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Dia Compe 981 Installation Help

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Dia Compe 981 Installation Help

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Old 01-18-09 | 03:40 PM
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Dia Compe 981 Installation Help

Very simply, how do you install these things!********** When I tighten down the mounting bolt and swing the brake arm away from the the wheel, the springs hang back and gets in the way of the wheel. Can anyone tell me what I am doing wrong?

I am trying to install them on a 1985 Schwinn Passage frame. The canti mounting post(s) only have one hole to accept the spring.
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Old 01-18-09 | 04:02 PM
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Maybe this pic will help:



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Old 01-18-09 | 05:12 PM
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I always follow Sheldon Brown's advice and slide the brake shoe holders all the way into the eyebolts on medium and wide profile cantilevers. This is probably no help with the OP's question, but those pictures bother me.
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Old 01-18-09 | 06:36 PM
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Is your concern then, because I have the brake shoe posts with much metal showing on the pad side of each arm? The amount of angular dive is minimized via this configuration and that's why I set it up like this. Braking action is very good, lacking chatter. Is this a poor set-up?

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Old 01-18-09 | 06:58 PM
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It's not a poor setup if it works for you. Sheldon said that "best practice" is to slide them all the way in, so that's the way I do it.
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Old 01-19-09 | 03:38 AM
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Here is a whole set of detailed photos showing one of my own 981 calipers... and the captions describe the ease with which they can be set up on a bike

https://www.flickr.com/photos/strongl...523956/detail/

Yep, I really love those brakes!
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Old 01-19-09 | 06:47 AM
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It should be pointed out that the only way to equalize those is to bend the springs. It's the same with my favorite, the 983, but it has the extra complication of the eccentric barrel on the mounting post.

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Old 01-19-09 | 12:16 PM
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Thanks for the pics all. Stronglight, I had found your site previously, still I am having trouble. Here are the pics. Please help me understand why I am so dense!

[IMG][/IMG]

[IMG][/IMG]
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Old 01-19-09 | 12:53 PM
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You have no spring tension. Spin that left brake one turn clockwise. Do the opposite with the right one.
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Old 01-19-09 | 01:41 PM
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I think your springs are bent out of their proper orientation. You may have to re-bend the coil - my guess would be maybe pull it "looser"? At rest, the loop should be almost 180 degrees opposite the end which pokes through the hole of the mounting post on the frame. You might try switching the brake springs onto different posts. But, in any case, you want to get a match the spring in this quick photo I just shot.

This is a LEFT REAR brake, viewed looking forward from the rear of the bike. It shows the unique (okay, "odd") spring correctly mounted. When you rotate the brake caliper back down, just gently press the bottom of the big spring loop forward and the spring should easily drop right back in place over the nut of the brake pad stud.

These springs can indeed be rather confusing when mounting these brakes. ... But, they are REALLY a very simple and useful design - great for easy consumer adjustment or replacement of the brake pads... uh... that is, when they are placed on the bike correctly first.

Good Luck!


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Old 01-19-09 | 02:10 PM
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This may be an even more useful photo showing the same LEFT rear stay with only the return spring when properly mounted in place.

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Old 01-19-09 | 02:21 PM
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Turning the brake like I said will wind up the coil and create spring tension.
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Old 01-19-09 | 05:18 PM
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Dirtdrop & Stronglight,

Thanks. I did wind up the spring to create tension. The issue I have is that tightening down the caliper seems to bind it up. Loosening it allows the caliper to move but it has some lateral slop. How tight are these supposed to be on the post? They feel to loose to me, the caliper tightening bolts.

I am using a set from a 1984 Raliegh Seneca mountain bike and the original mounting bolts are to long. I swapped them out with a set of Tektro Oryx mounting bolts. Thanks for any additional tips. Getting closer to being finished!

Last edited by fender1; 01-19-09 at 07:13 PM.
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Old 01-19-09 | 09:40 PM
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Ok. The brakes are in and the cables run. How do you account for spring tension/ unequal spring tension when you are settting them up?
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Old 01-20-09 | 12:37 AM
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Originally Posted by fender1
Ok. The brakes are in and the cables run. How do you account for spring tension/ unequal spring tension when you are settting them up?
Because there are no centering screw(s), it can be a little tricky. Firstly, I make sure that the wheel is absolutely dead centre in the frame/fork - this is a paramount! Then, I try and achieve symmetry between the two sides; i.e. - when the brakes are applied to the rim, the angles of the two arms should be pretty close to matching, as should be the angles and positions of the pads. Then, if the spring tension is unequal, I typically find its a case of either 1) trying to actually bend one of the springs to increase its tension (don't overdo it!) or 2) playing around with the in/out position (sliding the mounting post of the pad in or out) to counteract it, which will of course lose the symmetry between the two sides.
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