure what other options there are at this point. I'll probably get a shorter nut, torque it down to the full 10nm and hope that I can get an extra thread or so in there. Given that it is my front brake, my main concern is safety. Any other suggestions?

[sfhbike]

Also, these forks are apparently discontinued and they won't be receiving anymore in the 45 rake (which is what my bike is spec'd for). So if I return it, no matchy matchy fork for me. :rolleyes:

[cadence90]

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[Kontact]

How much clearance between the caliper and fork do you actually need? Different star washers are different thicknesses, so you could certainly find a combination that gives you a the minimal clearance and produces an extra 1mm of brake bolt length.

The other thing you can do is take a longer brake nut and grind it down to the maximum length that will fit between the two fork hole shoulders. This may be longer than the 24mm brake nut, gaining you an extra millimeter of thread engagement that way.


Third option - modify the brake so it sits further forward on its brake bolt so it has more clearance and needs fewer star washers. That would mean having less brake bolt shaft inside the portion of the caliper that says "Bearings" in you photo. The round piece with the set screw might be key to that modification.

Fourth option - grind down or replace the domed nut on the back of the left side pivot so it doesn't hit the fork leg with one star washer installed.


I would avoid modifying the fork, but I could see making sure there is no paint down inside the internal shoulder. That might buy you 1/2mm of added brake nut depth.

You can combine all of those to get a 1/2mm here and 1/2mm there to add up to what you need.

[sfhbike]

I can see all the images now, thanks.


So, Jeremiah basically recommended the "shorter nut + longer bolt approach"?
Fine, but did he offer to send you one of the "The nut that we recommend is the 12mm (length from under the head to end of nut)"? It seems that Moots should be kind enough to send you one, what with all this hassle.

If they don't send you one, this eBay seller has a bunch of sizes (https://www.ebay.com/itm/NEW-Campagnolo-Recessed-Brake-Nut-Allen-Key-10-12-14-18-5-24mm-Authen-Campy-Nuts-/302305031836), including 12mm long.

No mention of the longer bolt piece at all in our conversation. I'm still not entirely sure where to find such a thing and would appreciate suggestions. When I asked Jeremy, he said: "I am not aware of any longer aftermarket brake bolts, you could contact Campagnolo and see if they have a recommendation or another brake with would not require 2 washers."

For the nut, I was going to go with one of the ones listed on exactly that ebay listing, actually. But probably 14mm as I don't see a need to go as short and want to maximize my chances of getting as many threads as possible (might lose 1mm of thread with a 12mm if the distance to first shelf is 12mm and the head seats on it first).



But, unless I am misunderstanding, you currently have:
a 44mm deep fork; a 27mm long brake bolt/stud - 5mm serrated washers = 22mm effective length, and a 24mm long brake nut.
Your 27mm brake bolt barely engages the brake nut (by about 5mm) as it is.
So, if Moots recommends the 12mm brake nut, where are you going to find a brake bolt long enough to make up that difference, i.e. about 6mm (min engagement) + 32mm (length inside fork (44mm - 12mm) + 5mm serrated washers = +/- 43/45mm long brake bolt???
Did they advise re: that?


I don't think it needs to be quite as long as you say, but 30-32mm would be ideal. But as I said above, no recommendation or comment from Moots on the brake bolt piece of this at all. And I have no idea where to find one.

So this is one of the Moots-painted forks they have/had on sale? You certainly do have one of the last 45s in that case.

Yes, purchased last June. I think I might have gotten the last one at the time, but I feel like they might have come back in stock briefly after that.

I may be wrong, so don't quote me, but iirc those particular forks were Whisky forks, so Whisky might be able to help with the bolt/nut issue if Moots/Whisky will confirm that to you.

Just sent to Jeremiah asking that question. He said: "They were not made by Whisky, Whisky is just an in house brand of QBP they don’t make anything."

Just out of curiosity, since Jeremiah mentioned the "Campagnolo out-of-tolerance-thing"(...not my experience, but anyway...), do you have access to a different Campagnolo front brake, if only to see if the problem still exists even swapping out the brake (i.e. using a different brake bolt)? Just to try?

