# Paul Racer vs. Paul Canti Brakes



## Kraige (Mar 29, 2005)

I am in the (slow) process of building up a road bike that will accomodate long reach brakes so that I can run larger tires and fenders. I can use Shimano or Tektro long reach calipers. I would use this mainly for road riding, but also for some fire roads and light touring. 

Recently I saw someone with a Paul Racer setup on a light touring bike and it looked great and he said they performed well. After reading what I could find about Paul Racer brakes it got me to thinking - what would be the main differences between running Racers and Running a neo-retro/touring canti set up (besides the ability to use a center mount with the racer brakes)? 

Mud clearance is not an issue and it seems that this would be the main advantage of the cantis. Can someone comment about the pros and cons of these different setups for the bike I'm describing - racers, cantis, and long reach calipers. Since I will be ordering the frame from either IF or Waterford, the braze-on vs. center pull aspect is not such a big deal - I'd be able to choose. 

I'm curious to get opinions as I collect parts for this bike. Thanks.


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## Mark McM (Jun 18, 2005)

Centerpull brakes are antiquated technology. They provide no advantage over other types of brakes, and some disadvantages. The cantilever brakes will have more mud/tire/fender clearance, and have more leverage.


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## PeanutButterBreath (Dec 4, 2005)

Mark McM said:


> Centerpull brakes are antiquated technology.


Right. Not like canti brakes.  Bicycles are antiquated technology.



Mark McM said:


> They provide no advantage over other types of brakes, and some disadvantages. The cantilever brakes will have more mud/tire/fender clearance, and have more leverage.


I haven't used the Paul centerpulls (have you?). I have used the Neo Retros extensively, and they require more skill to set up than centerpulls. They have more mud clearance but less leg clearance (I've got ripped knee warmers to prove it).

Since this is a road bike and not a cyclocross bike, I think it is fair to question whether the better power and mud clearance of the Neo Retros should trump the lower profile and cool factor of the Racers (they are not often seen, if nothing else).

Paul also makes the Touring canti which has a lower profile than the Neo Retro.


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## ispoke (Feb 28, 2005)

*Huh?*



Mark McM said:


> Centerpull brakes are antiquated technology. They provide no advantage over other types of brakes, and some disadvantages. The cantilever brakes will have more mud/tire/fender clearance, and have more leverage.


Come on Mark. Usually I enjoy your comments but today I disagree.

While I've not yet rode the Paul Racers, I spec'd a custom frame around them after reading reviews and comments about 'em in Bicycle Quarterly as well as some online forums. The centerpull is acknowledged to have superior modulation as well as overall power (as long as they're mounted on dedicated posts). And sure I wanted some cool bling factor. You betcha!

Take a look at modern sidepull calipers. Why did they evolve from the center-pivot and adopt "dual pivot" design? Because it's a closer approximation to a centerpull brake geometry like the Racer. Clearly Shimano and Campy see the wisdom of a better design, even though it made their calipers a tad heavier than the "old" center-pivots.

Most centerpulls have clearance for 45mm fenders and the only variable is reach. I compiled user feedback indicating that the shortest reach Mafac may only fit 32mm tires (with 45mm fenders). The Paul Racer meets or exceeds that spec (going off memory here). Anyone who wants some more info can PM me and I'll email them the comments I received from users.

I'd be surprised if the Touring Canti was any different than the typical Tektro or Shimano low profile cantilever. They're all aiming for the same "don't rip my knee warmers" geometry and the performance compromises that come with it...


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## MB1 (Jan 27, 2004)

I've used all three Paul brakes we are talking about here. 

In function I would say they are are all first rate. They can have great modulation and can easily lock up a wheel if adjusted correctly.

My favorite is the "Racer" for the ease and range of adjustment but mostly for the looks.

My least favorite (I got rid of them) are the Neo-Retro, I didn't care for the way they stuck out so far. I was always banging into the rear arms OTOH they were just as easy to setup as all Paul brakes are.

Waterford made my frame that has the Racer brakes. I had Paul send the brakes directly to Waterford to make sure the placement of the bosses was done correctly. After a couple years of use (10,000-15,000 miles) I still love everything about them.

BTW I use the Moon Units too but other than looks I don't think they are anything special....

BTW2 IME you can set up any of the Paul brakes way too strong and have all sorts of grabbing and vibration problems. A light setup is the way to go.


