Adjusting Cantilever Brakes

[John Everett]

Last fall I purchased a (barely) used Fuji Touring Series. It has Shimano STX brakes activated by
RSX STI levers. I haven't been happy with the braking performance since I got the bike. They just
don't have the "feel" of the brakes on any of my other bike's (except perhaps the Mafac Racers on my
PX10) conventional or V-Brakes. While they are okay riding around the midwestern flatlands, I'd like
to improve things before this summer's trip to the Rockies.

I'd like to increase the mechanical advantage by shortening the transverse cable, but these brakes
come equipped with a little button a bit smaller than a US nickel in the middle of the cable. A
short cable that looks to be of fixed length goes to one brake arm, while the brake cable itself
passes through the little button and connects directly to the other arm.

Is this a case of Shimano deciding for me what the mechanical advantage should be, user be damned;
or can these things be adjusted? From a cursory inspection it's not obvious that they can.

Alternatively, does Shimano (or anyone else) market that short little cable in varying lengths?

jeverett3<AT>earthlink<DOT>net http://home.earthlink.net/~jeverett3

 

[Sheldon Brown]

John Everett wrote:
> Last fall I purchased a (barely) used Fuji Touring Series. It has Shimano STX brakes activated by
> RSX STI levers. I haven't been happy with the braking performance since I got the bike. They just
> don't have the "feel" of the brakes on any of my other bike's (except perhaps the Mafac Racers on
> my PX10) conventional or V-Brakes. While they are okay riding around the midwestern flatlands, I'd
> like to improve things before this summer's trip to the Rockies.
>
> I'd like to increase the mechanical advantage by shortening the transverse cable,

If you're unhappy with the "feel" it is not unlikely that you already have _too_much_ mechanical
advantage. The greater the mechanical advantage, the more "spongy" the brakes will feel, because
their greater leverage will squish the pads and deform the rubber.

This is all very counterintuitive, because automobile brakes have accustomed us to supposing that
sponginess indicates a malfunction.

> but these brakes come equipped with a little button a bit smaller than a US nickel in the middle
> of the cable. A short cable that looks to be of fixed length goes to one brake arm, while the
> brake cable itself passes through the little button and connects directly to the other arm.
>
> Is this a case of Shimano deciding for me what the mechanical advantage should be, user be damned;
> or can these things be adjusted? From a cursory inspection it's not obvious that they can.
>
> Alternatively, does Shimano (or anyone else) market that short little cable in varying lengths?

These are available in varying lengths, and actually the represent a considerable improvement over
the traditional yokes.

If you want more mechanical advantage without replacing any parts, I'd suggest extending the pads
farther inward toward the rim.

I have a couple of articles that address cantilever brakes in considerable detail, both from a
practical and theoretical point of view.

See: http://sheldonbrown.com/cantilever-adjustment.html

and: http://sheldonbrown.com/cantilever-geometry.html

Upgrading the brake shoes from the original Shimano ones will also likely make a considerable
improvement. I particularly recommend the Kool Stop Eagle 2 for this application. Get the "salmon"
color, it works much better than the others.

http://sheldonbrown.com/harris/brakeshoes.html

Sheldon "STOP!" Brown +---------------------------------------+
| I must study politics and war | that my sons may have the liberty | to study mathematics and
| philosophy | ...in order to give their children | the right to study painting, poetry | and
| music. --John Adams |
+---------------------------------------+ Harris Cyclery, West Newton, Massachusetts Phone
617-244-9772 FAX 617-244-1041 http://harriscyclery.com Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

 

[Chris B.]

On Wed, 07 May 2003 21:57:12 GMT, John Everett <[email protected]> wrote:

>Last fall I purchased a (barely) used Fuji Touring Series. It has Shimano STX brakes activated by
>RSX STI levers. I haven't been happy with the braking performance since I got the bike. They just
>don't have the "feel" of the brakes on any of my other bike's (except perhaps the Mafac Racers on
>my PX10) conventional or V-Brakes. While they are okay riding around the midwestern flatlands, I'd
>like to improve things before this summer's trip to the Rockies.
>
>I'd like to increase the mechanical advantage by shortening the transverse cable, but these brakes
>come equipped with a little button a bit smaller than a US nickel in the middle of the cable. A
>short cable that looks to be of fixed length goes to one brake arm, while the brake cable itself
>passes through the little button and connects directly to the other arm.

