Go Back  Bike Forums > Bike Forums > Classic & Vintage
Reload this Page >

I performed the experiment - brake pad toe-in

Notices
Classic & Vintage This forum is to discuss the many aspects of classic and vintage bicycles, including musclebikes, lightweights, middleweights, hi-wheelers, bone-shakers, safety bikes and much more.

I performed the experiment - brake pad toe-in

Old 08-12-22, 02:19 PM
  #1  
smontanaro 
Senior Member
Thread Starter
 
Join Date: Aug 2007
Location: Evanston, IL
Posts: 5,083

Bikes: many

Mentioned: 57 Post(s)
Tagged: 0 Thread(s)
Quoted: 1121 Post(s)
Liked 824 Times in 452 Posts
I performed the experiment - brake pad toe-in

I have anodized rims on my Redcay (currently Ambrosio Synthesis Durex, but something else originally).The brakes have always screamed like banshees. It's been hanging in the basement for a long while, in large part due to the noise. Some time ago, I acquired a set of Modolo Sinterized pads & holders. My thinking was they might help wear down the anodizing on the brake tracks. After three rides, totally about 130 miles, I couldn't detect a difference than when I was using Campy pads (well, Kool-Stop) and holders.

So, on my ride today, I came to the conclusion that I should explore the possibility of adding some toe-in. It seems to me that many toe-in recommendations over the years involved twisting the calipers. That was something I wasn't willing to do (maybe for horribly cheap stamped steel calipers, but not for my Campy Record parts). I had received the Modolo parts for free. They were new and huge, so big I could only squeeze them between calipers and rims by sanding off some material and running with the quick releases wide open. I was willing to sacrifice them for the sake of science.

I wound up tapering them so the front is about 1.5-2.0 mm thicker than the back of the pads. The resulting profile looks pretty crude, but since these are going to wind up in something like the Box O' Crap, I didn't really care.



I used a sanding wheel on my Dremel. This generated a ton of brake pad dust. If you do this, WEAR YOUR MASK!



I haven't gone on an actual ride with the "new" pads yet, but did go up and down the street. Blessed silence! Once I get some new Campy holders for the Redcay (of course, I forgot what they were for and sold the originals out of my parts bin. I will also have to rig up some sort of jig to make a cleaner, smaller, and more reproducible cut. For the time being though, I won't be scaring the bejeezus out of anyone in my immediate surroundings.

Edit: I don't recall anybody explaining exactly why adding toe-in works, but I have a hypothesis (though no experimental data to back it up, so it's not a theory). I think when you squeeze the calipers they twist ever-so-slightly. As they try to return to their prior shape, they exert more force on the fronts of the holders. Some of you engineers who aced your dynamics classes in college feel free to chime in.
__________________
Contact me to help Doug Fattic's colleagues in Ukraine


Last edited by smontanaro; 08-12-22 at 02:24 PM. Reason: add my hypothesis
smontanaro is offline  
Likes For smontanaro:
Old 08-12-22, 03:55 PM
  #2  
gaucho777 
Senior Member
 
gaucho777's Avatar
 
Join Date: Aug 2009
Location: Berkeley, CA
Posts: 7,217

Bikes: '72 Cilo Pacer, '72 Gitane Gran Tourisme, '72 Peugeot PX10, '73 Speedwell Ti, '74 Peugeot UE-8, '75 Peugeot PR-10L, '80 Colnago Super, '85 De Rosa Pro, '86 Look Equipe 753, '86 Look KG86, '89 Parkpre Team, '90 Parkpre Team MTB, '90 Merlin

Mentioned: 81 Post(s)
Tagged: 0 Thread(s)
Quoted: 734 Post(s)
Liked 1,463 Times in 421 Posts
Nice work. I've also filed a washed so it is thicker on one side than the other and used that between the nut and caliper to create toe-in. Filing the pads works, too.

Jobst Brandt on brake squeal:
https://www.sheldonbrown.com/brandt/brake-squeal.html
gaucho777 is offline  
Likes For gaucho777:
Old 08-12-22, 03:59 PM
  #3  
P!N20
Senior Member
 
P!N20's Avatar
 
Join Date: Aug 2010
Posts: 1,967
Mentioned: 27 Post(s)
Tagged: 0 Thread(s)
Quoted: 854 Post(s)
Liked 1,261 Times in 645 Posts
Approved. I cut tapers into some Koolstop pads on my Monoplaners that were squealing at the slightest touch of the rim and now theyíre silent.