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## ispoke (Feb 28, 2005)

Here's a discussion of centerpulls for those interested in reading more:

http://velo-orange.blogspot.com/2006/06/centerpulls-are-swell.html


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## Mark McM (Jun 18, 2005)

*Reasons why centerpull brakes are antiquated*



ispoke said:


> The centerpull is acknowledged to have superior modulation as well as overall power (as long as they're mounted on dedicated posts).


The term "modulation" seems to be over-used for brakes. Everybody claims their own favorite design has better "modulation".

When you say "overall power" I assume you are refering to leverage ratio (brake force on the wheel relative to hand force on the lever). Dual pivot brakes typically have a leverage ratio of about 1.6:1. Sidepull brakes have a leverage of about 1:1. Centerpull brakes typically have a leverage of just under 1:1. In terms of "overall power", centerpull brakes are near the bottom, only better than traditional high-profile cantilevers.




ispoke said:


> Take a look at modern sidepull calipers. Why did they evolve from the center-pivot and adopt "dual pivot" design? Because it's a closer approximation to a centerpull brake geometry like the Racer.


That is incorrect. Dual pivot brakes operate with a completely different mechanism than centerpull brakes. Dual pivot brake have a mechanical linkage between the caliper arms which has two affects - in increase the resultant leverage ratio, and makes the caliper inherently self-centering (the self-centering linkage is why most dual pivots only require a single return spring on one caliper arm - the second arm is retracted its linkage with the first arm).

The self-centering mechanism is the real reason for the dual pivot design: The higher the leverage ratio of the brakes, the closer the pads must be set to the rim. However, the calipers on single pivot and centerpull brakes don't always retract equally, due to friction of the independent pivots and springs. So if the pads are set too close to the rim, they may not retract far enough to keep from rubbing. Enter the dual pivot brake, with its automatic self-centering feature - with this design, the pads can be set close to the rim, allowing a high leverage ratio, but both calipers are still guaranteed to retract correctly from the rim.



ispoke said:


> Most centerpulls have clearance for 45mm fenders and the only variable is reach. I compiled user feedback indicating that the shortest reach Mafac may only fit 32mm tires (with 45mm fenders). The Paul Racer meets or exceeds that spec (going off memory here).


A cantilever brake has far more clearance than a centerpull brake, and yet has an equal or greater leverage ratio - so the cantilevers allow bigger tires, wider fenders _and_ more braking power.

Another disadvantage to centerpull brakes is that the pads take a non-liner path to the rim - they arc upward as they approach the rim. The result is that as the pad wears, it can actually start rubbing the tire, damaging the casing.

The reason why centerpull brakes are antiquated is because there are other designs which get the job done better in nearly any circumstance.

Compared to a dual pivot sidepull brake, a centerpull brake has lower leverage ratio (less power), poorer self-centering, and a poorer pad travel arc.

Compared to a cantilever brake, a centerpull brake has less tire/fender clearance, and a lower leverage ratio (less power).

With better braking systems available, there really is no reason for centerpull brakes to still exist.


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## MB1 (Jan 27, 2004)

*I most respectfully disagree.*



Mark McM said:


> ...With better braking systems available, there really is no reason for centerpull brakes to still exist.


We have clearance Clarence.

_Roger Murdock: Flight 2-0-9'er, you are cleared for take-off. 
Captain Oveur: Roger! 
Roger Murdock: Huh? 
Tower voice: L.A. departure frequency, 123 point 9'er. 
Captain Oveur: Roger! 
Roger Murdock: Huh? 
Victor Basta: Request vector, over. 
Captain Oveur: What? 
Tower voice: Flight 2-0-9'er cleared for vector 324. 
Roger Murdock: *We have clearance, Clarence.* 
Captain Oveur: Roger, Roger. What's our vector, Victor? 
Tower voice: Tower's radio clearance, over! 
Captain Oveur: That's Clarence Oveur. Over. 
Tower voice: Over. 
Captain Oveur: Roger. 
Roger Murdock: Huh? 
Tower voice: Roger, over! 
Roger Murdock: What? 
Captain Oveur: Huh? 
Victor Basta: Who? _


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## ispoke (Feb 28, 2005)

*ok, but...*



Mark McM said:


> ...Compared to a dual pivot sidepull brake, a centerpull brake has lower leverage ratio (less power), poorer self-centering, and a poorer pad travel arc...


Thanks for the info Mark. Clearly you’ve done the math, and alas I have not. In fact it seems I’ve repeated too much hearsay (some published) which is perhaps all I relied on when I thought the Racer sounded like a good brake. If the term “modulation” seems overused, maybe it’s because it speaks to peoples’ priorities. After all, to a layman the term “low leverage ratio” may have negative connotations whereas “good modulation” better describes an improved condition they desire. Sorry, but that’s language.

