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I am looking around for an old mountain bike to ride this winter (and this summer when it is wet).

I was just browsing around and was curious what the difference was between

Direct pull brakes:

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And Center-pull Cantilevers:

enter image description here

Sheldon Brown has a good description of both kinds of brakes but he does not give pros and cons. Or suggest which are better.

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7 Answers 7

up vote 5 down vote accepted

The main reason that the V brake was invented is that it approximates a center-pull cantilever in terms of balanced force and leverage, while not requiring that the cable be anchored at some point above the wheel. This is important for front wheels on suspension forks, but not significant for most other uses.

Another slight advantage of the V brake is that it doesn't generally protrude out of the profile of the bike quite as much and is thus somewhat less likely to be damaged in off-road use.

Neither advantage is of any importance for a road bike without a suspension fork. However, there is the problem that the two require different levers (because the cable travel length is different) and the old cantilevered levers are getting hard to find, should you break one.

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You've missed out the main marketing point of direct pull. By having the bowden cable pull in the same direction as the direction of travel on the brake, more of your pull translates of braking power (some physics fluff about F being proportional to the normal (perpendicular) force). Centre pull loses about a third of the pull by pulling upwards as well (which is useless). –  Aron May 14 at 15:41
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@Aron - You must have missed the place in physics class where levers were explained. Arguments about perpendicular force, et al, are pure bull -- work = force x distance. Period. –  Daniel R Hicks May 14 at 22:03
    
I must have missed that class between Quantum Mechanics, Advanced Particle Physics and General Relativity. I always thought that E = F . x or E=Fd cos theta. The fact that the Bowden cable pulls at an angle to the two arms of the Y made me think that cos theta was no longer unity. Thank you for schooling me in basic Physics. –  Aron May 15 at 5:26
    
Besides, this has nothing to do with the work function on the brake pads, but the normal contact force of the on the brake pads and the coefficient of friction. –  Aron May 15 at 5:31
    
@Aron - You never heard of a "lever" -- force multiplier? –  Daniel R Hicks May 15 at 12:06

Direct-pull or "V" brakes are stronger, easier to set up and maintain, and are usually considered an improved technology. Well set-up cantis are not bad, however, and the pads do last a long time.

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5  
Agreed. One thing: While V-brakes are more powerful, they have very little modulation, so it takes a more skilled rider to control a stop well. But canti's aren't as powerful, and may not stop you in time at all. Most consider V-brakes to be the better choice. –  zenbike Jul 15 '11 at 3:56
    
I've seen some people run rear v-brakes on mountain bikes a hair off center to compensate for grabbiness. Obviously, the downside is that it wears on one pad more. –  krs1 Oct 26 '11 at 20:20
    
"Power" vs "grabby" is a design trade-off based on the geometry of the levers involved. V-brakes are mostly designed to have more "leverage" and thus you get more force on the pads for a given brake lever force. This makes the brake "grabbier" and with less modulation. Simply changing the brake levers slightly (the distance between pivot and cable attachment) would change this -- has nothing to do with the overall scheme. (I suspect that Shimano chose to make the brakes "grabbier" to be more "impressive", even though they are often too "grabby" for good bike control.) –  Daniel R Hicks May 15 at 12:12

...where to begin!

So much was wrong with cantilevers and linear-pull came along and made the cycling world a happier place.

This list will grow, but, as I remember, the following things were morally wrong with cantilevers:

the front cable often routed via the stem on a pulley hidden inside the stem. Over time this pulley would fray the cable and the cable would break on the front brake with no external signs of anything wrong.

Unless a reflector bracket or mudguard was in the way, the broken front brake cable would release the stirrup wire to then catch against the front wheel. This would cause an instant straight-over-the-handlebars disaster.

Even in peace-time the arrangement was not too good, the brake adjustment depended on stem height.

Some bikes did not use the stem to hold the front brake cable. Instead they used an extra bracket in the headset. When suspension came along a bracket had to be added to the forks to hold the cable.

