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

Struggling to generate braking power with new cantis

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.

Struggling to generate braking power with new cantis

Old 04-29-12, 02:40 AM
  #1  
martyn3200
Senior Member
Thread Starter
 
Join Date: May 2011
Location: Bristol, United Kingdom
Posts: 82

Bikes: Giant Peloton Lite

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Struggling to generate braking power with new cantis

I've recently ventured into the world of cantis and I'm beginning to wish I never had. After struggling to get decent power with some old cheap cantis I bought off eBay, I decided that the brakes were the problem so bought some Tektro CR520 to try and solve the problem. I'm running them on my cyclocross bike with Campagnolo Veloce Ergos from pre '11. The front cable is routed over the stem and into a hanger on the fork steerer and the rear runs through a cable stop built into the frame on the seat stays.

I've played around with yoke height and straddle cable length and have found that I get the most braking power with the yoke two fingers height from my tyre, folllowing the advice from this article: (http://www.cxmagazine.com/gut-wrench...ys-brake-setup)

I still can't generate enough power to lock the back wheel in dry conditions. When I squeeze the rear lever the brake reaches the rim with plenty of travel left on the lever, but I can continue to squeeze the lever until it hits the drops on my bars. It feels like the brake is really spongy. I have got fairly cheap cables on, but never had any trouble with them with caliper brakes I've used in the past. Any help is much appreciated!
martyn3200 is offline  
Old 04-29-12, 03:42 AM
  #2  
MichaelW
Senior Member
 
Join Date: Feb 2001
Location: England
Posts: 12,949
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 17 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
You have one of the best canti setups: 520s with an up-hanger. Maybe your cables are still stretching and bedding in. Are you using ferrules on your cut cable outers. Are they fitted properly?
The best brake blocks are probably Kool-stop salmon. New blocks have a mould release agent which needs wearing off.
MichaelW is offline  
Old 04-29-12, 07:34 AM
  #3  
Altbark
Senior Member
 
Join Date: Jan 2012
Location: Trenton On
Posts: 245

Bikes: 2010 Cannondale T1, 1998 Specialized FSR

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Try to make sure that you are using the thick washer next to the brake pad if you can. It will incease the mechanical advantage. I've had a similar problem with the canti's on my Cannondale T1. I got some great advice from the folks on this forum. The best has to be going to V brakes. I'm waiting for mine to arrive. From my perspective, the only reasons for leaving canti's on a bike are to maintain historical accuracy, mud clearence should you actually use your CX bike for CX or off-road and cost issues. I've got a 1998 Specialized FSR with its original V brakes and pads. It still stops on a dime with two fingers and no squealing. Can't ask for more than that. Al
Altbark is offline  
Old 04-29-12, 08:57 AM
  #4  
dsbrantjr
Senior Member
 
dsbrantjr's Avatar
 
Join Date: Sep 2010
Location: Roswell, GA
Posts: 6,222

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

Mentioned: 13 Post(s)
Tagged: 0 Thread(s)
Quoted: 654 Post(s)
Likes: 0
Liked 47 Times in 43 Posts
Take the first piece of advice offered in the article you quoted: "First, get the best housing and cables you can." They don't have to be the latest unobtanium; lined housings and die-drawn stainless wires by Shimano or Jagwire or the like will do fine. Then prepare them properly; cut the housings straight to the correct lengths, grind or file the cut ends flat and install the correct METAL ferrules on each end. Here's an article to peruse: http://sheldonbrown.com/cables.html The yokes and straddle wires which came with your brakes should be fine. The pads may be so-so, Kool Stop Salmon pads are a highly recommended upgrade. Make sure that the pads and braking surfaces of your rims are in good condition and free from any grease or oil.
dsbrantjr is offline  
Old 04-29-12, 11:08 AM
  #5  
jeffpoulin 
Senior Member
 
Join Date: Jul 2008
Posts: 2,292
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 46 Post(s)
Likes: 0
Liked 1 Time in 1 Post
I have cantis on my crosscheck (Shimano BR-R550) and they work really well now, although they were spongy at first. Here's what I did to make them better:

1) On the brake mount post, there are 3 small holes for the brake anchor. I originally tried the middle hole, but moved it to the top hole to increase the tension on the springs.
2) I replaced the stock pads with Kool Stop black. These not only grip better than the Shimano pads, they eliminated the squeaking too.
3) Made sure the pads were toed in 1mm by placing a penny between the rear of the pad and the rim, then tightening the bolt.