So if I had researched this better, or perhaps read more of Sheldon, I might have repeated that either a dual pivot caliper or a cantilever can be set up with high leverage. Whereas either a single pivot caliper or apparently a Racer-style centerpull are low leverage. But doesn’t the distance from pivot to brake shoe affect the leverage? So we couldn’t fairly compare a “short” caliper set at 45mm reach with a Racer set at 60mm (or more). At least we couldn’t compare them if we assumed that either would be used for the same bike requiring fenders and fat tires. So I’m curious if your calcs show such a difference in leverage if you compare the Racer to an equivalent reach dual-pivot such as the Tektro R556?

There’s another design issue. It seems that most calipers, and some centerpulls (Dia Compe comes to mind), have thin arms that are more prone to bending (lower cross sectional moment of inertia) – thus arguably reducing leverage. While the Paul Racer has rather fat arms and apparently a “T” cross section at the pad (to resist bending moments, I presume) and so perhaps that at least somewhat equalizes the comparison when it comes to leverage (and modulation!)?

Sorry I don’t mean to be testy here, but you knew when you brushed off a brake with a cult following that it might raise an eyebrow. So help further enlighten those of us who are blinded by bling. My frame is many weeks away from fabrication and I am open to changing details if the reasons are persuasive enough…


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## ispoke (Feb 28, 2005)

Perhaps I'm beating a dead dog, but curiosity drives me to better define this comparison. Alex succinctly describes the limitations of long reach dual pivot brakes here:

http://blogs.phred.org/blogs/alex_wetmore/archive/2006/03.aspx

Also, the dual pivot design only has correct "pad travel" on one side. The other side still travels upward as it wears. So both the d.p. and centerpull have this limitation:

http://www.cyclingnews.com/tech/fix/?id=caliperbrakes

Cantilevers are favored by many, but if a cyclist is spec'ing a custom frame and isn't happy with cantis, then there are still options. It appears that Paul Racers have design benefits over other brakes, but since Paul doesn't detail those differences (from an engineering standpoint), perhaps all we're left with is the positive published reviews and the satisfied users such as MB1...


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## blackhat (Jan 2, 2003)

Mark McM said:


> Centerpull brakes are antiquated technology. They provide no advantage over other types of brakes, and some disadvantages. The cantilever brakes will have more mud/tire/fender clearance, and have more leverage.


I've got no real opinion regarding centerpulls, but Boonen's rocking them on his tt bike. gotta be good, right?<br>
<center><img src="https://www.letourguide.com/news/images/pro_boontt_07_5.jpg"><img src="https://www.letourguide.com/news/images/pro_boonen_tt_07.jpg">


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## MB1 (Jan 27, 2004)

*Boonen*



blackhat said:


> I've got no real opinion regarding centerpulls, but Boonen's rocking them on his tt bike.....


What a luddite.


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## PeanutButterBreath (Dec 4, 2005)

But that bike is out of the freakin stone ages! :nonod:

I think the real point is that there is more to choosing a brake than leverage ratio. It depends on the application.


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## Mark McM (Jun 18, 2005)

ispoke said:


> But doesn’t the distance from pivot to brake shoe affect the leverage? So we couldn’t fairly compare a “short” caliper set at 45mm reach with a Racer set at 60mm (or more). At least we couldn’t compare them if we assumed that either would be used for the same bike requiring fenders and fat tires. So I’m curious if your calcs show such a difference in leverage if you compare the Racer to an equivalent reach dual-pivot such as the Tektro R556?
> 
> There’s another design issue. It seems that most calipers, and some centerpulls (Dia Compe comes to mind), have thin arms that are more prone to bending (lower cross sectional moment of inertia) – thus arguably reducing leverage. While the Paul Racer has rather fat arms and apparently a “T” cross section at the pad (to resist bending moments, I presume) and so perhaps that at least somewhat equalizes the comparison when it comes to leverage (and modulation!)?


Clearly, there are many variables which can affect brake performance. You're right, the further the pads are set from the pivot, the lower the leverage ratio. However, since the dual pivot mechanism boosts the leverage ratio by about 60% (typically), a long reach dual pivot brake will still have a leverage ration higher than a centerpull brake. On the other hand, the design leverage ratio of a brake may not be fully realized, if some of the lever/cable travel is used up in flexing the caliper arms. If a long reach dual pivot brake has very flexible arms, the practical leverage ratio might end up being less than a centerpull brake with very rigid arms (but the arms on the dual pivot would have to be very flexible indeed). This is covered well by the Alex Wetmore article linked below. And, like the Wetmore article indicates, if you really need that much tire/fender clearance, you are probably better served by cantilever brakes.


