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

Canti brake mechanical advantage?

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.

Canti brake mechanical advantage?

Old 09-21-19, 06:31 PM
  #1  
Road Fan
Senior Member
Thread Starter
 
Road Fan's Avatar
 
Join Date: Apr 2005
Location: Ann Arbor, MI
Posts: 16,853

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

Mentioned: 49 Post(s)
Tagged: 0 Thread(s)
Quoted: 1851 Post(s)
Liked 654 Times in 498 Posts
Canti brake mechanical advantage?

Which Canti brake geometry has the best mechanical advantage when used with road levers, low profile or conventional geometry?
Road Fan is offline  
Old 09-21-19, 07:35 PM
  #2  
Miele Man
Senior Member
 
Join Date: Jun 2014
Location: Ontario, Canada
Posts: 4,655

Bikes: iele Latina, Miele Suprema, Miele Uno LS, Miele Miele Beta, MMTB, Bianchi Model Unknown, Fiori Venezia, Fiori Napoli, VeloSport Adamas AX

Mentioned: 16 Post(s)
Tagged: 0 Thread(s)
Quoted: 1324 Post(s)
Liked 927 Times in 640 Posts
Originally Posted by Road Fan
Which Canti brake geometry has the best mechanical advantage when used with road levers, low profile or conventional geometry?
I like my conventional geometry cantilever brakes with an old-school straddle cable and yoke where the yoke is similar or the same as the ones centerpull brakes use. With that system I can adjust the mechanical advantage to fit my needs/wants.


Cheers
Miele Man is offline  
Old 09-21-19, 08:29 PM
  #3  
cpach
Senior Member
 
Join Date: Oct 2009
Location: Mt Shasta, CA, USA
Posts: 2,140

Bikes: Too many. Giant Trance X 29, Surly Midnight Special get the most time.

Mentioned: 26 Post(s)
Tagged: 0 Thread(s)
Quoted: 530 Post(s)
Liked 311 Times in 235 Posts
The short profile cantis have a narrower range of acceptable straddle height and vary mechanic advantage more during their travel (unfortunately decreasing in MA as you get deeper into the lever), but have shorter arms and in most cases will feel more powerful. They also will interfere less with racks/fenders/panniers less if that's relevant, and also can be nice to have more tucked in on the rear for mounts/dismounts during cross racing. Medium (truly long is pretty much extinct) cantis are less sensitive to straddle height. Both work fine with road levers.

https://www.sheldonbrown.com/cantilever-geometry.html is a pretty good lay guide. I had an article that laid out the physics of cantis in insane/academic detail but can't find it right now.

For practical advise, try to get cantis that use threaded linear pull style pads--they're way easier to set up than older smooth post pads, even though both work totally fine in the end.

There's a lot of advise that creating a 90 degree straddle angle leads to highest MA, but really pretty much the lower the straddle wire, the higher MA in all real world scenarios.
cpach is offline  
Old 09-22-19, 01:07 AM
  #4  
rseeker
Senior Member
 
rseeker's Avatar
 
Join Date: May 2016
Location: Southeast US
Posts: 937
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 318 Post(s)
Liked 149 Times in 104 Posts
Originally Posted by cpach
short profile cantis
Could you say what that means (for a newbie canti owner)? Is that just how far out to the side the arms go?
rseeker is offline  
Old 09-22-19, 02:38 AM
  #5  
cpach
Senior Member
 
Join Date: Oct 2009
Location: Mt Shasta, CA, USA
Posts: 2,140

Bikes: Too many. Giant Trance X 29, Surly Midnight Special get the most time.

Mentioned: 26 Post(s)
Tagged: 0 Thread(s)
Quoted: 530 Post(s)
Liked 311 Times in 235 Posts
Originally Posted by rseeker
Could you say what that means (for a newbie canti owner)? Is that just how far out to the side the arms go?
Yeah, pretty much. Short cantis have arms that are nearly vertical at rest, whereas mediums have arms that are way farther out.

A pretty common combo is medium in front and short in the rear, for reasons of dismounting/rack/pannier clearance on the rear. This is what I run on my CX bike (Tektro CR720 in front, Oryx in rear) which I am happy (but not crazily so) with.
cpach is offline  
Likes For cpach:
Old 09-22-19, 03:55 AM
  #6  
hokiefyd 
Senior Member
 
hokiefyd's Avatar
 
Join Date: Feb 2017
Location: Northern Shenandoah Valley
Posts: 4,124

Bikes: More bikes than riders

Mentioned: 36 Post(s)
Tagged: 0 Thread(s)
Quoted: 1438 Post(s)
Liked 749 Times in 559 Posts
Originally Posted by cpach
For practical advise, try to get cantis that use threaded linear pull style pads--they're way easier to set up than older smooth post pads, even though both work totally fine in the end.
This is good advice. I have Tektro CR510s on my Trek 750, and use Avid 20R pads in them. This is working very well for me -- these liner pull pads are strong and quiet, and very easy to setup and adjust in these cantilever brakes.

