Caliper road brakes and direct pull cantilever levers

Earthstick wrote:
> I understand that direct pull cantilever, V brakes, have more
> mechanical advantage than other brakes and the levers are made to have
> less advantage so that the braking force is in a useful range. If I
> were to mount road caliper brakes which have less mechanical advantage
> which levers would I use?
>
> This is for a flat bar commuting/city bike so road levers are not an
> option but the V-brake levers will lessen the braking ability. The
> reason for the query is that most forks do not have the bosses for
> V-brakes to mount to so v-brakes limit the choice of forks.
>

Brake levers that are made for cantilevers. E.g.
http://www.lickbike.com/productpage.aspx?PART_NUM_SUB='1354-00'

Robin Hubert

On 29 Jan 2006 12:46:13 -0800, "Earthstick"
<[email protected]> wrote:

>I understand that direct pull cantilever, V brakes, have more
>mechanical advantage than other brakes and the levers are made to have
>less advantage so that the braking force is in a useful range. If I
>were to mount road caliper brakes which have less mechanical advantage
>which levers would I use?
>
>This is for a flat bar commuting/city bike so road levers are not an
>option but the V-brake levers will lessen the braking ability. The
>reason for the query is that most forks do not have the bosses for
>V-brakes to mount to so v-brakes limit the choice of forks.

Dual Pivot road brakes have excellent mechanical advantage and are
equal to or better than "V" brakes. Dual pivot brakes are available in
both short reach and standard reach. Cantilever brakes such as Avid
Shorty work as well if not better than "V" brakes. Ca,py makes road
levers for flat bars. Shimano probably does too.

You can get fatter tires between V and Cantilever brakes than Dual
Pivots.

Earthstick wrote:
> I understand that direct pull cantilever, V brakes, have more
> mechanical advantage than other brakes and the levers are made to have
> less advantage so that the braking force is in a useful range. If I
> were to mount road caliper brakes which have less mechanical advantage
> which levers would I use?
>

You need to use "standard-pull" brake levers, as opposed to "V-brake"
levers. These are available anywhere, since they were the standard
before V-brakes became available in 1996.

Here's a couple variations:
http://sheldonbrown.com/harris/brake-levers-up.html
http://www.biketoolsetc.com/index.cgi?&c=Components&tc=MTB-Levers-Cantilever

Jeff

Ok, thanks for informing me

Could I use the Avid Speed Dials that I use now?

Earthstick wrote:
> Could I use the Avid Speed Dials that I use now?

I've never tried it, but I'd say yes. Set them to the maximum
leverage/minimum travel setting, then adjust from there.

Jeff

Paul Kopit wrote:
>
> Dual Pivot road brakes have excellent mechanical advantage and are
> equal to or better than "V" brakes.

Straight up hogwash. They might have similar initial lever response in
some setups, but dual-pivot sidepulls can't match the power of any
half-decent stud-mounted brake. You must have limited your experience
to some exceedingly gimpy V-brakes.

Chalo

JeffWills wrote:
> Earthstick wrote:
>> Could I use the Avid Speed Dials that I use now?
>
> I've never tried it, but I'd say yes. Set them to the maximum
> leverage/minimum travel setting, then adjust from there.

Some official sources say that you can't use V-brake Avid SDs with cantis,
but I tend to agree that it'll work, although one might need to squeeze
extra-hard.
--
Phil, Squid-in-Training

"Chalo" <[email protected]> wrote:

>Paul Kopit wrote:
>>
>> Dual Pivot road brakes have excellent mechanical advantage and are
>> equal to or better than "V" brakes.
>
>Straight up hogwash. They might have similar initial lever response in
>some setups, but dual-pivot sidepulls can't match the power of any
>half-decent stud-mounted brake. You must have limited your experience
>to some exceedingly gimpy V-brakes.

FWIW, I ran a number of different cantis on my old Santana tandem, and
designed my new tandem around sidepulls. No comparison - the braking
is much, much better with sidepulls (especially the rear). And a
twofer is the ultimate brake test (even compared to half-bikes with
humongous riders).

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti frame

On Mon, 30 Jan 2006 16:22:56 -0800, Chalo wrote:

> Paul Kopit wrote:
>>
>> Dual Pivot road brakes have excellent mechanical advantage and are
>> equal to or better than "V" brakes.
>
> Straight up hogwash. They might have similar initial lever response in
> some setups, but dual-pivot sidepulls can't match the power of any
> half-decent stud-mounted brake. You must have limited your experience
> to some exceedingly gimpy V-brakes.