This is a "link wire".

>Is this a case of Shimano deciding for me what the mechanical advantage should be, user be damned;
>or can these things be adjusted? From a cursory inspection it's not obvious that they can.

I don't think so. I imagine the only advantage they have is the wheel will not lock up should the
cable break. I imagine that this is the reason they came about, sort of like lawyer lips.

>Alternatively, does Shimano (or anyone else) market that short little cable in varying lengths?

Scrap the link wire altogether and switch to a straddle cable setup, like cantilever equipped bikes
used to come with. I think Tektro still makes one and you should be able to find one without too
much difficulty. For safety, you need to have a mudguard, reflector bracket or even a long bolt to
catch the straddle cable should your primary cable break (on the front at least) so that it is not
driven into the tire.

Chris Bird

 

[A Muzi]

"John Everett" <[email protected]> wrote in message
news:[email protected]...
> Last fall I purchased a (barely) used Fuji Touring Series. It has Shimano STX brakes activated by
> RSX STI levers. I haven't been happy with the braking performance since I got the bike. They just
> don't have the "feel" of the brakes on any of my other bike's (except perhaps the Mafac Racers on
> my PX10) conventional or V-Brakes. While they are okay riding around the midwestern flatlands, I'd
> like to improve things before this summer's trip to the Rockies.
>
> I'd like to increase the mechanical advantage by shortening the transverse cable, but these brakes
> come equipped with a little button a bit smaller than a US nickel in the middle of the cable. A
> short cable that looks to be of fixed length goes to one brake arm, while the brake cable itself
> passes through the little button and connects directly to the other arm.
>
> Is this a case of Shimano deciding for me what the mechanical advantage should be, user be damned;
> or can these things be adjusted? From a cursory inspection it's not obvious that they can.
>
> Alternatively, does Shimano (or anyone else) market that short little cable in varying lengths?

You can make quite a bit of change by moving the shoes farther in from the arms. The angle of the
fixed-length "link wire" flattens appreciably.

And yes, you can get link wires in many various lengths ( Shimano and others) at any LBS which
services bicycles, but it isn't necessary to do what you ask.

--
Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971

 

[John Everett]

On Wed, 07 May 2003 23:15:54 GMT, Sheldon Brown <[email protected]> wrote:

>John Everett wrote:
>> Last fall I purchased a (barely) used Fuji Touring Series. It has Shimano STX brakes activated by
>> RSX STI levers. I haven't been happy with the braking performance since I got the bike. They just
>> don't have the "feel" of the brakes on any of my other bike's (except perhaps the Mafac Racers on
>> my PX10) conventional or V-Brakes. While they are okay riding around the midwestern flatlands,
>> I'd like to improve things before this summer's trip to the Rockies.
>>
>> I'd like to increase the mechanical advantage by shortening the transverse cable,
>
>If you're unhappy with the "feel" it is not unlikely that you already have _too_much_ mechanical
>advantage. The greater the mechanical advantage, the more "spongy" the brakes will feel, because
>their greater leverage will squish the pads and deform the rubber.
>
>This is all very counterintuitive, because automobile brakes have accustomed us to supposing that
>sponginess indicates a malfunction.

That's why the comparison to the Mafac Racers, the brakes on the Fuji feel hard as rocks with no
appreciable spongy feel that aids in brake modulation.

>> but these brakes come equipped with a little button a bit smaller than a US nickel in the middle
>> of the cable. A short cable that looks to be of fixed length goes to one brake arm, while the
>> brake cable itself passes through the little button and connects directly to the other arm.
>>
>> Is this a case of Shimano deciding for me what the mechanical advantage should be, user be
>> damned; or can these things be adjusted? From a cursory inspection it's not obvious that
>> they can.
>>
>> Alternatively, does Shimano (or anyone else) market that short little cable in varying lengths?
>
>These are available in varying lengths, and actually the represent a considerable improvement over
>the traditional yokes.
>
>If you want more mechanical advantage without replacing any parts, I'd suggest extending the pads
>farther inward toward the rim.