I just used a hacksaw.

Only did the front as the rear doesnít seem to squeal.
P!N20 is online now  
Likes For P!N20:
Old 08-12-22, 05:26 PM
  #4  
steelbikeguy
Senior Member
 
steelbikeguy's Avatar
 
Join Date: Feb 2008
Location: Peoria, IL
Posts: 3,541
Mentioned: 74 Post(s)
Tagged: 0 Thread(s)
Quoted: 1369 Post(s)
Liked 1,944 Times in 956 Posts
This has gotten discussed on the Bob list and other spots over the many years, and it's fairly well proven.
I've been using a coarse wood rasp to remove material from the rear of some of my problematic brake pads in a similar fashion, and have seen reduced squealing.

I will add that I've had more troubles with KoolStop red brake pads, which seem to get stickier in humid conditions (i.e. summer here in the midwest). Older pads that have had a chance to harden are less sticky and less prone to squealing. Still, I've been surprised that the red Koolstop pads in the Campy Record brakes on my Olmo can squeal enough on a soggy summer day that it will cause the quick release lever to gradually open up! Some additional work with the rasp has improved the behavior, although I'm not sure that it is completely cured.

Steve in Peoria
steelbikeguy is offline  
Likes For steelbikeguy:
Old 08-13-22, 11:19 AM
  #5  
jethin
Senior Member
 
jethin's Avatar
 
Join Date: Oct 2009
Posts: 974
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 222 Post(s)
Liked 169 Times in 92 Posts
NB: Iíve read that some of the older Modolo sinterized pads may contain asbestos. Itís pretty much always a good idea to wear a mask when sanding IMO.
jethin is offline  
Old 08-13-22, 11:43 AM
  #6  
zandoval 
Senior Member
 
zandoval's Avatar
 
Join Date: May 2010
Location: Bastrop Texas
Posts: 3,345

Bikes: Univega, Peu P6, Peu PR-10, Ted Williams, Peu UO-8, Peu UO-18 Mixte, Peu Dolomites

Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 530 Post(s)
Liked 803 Times in 525 Posts
Definately a Win, Win...

In that all my bikes are Frankenized I have had no problems grafting newer style brake pads on to my vintage brake sets. On vintage Universal Brake Sets I was able to eliminate squeal by just dyking about 1/8"-3mm off the front corner of the pads. It was a crude solution. Sanding them down nice a pretty is better...
__________________
No matter where your at... There you are... Δf:=f(1/2)-f(-1/2)
zandoval is offline  
Old 08-13-22, 02:22 PM
  #7  
Mad Honk 
Senior Member
 
Join Date: May 2019
Location: Bloomington, IN
Posts: 2,002

Bikes: Schwinn Paramounts, Othon Ochsner, Masi, Faggin

Mentioned: 66 Post(s)
Tagged: 0 Thread(s)
Quoted: 836 Post(s)
Liked 893 Times in 611 Posts
Skip,
I think the squealing is a result of vibration in the pad caused by the action of the rear catching first and creating the vibration. We used to use a bit of the carboard from the brake pad shipping card and position it between the pad and the rim. It allowed the pad to create the toe in to keep the vibrations from happening. In the early 80's the cantilever calipers had toe in adjusting washers that allowed for the same thing. Smiles, MH
Mad Honk is offline  
Old 08-13-22, 03:04 PM
  #8  
randyjawa 
Senior Member
 
randyjawa's Avatar
 
Join Date: Apr 2007
Location: Thunder Bay, Ontario, Canada - burrrrr!
Posts: 11,340

Bikes: 1958 Rabeneick 120D, 1968 Legnano Gran Premio, 196? Torpado Professional, 2000 Marinoni Piuma

Mentioned: 202 Post(s)
Tagged: 0 Thread(s)
Quoted: 1272 Post(s)
Likes: 0
Liked 1,407 Times in 790 Posts
Originally Posted by jethin View Post
NB: Iíve read that some of the older Modolo sinterized pads may contain asbestos. Itís pretty much always a good idea to wear a mask when sanding IMO.
That is true and it is always a good idea to protect one's self from particulate suspended in the air. Good advice no matter what the substance but asbestos is the worst of the worst!
__________________
"98% of the bikes I buy are projects".
randyjawa is offline  
Likes For randyjawa:
Old 08-14-22, 06:21 AM
  #9  
old's'cool
curmudgineer
 
old's'cool's Avatar
 
Join Date: Dec 2009
Location: Chicago SW burbs
Posts: 4,428

Bikes: 2 many 2 fit here

Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 263 Post(s)
Liked 106 Times in 66 Posts
The idea is to prevent the brake from self energizing, which is what happens if the rear of the pad has equal or greater contact pressure than the front (roughly speaking). If the brake is self energizing, the contact pressure is no longer fully under your control, due to twisting of the caliper arm causing the contact pressure at the rear of the pad to increase, causing further increase in braking force (that is the self energizing part), until the caliper deflects so much that the braking force finally reduces. The cycle repeats at a frequency determined by the system properties, which is typically in the audible range.
old's'cool is offline  
Old 08-15-22, 10:25 AM
  #10  
Road Fan
Senior Member
 