This is my only Campy brakeset.

[Kontact]

Whisky is just a rebranding. Some Whiskey frames look identical to some model Deng-Fu or whatever Chinese off-brand.


My previous post includes ways of making you existing brake bolt incrementally longer.

And it really isn't a huge amount you need if Moots thinks a Shimano brake with a 27mm brake bolt and one star washer is sufficient. Your one extra star washer means that you are only 2-2.5mm short from that.

[cadence90]

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[sfhbike]

How much clearance between the caliper and fork do you actually need? Different star washers are different thicknesses, so you could certainly find a combination that gives you a the minimal clearance and produces an extra 1mm of brake bolt length.

Good suggestion. I was actually just using one star washer and a regular washer (I didn't have a spare star washer on hand). I only need about 1mm extra for the brake to clear the fork.

The other thing you can do is take a longer brake nut and grind it down to the maximum length that will fit between the two fork hole shoulders. This may be longer than the 12mm brake nut, gaining you an extra millimeter of thread engagement that way.

Right. Definitely not planning on going with the 12mm nut. A 14mm sounds right to get me close to the needed length with maximum thread engagement.

Third option - modify the brake so it sits further forward on its brake bolt so it has more clearance and needs fewer star washers. That would mean having less brake bolt shaft inside the portion of the caliper that says "Bearings" in you photo. The round piece with the set screw might be key to that modification.

What would modifying this look like? Not clear on this.

Fourth option - grind down or replace the domed nut on the back of the left side pivot so it doesn't hit the fork leg with one star washer installed.

I would avoid modifying the fork, but I could see making sure there is no paint down inside the internal shoulder. That might buy you 1/2mm of added brake nut depth.

You can combine all of those to get a 1/2mm here and 1/2mm there to add up to what you need.

Great suggestions. I think what I'll do at this point is probably pick up a new ~14mm nut and head over the the LBS for some troubleshooting.

[Kontact]

All good options, but especially option #3 imo.
Which brings up the question, though:
if the op switches out the ~24mm recessed brake nut for a ~12mm recessed brake nut, where is he going to get a longer brake bolt (option #3) that will be long enough to make up that difference? Because there is no way he will make up ~14mm by just adjusting the position of the brake bolt relative to the caliper.

Or are you saying that the op retain the current 24mm recessed brake nut, and simply adjust the position of the brake bolt to the caliper in order to gain a few mms of length inside the fork?

That seems like it could work, since he would be adjusting by 2 or 3 turns maximum. Adjusting the position of the bolt relative to the caliper would not really weaken anything up there, correct, i.e. leaving the caliper out there "hanging" too much? Again, I'm not a mechanic.

Man, what a headache.
I'm with you: I think this is fundamentally a fork issue, and if it is the fork I think it is could also explain why Moots no longer supply that brand.
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I misspoke and edited my post:

I meant longer than the 24mm nut. Essentially, if there are 25mm between the two shoulders, I'd want a modified nut that is 24.9mm between shoulder and end.

That would add more nut length, and then modifying the way the caliper is assembled could eliminate a star washer, giving more brake bolt length. Between the two you could easily add 3mm of extra engagement.

[sfhbike]

I misspoke and edited my post:

I meant longer than the 24mm nut. Essentially, if there are 25mm between the two shoulders, I'd want a modified nut that is 24.9mm between shoulder and end.

That would add more nut length, and then modifying the way the caliper is assembled could eliminate a star washer, giving more brake bolt length. Between the two you could easily add 3mm of extra engagement.

Just to clarify, it is 25mm total to the last shoulder, inclusive of the 12mm to the first shoulder.

[cadence90]

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[sfhbike]

Yes, those are all good suggestions which work as long as the op keeps the existing 24mm recessed nut, right?

But if the op decides to more-or-less follow the Moots suggestion for a shorter recessed nut and go with a 14mm rather than a 12mm recessed nut, where can he make up that missing ~10mm in the brake bolt length?