Good suggestion. I just looked and the previous owner (or his LBS) has the pads so far out they're
in contact with the arms.

>I have a couple of articles that address cantilever brakes in considerable detail, both from a
>practical and theoretical point of view.
>
>See: http://sheldonbrown.com/cantilever-adjustment.html
>
>and: http://sheldonbrown.com/cantilever-geometry.html

I actually read the above before the OP. I was looking for specific suggestions about adjusting the
"button" type transverse linkage.

>Upgrading the brake shoes from the original Shimano ones will also likely make a considerable
>improvement. I particularly recommend the Kool Stop Eagle 2 for this application. Get the "salmon"
>color, it works much better than the others.
>
>http://sheldonbrown.com/harris/brakeshoes.html

Bike's currently equipped with Shimano "M65/T for Aluminum" pads. Kool Stop Salmons would be my next
step if shortening the transverse cable doesn't provide enough benefit.

jeverett3<AT>earthlink<DOT>net http://home.earthlink.net/~jeverett3

 

[Mike S.]

"John Everett" <[email protected]> wrote in message
news:[email protected]...
> Last fall I purchased a (barely) used Fuji Touring Series. It has Shimano STX brakes activated by
> RSX STI levers. I haven't been happy with the braking performance since I got the bike. They just
> don't have the "feel" of the brakes on any of my other bike's (except perhaps the Mafac Racers on
> my PX10) conventional or V-Brakes. While they are okay riding around the midwestern flatlands, I'd
> like to improve things before this summer's trip to the Rockies.
>
> I'd like to increase the mechanical advantage by shortening the transverse cable, but these brakes
> come equipped with a little button a bit smaller than a US nickel in the middle of the cable. A
> short cable that looks to be of fixed length goes to one brake arm, while the brake cable itself
> passes through the little button and connects directly to the other arm.
>
> Is this a case of Shimano deciding for me what the mechanical advantage should be, user be damned;
> or can these things be adjusted? From a cursory inspection it's not obvious that they can.
>
> Alternatively, does Shimano (or anyone else) market that short little cable in varying lengths?

Talk about a lost art! Adjusting cantis is going the way of the dodo. Having said that, the little
straddle wires that Shimano sent with your cantis can be switched out for a pair of straddle wires,
but I'm not sure why you'd really need to.

The "B" cable goes on the front, the "A" on the rear.

There's a little line on the front of the "button" that tells you the "optimum" angle for the wire
going to the fixing bolt. Steeper than that and there's less power, lower than the line means more
power, but the brakes can get mushy or built up with mud.

Your best bet is to experiment with the equipment you have. Lower the angle of the straddle wire,
try it. Raise it, try it till you find a spot that you like best.

Mike

 

[John Everett]

On Thu, 8 May 2003 08:37:09 -0700, "Mike S." <mikeshaw2@coxDOTnet> wrote:

>Talk about a lost art! Adjusting cantis is going the way of the dodo.
>
>Your best bet is to experiment with the equipment you have. Lower the angle of the straddle wire,
>try it. Raise it, try it till you find a spot that you like best.

Lost art indeed! I just spent the better part of an hour fiddling around with the rear. As I said in
my response to Sheldon, the previous owner had the pads all the way into the arms, so a very low
mechanical advantage.

I tried moving the pads out almost to the end of their stems. This resulted in a high mechanical
advantage but introduced other problems. I had to run the pads so close to the rim (so the lever
wouldn't bottom out) that there wasn't enough travel to release the tranverse cable. No release, no
way to remove the wheel. :-(

I fooled around with pad extension until I finally found a position that gives pretty good feel,
doesn't bottom the levers, and still allows the cable to be unhooked from the brake arm.

I adjusted the rear because that was the set that had the worst setup. I think once I'm done with
the front (doesn't require such a major adjustment) I'll feel pretty confident taking the bike down
some of the passes in the Rockies.

jeverett3<AT>earthlink<DOT>net http://home.earthlink.net/~jeverett3