Setting up low-profile cantis with drop bar levers.

[Captain Stupido]

It’s really hilly round here. Taking me a while to get used to it...

Went for a sweet ride this morning. The roads were new to me and very steep so I was being ultra cautious on the descents and taking it real slow. Also I wanted to enjoy the view.

I’ve found that the cantis on my Raleigh Royal seem to start to fade pretty quickly in continuous use. Red Ritchey pads. After a bit they start to make a grinding sound and lose effectiveness. On/off braking does seem to help but it’s not always practical.

Part of the issue is the overall setup, I need to tweak the position of the bars and levers so that I can brake comfortably in the drops (currently i’m constantly on the hoods and it’s hard to get a good pull on the levers). I also think the angle of the brakes/straddle length needs tweaking to get a bit more (or less?) mechanical advantage. Lever feel is perhaps a bit too firm, and compared to really well set-up brakes they lack power.

Just wondering if there’s any way to reduce this effect? Are different pads different in this respect? This bike seems particularly bad for it, wondering why...

 

[mdvineng]

Re: Brake fade with cantis

Cool stop pads worked for me (red) also experiment with lowering the height of the straddle wire to give you a better mechanical advantage, it'll mean making more frequent adjustments but that often to be a problem.

 

[Captain Stupido]

Re: Brake fade with cantis

Cool stop pads worked for me (red) also experiment with lowering the height of the straddle wire to give you a better mechanical advantage, it'll mean making more frequent adjustments but that often to be a problem.

Thanks. It’s got fixed length link wires on it at the moment. But as luck would have it the postie delivered these this morning... might have to put the other build on hold and get this braking sweet...

 

[Captain Stupido]

Re: Brake fade with cantis

Had a play. As originally set up the rear was better. Less of an on/off feel at the lever.

Rear:


So decided to tweak setup on the front.

Before:


After:


There’s an improvement in feel - it’s now closer to the rear. And messing about in the front garden I’m able to lock up the front wheel.

But on a test ride they’re still a bit meh. I’m wondering about just changing them out completely for something wider profile... maybe you guys can see room for improvement in my setup?

 

[foz]

There's a good section on sheldon about canti setup, and I think LGF knows his cantis too. if the arms are more "vertical" and straddle shorter and more horizontal (as in the first picture of the front above) then "power" will be greater but modulation will be worse. Wider arms and longer straddle will mean better modulation, but you need to get the correct setup so that you have maximum angles and greatest power before the levers hit the bars (sheldon explains this well). The rear might have better modulation due to the longer cable, especially if it's a full outer cable all the way from lever to canti, unless you've installed really good compressionless outers then there is always a bit of give

 

[Woz]

Re:

They both don't seem set-up right according to the Shimano M-System instructions.

When the pads hit the rim, the cable and engraved line on the cable straddle join should line up perfectly.

The A straddle length is the shortest which sounds about right.

Unless the distance between the bosses is very short, or your rims very narrow I can't see them not working as they should.

viewtopic.php?f=23&t=407551

 

[Captain Stupido]

Re:

There's a good section on sheldon about canti setup, and I think LGF knows his cantis too. if the arms are more "vertical" and straddle shorter and more horizontal (as in the first picture of the front above) then "power" will be greater but modulation will be worse. Wider arms and longer straddle will mean better modulation, but you need to get the correct setup so that you have maximum angles and greatest power before the levers hit the bars (sheldon explains this well).

Thanks. I’ve read the Sheldon article many times. And yep no doubt that LGF knows what he's doing. I think getting things right, at this level, is partly personal. But also canti setup is one area where opinions seem to differ massively - e.g. see the thread below where the consensus seems to be that Sheldon was wrong, at least on the maths side of things...

:shock:

https://forum.cyclinguk.org/viewtopic.php?f=5&t=57410

I'm not sure about the power vs modulation thing thing you're describing but maybe I misunderstand you - I'm not sure about modulation, but I think feel and power are down to the level of mechanical advantage in the system. More mechanical advantage = a spongier feel, but more actual power. The downside as you point out is that too much mechanical advantage means you might run out of brake lever travel. It's a bit like having a lower gear on the brakes. Also it gets complicated because mechanical advantage changes as the brakes move...

In the switch from the before to the after pic I was attempting to increase the mechanical advantage of the system by lowering the straddle wire and bringing the brake arms out wider. It has worked to some extent but I'm not 100% happy.

They both don't seem set-up right according to the Shimano M-System instructions.

When the pads hit the rim, the cable and engraved line on the cable straddle join should line up perfectly.

The A straddle length is the shortest which sounds about right.

Unless the distance between the bosses is very short, or your rims very narrow I can't see them not working as they should.

I agree with you, but IMO the "M-System" approach isn't going to work because it's a not an MTB, so the distance between the bosses IS pretty short, the rims ARE fairly narrow, and probably more importantly the brake levers are not as-per Shimano's specs.

Lovely bike in the link.

https://forum.cyclinguk.org/viewtopic.php?f=5&t=73781

It's a tricky one... my gut feeling is that while wide profile cantis will work with road levers without too much fiddling about, getting low profile ones to work really well is a bit of a PITA at best. Historically canti bosses were fitted to touring bikes in the days of Mafacs etc and the tradition continues... It depends what your expectations are I suppose but you ought to get much better stopping power than you do from standard road calipers otherwise what's the point?

 

[mdvineng]

I wouldn't of widened the canti's, just lower the straddle wire, nothing more apart from correct alignment of the pads.

 

[Woz]

Re:

Years ago, and it may still be on the web, Keith Bontrager did an excellent artical on canti setup.

 

[hamster]

One of the problems that's hard to overcome is that low-profile cantis need a bit more cable pull than wide cantis. Shiamno actually changed their MTB levers to match this extra pull. With conventional road levers you encounter problems with setting the whole lot up again as pads wear.

Dia-Compe did a special lever which pulls a bit extra, the 287 (not the 287V which is for V-brakes).

I've a pair you are welcome to for £10 posted. Otherwise, it's easier to get some wide profile cantis.