Brakes juddering

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ricksavery

Über Member
Location
Poole, Dorset
Hello
I have been experiencing a bit of brake judder on the front, which at first I thought was a problem with the headset. Found that the brakes are moving forward and back ever so slightly on the bosses when the brake is applied. It only has an noticable effect when the front brake is applied on its own. The allen bolts on the bosses can't be tightened any more so I'm not sure what to do about it. Any advice please.
I have Tektro CR720 cantilevers on the front and back, and the frame is a Surly LHT.
Thanks
Rick
 

Zoiders

New Member
It's your actual pad set up/adjustment - canti's are indeed fiddly to remove squeal or judder from.

Try a little toe-in, try sheldon browns page if you struggle.
 
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ricksavery

ricksavery

Über Member
Location
Poole, Dorset
Thanks Zoiders, good thought. I checked that though and the alignment of the pads is fine. It's definitely the brake itself moving slightly on the boss.
 
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ricksavery

ricksavery

Über Member
Location
Poole, Dorset
I know what you mean about toe-ing in the pads, it is fiddly and can lead to the brakes juddering. But it's not that, honest. I probably shouldn't have used the word judder - sends the wrong message.
When I clamp the front brake on, and rock the bike backwards and forwards it feels like there is play, just like it would if the headset was loose -which is why i was initially worried, but that's not the problem.
With the same movement applied, and my hand on the brake assembly, you can feel the brake moving on the boss slightly. I assume it is moving on the bush but not sure. Never experience this much play before, and not convinced it is good, so wanted to find a way of dealing with it.

Hope I've made that clearer Zoiders, sorry if I misled you.
 

gbb

Legendary Member
Location
Peterborough
Ive seen some of those bushings get really worn out when stripping and playing with various bikes. i can imagine that'd cause some problems. As Zoiders says, run em into the ground or until you can't do with it any more and replace.
 
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ricksavery

ricksavery

Über Member
Location
Poole, Dorset
Sounds like a plan! Shame though as they are less than a year old. Wouldn't have expected the bushes to have worn on all four in that time.
 

asterix

Comrade Member
Location
Limoges or York
Agreed, I have some really ancient cantis that are fine (mid-80's). I can't see how brakes can actually move forwards and back except at high frequency, a.k.a. squeal or judder.

My Avids used to squeal badly unless toed in quite a lot. Then I fitted some new pads (Massi's, bought in France) and they have been fine (really nice pads). I can also recommend Koolstops that I used in the Pyrennees althought that was on dual pivot mechs and I don't know if they are available for cantis. Spa Cycles fixed me up.
 

the snail

Guru
Location
Chippenham
The brake has a bushing inside it, they all move ever so slightly.

Pad adjustment is what sets them juddering, get it right with toe in and they dont do it.

+1 my tectro oryx have that play, but they were like that from new. They squeal like a stuck pig at times. Changing pads helped, but getting the toe-in adjustment right cured it on the back, almost got rid of the squeak on the front. It's taken me a couple of tries to get to that point, so keep fiddling with the pads I reckon.
 

smiorgan

New Member
I had the same problem with the Avid single digit 7's that I installed on my Cross Check.

Firstly there was a judder when applying the brakes hard. I fixed it by toeing the pads in. But this isn't the problem.

Secondly there was exactly the play described above on the posts, with the canti stud bolts torqued down. This was tightened up when I tightened the balance springs on either side. Now I get nice progressive braking with no play and no judder.

You should be able to do the same with your CR720s.
 
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ricksavery

ricksavery

Über Member
Location
Poole, Dorset
I think I have sorted it! There is no play on the bushes or from the pads / alignment . . but, the bosses themselves are are a bit snug with a very slight bulge at the end. this makes the cantis very difficult to get on and off. I think because of this problem the bolts holding the brakes on aren't done up as tight as they should be allowing play at the frame end of the boss (I hope that makes sense - terrible at describing these things). I have taken some emery cloth to the bosses and now the brakes slide on and off much easier and the bolts do up tight whilst still allowing the brakes to rotate - no play!
Although it's not exactly the same as your problem smiorgan, I think (?) they are related
Many thanks for the (as always) helpful advice
 

Davidc

Guru
Location
Somerset UK
I have problems making my Tektro oryx cantis work quietly and smoothly.

I've had to do very much what you have to tame them and they still need a silly amount of toe-in. I really don't like cantilever brakes much.

I keep threatening to put double pivot caliper brakes on instead but haven't - yet.
 
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