I think the OP was referring to the pad-motion for a given cable pull as
the idea of "mechanical advantage", not maximum force.

But I disagree with you here. You have to counter the amount of force you
can apply with the angle at which it is applied. V-brakes or canti's
apply their braking force at a 45-degree angle to the rim, so lose a fair
fraction of that force pushing the pad down, not in.

Since the overall mechanical advantage (lever + caliper) has to be about
the same for any brake, to get from reasonable separation to max pressure
without bottoming out the lever, the available pressure would be about the
same for both kinds. V brakes have both the angle problem (reducing the
max force by almost 30%), and the extra flex of the fork blades, studs,
and brake arms, so that a caliper should be measurably stronger -- unless
they are set up with very tight pad clearance, which presents its own
problems.

the main disadvantage of calipers is that they aren't big enough for fat
tires.

--

David L. Johnson

__o | When you are up to your ass in alligators, it's hard to remember
_`\(,_ | that your initial objective was to drain the swamp. -- LBJ
(_)/ (_) |

David L. Johnson wrote:
>
> V brakes have both the angle problem (reducing the
> max force by almost 30%), and the extra flex of the fork blades, studs,
> and brake arms, so that a caliper should be measurably stronger -- unless
> they are set up with very tight pad clearance, which presents its own
> problems.
>
> the main disadvantage of calipers is that they aren't big enough for fat
> tires.

The main disadvantage of caliper brakes is the fact that they are
dangled off of a single 6mm fastener with very short bushing surfaces
and 1-1/2 to 3-1/2 inches of lever arm from pivot to pad. Compare
cantilever brakes with two cylindrical studs of 8mm diameter and
something like 16mm of bushing length each, and only 1" from pivot to
pad.

I have a Shimano dual pivot caliper brake on one of my bikes, and I set
the pads to contact the rim with at least 2mm clearance to the rim
edge. When I apply the brake strongly, the caliper flexes enough to
deflect the tips of the brake pads more than 4mm into the tire
sidewall. I can hear them scream against the tire's molded serrations
and I can see the evidence of them having made contact. I have had
this verified visually by one of my friends riding alongside.

At the same time they do that, they don't exert nearly as much braking
power as the completely ordinary and somewhat worn-out pair of
low-profile cantilevers on the back of the same bike-- with the same
pads.

Most people don't distinguish between the maximum power of different
brakes because they simply can't use that much braking power before
they skid in the rear or tip up with the front. Since I can apply
about twice as much braking force as a typical rider before these
things happen, I find it easy to discern the difference between brakes
when it comes to their maximum power. Sidepulls just don't deliver the
goods like U-brakes, cantilevers, linear-pulls, and rollercams can.

Chalo

Mark Hickey wrote:
>
> FWIW, I ran a number of different cantis on my old Santana tandem, and
> designed my new tandem around sidepulls. No comparison - the braking
> is much, much better with sidepulls (especially the rear).

That must be why sidepulls are the hands-down choice of tandemists for
as long as anybody can remember. (Not.)

Every time I ride, I get to observe the comparative merits of different
brakes. With some 15 bikes to choose from that have lever-actuated
brakes of all sorts, I get to try a pretty good cross-section of what's
available.

In my observation, dual-pivot calipers are noticeably more powerful
than drum brakes. Flimsy cantilever brakes in turn are more powerful
than calipers, and disc brakes and U-brakes are stronger yet. Good
strong linear-pulls and self-energizing cantilevers are the most potent
brakes of all, when they are equipped with booster arches to limit
flex. Linking the top of the booster arch to the fork crown or
suspension fork slider bridge makes a noticeable difference too.

I have noticed that the initial lever response of a brake is not
necessarily a good indication of its maximum power. Drum brakes have
better maximum power than BMX calipers, although their initial response
often isn't as good. Likewise discs have fantastic initial bite-- much
better than that of U-brakes-- while U-brakes can offer maximum power
equal to or better than that of most discs.

It is in their initial response that dual-pivots perform well, before
braking forces flex them out of alignment. That makes them a
reasonable choice for short-wheelbase bikes (easily tipped up) that are
often ridden without a strong grip on the levers (hands on the hoods)--
which unsurprisingly is how they are used.