I can see gaining 2, 4, maybe even 6mm by combining the suggestions, but gaining ~10mm safely seems like a lot to ask, no, if I'm understanding all the dimensions?
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I think somewhere your measurements got thrown off. It is ~25mm to the final shelf, and then another ~19-20mm of carbon around the bolt width (which is the problem area since after adding 3mm or so of washers I only have 4mm of post left) for a total hole length of ~44-45mm as you showed in your original pic.

The 12mm is just how far in the first shelf is along that 25mm, meaning that the head of the nut can recess as far as 12mm down into the hole when threading onto the bolt before the head bottoms out. The problem with a 24mm nut is that it was bottoming out on the far hole and still sticking out the back (24mm of threads, plus 2-3mm head). A much shorter bolt would be just fine, but 12mm is too short to engage all the threads possible.

[Kontact]

Good suggestion. I was actually just using one star washer and a regular washer (I didn't have a spare star washer on hand). I only need about 1mm extra for the brake to clear the fork.


Right. Definitely not planning on going with the 12mm nut. A 14mm sounds right to get me close to the needed length with maximum thread engagement.


What would modifying this look like? Not clear on this.


Great suggestions. I think what I'll do at this point is probably pick up a new ~14mm nut and head over the the LBS for some troubleshooting.

I guess I'm a little confused about how you and Cadence and Moots are referring to the brake nut length. It needs to reach nearly to the inner shoulder, since front brakes only come with 27mm brake bolts. So you'll have to tell me if this 12mm bolt length thing makes any sense, but your diagram indicates that the distance between the two shoulders is 25mm and that you only have a few mms of brake bolt exposed past that inner shoulder. So 12 and 14mm brake nuts don't make much sense to me.

It sounds like your brake nut would need to be 25mm plus whatever thickness the head is - so 28mm in total. If not, your diagram is wrong.


As for modifying the caliper, in the picture you have black part that says "bearings" and the round silver piece on the bolt shaft that has a set screw in the top of it. Take the caliper apart and put a 1-2mm washer between those two parts. That will extend the caliper forward on the brake bolt shaft, producing more clearance so you won't need as much star washer thickness.



If a Shimano 27mm calipler works fine in this fork with one star washer, than you only need to find 1 or 2mm of extra overlap to make you 27mm caliper work the same. Or would you be rejecting the way the Shimano works as well?

[DRietz]

Gotta be honest, y’all, this thread is hilarious. How many bicycle forum engineers does it take to say:

OP, you have two options within the realm of easiest possibility: 1) find yourself the optimal nut length and live with the engagement - use blue threadlocker, it’ll be okay 2) put your old fork back on.

Finding a longer bolt that works with your Campagnolo system is going to be difficult. If you like treasure hunts, go for it. If you don’t, but want your fancy Moots fork, just don’t be too hamfisted when tightening your nut.

Godspeed, gentlefolk.

[Kontact]

Gotta be honest, y’all, this thread is hilarious. How many bicycle forum engineers does it take to say:

OP, you have two options within the realm of easiest possibility: 1) find yourself the optimal nut length and live with the engagement - use blue threadlocker, it’ll be okay 2) put your old fork back on.

Finding a longer bolt that works with your Campagnolo system is going to be difficult. If you like treasure hunts, go for it. If you don’t, but want your fancy Moots fork, just don’t be too hamfisted when tightening your nut.

Godspeed, gentlefolk.
Just because you can't imagine all of the other solutions doesn't mean they aren't useful.

[DRietz]

Just because you can't imagine all of the other solutions doesn't mean they aren't useful.

Gotta be honest, dude, the bolded portion of your statement is not only childish, but also ignoring the fact that I clearly state “within the realm of easiest possibility,” which I’m pretty sure gives credence to the fact that I recognize the other solutions.

I wish you success in this trivial endeavor, as you are obviously more committed to it than I.

[Kontact]

Gotta be honest, dude, the bolded portion of your statement is not only childish, but also ignoring the fact that I clearly state “within the realm of easiest possibility,” which I’m pretty sure gives credence to the fact that I recognize the other solutions.

