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-   -   expedition canti brake replacement - front (http://www.bikeforums.net/touring/966957-expedition-canti-brake-replacement-front.html)

gramphighgate 08-19-14 02:30 PM

expedition canti brake replacement - front
 
hi all,

i need a replacement brake for my 83/84 expedition. as noted elsewhere on this forum, the tekro cr720 canti doesn't fit (it can't clear the fork blade).

can anyone recommend a canti that certainly fits? i'd prefer to buy something new than mess around with used. thanks so much

cyccommute 08-19-14 03:12 PM

Quote:

Originally Posted by gramphighgate (Post 17051975)
hi all,

i need a replacement brake for my 83/84 expedition. as noted elsewhere on this forum, the tekro cr720 canti doesn't fit (it can't clear the fork blade).

can anyone recommend a canti that certainly fits? i'd prefer to buy something new than mess around with used. thanks so much

When you say that it can't clear the fork blade, do you mean that the pads hit the fork? Or is there some other clearance problem? If the pads hit the fork blade when opened, that's fairly normal. As you can see in this picture

http://i144.photobucket.com/albums/r...right-fork.jpg

The pads won't clear the blades. You could get shorter pads but I'd rather have clearance issues than braking issues.

gramphighgate 08-19-14 03:16 PM

no it's much worse than that--it is impossible to line the pads up with the rim--i.e. it is impossible to square the braking surface of the rim and the braking surface of the pad. the tektro brake simply can't produce the right angle--not even close. the brake is fundamentally incompatible with the fork. even switching out the pad to something shorter didn't work.

cyccommute 08-19-14 03:51 PM

Quote:

Originally Posted by gramphighgate (Post 17052118)
no it's much worse than that--it is impossible to line the pads up with the rim--i.e. it is impossible to square the braking surface of the rim and the braking surface of the pad. the tektro brake simply can't produce the right angle--not even close. the brake is fundamentally incompatible with the fork. even switching out the pad to something shorter didn't work.

Did you try putting the longer orbit washer and spacer on the inside of the pads. This will sometimes change the angle of the pad enough to make the pads hit better. You could also try turning the spacer around so that the orbit washer (the shorter convex piece) is either in the front or the back which may give you some freedom of movement. That's the cheap solution and what I'd try first.

The more expensive solution is to go to another brake. I have Paul Cantis on the same bike above now

http://i144.photobucket.com/albums/r...ps402996af.jpg

I've found them much easier to adjust than most other brakes I've worked on. Their a lot more expensive than the Tektros but they are a lot better brake too.

gramphighgate 08-19-14 03:56 PM

new brake is apparently the answer from the miyata/specializing touring yahoo group. even with a simple kool stop bolt on pad it didn't work.

here's what will, it seems:
"shimano cx50/cx70 will work. use the thinnest conical washer. pair the brakes with koolstop thinline pads if you need more clearance. i have this set up on my '83 expedition"

thanks for your help!

unterhausen 08-19-14 04:15 PM

is the tektro too short or too long? I think they are longer than most cantis

fietsbob 08-19-14 06:53 PM

The fork posts the brakes fit on , were close together.. back then ..

clasher 08-20-14 10:42 AM

I had the same issue on an early 80 Bianchi, the canti posts were spaced closer together. I would just buy a newer replacement brake like this one and put some new koolstop pads in.

robert schlatte 08-21-14 11:41 AM

2 Attachment(s)
I just replaced tektro 720s with Paul touring cantis. They use Kool stop slim line pads. They are expensive but they are great brakes. They allow you to adjust the spring tension in subtle amounts so you can get them dialed in perfectly.

http://bikeforums.net/attachment.php...hmentid=400795http://bikeforums.net/attachment.php...hmentid=400796

egear 08-21-14 05:25 PM

Second the Paul's touring canti's. They are awesome brakes.

surfjimc 08-21-14 08:10 PM

Quote:

Originally Posted by egear (Post 17058884)
Second the Paul's touring canti's. They are awesome brakes.