Chalo Colina

In article
<[email protected]>,
"Chalo" <[email protected]> wrote:

> David L. Johnson wrote:
> >
> > V brakes have both the angle problem (reducing the
> > max force by almost 30%), and the extra flex of the fork blades, studs,
> > and brake arms, so that a caliper should be measurably stronger -- unless
> > they are set up with very tight pad clearance, which presents its own
> > problems.
> >
> > the main disadvantage of calipers is that they aren't big enough for fat
> > tires.
>
> The main disadvantage of caliper brakes is the fact that they are
> dangled off of a single 6mm fastener with very short bushing surfaces
> and 1-1/2 to 3-1/2 inches of lever arm from pivot to pad. Compare
> cantilever brakes with two cylindrical studs of 8mm diameter and
> something like 16mm of bushing length each, and only 1" from pivot to
> pad.
>
> I have a Shimano dual pivot caliper brake on one of my bikes, and I set
> the pads to contact the rim with at least 2mm clearance to the rim
> edge. When I apply the brake strongly, the caliper flexes enough to
> deflect the tips of the brake pads more than 4mm into the tire
> sidewall. I can hear them scream against the tire's molded serrations
> and I can see the evidence of them having made contact. I have had
> this verified visually by one of my friends riding alongside.
>
> At the same time they do that, they don't exert nearly as much braking
> power as the completely ordinary and somewhat worn-out pair of
> low-profile cantilevers on the back of the same bike-- with the same
> pads.
>
> Most people don't distinguish between the maximum power of different
> brakes because they simply can't use that much braking power before
> they skid in the rear or tip up with the front. Since I can apply
> about twice as much braking force as a typical rider before these
> things happen, I find it easy to discern the difference between brakes
> when it comes to their maximum power. Sidepulls just don't deliver the
> goods like U-brakes, cantilevers, linear-pulls, and rollercams can.

Thanks for this.

Most brakes are perfectly adequate for non-heavy riders. I
can haul on my single pivot 60 mm side pull brakes and
apply more braking power than I and my bike can use while
maintaining stability. I find this not by accident or
opinion. I find this to be so by practicing; by riding in
a situation where I need little attention for anything but
exploring the limits of my brake system and braking
technique.

--
Michael Press

"Chalo" <[email protected]> wrote:

>Mark Hickey wrote:
>>
>> FWIW, I ran a number of different cantis on my old Santana tandem, and
>> designed my new tandem around sidepulls. No comparison - the braking
>> is much, much better with sidepulls (especially the rear).
>
>That must be why sidepulls are the hands-down choice of tandemists for
>as long as anybody can remember. (Not.)

But they are becoming more and more popular (note that many of the
high-performance tandem forks are set up for caliper brakes. I agree
that the old single-pivots (with their lower mechanical advantage)
would have been marginal.

>Every time I ride, I get to observe the comparative merits of different
>brakes. With some 15 bikes to choose from that have lever-actuated
>brakes of all sorts, I get to try a pretty good cross-section of what's
>available.
>
>In my observation, dual-pivot calipers are noticeably more powerful
>than drum brakes. Flimsy cantilever brakes in turn are more powerful
>than calipers, and disc brakes and U-brakes are stronger yet.

That's just not my observation - particularly not with cantis mated to
road brake levers. I tried the long-pull DiaCompe levers as well - it
helped, but the braking was still mediocre. Solid straddles helped
the cantis more, but I eneded up going with an odd hydraulic canti on
the front of my old tandem.

With the new one, I slapped on a pair of Campy calipers (mated to
Campy levers of course), and the stopping power is at least as good as
my old tandem, and is a heck of a lot easier to keep in adjustment.

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti frame

Michael Press wrote:
> In article
> <[email protected]>,
> "Chalo" <[email protected]> wrote:

>>Most people don't distinguish between the maximum power of different
>>brakes because they simply can't use that much braking power before
>>they skid in the rear or tip up with the front. Since I can apply
>>about twice as much braking force as a typical rider before these
>>things happen, I find it easy to discern the difference between brakes
>>when it comes to their maximum power. Sidepulls just don't deliver the
>>goods like U-brakes, cantilevers, linear-pulls, and rollercams can.
>
>
> Thanks for this.
>
> Most brakes are perfectly adequate for non-heavy riders. I
> can haul on my single pivot 60 mm side pull brakes and
> apply more braking power than I and my bike can use while
> maintaining stability. I find this not by accident or
> opinion. I find this to be so by practicing; by riding in
> a situation where I need little attention for anything but
> exploring the limits of my brake system and braking
> technique.
>

I've got to agree with Chalo's comments, they pretty much agree with my
(more limited) experience.

Re: single pivot side pulls, I have these on my fixed gear and find that
they can lift a rear wheel OK, which means that they're strong enough
usually, but in wet weather they seem to take longer to "squeegee" the
rims than more powerful canti's on another bike (I swap the same front
wheel). Net effect is dry stops adequate, wet stops, not.