Road Fan's Avatar
 
Join Date: Apr 2005
Location: Ann Arbor, MI
Posts: 16,212

Bikes: 1980 Masi, 1984 Mondonico, 1984 Trek 610, 1980 Woodrup Giro, 2005 Mondonico Futura Leggera ELOS, 1967 PX10E, 1971 Peugeot UO-8

Mentioned: 43 Post(s)
Tagged: 0 Thread(s)
Quoted: 1577 Post(s)
Liked 466 Times in 356 Posts
Originally Posted by steelbikeguy View Post
This has gotten discussed on the Bob list and other spots over the many years, and it's fairly well proven.
I've been using a coarse wood rasp to remove material from the rear of some of my problematic brake pads in a similar fashion, and have seen reduced squealing.

I will add that I've had more troubles with KoolStop red brake pads, which seem to get stickier in humid conditions (i.e. summer here in the midwest). Older pads that have had a chance to harden are less sticky and less prone to squealing. Still, I've been surprised that the red Koolstop pads in the Campy Record brakes on my Olmo can squeal enough on a soggy summer day that it will cause the quick release lever to gradually open up! Some additional work with the rasp has improved the behavior, although I'm not sure that it is completely cured.

Steve in Peoria
On Mrs. Road Fan's Paul MiniMotos, I used the popsicle stick spacer trick to toe-in the shoes front and rear, taking advantage of the spherical washers provided on the Kool-Stops. Worked like a champ - smiling wife, good stopping, good pad positioning. Final positioning took a little while!

I was going to do the same thing on the Paul cantis on my 650b, but I must have done those last year or the year before - they brake very well and quietly.
Road Fan is offline  
Old 08-15-22, 08:21 PM
  #11  
old's'cool
curmudgineer
 
old's'cool's Avatar
 
Join Date: Dec 2009
Location: Chicago SW burbs
Posts: 4,428

Bikes: 2 many 2 fit here

Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 263 Post(s)
Liked 106 Times in 66 Posts
It seems logical that over time the natural wear of the brake pads will cause the rear to wear more than the front (due to twisting of the caliper and/or its mounting, under the force of braking), creating a taper that should diminish or eliminate the self-energizing property. But I have never had this happen, to the extent of eliminating squeal, in my own experience. If I didn't do something deliberately to angle the brake pads, they never got quiet on their own. Maybe I don't ride enough, or perhaps I don't use my brakes enough
old's'cool is offline  
Old 08-16-22, 05:43 AM
  #12  
smontanaro 
Senior Member
Thread Starter
 
Join Date: Aug 2007
Location: Evanston, IL
Posts: 5,083

Bikes: many

Mentioned: 57 Post(s)
Tagged: 0 Thread(s)
Quoted: 1121 Post(s)
Liked 824 Times in 452 Posts
Originally Posted by old's'cool View Post
It seems logical that over time the natural wear of the brake pads will cause the rear to wear more than the front (due to twisting of the caliper and/or its mounting, under the force of braking), creating a taper that should diminish or eliminate the self-energizing property. But I have never had this happen, to the extent of eliminating squeal, in my own experience. If I didn't do something deliberately to angle the brake pads, they never got quiet on their own. Maybe I don't ride enough, or perhaps I don't use my brakes enough
My thought was that toe-in would eventually disappear as the front of the pad wears more (it contacts the rim first and the pressure would seem to be higher there). Eventually, I'd be back to a squealing system. That was what kept me from trying this experiment for so long.