Originally Posted by cpach
There's a lot of advise that creating a 90 degree straddle angle leads to highest MA, but really pretty much the lower the straddle wire, the higher MA in all real world scenarios.
This is generally true (lower straddle cable = higher mechanical advantage) for most low- and medium-profile cantilevers, because they need to be pulled in, towards each other, for best brake force. This isn't true for the traditional designs like the CR520/CR720, old MAFACs, etc. With these, because the cable attachment on the cantilever brake arm is so low (below the pivot, actually), they need to be pulled up to achieve the best brake force. With these, the longer straddle cables work better.
hokiefyd is offline  
Likes For hokiefyd:
Old 09-22-19, 08:32 AM
  #7  
63rickert
Senior Member
 
Join Date: Dec 2013
Posts: 2,068
Mentioned: 44 Post(s)
Tagged: 0 Thread(s)
Quoted: 1090 Post(s)
Liked 329 Times in 245 Posts
The answer to OP's question is less than clear and there is much disagreement. The two best cantis ever, IMO, would be Campagnolo Record O.R. (1992-1995) and the current production Rene Herse. Which have completely different geometry. The basic inexpensive and still available Shimano CX50 was used by many cyclocross pros right up until the sponsors just would not have it. That brake has little in common with the other two above. Paul Components sells cantis with widely differing geometries and all of them are more than good enough. I would suggest try the CX50 at the very modest price and see what you think. The different brakes are not all the same and user expectations and requirements are all over the place.
63rickert is offline  
Old 09-22-19, 02:34 PM
  #8  
cpach
Senior Member
 
Join Date: Oct 2009
Location: Mt Shasta, CA, USA
Posts: 2,140

Bikes: Too many. Giant Trance X 29, Surly Midnight Special get the most time.

Mentioned: 26 Post(s)
Tagged: 0 Thread(s)
Quoted: 530 Post(s)
Liked 311 Times in 235 Posts
Originally Posted by hokiefyd
This is good advice. I have Tektro CR510s on my Trek 750, and use Avid 20R pads in them. This is working very well for me -- these liner pull pads are strong and quiet, and very easy to setup and adjust in these cantilever brakes.



This is generally true (lower straddle cable = higher mechanical advantage) for most low- and medium-profile cantilevers, because they need to be pulled in, towards each other, for best brake force. This isn't true for the traditional designs like the CR520/CR720, old MAFACs, etc. With these, because the cable attachment on the cantilever brake arm is so low (below the pivot, actually), they need to be pulled up to achieve the best brake force. With these, the longer straddle cables work better.
I may have overstated at "all real world scenarios" because people are indeed rolling around on old Mafacs etc, but for literally everything in current production or in production in the last 20 years this has been true. Even a CR720 is really a medium profile because the arms actually are still above the pivot--at least they are as installed on my personal CX bike.
cpach is offline  
Old 09-23-19, 12:17 PM
  #9  
Clem von Jones
Senior Member
 
Join Date: Sep 2008
Posts: 660
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 151 Post(s)
Liked 23 Times in 16 Posts
The CR720s work really well with short-pull road style brifters and feel identical at the levers to road calipers. In general these wide profile cantilevers work much much better than medium or low profile cantis. I see the person above me called them "medium profile" and it's true there are other ones with with even a wider profile but the 720s are wide enough to work well. The only reason to not always use wide profile cantis which have so much more mechanical leverage is the unfortunate fact they stick out far, can interfere with panniers if you have racks, and worst of all they might hit your heels if you have large feet and ride a smaller frame size, or they might scratch your legs as you dismount. If you can run wide on both front and back though do it because wide cantis work and feel great. I would call the CX50 medium-profile cantis. Low profile cantis are hell on earth with short-pull brake levers, don't go there, there's isn't enough leverage and your hands will never be strong enough.

Last edited by Clem von Jones; 09-23-19 at 12:37 PM.
Clem von Jones is offline  
Old 09-25-19, 11:27 PM
  #10  
cpach
Senior Member
 
Join Date: Oct 2009
Location: Mt Shasta, CA, USA
Posts: 2,140

Bikes: Too many. Giant Trance X 29, Surly Midnight Special get the most time.

Mentioned: 26 Post(s)
Tagged: 0 Thread(s)
Quoted: 530 Post(s)
Liked 311 Times in 235 Posts
Originally Posted by Clem von Jones
The CR720s work really well with short-pull road style brifters and feel identical at the levers to road calipers. In general these wide profile cantilevers work much much better than medium or low profile cantis. I see the person above me called them "medium profile" and it's true there are other ones with with even a wider profile but the 720s are wide enough to work well. The only reason to not always use wide profile cantis which have so much more mechanical leverage is the unfortunate fact they stick out far, can interfere with panniers if you have racks, and worst of all they might hit your heels if you have large feet and ride a smaller frame size, or they might scratch your legs as you dismount. If you can run wide on both front and back though do it because wide cantis work and feel great. I would call the CX50 medium-profile cantis. Low profile cantis are hell on earth with short-pull brake levers, don't go there, there's isn't enough leverage and your hands will never be strong enough.
Read the Sheldon link and you'll see why I call them medium profile. It's a bit of a historical term, because truly wide cantilevers have not been produced in some time, for some sound mechanical reasons. Wider than medium work worse.

I've had the opposite experience with short cantis. The best setup I rode was probably some Shorty Ultimates. You do absolutely need to set the straddle low with short cantis--their MA curve varies much more wildly with straddle height. Short cantis have the disadvantage of a more regressive MA curve, but have the advantage of having shorter arms that will, all things being equal, be less flexible.
cpach 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 -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.