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V-brake shoe question



 
 
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  #1  
Old January 13th 20, 12:02 PM posted to rec.bicycles.tech
Tanguy Ortolo
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Posts: 55
Default V-brake shoe question

Hello,

There is one thing that always puzzled me with V-brake shoes. There is
one thing that I like with these modern brake shoes, which is that their
attachmend to the caliper offers less degrees of freedom than the one of
cantilever brakes, which I found very hard to adjust correctly.

To keep some degree of freedom in roll and yaw (I take the bicycle as a
reference to name these), the V-brake shoe bolts are equipped with two
pairs of rounded (concave and convexe) bushings. One of these bushing
pairs is longer than the other, and the longest one is supposed to be
installed on the internal side. When the brake pads are new, this leads
to the caliper arms forming a \ / shape rather than a | | shape. For
some reason, I do not like that, and I always swap the bushing pairs to
put the shortest one inside. Am I wrong to do so, and is there a reason
to mount the caliper arms in a \ / shape ?

Bicycly,

--
Tanguy
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  #2  
Old January 13th 20, 12:41 PM posted to rec.bicycles.tech
Sir Ridesalot
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Posts: 4,767
Default V-brake shoe question

On Monday, 13 January 2020 06:02:23 UTC-5, Tanguy Ortolo wrote:
Hello,

There is one thing that always puzzled me with V-brake shoes. There is
one thing that I like with these modern brake shoes, which is that their
attachmend to the caliper offers less degrees of freedom than the one of
cantilever brakes, which I found very hard to adjust correctly.

To keep some degree of freedom in roll and yaw (I take the bicycle as a
reference to name these), the V-brake shoe bolts are equipped with two
pairs of rounded (concave and convexe) bushings. One of these bushing
pairs is longer than the other, and the longest one is supposed to be
installed on the internal side. When the brake pads are new, this leads
to the caliper arms forming a \ / shape rather than a | | shape. For
some reason, I do not like that, and I always swap the bushing pairs to
put the shortest one inside. Am I wrong to do so, and is there a reason
to mount the caliper arms in a \ / shape ?

Bicycly,

--
Tanguy


I mount my V-brake shoes so that the pads and the rim have the maximum amount of contact. One thing to watch out for if you do use the shorter washers on the inside of the caliper arm is that the brake doesn't bottom out. That is that the brake lever doesn't hit the handlebar before the most braking occurs.

Cheers
  #3  
Old January 13th 20, 03:22 PM posted to rec.bicycles.tech
Tanguy Ortolo
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Posts: 55
Default V-brake shoe question

Sir Ridesalot, 2020-01-13 12:41+0100:
I mount my V-brake shoes so that the pads and the rim have the maximum amount of contact. One thing to watch out for if you do use the shorter washers on the inside of the caliper arm is that the brake doesn't bottom out. That is that the brake lever doesn't hit the handlebar before the most braking occurs.


Sure, I always do that, by adjusting the cable length. Using the shorter
washers on the inside of the caliper arm means a different, lower cable
length than the reverse configuration, that is all.

I just found https://si.shimano.com/pdfs/dm/DM-GN0001-21-ENG.pdf,
which explains on page 116, that the thin or thick washer should be used
in order to have at least 32 mm of cable between both sides of the
brake. My guess is that is simply to avoid compressing the rubber boot.

So, the configuration I use, with the thin washer inside, is correct as
it gives an open cable lenght of 50 mm. The opposite configuration would
give a longer cable length, which would be correct too, but probably
sub-optimal in terms of mechanical advantage.

For what I see, many bikes are assembled with the thick washer inside,
probably because this is always a safe configuration regardless of the
rim and form dimensions.

--
Tanguy
  #4  
Old January 13th 20, 04:22 PM posted to rec.bicycles.tech
AMuzi
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Posts: 11,157
Default V-brake shoe question

On 1/13/2020 5:02 AM, Tanguy Ortolo wrote:
Hello,

There is one thing that always puzzled me with V-brake shoes. There is
one thing that I like with these modern brake shoes, which is that their
attachmend to the caliper offers less degrees of freedom than the one of
cantilever brakes, which I found very hard to adjust correctly.