Last edited by smontanaro; 08-17-22 at 04:17 AM.
smontanaro is offline  
Old 08-16-22, 05:48 AM
  #13  
iab
Senior Member
 
iab's Avatar
 
Join Date: Jun 2006
Location: NW Burbs, Chicago
Posts: 11,393
Mentioned: 177 Post(s)
Tagged: 0 Thread(s)
Quoted: 2534 Post(s)
Liked 2,295 Times in 955 Posts
Originally Posted by smontanaro View Post
My thought was that toe-in would eventually disappear as the front of the pad wears more (it contacts the run first and the pressure would seem to be higher there). Eventually, if be back to a squealing system. That was what kept me from trying this experiment for so long.
This is my experience. On my off-topic fixed-gear commuter with a single V-brake up front. It has the proper washers to do a toe-in adjustment. It lasted about 6 months before the squeal came back. I decided I like it. Better and louder than any bell or horn.
iab is offline  
Old 08-16-22, 10:15 PM
  #14  
bamboobike4
Banned.
 
Join Date: Jan 2022
Posts: 1,072
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 359 Post(s)
Liked 557 Times in 328 Posts
Originally Posted by Chuckk View Post
I use a belt sander to resurface old pads. It brings them back to functionality.
Emory board, and my nails look a lot better, to.
bamboobike4 is offline  
Likes For bamboobike4:
Old 08-17-22, 06:43 AM
  #15  
rhm
multimodal commuter
 
rhm's Avatar
 
Join Date: Nov 2006
Location: NJ, NYC, LI
Posts: 19,782

Bikes: 1940s Fothergill, 1959 Allegro Special, 1963? Claud Butler Olympic Sprint, Lambert 'Clubman', 1974 Fuji "the Ace", 1976 Holdsworth 650b conversion rando bike, 1983 Trek 720 tourer, 1984 Counterpoint Opus II, 1993 Basso Gap, 2010 Downtube 8h, and...

Mentioned: 555 Post(s)
Tagged: 0 Thread(s)
Quoted: 1874 Post(s)
Liked 409 Times in 265 Posts
Originally Posted by Chuckk View Post
Squalling brakes are the classic way of telling the rider in front of you that he's too slow.
I think the French did it on purpose - think of the knurled brake surface on some wheels.
The extremely loud freewheels of a decade or so ago were created for the same purpose.
Yeah, you're not the first person to say, that.

But I don't believe it. A squealing brake has a lot less stopping power than a properly adjusted brake.
__________________
www.rhmsaddles.com.
rhm is offline  
Old 08-17-22, 01:04 PM
  #16  
smontanaro 
Senior Member
Thread Starter
 
Join Date: Aug 2007
Location: Evanston, IL
Posts: 5,083

Bikes: many

Mentioned: 57 Post(s)
Tagged: 0 Thread(s)
Quoted: 1121 Post(s)
Liked 824 Times in 452 Posts
Originally Posted by rhm View Post
But I don't believe it. A squealing brake has a lot less stopping power than a properly adjusted brake.
I have a Schwinn Speedster with a Racer front brake and a Sturmey-Archer XRD3 rear (drum brake). I can manage with the somewhat reduced stopping power in front because there drum brake rear has loads. The squeal is an added bonus.
__________________
Contact me to help Doug Fattic's colleagues in Ukraine

smontanaro is offline  
Old 08-17-22, 01:53 PM
  #17  
79pmooney
A Roadie Forever
 
79pmooney's Avatar
 
Join Date: Oct 2014
Location: Portland, OR
Posts: 10,761

Bikes: (2) ti TiCycles, 2007 w/ triple and 2011 fixed, 1979 Peter Mooney, ~1983 Trek 420 now fixed and ~1973 Raleigh Carlton Competition gravel grinder

Mentioned: 115 Post(s)
Tagged: 0 Thread(s)
Quoted: 3565 Post(s)
Liked 2,367 Times in 1,548 Posts
Squealing brakes - the old Mafac RACERs! I used to set them up so moderate stops weren't too loud but if a car cut me off (Boston city traffic) I'd hit the front extra hard. Every pedestrian within a block would turn and look at me. I'd point to the driver. Eyes follow my point. Driver gets awakened from his stupor by the squeal, looks up - and everybody is looking at him! Driver slinks off like a guilty cat. It was rather fun and well worth the effort to dial in the squeal.
79pmooney is offline  
Likes For 79pmooney:
Old 08-17-22, 01:57 PM
  #18  
79pmooney
A Roadie Forever
 
79pmooney's Avatar
 
Join Date: Oct 2014
Location: Portland, OR
Posts: 10,761

Bikes: (2) ti TiCycles, 2007 w/ triple and 2011 fixed, 1979 Peter Mooney, ~1983 Trek 420 now fixed and ~1973 Raleigh Carlton Competition gravel grinder

Mentioned: 115 Post(s)
Tagged: 0 Thread(s)
Quoted: 3565 Post(s)
Liked 2,367 Times in 1,548 Posts
Originally Posted by rhm View Post
Yeah, you're not the first person to say, that.