The bolt at the end of the cable holding the yoke that connects to the straddle wire was also a bit of a problem. Typically these were setup crooked. In use the stirrup could get knocked to one side, compromising the brake balance.

As for the rear brake, the big problem on early models was how they stuck out to catch your heel. This was solved when Dia-Compe came along with the 986 to replace the 983. Shimano copied the hi-rise idea shortly thereafter.

Here is a 983:

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And here is the 986:

enter image description here

We are talking twenty+ years ago with this 'big change' to the cantilever. There were many, many iterations to get to the linear-pull brake you have today.

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Regarding the straddle cable catching on the wheel when the main cable breaks: modern cantis don't have this problem, because they don't use a straddle cable. See Sheldon Brown's in-depth discussion: sheldonbrown.com/canti-trad.html –  Mike Baranczak Jul 15 '11 at 16:05
    
@ Mike Baranczak I beg to differ with Sheldon Brown on that one - if the cable breaks above the link-wire in your stem then you are still heading for some airtime over the handlebars. You can demonstrate this for yourself if you have a headset-mounted cable stop with quick-release - the side arms still pull outwards and the cable plus link wire still drops onto the wheel. At the time I thought the innovation had more to do with ease of setup (one bolt instead of two) and better centering. –  ʍǝɥʇɐɯ Jul 15 '11 at 17:42
    
Yeah, the cable would drop down towards the tire, but there won't be any tension in the cable, since at that point, only one end of it is attached to something. You might get some drag on the tire (especially if it's knobby) but it can't be nearly as bad as the old design. –  Mike Baranczak Jul 15 '11 at 22:54

Difference on canti and v brake's can be affected by your use, which is implied but not explicit in some of the responses.

Canti pull ratio works with the pull ratio of road bikes--which is why they are used on cross bikes--not because of mud clearance since cross bikes use road brake/shifter levers.

You can use V-brakes with a road brake/shift lever but it requires the use of a travel agent to alter the cable pull from the cant ratio to the V brake ratio. These can be complicated to install, don't always work well, and can become fouled in the mud of cyclocross.

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I believe one pro of canti's are that they tend to have more mud clearance. I think that is one of the reasons that cyclocross bikes run them, at least until they started allowing discs.

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Mud clearance, for either canti's or V-brakes, is a function of brake boss placement and for design. Both are pretty equal in this category. –  zenbike Jul 15 '11 at 3:54

95 custom specialized hard rock with aftermarket front shock. Love the bike light great factory equipment. I run best of both worlds. Front center pull with canti brake hand lever and factory rear canti factory hand lever. Hand lever made no diff mostly just wanted same hand levers for looks however front brakes are spongy but grab and will lock up wheel of you know what your doing. Rear break hard as rock at handle easy to pull stops you fast but has a hard time holding wheel without movement. Which is fine by me cause I use 85 90% front brake to stop mostbof the time anyway. And I have never found a disc brake I like yet....center pulls are a bit harder to get adjusted to your liking but you just have to be smarter than the brake and you'll be fine! Also kinda dig not having cable running down the center of the goose neck to what I call the snatchblock. I ride 60 80 miles a week and its the perfect spot for my speedo and recording app I have on my phone. If you fly over the handlebars on your bike because of a failed piece of brake equipment it's your own fault you should inspect your equipment more often. Been riding for 20 some yrs and its never once been an issue.

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Note that the difference in cable pull between a center pull and cantis is minimal, whereas there is about 2x that pull for V-brakes. –  Daniel R Hicks 4 hours ago

V brakes transfer 100% of the pulling force into the rim face. Cantis only transfer around 40-60% and some is lost pulling on the boss.

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Utter bull. More force is lost in the V brake "noodle" than in the canti pivots, and leverage is leverage -- the manufacturer can adjust it however they please. –  Daniel R Hicks May 12 at 13:12

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