With the setup now, I can easily lock the rear wheel. The front doesn't skid, but it stops very well. I'm sure I could endo if I clamped hard enough.
jeffpoulin is offline  
Old 04-29-12, 11:32 AM
  #6  
pmt
Experienced
 
Join Date: Sep 2007
Posts: 1,036
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Yep, I have Avid Shorty 4s with Kool-Stop Mountain pads and can lock it up, front and back, rain or shine. No trouble at all.
pmt is offline  
Old 04-29-12, 12:47 PM
  #7  
martyn3200
Senior Member
Thread Starter
 
Join Date: May 2011
Location: Bristol, United Kingdom
Posts: 82

Bikes: Giant Peloton Lite

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Thanks for the feedback. I'll overhaul the brakes with Jagwire cables, metal ferules, file the cable ends and see how they perform. The pads are brand new, so I'll try breaking them in with some long descents, I'll also give the rims and pads a clean in case they're greasy. I'll then use the top spring hole and compare the performance. If the brakes are still not good I'll maybe replace the pads. If they're still not working properly I'll report back!
martyn3200 is offline  
Old 04-29-12, 01:27 PM
  #8  
fietsbob 
coprolite
 
fietsbob's Avatar
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Posts: 41,650

Bikes: 8

Mentioned: 188 Post(s)
Tagged: 0 Thread(s)
Quoted: 6836 Post(s)
Likes: 0
Liked 215 Times in 179 Posts
You can scuff up the new pads with sandpaper , grit side up , against the rim..

and if you use Low Profile type [half a Y instead of the L shape]
set the pads to be pretty close to the rim, so there is not much lever motion,
before the pad strikes the rim.
fietsbob is offline  
Old 04-29-12, 02:53 PM
  #9  
Altbark
Senior Member
 
Join Date: Jan 2012
Location: Trenton On
Posts: 245

Bikes: 2010 Cannondale T1, 1998 Specialized FSR

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by martyn3200 View Post
Thanks for the feedback. I'll overhaul the brakes with Jagwire cables, metal ferules, file the cable ends and see how they perform. The pads are brand new, so I'll try breaking them in with some long descents, I'll also give the rims and pads a clean in case they're greasy. I'll then use the top spring hole and compare the performance. If the brakes are still not good I'll maybe replace the pads. If they're still not working properly I'll report back!
Do what you have to do but at the end of the day you will have "adequate brakes" but not great brakes. All of the suggestions you've read are good but those canti's will never be as good as a set of V brakes. Go down to your local department store and look at what they are installing on the cheap bikes. All V brakes and no cantilevers. Why? Because the things work well even if they aren't set up particularly well and they don't for the most part squeal. Everyone talks about toe-in on the brakes but check the installation instructions for Tektro canti's. They don't mention toe-in at all. The V brakes on my FSR are set flat to the rim and have no issues. Similarly, the Tektro dual pivots on my singlespeed are also set flat to the rim and work flawlessly.

I've got a set of Tektro canti's sitting in a bag on my workbench. Given that they came off my Cannondale T1 (which is not a cheap bike), I can, without reservation, say that they are the worst brakes I have ever used on a bike. If you can't lock up the rear wheel on a modern bike with moderate pressure on adequately set up brakes then the brakes are garbage. And that was the case with the Tektros on my bike. Good luck. Al
Altbark is offline  
Old 04-29-12, 07:31 PM
  #10  
Pilky 
Senior Member
 
Pilky's Avatar
 
Join Date: Aug 2007
Location: Massachusetts
Posts: 112
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 15 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by Altbark View Post
Do what you have to do but at the end of the day you will have "adequate brakes" but not great brakes. All of the suggestions you've read are good but those canti's will never be as good as a set of V brakes. Go down to your local department store and look at what they are installing on the cheap bikes. All V brakes and no cantilevers. Why? Because the things work well even if they aren't set up particularly well and they don't for the most part squeal. Everyone talks about toe-in on the brakes but check the installation instructions for Tektro canti's. They don't mention toe-in at all. The V brakes on my FSR are set flat to the rim and have no issues. Similarly, the Tektro dual pivots on my singlespeed are also set flat to the rim and work flawlessly.
l
What is the purpose of toe-in anyway? I just installed a set of Aztec 2 pads on my bike and it suggested using the packaging as a shim.
Pilky is offline  
Old 04-29-12, 07:42 PM
  #11  
roccobike
Bike Junkie
 
roccobike's Avatar
 
Join Date: Jun 2005
Location: South of Raleigh, North of New Hill, East of Harris Lake, NC
Posts: 9,552

Bikes: Specialized Tarmac, Specialized Roubaix, Giant OCR-C, Specialized Stumpjumper FSR, Stumpjumper Comp, 88 & 92Nishiki Ariel, 87 Centurion Ironman, 92 Paramount, 84 Nishiki Medalist