But I don't believe it. A squealing brake has a lot less stopping power than a properly adjusted brake.
I learn something new every day. I've done hard stops for 50 years on squealing brakes and never had any idea I actually wasn't stopping fast. (So that noise isn't coming from our kinetic energy being turned into sound waves but is coming from somewhere else?)
79pmooney is offline  
Old 08-17-22, 02:47 PM
  #19  
rhm
multimodal commuter
 
rhm's Avatar
 
Join Date: Nov 2006
Location: NJ, NYC, LI
Posts: 19,782

Bikes: 1940s Fothergill, 1959 Allegro Special, 1963? Claud Butler Olympic Sprint, Lambert 'Clubman', 1974 Fuji "the Ace", 1976 Holdsworth 650b conversion rando bike, 1983 Trek 720 tourer, 1984 Counterpoint Opus II, 1993 Basso Gap, 2010 Downtube 8h, and...

Mentioned: 555 Post(s)
Tagged: 0 Thread(s)
Quoted: 1874 Post(s)
Liked 409 Times in 265 Posts
Originally Posted by 79pmooney View Post
I learn something new every day. I've done hard stops for 50 years on squealing brakes and never had any idea I actually wasn't stopping fast. (So that noise isn't coming from our kinetic energy being turned into sound waves but is coming from somewhere else?)
Well, it varies. YMMV, as they say.

And yes, i have had that experience with MAFAC Racers, they can squeal and still stop the bike.
I've also had brakes that, when that squealing started, the brake had very little stopping power. The pads were basically bouncing off the rim at high frequency, not spending much time in contact with the rim.
__________________
www.rhmsaddles.com.
rhm is offline  
Old 08-18-22, 02:55 PM
  #20  
Classtime 
Senior Member
 
Classtime's Avatar
 
Join Date: Jan 2015
Location: Los Angeles
Posts: 3,532

Bikes: 82 Medici, 2011 Richard Sachs, 2011 Milwaukee Road

Mentioned: 39 Post(s)
Tagged: 0 Thread(s)
Quoted: 1375 Post(s)
Liked 903 Times in 564 Posts
If my brakes are squealing, they do not work very well because I will only gently squeeze the lever until I turn around, get back to the garage, adjust the toe in, and try again. I've never had more trouble with Mafacs than any other vintage brake wrt squealing. A course Nicholson is my usual go to and there is plenty of material on vintage brake blocks.
__________________
I don't do: disks, tubeless, e-shifting, or bead head nymphs.
Classtime is offline  
Old 08-18-22, 06:43 PM
  #21  
bamboobike4
Banned.
 
Join Date: Jan 2022
Posts: 1,072
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 359 Post(s)
Liked 557 Times in 328 Posts
Toeíd in.

With a 106-miler in 2 days, I toe’d in the new pads using a third hand tool and 3 slivers of card stock. I think they are ready. The 11-36 cassette is ready, Di2 shifting smoothly with the Roadlink and the B-screw in half way. The +1 is ready to ride.

After a terrifying drive over Loveland Pass, I’m skipping the ride. Good thing, because her Edge 1000 failed as well as her Varia headlight. She’ll be using mine.

Appreciate the toe-in advice.
bamboobike4 is offline  
Old 08-21-22, 11:54 AM
  #22  
Road Fan
Senior Member
 
Road Fan's Avatar
 
Join Date: Apr 2005
Location: Ann Arbor, MI
Posts: 16,212

Bikes: 1980 Masi, 1984 Mondonico, 1984 Trek 610, 1980 Woodrup Giro, 2005 Mondonico Futura Leggera ELOS, 1967 PX10E, 1971 Peugeot UO-8

Mentioned: 43 Post(s)
Tagged: 0 Thread(s)
Quoted: 1577 Post(s)
Liked 466 Times in 356 Posts
Originally Posted by iab View Post
This is my experience. On my off-topic fixed-gear commuter with a single V-brake up front. It has the proper washers to do a toe-in adjustment. It lasted about 6 months before the squeal came back. I decided I like it. Better and louder than any bell or horn.
I'll see how that works with my wife's Terry. By refusing to ride her bike until I "got rid of that awful noise" she got this whole thing started. I want to think it will work out as you say!!
Road Fan is offline  

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.