Kommisar89

I had always heard that cantis offer better stopping power but I've never been happy with those on my PT-3500. They have plenty of stopping power if you are in the drops where you can grab a handful of brake lever and squeeze hard but I typically ride it with my hands on the hoods and from there the stopping power is mediocre. There just isn't enough leverage. I'm using Shimano "aero" levers and the original Shimano canti brakes with some good pads. Modern dual-pivots will damned near throw you over the handlebars from the hood position but even a very firm squeeze on these just slows me down. It's not a fair comparison because I can't really operate the brakes on my Bottecchia or Peugeot from the hoods due to the older style levers but from the drops they have much better brake feel and stopping power with the Universal and MAFAC center-pulls. Any suggestions? Different levers? Different canti brakes? Adjustments to the hangers? I'm open to ideas.

You can see the setup here - those are not the pads that I'm using now but everything else is the same:

gt eunuch

What pads are you using now?

ColonelJLloyd 

Your brakes can be setup to stop better than dual pivot sidepulls with those levers. New Kool Stop or other good pads with proper toe in is key, but I think adjusting your cable yoke length will change the mechanical advantage to give you the braking you're looking for.

Looking closely at your brakes, I think you may be missing a concave washer directly behind the brake pad post.

jimmuller 

Shorten the straddle cable a little by repositioning it in the left-side clamp. This works on any canti where the outboard ends of the straddle cable are above the pivot points of the canti arms. You may have to lengthen the main cable a little, of course.

John E

Good advice around.

My experience w/ Shimano pads has been miserable -- you definitely want KoolStop salmons. The aero brake handles are already giving you a 10% leverage advantage over older designs. The shorter the straddle cable, the greater the leverage. You already have aluminum rims, so you are doing that part right. (I don't know about others here, but I find that black anodized aluminum rims reduce my braking power a bit, although steel rims are still by far the worst.)

wrk101

+1 To everything so far, and your pads are way too far away from the rims.

mparker326

Is the housing you are using modern lined housing? I've had a lot of brakes perform much better after I replaced the old unlined housing.

Kommisar89

Aztecs: https://www.bikepro.com/products/brak...tec_pads.shtml

Kommisar89

They aren't like that now - that pic was snapped several years ago right after I brought the bike home. It has fenders now so it would have been harder to see the brakes if I had taken a new picture.

miamijim

I'll go against the consensus and say to raise the cable carrier and get new brake pads. Those Shimano cantilevers are stout units.

CenturionIM

Kool Stop salmon pad continental

Kommisar89

Yes, I replaced the housing when I set it up. So the complete setup today is the original Shimano BR-AR50 canti brakes, Aztec pads adjusted close to the rims, Shimano "aero" levers, modern lined housing.

Kommisar89

Hmmm, where would that go? The current Aztec pads are molded onto the posts so that may not be relevant to those.

Kommisar89

Ok, here are the current pads:



Any reason to believe Koolstop Salmons would be an improvement?

old's'cool

I have a set of Shimano cantis that look like that, and they stop better than anything else in my fleet. AFAIK the pads are original, as I got the brakes off Ebay and used them as is. I once endo-ed the bike on which they're mounted, in a panic stop, from the hoods, with a heavy load in the rear panniers to boot.

wrk101

Myself, I would play with straddle cable height first. Its bought and paid for, no waiting on parts, and since you got opposing views on this, I would try it one direction first, then the other.

WNG

Sheldon Brown explained it well on how to set up Cantis for maximum stopping power. I'd go read his page on it.
Basically, with the pads contacting the rim...pivot point, straddle wire point and yoke point should form 90 degrees for most leverage.

I clamp the pads to the rim, then adjust the arms and straddle cable until I eyeball 90 degrees and mark and tighten everything up. Set up is quick and haven't had any trouble with canti brakes.

So, I'm with MiamiJim, the straddle cable looks like it needs to be longer.

Kommisar89

Ok, I tore them down, cleaned them up, put new Koolstop pads on since the Aztecs were pretty well worn anyway. Better but not spectacular. Then I shorted the straddle cable just to see since lengthening it isn't an option unless I get a new one. Better still. I can lock the rear wheel from the hoods if I squeeze really hard. I know it's subjective but I think it's better than the centerpulls on my other bikes now from the drops which is pretty good. OTOH, still doesn't seem anything like the Bianchi from the hoods. Put it this way, I've never thought I needed any more braking power on my other bikes but I'd still be tempted to take my hands off the hoods and get into the drops on these if I thought I might need to stop really short.

dddd

Braking may further improve as the remaining anodize wears off your rims as the pads also wear in to better conform to the rim.

