Monday, March 18, 2019

Modifying Kool Stop Brake Pads

Updating vintage brakes with modern pads and cables is a great and easy way to improve their performance. Modern cables often have less friction, which can lighten the "feel" of an old pair of brakes, and modern brake pad compounds are quite a bit better than what was available "back in the day." If you have vintage brakes and are still using vintage pads, those pads may not have been anything great to begin with, and by now they are probably so hard and dry that it's a wonder they can stop a bike at all.

I've found the brake shoes from Kool Stop to be a good choice for improving older brakes - they come in a couple of different compounds (black, or salmon), have some adjustability for toe-in, are fairly inexpensive, and will work with a lot of different vintage brakes. One issue with them, however, is that they are made to be uni-directional, with a long "tail" that sometimes interferes with the forks on older bikes. In some cases, the tail of the pads gets caught up on the forks with the result that the brakes won't open up wide enough to get the wheel out. Kool Stop does make a version they call "Continental" pads which are shorter and simply rectangular - but they also don't have the toe-in adjustability, which in my view is a strike against them.

The good thing is that the longer pads can be easily modified - and here I'll show you how.

I just installed these new Kool Stop Eagle Claw Salmon shoes on this set of vintage Dia Compe center pulls. You can see that the tail of the pads extends back into the fork. In this instance, the spacing is actually not too bad and the brakes will probably open up wide enough despite the pad/fork interference - but I'm going to trim them anyhow.
 One thing you need to know about the Kool Stop brake shoes is that they are molded around a steel "foot" that runs most of the length of the shoe - stopping just short of the tail end of the pad. If you cut the shoe, you want to make sure you clear the metal foot.

Looking at the braking surface of the shoe, you can see there are two "rain grooves" that divide the pad into 3 sections. The metal "foot" that is inside the shoe ends just about where the second rain groove is at the tail end of the pad. That little ¼ in. section at the tail is the part we're going to cut off. You could probably use a basic utility knife for this, but I personally prefer a straight razor blade (nice, new, and sharp) for the job.
The blue lines show the approximate location of the metal foot. I suggest cutting on a bit of an angle through the tail end of the rain groove and outward - to make sure you don't run into the foot. If you do hit and expose it, it's not the end of the world (once on the bike, it's doubtful anyone would notice) but I'm anal retentive enough that it would drive me nuts.
Cuts like butter.
The cut is smooth and straight. When on the bike, the cut will disappear. 
It's usually only necessary to do this to the front pads - as the rear brakes often have a little more space between the seat-stays - and the brakes are usually oriented so that the long tail of the pads points away from the stays to the rear of the bike.
On the bike, you can't tell the shoe was cut, but it has increased the clearance. The next thing is the mounting posts. On the threaded versions of these shoes, the post is really long. It's possible they make it long so it works with more models of brakes - but I can't imagine any brake that needs the posts to be as long as these are. No problem. After the brakes are set up, with the position and angle you want, it's easy to cut off the end of the post with a Dremel tool. I do it with the pads mounted in the brakes, and use a file or a small abrasive wheel (also mounted in the Dremel tool) to smooth the end. If you cut the post prior to mounting, you might find it hard to get the nut started on the threads after cutting.
That's all for now. More updates on the bike projects will be coming soon.

12 comments:

  1. We always adjusted toe on the bikes with the Continental style pads by gently tweaking the brake caliper where the pad mounts.

    Aaron

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    Replies
    1. that does work - and I've done it in some cases where necessary, but it makes me cringe every time.

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    2. If you want to keep your vintage brakes vintage looking, Kool-Stop makes pads that are direct replacements for Weinmann (Dia-Compe)brake shoes. Their "Weinmann 4-dot" pads would have fit great in the original aluminum shoes that your brakes came with. You just might have to break off the the tab at the rear of the shoe to be able to remove/install the pad, which is easy to accomplish.

      They also make replacements for MAFAC, vintage Campagnolo, Shimano, etc. Little known fact: Kool-Stop C89 series pads fit MAFAC shoes perfectly, and add a modern shape and a little more rubber to the brake.

      As far as toe-in, you gotta go with the time-honored traditional method - a great big crescent wrench.



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    3. that's true - that they make versions to fit some of the vintage pad holders. In some cases - like this one - I'm not interested in keeping a vintage "look" or doing a "correct" restoration. But again - the great big crescent wrench method for toe-in is effective, but makes me cringe.

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  2. I've never intentionally bent the brake caliper to get the toe-in, but I have ground flat washers at an angle and inserted them between the pad and caliper to good effect.

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  3. I'm lucky to have access to some pretty nice equipment at my shop. I band saw the tails off and then shape them up a bit on the belt sander.

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  4. Thanks for sharing that trick. Kool Stop makes a "Thinline" model that might allow more opening of the caliper - it's long but thinner. Not sure if the thin pad might adversely affect the geometry of the brake, but you can move the washers around to compensate for that. They also make some models that are shorter than the Eagle or Supra. The new "City" model appears to be shorter and symmetrical, but unfortunately their web site does not show the length. Like many of their models, it uses Allen-head fasteners instead of the simple nuts of the Continental and Eagle pads. These stick out quite a bit.
    Jon Blum

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    1. They apparently make a lot of different shapes and sizes for a bunch of different applications. As I understand it, the company is pretty responsive to customers -- a couple of years ago, based on the requests from some customers they started making new pads to fit old SunTour Superbe brake pad holders (the originals had kind of a unique shape, and the pads were sort of rust-colored, so the Kool Stop salmon pads were pretty close in color). The way I understand it, it was simply "can you make these?" and the company said "OK" - done.

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  5. Great tip! It’s easy to clean up the cut pad with a file or sandpaper, too.

    To avoid any risk of damaging the bike or sending metal filings all over your bike, try this when cutting pad posts: Mount the pad on the bike. Mark where you want to cut with a permanent marker. Remove the pads, but reinstall the nut. Cut the post, clean up the threads. Before removing the nut from the post, work it over the cut threads a few times to be sure it will move freely. It should be easy to remount on the brake,

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    Replies
    1. They also make cone-shaped drill attachments that you can use to chamfer (?) the cut post.

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  6. Thanks for the SunTour pad tip. I wonder if those would fit the pad holders in my old SunTour Sprint brakes. It would be cool to be able to use the original pad holders.
    Jon

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