I wish you success in this trivial endeavor, as you are obviously more committed to it than I.

Then let me be honest - I found your first post condescending and rude, so I responded in kind.

The OP needs to buy 2mm of thread, and there are a number of relatively simple ways of doing that on his non-trivially expensive bike instead of throwing out the fork or praying to the threadlocker God. This isn't a Huffy where you just give up because it is taking more than 30 seconds to fix.

[cadence90]

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[cadence90]

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[Kontact]

May you be so lucky to elicit similarly well-intentioned and possibly actually helpful responses if/when you ever run up against a problem that vexes you. I mean, if/when that ever happens to you, of course.... :rolleyes:
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He's also a shop mechanic, but with a bit less experience than me. So maybe/maybe not.

[DRietz]

Just a lowly shop mechanic, of the condescending variety.

Sorry, everybody. Have a nice day!

[cadence90]

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[sfhbike]

http://i1360.photobucket.com/albums/r654/traghetter/Recessed%20Nut_01_zpst1bnnl4b.jpg (http://s1360.photobucket.com/user/traghetter/media/Recessed%20Nut_01_zpst1bnnl4b.jpg.html)
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Thank you! Perfect diagram of where the situation is with a shorter nut. Kontact, does that make more sense now? Distance between the two shoulders is ~13mm, not 25mm.

As for modifying the caliper, in the picture you have black part that says "bearings" and the round silver piece on the bolt shaft that has a set screw in the top of it. Take the caliper apart and put a 1-2mm washer between those two parts. That will extend the caliper forward on the brake bolt shaft, producing more clearance so you won't need as much star washer thickness.

Doesn't it not really matter where I put a washer? Whether I put it down by the star nut or between the set screw and the bearing section, it still will push the entire bolt further out of the fork and lose the same amount of thread engagement.

[Kontact]

Doesn't it not really matter where I put a washer? Whether I put it down by the star nut or between the set screw and the bearing section, it still will push the entire bolt further out of the fork and lose the same amount of thread engagement.

It matters, because I'm describing keeping the set screw piece in place and moving the caliper further out in front of it. Whatever you add in front of that part is what you can subtract from washers behind it, making the back end of the brake bolt longer.

I just don't know if it will work or not - I've never taken that brake apart.

Or, you can replace the left side pivot nut with a flat one so you can get the brake bolt further into the fork.



On the brake nut, if you have 13mm inside, I'd want a 13mm nut. I wouldn't want any more than that, because the fork isn't made to be tightened down on the inner shoulder - make sure it is short enough to tighten against the outer shoulder.

[cadence90]

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[sfhbike]

It matters, because I'm describing keeping the set screw piece in place and moving the caliper further out in front of it. Whatever you add in front of that part is what you can subtract from washers behind it, making the back end of the brake bolt longer.

Here's a diagram of the brake bolt section. Not sure if I'm being really dense or what. If I have a set bolt size, and I put the same number of washers at any point in front of the fork, it shouldn't make any difference whether they are behind or in front of the set screw. The brake will move by the distance of the washers regardless of where I put them. I'm just removing washers from one place and putting them somewhere else. The bolt still has 27mm - Xmm of washers regardless. How does this get me any more length? Sorry if I'm not seeing something obvious here...

https://farm1.staticflickr.com/903/40175939550_63101cdeca.jpg

Or, you can replace the left side pivot nut with a flat one so you can get the brake bolt further into the fork.

This might be something to try, though I think there is a bolt that reaches the end of that nut, so both would have to get shorter.

On the brake nut, if you have 13mm inside, I'd want a 13mm nut. I wouldn't want any more than that, because the fork isn't made to be tightened down on the inner shoulder - make sure it is short enough to tighten against the outer shoulder.

Probably best practice. However, I never actually torqued the whole setup to the recommended 10nm. I wonder how much more thread might be engaged at that point, and whether it is enough for a 14mm or if I should stick with 12mm. What harm do you see in torquing it down on the inner shelf vs. the top one? Heck if it "wears down" slightly, that might be a good thing for thread engagement. Or are we worried about structural integrity of the fork?