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 47 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Sometimes the $5.95 Bell cable/housing kit at Walmart just doesn't cut it. As has been said, replace with good quality cable and good quality housing. I recently fixed a problem brake on a vintage roadie by replacing the pads with salmon colored Kool Stops. Wow, what a difference. They should nick-name them "Power Brakes".
__________________
Roccobike BF Official Thread Terminator
roccobike is offline  
Old 04-29-12, 08:13 PM
  #12  
xenologer
Senior Member
 
Join Date: Aug 2008
Posts: 2,592
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 237 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
re-arrange the brake pad spacers so the small one is on the inside, this will allow the tips of the brake arms to be angled upwards ever so slightly more, and slightly closer together. which will help in making the straddle wire angle shallower.
lower the straddle even less than 2 fingers, millimeters matter with these brakes as the mechanical advantage increase is non-linear as the straddle approaches horizontal.

install a brake booster, this will reinforce the canti studs and reduce flex, resulting in better braking power-especially helpful on rear brake where thin seatstays tend to flex easily
make sure the rims are true, this allows the brakes to be adjusted tighter
tektro cr720s are wide profile and inherently weaker than mid-narrow profile cantis, trade them for tektro cr710, or avid shorty 4/6
do the kool stop pad thing (tho, on one of my bikes with my avid shortys, mechanical advantage is already high enough that I can endo with ordinary pads; kool stopping would probably make that bike uncontrollable...)
xenologer is offline  
Old 04-29-12, 09:35 PM
  #13  
fuzz2050
Real Men Ride Ordinaries
 
fuzz2050's Avatar
 
Join Date: Sep 2008
Posts: 3,723
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 16 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Originally Posted by Altbark View Post
Go down to your local department store and look at what they are installing on the cheap bikes. All V brakes and no cantilevers. Why? Because the things work well even if they aren't set up particularly well and they don't for the most part squeal.l
Try spending a few days at a bike co-op trying to help someone get the brakes on their department store Magnas to work. The older ones with cantilevers can be made to work pretty well with proper set-up. Lots of toe-in, new cables and brake pads, plus a few hours to fiddle will get most any cantilever working. The V-brakes are just hopeless though, no amount of tweaking can make a cheap v-brake any more effective.

[QUOTE=xenologer;14159851]tektro cr720s are wide profile and inherently weaker than mid-narrow profile cantis,

II think that it isn't as much about increasing mechanical advantage, but making sure that the mechanical advantage of the system (in this case, brake lever and brake) is well suited for the rider. I have a bike with a set of old Mafac style massive wide angle cantilevers, and it can stop itself on a dime. Because the brakes themselves have so little mechanical advantage, I have a set of old Magura motorcycle brake levers installed.

The levers have enough mechanical advantage to balance out the brakes; in the end I get the cool looking brakes, some pretty nifty brake levers, and a brake set-up that works. However, if I were to try to swap out the levers to an older style road lever (with rather low mechanical advantage), all of the sudden I would have a system with almost no mechanical advantage, and would have almost no braking power.

Last edited by fuzz2050; 04-29-12 at 09:45 PM.
fuzz2050 is offline  
Old 04-29-12, 09:53 PM
  #14  
surreal
Senior Member
 
surreal's Avatar
 
Join Date: Mar 2002
Location: NJ
Posts: 3,084
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Toe-in really does seem to be important to eliminate squeal on Cantis, 990-style U-brakes, and other old centerpull calipers. But, it's something that seems to matter less with v-brakes and dual-pivot calipers. I still tend to toe 'em all in, anyway.

Although the post lacked tact, AltBark's take on cantilevers does have some merit. I gotta say, though, that cantis can be very very good if properly set-up. First time I installed them, I though I'd done a great job, but was underwhelmed by performance. Then, I test-rode a friend's CX bike (he had worked for awhile as a mechanic), and I saw that something was wrong with my set-up; his brakes stopped on a dime! With his help, we got mine working much better. In my experience, Cantis need careful set-up for proper performance; lots of time spent playing with cable tension, pad positioning, and the little spring tension adjustment screws. It takes patience, but once they're dialed, they can be really good brakes.

However, my laziness has led me to use v-brakes whenever I can b/c they are simply superior brakes, with far easier installation.
surreal is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
everyman07
Classic & Vintage
5
01-21-18 03:29 PM
Sundog3478
Cyclocross and Gravelbiking (Recreational)
9
10-08-15 11:26 AM
Taintkick
Road Cycling
25
11-06-09 12:31 PM
Vanguard
Commuting
4
06-29-07 04:25 PM
Curiouswill
Classic & Vintage
12
04-10-07 05:57 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

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.