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Beware length of brake center bolt
#1
Been discussing this on a different post, but with what has happened I thought I would just make anyone interested aware of a problem. I bought a new carbon fiber road frame and a new 105 groupo. I now find that, due to the chunky nature of the new carbon frames, the standard front brake centerbolt is about 1 1/4" short of making it through the bridge and the rear is about 3/4" short for the rear bridge. With the frame construction, finding longer nuts is not an option.
Does anyone know where I can find a 3 3/8" long (total length)bolt for a shimano brake? I will be calling Shimano tech support when they wake up. I can use the front brake on the back with the removal of about 1/8", so that doesn't bother me.
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#2
I don't know about Shimano; but Tektro offers many of their dual pivot side pull brakes with a "nutted" option for those of us with older frames before recessed nuts came out. The "nutted" versions have much longer bolts, and come with standard hex nuts. You can substitute recessed nuts for the standard nuts.

Alternatively, with some, to a great deal of difficulty, you can change the bolts on the calipers.
Nigel
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#3
I'm pretty sure that I am going to have to tear the calipers down and remove the center bolt. Have done older brakes before and these new ones don't seem too difficult, removing and replacing the spring is usually the problem, but I have a plan for that.
When I get the bolt in my hand, I'll see if I can utilize some standard bolt or threaded rod. If not, my last resort is my master machinist friend, who can work magic on a small lathe.
Just spent over an hour on hold to Shimano, hoping to get their imput, I guess I'll try again later, but I bet they don't even stock bolts 3-3/8" long. I can use the intended front brake on the back, I just have to shorten that bolt by about 1/4" and that is fixed, so I only have to strip one caliper.
Bike sat there ready to ride but held up by one brake.
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#4
If you end up going the threaded rod route, make sure that you get good quality chrome-moly threaded rod, and do NOT use the cheapie steel rod from a DIY center (Home Depot, etc). There is more than 3X difference in strength - absolutely critical for the front brake.
Nigel
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#5
Going to and fro like a ping pong ball on this one Nigel. Talked to Shimano and they were adamant that you cannot duplicate that bolt, they may be bs'ing me. They said discuss it with the frame manufacturer - like I can speak Mandarin !! New route in the mill now, As you mentioned, Tektro have a brake very similar to the 105 - it's black anyway! On Amazon for $29.00, I have e-mailed the offerer, Niagra Cycle, with all of my required lengths, to see if they can match it. I may end up drilling out the shoulder at the bottom of the recess on the front bridge, to let a 'long nut' pass through and then using a washer under the shoulder on the nut, to pull up on the rear face of the bridge.
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#6
These might be useful:
http://www.niagaracycle.com/categories/problem-solvers-steel-brake-mounting-nut-30mm-long
http://www.niagaracycle.com/categories/problem-solvers-steel-brake-mounting-nut-22mm-long
and I think that you had already found them.
Nigel
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#7
This is totally crazy! you should start a new post on how to destroy a decent groupset and $5000 frameset. It just does not add up, If this is your first build of this type, I highly recommend you seek eyes on local help from a qualified shop. You are well on your way to void any such warranty you have. not to mention being dis satisfied with a $8000 or whatever bike. This frameset should take standard post recessed brakes. I have never had a problem with any frame that the proper nut length did not suffice.
There are two kinds of people in the world, "Those who help themselves to people, and those who help people!"
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#8
I made a small sketch and had it scanned, there you can see the exact problem that I have and it's no mistake, it's beautifully made.
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#9
looks like if your bolt is 27mm, that is what my 105 is. I have 10mm
of thread, subtract 27mm from 50mm. is 23mm with 10mm of thread. which a 30mm recessed nut would work fine. so take your bolt length and thread length and do the same math.. Your 10mm deep means nothing, work with the 50mm if you are correct, subtract your post length from 50mm the remainder would be the flush butt of your nut, take that and add roughly 70 to 80% of your threads and order that length of proper nut and it will be fine.
There are two kinds of people in the world, "Those who help themselves to people, and those who help people!"
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#10
easily obtained, even site to store with free shipping if you have a Walmart, Wheels Mfg. is a good source.
http://www.walmart.com/ip/32306640?wmlspartner=wlpa&adid=22222222227021196516&wl0=&wl1=g&wl2=c&wl3=34326188101&wl4=&wl5=pla&wl6=60864000901&veh=sem
There are two kinds of people in the world, "Those who help themselves to people, and those who help people!"