[sfhbike]

By the way, here's the whole parts diagram for reference. Bottom one is front brake:

https://farm1.staticflickr.com/971/41983335111_502fa8a5f9_c.jpg

[Kontact]

Here's a diagram of the brake bolt section. Not sure if I'm being really dense or what. If I have a set bolt size, and I put the same number of washers at any point in front of the fork, it shouldn't make any difference whether they are behind or in front of the set screw. The brake will move by the distance of the washers regardless of where I put them. I'm just removing washers from one place and putting them somewhere else. The bolt still has 27mm - Xmm of washers regardless. How does this get me any more length? Sorry if I'm not seeing something obvious here...

https://farm1.staticflickr.com/903/40175939550_63101cdeca.jpg



This might be something to try, though I think there is a bolt that reaches the end of that nut, so both would have to get shorter. The only thing you could possibly due with that is to use a thinner washer in place of the BR-SR004 one between the black section and BR-SR030, a long as it didn't mess with the non-threaded sections of the brake bolt.


Probably best practice. However, I never actually torqued the whole setup to the recommended 10nm. I wonder how much more thread might be engaged at that point, and whether it is enough for a 14mm or if I should stick with 12mm. What harm do you see in torquing it down on the inner shelf vs. the top one? Heck if it "wears down" slightly, that might be a good thing for thread engagement. Or are we worried about structural integrity of the fork?
No, my idea with the brake bolt won't work now that I see the diagram. I was hoping it had a nut on the front end, too. Never mind.

Getting your brake bolt to max length, using the thinnest possible additional washer under the star washer and/or reducing the left pivot bolt and nuts are your best avenues.

[sfhbike]

No, my idea with the brake bolt won't work now that I see the diagram. I was hoping it had a nut on the front end, too. Never mind.

Getting your brake bolt to max length, using the thinnest possible additional washer under the star washer and/or reducing the left pivot bolt and nuts are your best avenues.

Agreed. Thanks for all the feedback and sticking with this thread. I'll probably buy both 12mm and 14mm nuts and see what I can do. But I am definitely puzzled as to why I'm the only one dealing with this issue.

[Kontact]

..

[Kontact]

Agreed. Thanks for all the feedback and sticking with this thread. I'll probably buy both 12mm and 14mm nuts and see what I can do. But I am definitely puzzled as to why I'm the only one dealing with this issue.

Probably because when most people insert the nut they don't consider if it is engaging enough threads or not.

[cadence90]

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[sfhbike]

Did Jeremiah at Moots state that the 12mm recessed nut alone definitely resolved the issue, or just that he was suggesting trying that approach?

I don't think he was suggesting it would really "resolve" my issue, just that this is what the fork was spec'd for. He pretty much acknowledged that it would get "over the 5mm" engagement recommended by Shimano, which only uses one serrated washer, but that since Campy says 6 threads and I need two washers, "Unfortunately sometimes with Campagnolo we have weird issues like this come up because their dimensions can fall outside of the industry standard (shimano)." . . . His exact words were "If it was my fork I would try a 12mm nut, the minimum width of washers required to not have the brake contact the fork and see if I was sufficed with the amount of thread engagement." Basically, try it and see if it will make you happy. And this fork likes Shimano more than Campy.

And...you're certain that the front brake bolt (BR-SR004) was never shortened by somebody, for some reason? People do weird stuff, sometimes.
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It's 27mm and the end looks very intact, so doubtful.

[Kontact]

I don't think he was suggesting it would really "resolve" my issue, just that this is what the fork was spec'd for. He pretty much acknowledged that it would get "over the 5mm" engagement recommended by Shimano, which only uses one serrated washer, but that since Campy says 6 threads and I need two washers, "Unfortunately sometimes with Campagnolo we have weird issues like this come up because their dimensions can fall outside of the industry standard (shimano)." . . . His exact words were "If it was my fork I would try a 12mm nut, the minimum width of washers required to not have the brake contact the fork and see if I was sufficed with the amount of thread engagement." Basically, try it and see if it will make you happy. And this fork likes Shimano more than Campy.