To keep some degree of freedom in roll and yaw (I take the bicycle as a
reference to name these), the V-brake shoe bolts are equipped with two
pairs of rounded (concave and convexe) bushings. One of these bushing
pairs is longer than the other, and the longest one is supposed to be
installed on the internal side. When the brake pads are new, this leads
to the caliper arms forming a \ / shape rather than a | | shape. For
some reason, I do not like that, and I always swap the bushing pairs to
put the shortest one inside. Am I wrong to do so, and is there a reason
to mount the caliper arms in a \ / shape ?

Bicycly,


You can swap the thick pair and the thin set as needed for
any given brake mounts/rim combination. Just avoid the arms
going past vertical at rim contact.

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


  #5  
Old January 14th 20, 05:31 AM posted to rec.bicycles.tech
Sir Ridesalot
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Posts: 4,767
Default V-brake shoe question

On Monday, 13 January 2020 10:22:54 UTC-5, AMuzi wrote:
On 1/13/2020 5:02 AM, Tanguy Ortolo wrote:
Hello,

There is one thing that always puzzled me with V-brake shoes. There is
one thing that I like with these modern brake shoes, which is that their
attachmend to the caliper offers less degrees of freedom than the one of
cantilever brakes, which I found very hard to adjust correctly.

To keep some degree of freedom in roll and yaw (I take the bicycle as a
reference to name these), the V-brake shoe bolts are equipped with two
pairs of rounded (concave and convexe) bushings. One of these bushing
pairs is longer than the other, and the longest one is supposed to be
installed on the internal side. When the brake pads are new, this leads
to the caliper arms forming a \ / shape rather than a | | shape. For
some reason, I do not like that, and I always swap the bushing pairs to
put the shortest one inside. Am I wrong to do so, and is there a reason
to mount the caliper arms in a \ / shape ?

Bicycly,


You can swap the thick pair and the thin set as needed for
any given brake mounts/rim combination. Just avoid the arms
going past vertical at rim contact.

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


Also avoid one arm bottoming out against the noodle and the noodle holder. I've seen bikes with V-brakes where that happened if the brake lever was squeezed hard like in a panic stop.

Cheers
  #6  
Old January 14th 20, 05:27 PM posted to rec.bicycles.tech
[email protected]
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Posts: 231
Default V-brake shoe question

On Monday, January 13, 2020 at 8:31:19 PM UTC-8, Sir Ridesalot wrote:
On Monday, 13 January 2020 10:22:54 UTC-5, AMuzi wrote:
On 1/13/2020 5:02 AM, Tanguy Ortolo wrote:
Hello,

There is one thing that always puzzled me with V-brake shoes. There is
one thing that I like with these modern brake shoes, which is that their
attachmend to the caliper offers less degrees of freedom than the one of
cantilever brakes, which I found very hard to adjust correctly.

To keep some degree of freedom in roll and yaw (I take the bicycle as a
reference to name these), the V-brake shoe bolts are equipped with two
pairs of rounded (concave and convexe) bushings. One of these bushing
pairs is longer than the other, and the longest one is supposed to be
installed on the internal side. When the brake pads are new, this leads
to the caliper arms forming a \ / shape rather than a | | shape. For
some reason, I do not like that, and I always swap the bushing pairs to
put the shortest one inside. Am I wrong to do so, and is there a reason
to mount the caliper arms in a \ / shape ?

Bicycly,


You can swap the thick pair and the thin set as needed for
any given brake mounts/rim combination. Just avoid the arms
going past vertical at rim contact.

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


Also avoid one arm bottoming out against the noodle and the noodle holder.. I've seen bikes with V-brakes where that happened if the brake lever was squeezed hard like in a panic stop.

Cheers


Although I've stopped riding offroad except the occasional gravel trail which is usually flat, I was riding some extremely steep trails. Cantilevers never had anywhere like sufficient power. Properly set-up V-brakes were more than sufficient. They actually worked quite a bit better than disk brakes on a CX bike and I rode through water and dust etc. without ever a problem with a good V-brake. I can't even imagine bottoming out the V-brake against the end of travel. None of mine were even close. Perhaps you had MTB V-brakes on a CX or Touring bike - they have a lot longer and more flexible arm. I could see those bottoming out.
 




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