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#11
(06-17-2014, 10:54 PM)painkiller Wrote:  easily obtained, even site to store with free shipping if you have a Walmart, Wheels Mfg. is a good source.
http://www.walmart.com/ip/32306640?wmlspartner=wlpa&adid=22222222227021196516&wl0=&wl1=g&wl2=c&wl3=34326188101&wl4=&wl5=pla&wl6=60864000901&veh=sem
Bob; Same as the 30mm Problem Solvers that Niagara offers - see my post above......
Nigel
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#12
(06-17-2014, 10:56 PM)nfmisso Wrote:  
(06-17-2014, 10:54 PM)painkiller Wrote:  easily obtained, even site to store with free shipping if you have a Walmart, Wheels Mfg. is a good source.
http://www.walmart.com/ip/32306640?wmlspartner=wlpa&adid=22222222227021196516&wl0=&wl1=g&wl2=c&wl3=34326188101&wl4=&wl5=pla&wl6=60864000901&veh=sem
Bob; Same as the 30mm Problem Solvers that Niagara offers - see my post above......
Exactly, I know. Just having a bit of communication trouble figuring out exactly what Limey was saying, I do not call them a problem solver but the right nut for his application other than a slight possibility of a manufacturing error. Then all the talk in this new post about filing,cutting swapping etc.. I had to step in again, not to piss anyone off or anything but I could not bear the fact that with the amount of $$ wrapped up this sweet ride, what may have happened not to mention the regret. I hope you understand Limey, I am in your corner here. But these recessed holes are standard and yes due to variants in forks/materials the only difference should be the nut, or something else is wrong. I hope I did a better job this time of giving you an Idea of how to pick a nut. The key is to not bottom out the post threads before locking down the caliper. But Limey kept insisting that the nut length would not matter with his situation. that was and still is my confusion. But if he was talking drilling on the frame or fork, then NO! there must be a defect. So Limey chime in now and lets get it figured out for you brother
There are two kinds of people in the world, "Those who help themselves to people, and those who help people!"
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#13
The key to the whole problem is that the nut does not tighten down on its shoulder on the back of the fork like a normal set up, it tightens down when the leading face of the barrel bottoms out on the shoulder inside the 10mm deep recess. If I offered up a 30mm nut it would still only go into the fork 10mm and 20mm would be sticking out at the back. The only way to get a 30mm nut in far enough to reach the thread, is to drill out the 1/8" thick shoulder at the bottom of the recess to remove the blockage. I would then have to use an oversize washer, with the correct dia hole for the o.d. of the nut barrel, but with an outside dia. large enough to cover the 10mm dia. recess hole in the back of the bridge and tighten down per a normal bridge. At the moment the head of the nut fits inside the recess and is flush with the back of the fork, would look very neat if I could get a long nut !!
Whew, it's easy to understand the problem when you see it, but this is as good as I can describe it. Believe me, I'm a mechanical engineer and I understand the problem perfectly and the math involved, knowing what's available to solve it is very trying.This is why extending the bolt to the correct length solves the problem simply. To be honest, zapping that blockage in the recess wouldn't be that big of a deal a sharp drill bit would remove it with one zzzzzzzip. I have a message out to Niagra, but they are busy and say they will get back to me within 48 hours - very frustrating.
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#14
(06-17-2014, 11:12 PM)painkiller Wrote:  .... problem solver....
"Problem Solvers" is a brand name like "Wheels Manufacturing". Problem Solvers has a bunch of useful and often hard to get bicycle related little items.
Nigel
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#15
PROBLEM SOLVED !!!! Many thanks to y'all for helping me get to the solution. After explaining it in detail in my last post, it all came to me in a dream - literally. There was a manufacturing problem, the holes in the bridges were drilled just to the clearance for the threaded bolt, whereas the holes in the bottoms of the recesses should have been clearance for the barrel of the nut. I had to clean paint from the bore to get the bolt through, but it wasn't paint in the recess, because when I used the intended front brake on the back, the bolt was long enough to go through and protrude past the recess and I had to clean that hole just to get the bolt through - it was the same size as the front hole. Someone had not opened up the nut hole. (e-mail already on its way)
Anyway, at 4:00am, I drilled out the recess hole with a clearance drill for the nut barrel and now the nut shoulder goes all of the way to the bottom of the recess !!!! I will still need a slightly longer nut on the front, but now I understand the confusion between myself and Painkiller. With a frazzled tired brain, it's difficult not to believe that what you see is what was intended and I got lost trying to make it work. Thanlks. Eric.
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#16
Thanks for all the help.
[attachment=5172]Thanks for all the help.
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#17
Cool Limey! They just do not get much better than that do they?
There are two kinds of people in the world, "Those who help themselves to people, and those who help people!"
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#18
Thanks, first ride 7:00am tomorrow. I try to think what would have happened if I had shown up at the start line in 1953 with this ??????
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