It's 27mm and the end looks very intact, so doubtful.

I doubt Campy brake bolts are made of something different than Shimano's. I'd use the shorter Shimano standard.

[beeatnik]

Best thread ever! Can you guys help me with my fork issue? Jebediah lost interest after 2 emails.

https://forums.thepaceline.net/showthread.php?t=193397&highlight=moots

[m_sasso]

If you want to use the fork purchase yourself an 8mm bottom drill bit increase the depth of the brake recess bolt hole 3mm, purchase yourself the longest brake recess bolt usable 2mm shorter than the depth of the recess bolt hole. You will net your required threaded depth and you will not die. The shouldered recess bolt and remaining fork material will support the brakes adequately.

Done!

[sfhbike]

If you want to use the fork purchase yourself an 8mm bottom drill bit increase the depth of the brake recess bolt hole 3mm, purchase yourself the longest brake recess bolt usable 2mm shorter than the depth of the recess bolt hole. You will net your required threaded depth and you will not die. The shouldered recess bolt and remaining fork material will support the brakes adequately.

Done!

I don't think that's a bad idea if it comes to that. It's crossed my mind several times as a decent solution. Even after drilling, there will be more material there than my EDGE fork has between the brake and nut.

[m_sasso]

If you have any hesitations give Mike Lopez a call and let us know what he says. Then go ride your bike!

[sfhbike]

If you have any hesitations give Mike Lopez a call and let us know what he says. Then go ride your bike!

Sorry, who is that? And what's his number.

[sokyroadie]

If you want to use the fork purchase yourself an 8mm bottom drill bit increase the depth of the brake recess bolt hole 3mm, purchase yourself the longest brake recess bolt usable 2mm shorter than the depth of the recess bolt hole. You will net your required threaded depth and you will not die. The shouldered recess bolt and remaining fork material will support the brakes adequately.

Done!

Modifying carbon :hello: easy fix and perfectly fine IMHO for this application.

[m4rk540]

Sorry, who is that? And what's his number.

He's former Reynolds, Serotta carbon guru. He made the F Forks and tubes for Serotta's carbon bikes. He'll just repeat DRietz advice. Use your old fork.

Take the store credit and apply it to a Moots stem or seatpost.

[hollowgram5]

Sorry, who is that? And what's his number.

He's former Reynolds, Serotta carbon guru. He made the F Forks and tubes for Serotta's carbon bikes. He'll just repeat DRietz advice. Use your old fork.

Take the store credit and apply it to a Moots stem or seatpost.

In addition, he makes and sells forks through Bill Holland; Holland frames can be purchased with a Mike Lopez fork. I considered one for my Isogrid, but landed a good deal on an Enve instead.

From what I understand, he's a big portion of the HC frames that Holland has been putting out, and why they ride so well.

Additionally, he's a member of the forum and a composites geek.

[sfhbike]

In addition, he makes and sells forks through Bill Holland; Holland frames can be purchased with a Mike Lopez fork. I considered one for my Isogrid, but landed a good deal on an Enve instead.

From what I understand, he's a big portion of the HC frames that Holland has been putting out, and why they ride so well.

Additionally, he's a member of the forum and a composites geek.

What's his username?

EDIT: Nevermind "Mike Lopez"

[Kontact]

If you want to use the fork purchase yourself an 8mm bottom drill bit increase the depth of the brake recess bolt hole 3mm, purchase yourself the longest brake recess bolt usable 2mm shorter than the depth of the recess bolt hole. You will net your required threaded depth and you will not die. The shouldered recess bolt and remaining fork material will support the brakes adequately.

Done!

Given a choice of losing carbon to gain steel, I think I'd stick with having few-ish threads. Failed brake nuts aren't likely to cause a crash.

[cmbicycles]

Does this fork have an alloy crown or insert where the brake mounts, or is it all carbon?

[hokoman]

Did you try a different brake caliper? If it's a 45 offset, sell me the fork and put your edge back on. I'll deal with the headache. :)

[sfhbike]

Does this fork have an alloy crown or insert where the brake mounts, or is it all carbon?

