# Brake pivot bolt length?



## shockfinder (Apr 21, 2009)

I just got a Scott CR1 frame and built it today. I was transferring my Nashbar brake calipers which have been on my Specialized Allez and my Giant TCR C0 when I found the bolt wasn't long enough to attach the brakes either at the fork or to the rear of the frame. What am I missing? Are they longer than standard? The Nashbar brakes didn't have a specific bolt length listed. This is a possible opportunity to upgrade, but I need to know if there is a specific length I should be looking for. Any help would be appreciated.


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## frdfandc (Nov 27, 2007)

These brakes require a fork and frame to have recessed mounting to work properly. 

Have a picture of the brakes and/or the frame/fork?


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## Marc (Jan 23, 2005)

You can get longer brake nuts from your LBS. But be warned, they run $10-15 a piece.


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## wim (Feb 28, 2005)

shockfinder said:


> I found the bolt wasn't long enough to attach the brakes either at the fork or to the rear of the frame. What am I missing?


As said, you just need longer brake nuts to reach in there and grab that bolt (6 threads is recommended). But the $10-15 warning seems odd. Brake nuts generally sell for $5 or thereabouts.


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## djg21 (Oct 25, 2003)

http://loosescrews.com/index.cgi?c=Brake&sc=Recessed%20Nuts&id=63151879300

This is a "problem" with many of the newer carbon aero forks. Shimano brake calipers come with a number of the recessed nuts, but the longest in the package is 20mm and many aero forks require a 30mm nut. No big deal. They cost $7.50.




shockfinder said:


> I just got a Scott CR1 frame and built it today. I was transferring my Nashbar brake calipers which have been on my Specialized Allez and my Giant TCR C0 when I found the bolt wasn't long enough to attach the brakes either at the fork or to the rear of the frame. What am I missing? Are they longer than standard? The Nashbar brakes didn't have a specific bolt length listed. This is a possible opportunity to upgrade, but I need to know if there is a specific length I should be looking for. Any help would be appreciated.


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## gamara (May 20, 2002)

Take a straw & measure the inner length of both the fork & rear brake bridge. Then measure your bolts & subtract to give you the length that you're going to need. The nuts come in various lengths 5, 6, 10,12, 15, 20, 25 & 30 etc. So it pays to know which length you're going to need.


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## shockfinder (Apr 21, 2009)

A longer nut isn't going to work. The fork is 50mm and the rear is 30mm front to back. The problem is that there is a lip that prevents the nut form going any farther into the hole. The lip is at 15mm so the rest of the length has to be made up in pivot bolt length. Not the solution I wanted, but there it is.


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## ultimobici (Jul 16, 2005)

shockfinder said:


> A longer nut isn't going to work. The fork is 50mm and the rear is 30mm front to back. The problem is that there is a lip that prevents the nut form going any farther into the hole. The lip is at 15mm so the rest of the length has to be made up in pivot bolt length. Not the solution I wanted, but there it is.


Did the frame not come with the bolts? Time provided special bolts with my VXRS as they need to be a smidge slimmer.


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## shockfinder (Apr 21, 2009)

ultimobici said:


> Did the frame not come with the bolts? Time provided special bolts with my VXRS as they need to be a smidge slimmer.


No. Unridden frame from ebay. It's beautiful. I'm ready to ride it however.


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## gamara (May 20, 2002)

Contact Scott & see if they can offer a solution. Theres a possibility that the lip could be removed by drilling it out. Of course that would negate any warranty. So hopefully they can provide you with the proper bolts or some other alternative.


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## wim (Feb 28, 2005)

gamara said:


> Contact Scott & see if they can offer a solution.


I second that. There's a chance that Scott spec'd a bolt/nut combination which is different than "standard." Using the 2010 CR1 Comp as an example, Scott would have had the option of several pivot bolt lengths/nut lengths combination when purchasing the Tiagra (BR-4500) calipers from Shimano. See parts list under the linked exploded view.
http://techdocs.shimano.com/media/t...BR/EV-BR-4500-2589A_v1_m56577569830615759.pdf


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## Kerry Irons (Feb 25, 2002)

*Likely problem*



shockfinder said:


> A longer nut isn't going to work. The fork is 50mm and the rear is 30mm front to back. The problem is that there is a lip that prevents the nut form going any farther into the hole. The lip is at 15mm so the rest of the length has to be made up in pivot bolt length. Not the solution I wanted, but there it is.


