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V-brake on Cannondale Quick carbon fork question.

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V-brake on Cannondale Quick carbon fork question.

Old 01-12-19, 09:56 AM
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Gerryattrick
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V-brake on Cannondale Quick carbon fork question.

I have just been given a Cannondale Quick carbon fork plus V-brakes for a 700c hybrid I am building. I think I understand the fitting but would like opinions please. As far as I see there are no removable bosses for this fork but the V-brakes screw directly into the fork. There are separate fitments for the tension spring holes. Am I correct in saying that these fitments are put between the brake and fork and the pressure of bolting the brake will hold it in place? I've temporarily fitted them and they seem to work OK, but I don't really trust that the tension fitment will stay firmly fixed under repeated operation.

Here is a pic of the fork and brakes:
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Old 01-12-19, 10:12 AM
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Whomever installed the brakes, I suspect, either tightened the screws too much, or added too much loctite to the screws. You are looking at the stud sticking out the back of the brake arm.

Luckily, they usually have flats on them. Use a wrench to hold it whole you unscrew the mounting screw, then reinstall the studs in the fork.

If they can't be removed, the threads on the studs are typically treated with loctite. I would use blue, since you can't heat the fork safely to remove them.
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Old 01-12-19, 10:53 AM
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combined functions

That would appear to be true.... they comprise both the spring anchor hole and a flat washer to protect the carbon ..

NB:, thread lock compounds break down when heated ... they must be applied to a grease free surface..

the post is still in the brake, unscrew the center bolt to separate them .. (touching the brake post with a soldering iron heats just the post , first..)


permanent fitting into the fork would be with Epoxy. ,

JB Weld is a 2 part epoxy with aluminum powder in its resin portion.. that too must be applied to a clean surface..




...

Last edited by fietsbob; 01-12-19 at 11:05 AM.
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Old 01-12-19, 01:41 PM
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This is a more detailed pic showing the brake next to standard boss and bolt. There is no boss on this fork so there is not a standard boss bolt.

I can see no way for the bolt through the brake to be removed from the brake body but the setup does allow the arm to swivel around it as the thread does not continue through the brake body. The thread goes right to the brake body and there is no flat to grip.

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Old 01-12-19, 02:27 PM
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SO.. operating the brake unscrewed it from from fork? it may be seized up, you think?

I'd put a standard boss in , and use a more common V brake.. if I were you.
then the bushing in the brake can get greased , over the post in the fork.

(Or maybe you are just boned)
fork shopping time..

but do as you choose





...

Last edited by fietsbob; 01-12-19 at 07:51 PM.
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Old 01-12-19, 02:42 PM
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The thread in the fork is too small for a standard boss as shown in the second pic.

I have the feeling that this was a non-standard setup tried by Cannondale.
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Old 01-12-19, 02:57 PM
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Then abandoned .. It was probably done long after Cannodale left the US and joined the many getting made by the few in Taiwan. ....
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Old 01-12-19, 05:51 PM
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I wouldn't say there is a standard for brake boss threading, I have at least four different types in my parts bin. That's not including suspension fork specific ones, including those probably doubles the number. Cannondale has used proprietary brake boss threading, if I recall it was SAE or something wacky.

I'd red locktight those back in the fork and try removing the bolts in a few days.
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Old 01-12-19, 07:29 PM
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Originally Posted by Gerryattrick View Post
The thread in the fork is too small for a standard boss as shown in the second pic.

I have the feeling that this was a non-standard setup tried by Cannondale.
There are 5 or more "standard" boss threadings, that boss is only one of them.
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Old 01-12-19, 07:57 PM
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I use Magura's rim brake on V brake posts ... they use them as a mount not a pivot..
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Old 01-12-19, 08:14 PM
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Before you damage the boss/post by holding it's threaded base to then remove the arm's retaining bolt find a replacement pair of bosses/posts. better safe then sorry. Can you determine the bosses' threading? If so then can you get a nut with said threading? This nut will act as the holder of the boss/post instead of the fork's threaded hole doing so. As a nut will be steel and far more easily held (with a wrench or bench vice) any damage that might happen to the far more expensive fork won't happen. Clean off the boss threads with a solvent and using a high strength Locktight secure the nut onto the boses' base and let cure fully. Only then try to loosen the arm retaining bolts. Assuming the bolts come free you can find out if there's corrosion that held them in place tighter then the bosses were (in the fork) or if they were just tightened really hard. You can then remove the nuts from the boss bases by heating the combo in your oven (or with a propane torch) to soften the Locktight first. Generally the boss has a set of flats in the slightly larger diameter section at the bottom of the post, 8mm is a common width across these flats. If none then a slip joint pliers can hold the boss. But if you screw up you have your back up pair, remember them?

To reassemble use that same high strength Locktight on the fork's threads and screw in the bosses with the spring plate properly located. let it cure fully. Then reattach the brakes as usual using lube and proper care. Andy
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Old 01-13-19, 04:39 AM
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Thanks for the replies. Given me some thinking and searching out to do.
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Old 01-17-19, 08:01 AM
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Originally Posted by Gerryattrick View Post
Thanks for the replies. Given me some thinking and searching out to do.
I have had to separate brake arms from posts that unscrewed from the bosses by inserting an EZ out into the back end of the post and unscrewing the fixing bolt from it.
Cannondale used 5/16 x 18 threads in their brake bosses for a period of time, and that may be what you have.( My 1999 CAAD 4 has that size.) There are also 8 and 10 mm versions out there.
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