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## Mark McM (Jun 18, 2005)

*pad travel arcs*



ispoke said:


> Also, the dual pivot design only has correct "pad travel" on one side. The other side still travels upward as it wears. So both the d.p. and centerpull have this limitation:


That's true, but most dual pivot brakes offset the pivot from center less than centerpulls, so the travel of the offset arm is still more linear than with centerpulls.

Cantilever brakes have this problem also, except that since the pivots are below the rim, the pad arc sweeps downward instead of upward. Some may recall the phenomenon of "pad dive" with cantilever brakes, where the pad would slide below the rim. This problem was addressed the "parallel-push" mechanism on Shimano's V-brakes and the arch mechanism of Avid's Arch Rival and Arch Supreme brakes. Although I haven't seen it actually done, there is no reason that these mechanisms can't be applied to cantilever brakes.


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## MB1 (Jan 27, 2004)

*Hard to get this kind of clearance with anything but a Racer or canti/V brakes.*

1) As you can see the limiting factor is the frame not the brake. ROOMY!

2) Notice that the pivot points are mounted directly to the frame. SOLID!

3) Notice how long the arms are from the pivot point to the cable. POWERFUL!

4) Notice the spring tension adjustment at the pivot point with a 15mm open end wrench and a 5mm allen. SIMPLE TO ADJUST!

5) Notice that I should CLEAN MY BIKE! :blush2:


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## blackhat (Jan 2, 2003)

MB1 said:


> What a luddite.


apropos of nothing in particular...Time Trial..the clock and the road are constant!


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## Mark McM (Jun 18, 2005)

*Look again*



MB1 said:


> 1) As you can see the limiting factor is the frame not the brake. ROOMY!


These dual pivot Tektros look just as roomy:












MB1 said:


> 2) Notice that the pivot points are mounted directly to the frame. SOLID!


Possibly. But now you also have to account for flex in the cable hanger.



MB1 said:


> 3) Notice how long the arms are from the pivot point to the cable. POWERFUL!


Except that with a centerpull brake, the straddle cable divides the total cable force in half, so each arm only sees half the cable force. This is unlike a side pull brake, in which each arm sees the entire cable force, or a (low profile) cantiliever, in which the straddle cable angle multiplies the cable force. On your Paul's brakes, the cable side of the arm is less than twice the length of the pad side of the arm, so the leverage of each arm is less than 2:1. Then when you consider that the straddle cuts the cable force in half, the total leverage of the brake is less than 1:1. In other words these brakes are powerful NOT!



MB14) Notice the spring tension adjustment at the pivot point with a 15mm open end wrench and a 5mm allen. SIMPLE TO ADJUST![/QUOTE said:


> So you still need two tools (and two hands to adjust the centering. The Tektros above are centered with a single screw. so the Tektros are EVEN SIMPLER TO ADJUST!


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## buck-50 (Sep 20, 2005)

Mark McM said:


> These dual pivot Tektros look just as roomy:


Roomy, yes. But, according to VBQ, flexy as hell.

The real advantage of the Tektro long reach brakes is the cost- like 80 bucks for a pair vs. $250 for the Pauls.


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## MB1 (Jan 27, 2004)

Mark McM said:


> .....So you still need two tools (and two hands to adjust the centering. The Tektros above are centered with a single screw. so the Tektros are EVEN SIMPLER TO ADJUST!


#1) Those babies that you like so much won't fit on my bike because of the brazed on brake bosses so your point is moot.

#2) Ain't you gonna clean my bike?!??!


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## PeanutButterBreath (Dec 4, 2005)

buck-50 said:


> The real advantage of the Tektro long reach brakes is the cost- like 80 bucks for a pair. . .


Cheap materials & sloppy tolerances.


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## buck-50 (Sep 20, 2005)

PeanutButterBreath said:


> Cheap materials & sloppy tolerances.


You DARE to say bad things about one of Grant's pet projects?!?  

Blasphemer!


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## PeanutButterBreath (Dec 4, 2005)

buck-50 said:


> You DARE to say bad things about one of Grant's pet projects?!?
> 
> Blasphemer!


Those MUSA shorts are goofy too.


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## ispoke (Feb 28, 2005)

*so you still only see half the story...*



Mark McM said:


> ...Except that with a centerpull brake, the straddle cable divides the total cable force in half, so each arm only sees half the cable force...