I'm betting there is just a "paint lip" in the fork. All you have to do is take a drill bit of the appropriate size and ream it out by hand.


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## SilverStar (Jan 21, 2008)

Isn't the "lip" in there to provide something for the head of the recessed nut to butt up against? All my forks have that lip, and it hasn't been a problem for any combination of brakes.

In the extended nut, only the barrel of the nut is longer...the head is usually the same dimension as so-called "standard" nuts.


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## shockfinder (Apr 21, 2009)

Got it! So I spent yesterday afternoon at the LBS talking it through and looking for longer pivot bolts. Didn't have any and to order one through them would be as much as a new brake. Came home defeated and did some more internet research. Went to bed and as I lay there I thought that surely Scott wouldn't have set it up where 99.9% of brakes wouldn't have fit. I knew I wasn't take a drill to my new CF frame. So I got up and grabbed the recessed nut and put the 5mm allen wrench into it and sort of worked it around and it finally just slid all the way in. Grabbed the brake and tightened it down. Did the same for the rear brake. So problem solved. It just to a little work to get it to go all the way in and I've never had that happen before. Maybe it was paint or something, but the bike will be finished and I'll be riding it by this afternoon. I do think the lip is there to keep the head of the nut form going in farther. But now it's assembled! I may go ahead and get the longer brake nuts because I know they would work and I'd feel better with more turns of the threads. Thanks for helping me think this through. I feel like an idiot, but at least I'm not out anymore money!


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## wim (Feb 28, 2005)

shockfinder said:


> So I got up and grabbed the recessed nut


Glad to hear it all worked out. And even gladder to hear that I'm not the only one who gets up in the middle of the night and runs out to the workshop!


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## shockfinder (Apr 21, 2009)

wim said:


> Glad to hear it all worked out. And even gladder to hear that I'm not the only one who gets up in the middle of the night and runs out to the workshop!


Doesn't everyone do that? Actually It was in my guest room where we keep our trainers set up. I had taken my workstand and tools out to the back porch Saturday to build it up because it was beautiful outside and my wife was working in the yard. that way I could do "bike stuff" and still be around her. So my wife was mostly asleep and I mumbled "I've got an idea" and took off to the guest room and about 10 minutes later I hear her say "What are you doing?" I went in and told her that I'd figured it out and I'd be in bed in 10 minutes. God bless her for putting up with my obsessions! She still doesn't know what I figured out...she just nods and listens carefully and smiles and is happy for me. It's a good life.


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## wim (Feb 28, 2005)

shockfinder said:


> Doesn't everyone do that?


LOL, I don't know. With me, it's that sleep or dozing aparently shuts of my preconceived notion of the problem and opens my thinking to new possibilities. What got me on the wrong track with your issue was the lip being reported at 15 mm. I locked on the idea that it was machined into the fork to be exactly that deep for a specific reason. Wrong....

PS. My wife cares for horses and has to get up if there's a storm, or if there are strange noises coming from the pasture. So her working hours are even stranger than mine.


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## shockfinder (Apr 21, 2009)

There is a lip at 15mm, but it is to keep the nut head from going any further. It just took some work to get the nut body past it. What did it for me was not being able to find brakes with longer pivot bolts, at least not easily combined with the puzzled looks from the guys at the LBS. I should have carried the frame with me, but didn't want to bother because I thought it would be simple to find another pivot bolt. Not the case. Anyway, I finally decided Scott couldn't have done something so esoteric as to require longer pivot bolts when longer brake nuts would suffice. The simplest solution is usually the correct one.


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## Kerry Irons (Feb 25, 2002)

*Paint lip*



shockfinder said:


> I knew I wasn't take a drill to my new CF frame. So I got up and grabbed the recessed nut and put the 5mm allen wrench into it and sort of worked it around and it finally just slid all the way in.


So, there was a paint lip in there  You did with your nut what hand pressure with the right sized drill bit would have done.


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