I'd have to take a closer look, but my guess is it's all carbon. Why?

[cmbicycles]

I'd have to take a closer look, but my guess is it's all carbon. Why?
If it's an aluminum insert, it would be no big deal (imo) to drill it a couple mm deeper.

[sfhbike]

Mike Lopez had some very helpful feedback. If the fork is indeed solid carbon all the way through (anyone know for sure?), here's what he recommends:

If that's the case then you should be safe pushing the c'bore a bit deeper to get a few more threads of engagement. I would not hesitate to do that on any of the products I've made over the years. However, as I said, I honestly don't know how THAT one is made so it's your call. Or...get someone to ask Butch. He'll know what's inside there.

If you do decide to go for it you don't need a flat faced bit. A normal 8mm bit will work fine because you're just creating clearance, not a mating surface. And don't go crazy with a hand drill! Better to use a drill press so you can better control the depth or even by hand with the bit in a tap handle or old chuck etc. With a sharp bit it will cut easily and will be less likely to bind. Easy to control depth as well.


As soon as I confirm from Moots whether there's some sort of insert or if it is just carbon, I'll likely use the tap and drill bit as he recommends to get another 2-3mm of material out of that hole.

[Kontact]

Mike Lopez had some very helpful feedback. If the fork is indeed solid carbon all the way through (anyone know for sure?), here's what he recommends:



As soon as I confirm from Moots whether there's some sort of insert or if it is just carbon, I'll likely use the tap and drill bit as he recommends to get another 2-3mm of material out of that hole.

Put a thin layer of tape around the bit so it is less likely to open up the outer shoulder.

You're only removing 2mm, right?

[m_sasso]

Easy to make a flat bottom drill, https://www.youtube.com/watch?v=qwuSBJFa5uM

Thanks for posting up Mike's response, have fun and be sure to obey all stop signs.

[sfhbike]

Put a thin layer of tape around the bit so it is less likely to open up the outer shoulder.

You're only removing 2mm, right?

Good tip. Thanks. That combined with using a bit in a tap rather than a drill should make this idiot proof for me.

I'll need to play around with measurements a bit after I order a new nut and try everything with the washers I'm using. I'm thinking 3mm off with a 14mm nut should do the trick.

[sfhbike]

Finally got around to finishing this up. I used a tap and drill bit for a while, but that was slow going. I switched to a hand drill with some tape around the bit to keep it from taking any material on the sides and drilled carefully (short bursts, measure, rinse, repeat). I ended up taking about 5-6mm off in order to get the 18mm Campy nut to seat all the way in. Plenty of thread engagement now, and everything fits great.

Thanks for all the tips. If anyone wants an EDGE fork, I'll be listing it shortly.

https://farm1.staticflickr.com/835/28672703997_bd5fdae6d5_c.jpg (https://flic.kr/p/KFH6Xt)

[dddd]

Good to go. This post got me to thinking why someone said that 6 threads of engagement were needed.

In discussions with engineers, I've heard that 3 threads is sufficient to realize full tensile strength of a relatively coarse-threaded bolt such as the stud.

There is no cyclic loading (in tension or in bending) of the threaded engagement in use, since the toothed washer and adjacent faces do not rock relative to one another. An exception might occur if the bolt lost most of it's tension, so possibly having only 3 or 4 threads engaged might lead to further loosening in such instance.

More than three threads of engagement does enable threadlocking compounds to be more effective, and use of an alloy nut would require more threads of engagement, but installed with fresh Loctite I would think that 3-4 threads of engagement would be perfectly safe using a steel nut.

Also, it is normal for a tensioned brake stud installed in a carbon frame to lose enough tension after a day or two to allow some additional amount of nut rotation to achieve the original torque, (if only a small amount).

I've seen mechanics and even carpenters struggle with "squeeker" scenarios like this where just a small amount of additional clearance needs to be established. Some didn't end well, but usually some fudging is fine.
I've had the spring-retaining tab break off of a front derailer's link when I hastily tried to use judicious sanding (where the link met the seat tube upon shifting to low gear on a triple). That one stuck with me for the last ten years, now it's more "measure twice, cut once" than ever.