You know Mark, I read and reread your comments. And read some analysis by Jobst and Sheldon. If I understand Jobst correctly, typical dual-pivot calipers offer about 5.6:1 leverage whereas centerpulls about 4:1. His comments were a bit general but I assume both include the lever and caliper. I'm ignoring the cantilever since it seems that so many folks (including me) are ready for something else.

So apparently a "typical" (short reach) dual-pivot may be more powerful than a "typical" (old French) centerpull. But the long reach dual-pivot has so many opportunities for compromised strength due to design and manufacturing concerns. Whereas a high end centerpull like the Paul appears to have much better cross sections (moment of inertia to resist bending) and also tighter tolerances by using canti pivots.

It seems to me that you're willing to see only half the story, and ignore the positive (and published) reports of the Racer's performance. Or correct me if in fact you actually have used either the Tektro or Racer? I haven't, but I see that Jobsts' conventional wisdom was written (2 years ago) before today's long reach options allowed a fair apples-to-apples comparison.


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## Mark McM (Jun 18, 2005)

ispoke said:


> So apparently a "typical" (short reach) dual-pivot may be more powerful than a "typical" (old French) centerpull. But the long reach dual-pivot has so many opportunities for compromised strength due to design and manufacturing concerns. Whereas a high end centerpull like the Paul appears to have much better cross sections (moment of inertia to resist bending) and also tighter tolerances by using canti pivots.


What design and manufacturing concerns? There are fewer moving parts on a dual pivot brake, and due to its inherent self-centering, there are more tolerances in friction between the caliper arms. Also, you are comparing a $250 centerpull brake with a $75 dual pivot brake. If you made design and manufacturing improvements to the Tektro to exceed the rigidity of the Paul brake, it would still only cost half as much as the Paul brake.




ispoke said:


> It seems to me that you're willing to see only half the story, and ignore the positive (and published) reports of the Racer's performance. Or correct me if in fact you actually have used either the Tektro or Racer? I haven't, but I see that Jobsts' conventional wisdom was written (2 years ago) before today's long reach options allowed a fair apples-to-apples comparison.


I've learned to ignore the vast majority of bicycle product reviews, as there is far too much bias in most of them. Besides, before someone has gone out of the way to sink $250 into a set of boutique brakes, they have likely already already convinced themselves that they are superior, so why would you expect anything other than a glowing review? You'll find just as many positive reviews of Campagnolo's Delta brakes, even though they were probably even a worse brake overall.



ispoke said:


> I'm ignoring the cantilever since it seems that so many folks (including me) are ready for something else.


I think this cuts to the heart of your interest in the Paul brakes - that they are a unique and boutique product, not that they are inherently better. Interestingly, the Paul brakes started out as U-brakes - a design which was all the rage for a few years, and then quickly relegated to the trash bin of history because they were a poor concept, and there were better options readily available.


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## MB1 (Jan 27, 2004)

*Alas, wrong again.*



Mark McM said:


> ...U-brakes - a design which was all the rage for a few years, and then quickly relegated to the trash bin of history because they were a poor concept, .....


Still by far the most popular brake for freestyle bikes.


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## ispoke (Feb 28, 2005)

Mark McM said:


> There are fewer moving parts on a dual pivot brake...


There are? The Shimano assembly diagram appears to show three moving parts, and I assume Tektro is similar. What am I misunderstanding?



Mark McM said:


> I think this cuts to the heart of your interest in the Paul brakes - that they are a unique and boutique product, not that they are inherently better...


Perhaps we agree, in a way. There may be no inherent advantages between two "typical" products. But when you compare the $75 dual pivot to a centerpull that costs 3x as much, and the centerpull was made by a machinist to machining tolerances, and it uses large diameter canti studs instead of a smaller diameter center bolt, and it appears to improve upon the rigidity of stamped or forged calipers, there are many potential advantages which could overcome the modest difference in leverage in real world conditions.

I think your argument is fine when comparing two products at the same price point. And perhaps you have a grudge against anyone who wants to spend more on a boutique product. And clearly any review, whether published or scuttlebutt, can be drunkenly optimistic. Maybe I'm naive for thinking that an independent review that is only available on paid subscription could be any more reliable than internet chat.

One thing I learned while studying manufacturing engineering is that a good design can easily be compromised when put into mass production, and that some compromises are a given. And having done some machining and precision measuring long ago, I recognize the potential for better designs if well executed on a smaller (and costlier) scale.

I'm not saying the boutique brake is a slam-dunk decision, but I am saying that your certainty of its inferiority is misplaced.


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