I have these on my '84 Specialized Expedition. They work well on the rear, but have been rather unhappy on the front. It is a tight fit because I run a little wider rim, Mavic A719s. As suggested above, you use the thinnest washer on the inside. You still have issues with the rim width, which makes it very hard, if not impossible to toe the brakes in a manner that keeps them from squealing. I actually took a Dremmel to the brakes so I could lower the pad and make more room. It made the fit much better, but I still can't eliminate the squeal. Took it to the LBS and they couldn't get it to stop either. I think I am going to experiment with the other type of Paul canti brake to see if the design works better with this particular bike. If not, I may dremmel out a bit more material to lower and angle the pads, but I don't have much material left to work with and still maintain a viable brake.

cyccommute 08-22-14 05:47 AM

Quote:

Originally Posted by surfjimc (Post 17059327)
I have these on my '84 Specialized Expedition. They work well on the rear, but have been rather unhappy on the front. It is a tight fit because I run a little wider rim, Mavic A719s. As suggested above, you use the thinnest washer on the inside. You still have issues with the rim width, which makes it very hard, if not impossible to toe the brakes in a manner that keeps them from squealing. I actually took a Dremmel to the brakes so I could lower the pad and make more room. It made the fit much better, but I still can't eliminate the squeal. Took it to the LBS and they couldn't get it to stop either. I think I am going to experiment with the other type of Paul canti brake to see if the design works better with this particular bike. If not, I may dremmel out a bit more material to lower and angle the pads, but I don't have much material left to work with and still maintain a viable brake.

I'd suggest a different pad first. I've found that the salmon Koolstops that the Paul's come with can be squealy. Switching to the dual compound MTB pads like you can see in post 4 reduces or eliminates the squeal. It's cheaper than new brakes.

robert schlatte 08-22-14 07:15 AM

I had a terrible squeal issue that I think I have finally resolved. I replaced the steerer tube cable hanger with one that mounts on the fork to shorten the cable which eliminated a lot of the resonance. Also, toe in. Finally, it just seemed to go away- I guess with pad wear. I will have to try the dual compound when I replace the pads. I have also heard shorter pads helps.

surfjimc 08-22-14 06:32 PM

Quote:

Originally Posted by cyccommute (Post 17060001)
I'd suggest a different pad first. I've found that the salmon Koolstops that the Paul's come with can be squealy. Switching to the dual compound MTB pads like you can see in post 4 reduces or eliminates the squeal. It's cheaper than new brakes.

Thanks for the tip. I'll pick some up this weekend, probably have to order them though. I'll let you know how it goes. Getting rid of the problem with pads is much easier on the wallet, and the set up.

Toe in is the biggest issue. With the touring cantis and wideish rims there just isn't enough room to toe in properly. This squeal has been a problem since I switched to the Koolstop Salmons, so I'll try swapping the pads first.

Barrettscv 08-22-14 07:50 PM

Chances are the 1987ish Expedition has narrow cantilever post spacing. Most modern forks for Cantilever brakes have 75mm or wider post spacing. My vintage bikes have very narrow cantilever post spaces, less than 65mm. The Tektro CR 720 is not designed for this narrow post specification.

I found the Planet X Cantilever to be better than the CR 720 when working with narrow post centers. http://www.planet-x-usa.com/mobile/P...tCode=BCPXFRBO

http://i289.photobucket.com/albums/l...pse54d051a.jpg

fietsbob 08-23-14 08:10 AM

<guess>the above fork is more like the OP probably has .. I measure 6cm between the post centers on mine .
I have NL made Spooky cantilevers on it now .. a redesign of Mafacs .. I have Mafacs on another, older bike.

[pictured in 2nd, 4th, 9th post, post spacing is wider, a more common set up of late.. the CR 720 in OP would fit, there]


Shimano's new CX 70 may also work ..the pivot is offset towards the center ,
you can use thinner spacers under the brake shoe to make up for the width distance between pivot centers

surfjimc 08-24-14 09:36 AM

A quick update on my squeal. Last night I had to throw the bike up on the stand for some regular maintenance. I was looking at the front pads and noticed the ammount of wear had left a bit more room. I loosened the pad and slipped a screwdriver in the back end to create a little toe in. That gave me the ability to hold the toe in place. Tightened everything up and the squeal is finally gone. Can't tell you how nice it was to go for a quick ride and to be able to fully use the front brake and not modulate for sound control.


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