Go Back  Bike Forums > Bike Forums > Bicycle Mechanics
Reload this Page >

Brake Interrupter causing brakes to rub?

Notices
Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

Brake Interrupter causing brakes to rub?

Old 09-28-13, 10:05 PM
  #1  
corrado33
Senior Member
Thread Starter
 
Join Date: Jun 2013
Location: Bozeman
Posts: 4,094

Bikes: 199? Landshark Roadshark, 198? Mondonico Diamond, 1987 Panasonic DX-5000, 1987 Bianchi Limited, Univega... Chrome..., 1989 Schwinn Woodlands, Motobecane USA Record, Raleigh Tokul 2

Mentioned: 25 Post(s)
Tagged: 0 Thread(s)
Quoted: 1129 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Brake Interrupter causing brakes to rub?

Hey all,
I have a quick question. I have a bike that has brake interrupters (2nd set of brake levers on the tops of the bars). When I pull the brake using the main brake levers, the pads will spring back just fine, but when I use the interrupter, they don't spring back as well as they should. The brake itself has had it's pivots cleaned and lubed.

When I squeeze the interrupter, it'll just be a little "loose" after I let it go (there is play in the lever.) The if I squeeze the main lever it'll pull the interrupter "tight" and reset the brakes so they don't rub anymore.

What could be causing this problem? Do the cables need lubed? I lubed the pivots on the levers as well.

For the record, this isn't my bike, and the person's bike it is does not want to remove the interrupters.
corrado33 is offline  
Old 09-28-13, 10:10 PM
  #2  
FBinNY 
Senior Member
 
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 35,964

Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter

Mentioned: 124 Post(s)
Tagged: 1 Thread(s)
Quoted: 4362 Post(s)
Likes: 0
Liked 29 Times in 28 Posts
Could be a tight pivot in the intermediate lever, or possibly a cable friction problem that happens when the intermediate lever bends the wire or housing.

I'd start by disconnecting the cable from the brake and feel how much force it needs to pull back, when either lever is used. Then, I'd work back from there, checking cable friction and lever pivot friction.
__________________
FB
Chain-L site

An ounce of diagnosis is worth a pound of cure.

“Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FBinNY is offline  
Old 09-28-13, 10:41 PM
  #3  
bobotech
Senior Member
 
Join Date: Jan 2012
Location: Spokane, WA
Posts: 2,255

Bikes: Specialized Sequoia Elite/Motobecane Fantom Cross Team Ti/'85 Trek 520

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
Likes: 0
Liked 1 Time in 1 Post
I have seen where the cables leave the cross brakes to the cable stops on the frame and the cable has an extremely tight curve. I ended up routing one of my brake cables OVER the handlebars instead of under once it left the cross brake fitting. Works smoother even though it looks odd.

So I'm thinking that when you pull the cross brake lever, it causes the cable to make an even tighter curve which causes the friction.

Using the main brake lever doesn't cause that same friction because the cable runs are staying straighter.
bobotech is offline  
Old 09-28-13, 10:56 PM
  #4  
fietsbob
Banned
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Posts: 43,599

Bikes: 8

Mentioned: 197 Post(s)
Tagged: 0 Thread(s)
Quoted: 7607 Post(s)
Liked 1,316 Times in 827 Posts
the cable runs through un-interrupted , it's the housing that is .

were the cut ends of the housing ground off flat and free of burrs ?
no? that may be dragging.

Die drawn (whole spool, surface is slicked after they were made), cables are a big improvement.

maybe the return springs in the caliper, and the primary lever are weak? 'light action'..

Last edited by fietsbob; 09-29-13 at 08:22 AM.
fietsbob is offline  
Old 09-29-13, 07:01 AM
  #5  
Looigi
Senior Member
 
Looigi's Avatar
 
Join Date: Dec 2010
Posts: 8,951
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 14 Post(s)
Likes: 0
Liked 8 Times in 7 Posts
Yeah. The regular brake levers work by pulling on the cable. The interrupters work by pushing on the housing. As mentioned, if the interrupter pivots are dragging or there's any binding preventing the housing from moving and returning freely, that could cause the problem.
Looigi is offline  
Old 09-29-13, 08:00 AM
  #6  
dsbrantjr
Senior Member
 
dsbrantjr's Avatar
 
Join Date: Sep 2010
Location: Roswell, GA
Posts: 8,055

Bikes: '93 Trek 750, '92 Schwinn Crisscross, '93 Mongoose Alta

Mentioned: 26 Post(s)
Tagged: 0 Thread(s)
Quoted: 1333 Post(s)
Liked 821 Times in 574 Posts
"The interrupters work by pushing on the housing. As mentioned, if the interrupter pivots are dragging or there's any binding preventing the housing from moving and returning freely, that could cause the problem."

The section coming out of the interrupter lever and going towards the brake must be fully free to move and cannot be impeded from moving by being wrapped to the bar or otherwise attached to anything. Is your housing tie-wrapped to or rubbing against anything such as another brake or shift cable?
dsbrantjr is offline  
Old 09-30-13, 08:34 AM
  #7  
Kimmo 
bike whisperer
 
Kimmo's Avatar
 
Join Date: Dec 2009
Location: Melbourne, Oz
Posts: 9,134

Bikes: https://weightweenies.starbike.com/forum/viewtopic.php?f=10&t=152015&p=1404231

Mentioned: 14 Post(s)
Tagged: 0 Thread(s)
Quoted: 1175 Post(s)
Liked 436 Times in 315 Posts
IMO fitting interrupters well is quite a tricky operation.

If the bars have cable grooves you may need to position the levers in a less favourable position to straighten the cable run.

And it couldn't hurt to optimise the length of the housing - usually as short as possible without introducing any sharp bends and allowing full movement of the bars.

While you're at it, throw a couple of drops of oil in the housing.

And if the housing isn't lined, there's your problem; bin it.
Kimmo is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
ghas
Bicycle Mechanics
8
07-12-13 04:18 PM
weed eater
Singlespeed & Fixed Gear
23
05-30-13 06:49 AM
devinfan
Classic & Vintage
5
01-14-13 09:28 PM
trekday2100
Bicycle Mechanics
5
04-10-11 01:51 PM
Schwinn_Guy
Bicycle Mechanics
2
05-29-10 07:29 PM

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright © 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.