I've been down the exact same trail as you've followed using these brakes, pads and anno'd rims, and did notice improvements from all of your mods. I shortened the straddle as far as tire clearance allowed, and this definitely also improved leverage.

Narrower rims will also improve leverage, but at some increase in pad-dive angle.
Moving the pad adjustments around will not much change the leverage, even as the arm angles can be altered this way.

Lastly, I finally changed the rims from 27" to 700c, and this definitely increased brake force leverage, but again at the expense of a steeper pad-dive angle. I eventually went to a wider 700c rim, which moderated the pad-dive angle, while retaining most of the 700c leverage improvement.
Been riding this Trek 720 since the mid-1980's.

Kommisar89

The rim on the front now is not the one in the picture. A friend of mine had a Shimano generator hub (similar to this: https://www.peterwhitecycles.com/Shimano3N70.asp) built up with a wide 29er MTB rim and he gave it to me along with a Lumotec IQ Cyo light so I set that up with a 700x37mm tire. The rim is well broken in but of course the new pads need some miles yet.

Ciufalon

It's my understanding that when the brake pad contacts the rim, the post should be at a 90° angle to the rim. Is that how you have it set up? I have cantis on more than half my bikes and they work great - even with non cool-stop pads. One set I have is the same as yours. And as for the missing concave washer, you have it on yours. It is the washer with the grooves in it you can see behind the post in the pictures.

Edit: to correct the error in the first sentence. See quote below.

Sixty Fiver

Those AT50 cantis are brilliant brakes and were used on early mountain bikes as well as touring bicycles because they do provide such good stopping power.

The aero levers were designed to work with low profile cantilevers while conventional cantis like the AT 50 were designed to use conventional drop levers and there are some differences in how they apply force and this requires some fine tuning to get the most out of the brakes.

A simple rule that usually seems to work well is to set the yoke / straddle at a point where the yoke is sitting just above the fender mount on the fork... you can use a screwdriver to check the position and this would mean lowering the straddle to increase the leverage.

The pads should be closer than they are but not as close as you would set them on V brakes, this causes the pads to strike the rim too early and you want to be able to close your hand around the lever so you have the best physical leverage... maximum braking should be happening when the lever is approaching half it's travel and the action should feel light.

Sometimes you just have to play with things to find out how the lever and brakes interact... newer low profile cantis and road levers tend to create a state of too much mechanical advantage so raising the yoke addresses this while traditional cantis and modern aero levers tend to need a little more.

I use aero levers and low profile cantis on my touring bike and commuter, the stock Shimano straddle was replaced with a yoke and wire so I could reduce the straddle angle and optimize the braking.

Using better pads is always the first place to start.

jimmuller 

This is true but not for the reason many people think. The angle of the post per se has nothing to do with it, since the direction of movement and therefore the direction of force is determined by the relative position of the rim/pad contact w.r.t. the pivot. It would be whatever it would be if the pad hits the rim correctly.

The reason the post angle matters is because it determines how the pad contacts the rim. The critical property is to have the pad hit the rim squarely so as to maximize the contact surface. Of course once you've used up some of the pad it will conform to the rim anyway.

jimmuller 

Kommisar, you (and everyone else) should check out this thread:

https://www.bikeforums.net/showthread...p=15470722#top

I've 'splained it once. With pictures and everything. Well, maybe not everything. There's not enough room for everything.

Sixty Fiver

Any explanation on cantilever set up has to include the brake compatibility.

When Shimano introduced low profile cantilevers they also introduced compatible levers that do not work as well with conventional cantis... a good comparison is how you need specific levers for cantis and v-brakes. Shimano also introduced the fixed straddle wire which works well when you are matching parts but can cause issues when you swap levers, the conventional straddle and adjustable cable is a superior system for those who understand how cantilever brakes work and allows for fine tuning and adjustment.

Conventional cantilever brakes all but disappeared because Shimano had such market dominance.

I don't have any PhD's... am just a lowly wrench who has been setting up and using cantis from every era they have been produced starting from the original Mafacs on my Peugeot. The best cantilever brakes I have ever used are the first generation XTR that are mated to their matching sti levers... the stopping power is unbelievable and the action is beautiful, I could see these being used on a loaded touring bike or tandem.

A lot of mechanics I know despise cantilever brakes and will tell people they need to "upgrade" to v-brakes... this is only because they don't know how to set them up properly.