[sfhbike]

Yes, 4 threads would probably have been enough but I was following campy’s spec which calls for 6. I’m still surprised that Moots builds the forks this way. Since the solution was pretty straightforward, the piece of mind was worth it. I now have probably 10mm of threads engaged and threw on some blue loctitte for good measure. Overkill I’m sure but I never have to think about it again!

Good to go. This post got me to thinking why someone said that 6 threads of engagement were needed.

In discussions with engineers, I've heard that 3 threads is sufficient to realize full tensile strength of a relatively coarse-threaded bolt such as the stud.

There is no cyclic loading (in tension or in bending) of the threaded engagement in use, since the toothed washer and adjacent faces do not rock relative to one another. An exception might occur if the bolt lost most of it's tension, so possibly having only 3 or 4 threads engaged might lead to further loosening in such instance.

More than three threads of engagement does enable threadlocking compounds to be more effective, and use of an alloy nut would require more threads of engagement, but installed with fresh Loctite I would think that 3-4 threads of engagement would be perfectly safe using a steel nut.

Also, it is normal for a tensioned brake stud installed in a carbon frame to lose enough tension after a day or two to allow some additional amount of nut rotation to achieve the original torque, (if only a small amount).

I've seen mechanics and even carpenters struggle with "squeeker" scenarios like this where just a small amount of additional clearance needs to be established. Some didn't end well, but usually some fudging is fine.
I've had the spring-retaining tab break off of a front derailer's link when I hastily tried to use judicious sanding (where the link met the seat tube upon shifting to low gear on a triple). That one stuck with me for the last ten years, now it's more "measure twice, cut once" than ever.

[Mark McM]

In discussions with engineers, I've heard that 3 threads is sufficient to realize full tensile strength of a relatively coarse-threaded bolt such as the stud.

This is only true for standard nuts. For standard nuts, It's not so much a matter that 3 threads is sufficient for full tensile strength, its more a matter that the load is concentrated on first thread of engagement, and the portion of the load decreases on the additional threads of engagement. The reason for this is that bolt is under tension, and the nut is under compression, so while the bolt thread pitch is slightly stretched, the nut thread pitch is slightly compressed. The result is that about 90% of the total load is taken by the first 3 threads, and additional threads of engagement doesn't increase the load bearing strength by much.

But a recessed brake nut isn't a standard nut. The threaded flange of a recessed brake nut is under tension, just like the bolt, both the nut and bolt stretch together, and the loading on the threads is more uniform. Because of this, the load can be distributed over more threads of engagement than a standard nut, so it is very conceivable that 6 threads of engagement is stronger than 3. (By the way, this same concept is true for spoke nipples as well, which is why it is better to get far more than 3 threads of engagement on a spoke.)

There is no cyclic loading (in tension or in bending) of the threaded engagement in use, since the toothed washer and adjacent faces do not rock relative to one another. An exception might occur if the bolt lost most of it's tension, so possibly having only 3 or 4 threads engaged might lead to further loosening in such instance.

That's not quite true. The contact face between the brake and the crown certainly decreases bending stress on the bolt, but it doesn't totally eliminate it. And increasing the number of threads of engagement helps to reduce stress concentrations caused by the combined tension/bending on the bolt.

[dddd]

Very detailed and quantitative analysis!

I admit that I dismissed the need for greater tensile strength than offered by three regular nutted threads, since older bikes got by fine with hex nuts and their tensile strength limitations on the same 6mm stud.

I didn't imagine the mounting face rocking, either, or did you mean that the stud passes push/pull rocking stresses through the mounting hub?

One of the stress considerations of threaded fasteners that can be greater than the working load is the combined tension and torsion that occurs while actually tightening the nut. So any minor stress-concentration here during actual use might be of less magnitude and thus less importance as a "weakest link" (that contemporary design presumably provides redundancy or safety-factor against).