On 1 Feb 2006 20:53:39 -0800, "Chalo" <[email protected]> wrote:

>
> It is in their initial response that dual-pivots perform well, before
>braking forces flex them out of alignment. That makes them a
>reasonable choice for short-wheelbase bikes (easily tipped up) that are
>often ridden without a strong grip on the levers (hands on the hoods)--
>which unsurprisingly is how they are used.
>
>Chalo Colina


Not sure, but this may be the place[thread] to ask my brake question.

How do the different road calipers compare, in pull strength needed to
lock up the wheel?

Let me explain, on my 2002 LeMond, I still have the stock generic
calipers, described as "aluminum dual pivot", it may be made by
Tektro[?], no markings are on it. I have Kool Stop salmon pads on it.

The rear with my stronger, bigger, right hand, I can lock up, from the
hoods. The front, with my smaller weaker, fingers missing, left hand,
I can't lock up the front. I would like to more effectively use the
front brake, no I don't want to switch the front to the right lever.
The brake levers are Dura-Ace 7703 STI.

Would a DA, Ultegra, or a Campy do more at the caliper, with a light
pull, compared to my current caliper?
If so, which model? l Are the new shimano 7800, 6600 series better
than the 7700, 6500, or is the difference cosmetic? How do the Campy
calipers compare? Any other brands, that I should consider.
Price, and/or availibility, will determine whether I replace just the
front, or both.

Any info will be appreciated.
Thank you,
Jeff

On Wed, 01 Feb 2006 20:21:55 -0800, Chalo wrote:

> David L. Johnson wrote:
>>
>> V brakes have both the angle problem (reducing the
>> max force by almost 30%), and the extra flex of the fork blades, studs,
>> and brake arms, so that a caliper should be measurably stronger -- unless
>> they are set up with very tight pad clearance, which presents its own
>> problems.
>>
>> the main disadvantage of calipers is that they aren't big enough for fat
>> tires.
>
> The main disadvantage of caliper brakes is the fact that they are
> dangled off of a single 6mm fastener with very short bushing surfaces
> and 1-1/2 to 3-1/2 inches of lever arm from pivot to pad. Compare
> cantilever brakes with two cylindrical studs of 8mm diameter and
> something like 16mm of bushing length each, and only 1" from pivot to
> pad.

But the stresses on those bushings are greater than with a caliper brake,
as well.
>
> I have a Shimano dual pivot caliper brake on one of my bikes, and I set
> the pads to contact the rim with at least 2mm clearance to the rim
> edge. When I apply the brake strongly, the caliper flexes enough to
> deflect the tips of the brake pads more than 4mm into the tire
> sidewall.

Strange that I have my brake pads set with the same clearance, and never,
ever, have seen any evidence of contact with the sidewall. Is this a
long-reach caliper? Is there something unusual about the mounting?

--

David L. Johnson

__o | Accept risk. Accept responsibility. Put a lawyer out of
_`\(,_ | business.
(_)/ (_) |

Jeff Starr wrote:
>
> How do the different road calipers compare, in pull strength needed to
> lock up the wheel?
>
> Let me explain, on my 2002 LeMond, I still have the stock generic
> calipers, described as "aluminum dual pivot", it may be made by
> Tektro[?], no markings are on it. I have Kool Stop salmon pads on it.
>
> The rear with my stronger, bigger, right hand, I can lock up, from the
> hoods. The front, with my smaller weaker, fingers missing, left hand,
> I can't lock up the front. I would like to more effectively use the
> front brake, no I don't want to switch the front to the right lever.
> The brake levers are Dura-Ace 7703 STI.

?? You don't actually want to lock up the front, do you?

If you're talking about any sort of conventional bike, it's not going
to happen - at least, not on dry pavement. You'll fly over the bars
before you lock the front wheel.

And if you do lock the front wheel (say, on slippery pavement) you're
almost certainly going down. You can't steer to maintain balance. Try
it on an icy pond, if you must. You'll see.

Essentially, you can't get what you want, and you almost certainly
don't need it. More mechanical advantage, yes - but locking the front,
no.

- Frank Krygowski

Mark Hickey wrote:
>
> Chalo wrote:
> >
> >In my observation, dual-pivot calipers are noticeably more powerful
> >than drum brakes. Flimsy cantilever brakes in turn are more powerful
> >than calipers, and disc brakes and U-brakes are stronger yet.
>
> That's just not my observation - particularly not with cantis mated to
> road brake levers. I tried the long-pull DiaCompe levers as well - it
> helped, but the braking was still mediocre.

That probably accounts for it. I haven't used drop bars in years, but
when I did, I always had weak mushy brakes.

Chalo