Brake Post Differences / Cane Creek Direct Curve...
08-21-18, 02:32 PM
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Brake Post Differences / Cane Creek Direct Curve...
I've got this old set of Cane Creek Direct Curve brake arms I was looking to install.
Problem is illustrated in the attached photos: The Direct Curve (black set) has a section of the pivot that sticks out, and gets in the way between the brake arm and the face of the brake boss.
Compare this to the Tektro design (silver) where everything sits flush.
As shown in the second photo, because of this, the pin for the Direct Curve's tension spring can't completely engage the boss. On the Tektro or any other brake, the brake would sit flush against the boss and the pin would be fully engaged, and this gap wouldn't be present.
Looking at installation diagrams on Cane Creek's site, They show a different version of this brake where it's a flush fit, similar to the Tektro.
Cane Creek can't offer me any help as this is a discontinued product -- they've got no advice to give.
Any insight? Was this brake designed for a different style of brake boss?
Problem is illustrated in the attached photos: The Direct Curve (black set) has a section of the pivot that sticks out, and gets in the way between the brake arm and the face of the brake boss.
Compare this to the Tektro design (silver) where everything sits flush.
As shown in the second photo, because of this, the pin for the Direct Curve's tension spring can't completely engage the boss. On the Tektro or any other brake, the brake would sit flush against the boss and the pin would be fully engaged, and this gap wouldn't be present.
Looking at installation diagrams on Cane Creek's site, They show a different version of this brake where it's a flush fit, similar to the Tektro.
Cane Creek can't offer me any help as this is a discontinued product -- they've got no advice to give.
Any insight? Was this brake designed for a different style of brake boss?
08-21-18, 02:39 PM
#2
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In Person, Not on line, drop by a pro Bike shop?
Looks like the return spring pin will still go in the hole in the frame,
on the brake boss,... does it. ?
typically 1 to 3 holes on the inside of the brake post
what you got?
...
Looks like the return spring pin will still go in the hole in the frame,
on the brake boss,... does it. ?
typically 1 to 3 holes on the inside of the brake post
what you got?
...
Last edited by fietsbob; 08-21-18 at 02:51 PM.
08-21-18, 03:05 PM
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I agree with fietsbob, it looks like is should function just fine. As long as the spring engages and does its job there should not be a problem.
08-21-18, 03:24 PM
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I have worked with some cantis that didn't fully seat down all the way initially, paint is the usual culprit. Some filing/sanding of the brazed on boss's shaft base was needed to allow the arm to completely sit down on the boss and have the "spring pin" engage the holes. Looking at the photo it seem like this might be your case. There's a gap between the boss's spring hole plate and the canti's housing. If this, or another reason, makes the brake not work properly then the answer is to use another canti that does work. Andy
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08-22-18, 02:52 AM
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I have worked with some cantis that didn't fully seat down all the way initially, paint is the usual culprit. Some filing/sanding of the brazed on boss's shaft base was needed to allow the arm to completely sit down on the boss and have the "spring pin" engage the holes. Looking at the photo it seem like this might be your case. There's a gap between the boss's spring hole plate and the canti's housing. If this, or another reason, makes the brake not work properly then the answer is to use another canti that does work. Andy
The spring pin engags the mounting holes, but because of the gap, too much torque is being exerted on the pin. It's going to break.
It's also resulting in some extra friction when the mounting bolts are tightened.
I've already installed a Motolight, just assessing options before trashcanning these.
08-22-18, 10:38 AM
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Black sleeve added to reduce grease contamination of bronze bushing within?
Does the boss shoulder fit against the edge of the bronze bushing on the caliper?
Does the boss shoulder fit against the edge of the bronze bushing on the caliper?
08-22-18, 11:40 AM
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The direct curves don't seem to have a great reputation (Cane Creek Direct Curve 3 Brake System user reviews : 1.6 out of 5 - 5 reviews - mtbr.com). Don't stay adjusted, poor compression, poor clearance, and (becuase of the design issue you raise) a strong likelihood of breaking the spring or worse. Pretty clear that the direct curve design was intentionally different without much engineering reasoning guiding the difference. I don't approve.
My 2 cents is that the view isn't worth the climb, nor is it worth re-engineering apparently inferior design. I'd probably avoid installing these if I could. Sell on ebay, find some used Avids or XTRs or somesuch.
My 2 cents is that the view isn't worth the climb, nor is it worth re-engineering apparently inferior design. I'd probably avoid installing these if I could. Sell on ebay, find some used Avids or XTRs or somesuch.
09-04-19, 08:45 AM
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I've got this old set of Cane Creek Direct Curve brake arms I was looking to install.
Problem is illustrated in the attached photos: The Direct Curve (black set) has a section of the pivot that sticks out, and gets in the way between the brake arm and the face of the brake boss.
Compare this to the Tektro design (silver) where everything sits flush.
As shown in the second photo, because of this, the pin for the Direct Curve's tension spring can't completely engage the boss. On the Tektro or any other brake, the brake would sit flush against the boss and the pin would be fully engaged, and this gap wouldn't be present.
Looking at installation diagrams on Cane Creek's site, They show a different version of this brake where it's a flush fit, similar to the Tektro.
Cane Creek can't offer me any help as this is a discontinued product -- they've got no advice to give.
Any insight? Was this brake designed for a different style of brake boss?
Problem is illustrated in the attached photos: The Direct Curve (black set) has a section of the pivot that sticks out, and gets in the way between the brake arm and the face of the brake boss.
Compare this to the Tektro design (silver) where everything sits flush.
As shown in the second photo, because of this, the pin for the Direct Curve's tension spring can't completely engage the boss. On the Tektro or any other brake, the brake would sit flush against the boss and the pin would be fully engaged, and this gap wouldn't be present.
Looking at installation diagrams on Cane Creek's site, They show a different version of this brake where it's a flush fit, similar to the Tektro.
Cane Creek can't offer me any help as this is a discontinued product -- they've got no advice to give.
Any insight? Was this brake designed for a different style of brake boss?
Contrary to @WizardOfBoz's brief googling, these brakes have lots of positive reviews and cult following. Yes, they are finicky - especially for set-up. Doesn't make them bad - many many (older) brakes share such traits.
Also, the Direct Curve experienced several iterations along its lifespan, resulting in several models - some are better than others.
Anyway @Speedub.Nate, without seeing your entire brake or any of the other arms for comparison it appears you might be missing the linear spring (arm) and assembly. If you don't have a spring tension adjusting screw, then I think your answer is pretty clear - the brake is incomplete and will neither mount correctly or operate at all.
Let me know if you'd be willing to sell these to me
09-04-19, 02:13 PM
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09-04-19, 02:22 PM
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Guess I'll be looking at Pauls soon enough as well.. At least we still have them as options when no other USA made quality components seem to exist.
