a nice mod for single pivot sidepull calipers....

[sal bass]

so i picked up this pair of Nuovo (or Super) Record calipers on eBay
for $50...they were listed poorly and so i was the only bidder!

http://i15.photobucket.com/albums/a386/ipodusersmustdie/Mvc-040f.jpg

anyway...after mating them to some levers i noticed that the return
spring would rub quite hard against the spring retainer....i could feel
it at the lever...not very smooth.

sure...i could grease or oil that point and make a mess of it....have
road grit stick to it and then make it creak...or be lazy and put
nothing on it....

but i've seen the modern calipers have a plastic sleeve over the spring
ends.

so i removed the liner from a brake cable and slipped it over the
spring tips. still fits in the retainer...almost frictionless
movement...and no more grinding feel at the lever.

http://i15.photobucket.com/albums/a386/ipodusersmustdie/Mvc-045f.jpg

has this been done before? is this a common fix?

 

[Phil, Squid-in-Training]

sal bass wrote:
> so i picked up this pair of Nuovo (or Super) Record calipers on eBay
> for $50...they were listed poorly and so i was the only bidder!
>
> http://i15.photobucket.com/albums/a386/ipodusersmustdie/Mvc-040f.jpg
>
> anyway...after mating them to some levers i noticed that the return
> spring would rub quite hard against the spring retainer....i could
> feel it at the lever...not very smooth.
>
> sure...i could grease or oil that point and make a mess of it....have
> road grit stick to it and then make it creak...or be lazy and put
> nothing on it....
>
> but i've seen the modern calipers have a plastic sleeve over the
> spring ends.
>
> so i removed the liner from a brake cable and slipped it over the
> spring tips. still fits in the retainer...almost frictionless
> movement...and no more grinding feel at the lever.
>
> http://i15.photobucket.com/albums/a386/ipodusersmustdie/Mvc-045f.jpg
>
> has this been done before? is this a common fix?

Yep. The pair of brake calipers identical to yours that I just sold for $90
had no sleeve and were buttery smooth, if not stiff. In other words, they
were strong with no stiction. They were in really good, almost new
condition though.

I'd go the oil *and* sleeve route. Now that would be really smooth.
--
Phil, Squid-in-Training

 

[Ron Ruff]

I used to have a set of those that I picked up really cheap about 15
years ago. I like your solution for lowering the friction. One thing I
did with mine was to bend the springs in a bit so there wasn't so much
preload... it helped a lot.

 

[sal bass]

i thought of that...i'll ride them first and see how they
opperate....if they bind a bit later...i'll add the oil for sure. it
just seems a nice solution.


Phil, Squid-in-Training wrote:
>
> Yep. The pair of brake calipers identical to yours that I just sold for $90
> had no sleeve and were buttery smooth, if not stiff. In other words, they
> were strong with no stiction. They were in really good, almost new
> condition though.
>
> I'd go the oil *and* sleeve route. Now that would be really smooth.
> --
> Phil, Squid-in-Training

 

[sal bass]

that was my next question....why were the return spring preload soooo
strong? was the old housing not lined? compared with a modern
caliper, the things are like workout equipment.

did you bend them down by the tips or up higher?


Ron Ruff wrote:
> I used to have a set of those that I picked up really cheap about 15
> years ago. I like your solution for lowering the friction. One thing I
> did with mine was to bend the springs in a bit so there wasn't so much
> preload... it helped a lot.

 

[philcycles]

[email protected] wrote:
> sal bass wrote:
> > that was my next question....why were the return spring preload soooo
> > strong? was the old housing not lined? compared with a modern
> > caliper, the things are like workout equipment.
>
> I believe brake springs used to be much stronger because of friction in
> the cables, and because the levers had no springs.
>
> - Frank Krygowski

The second, not the first. And a drop of oil does the trick without a
plastic sleeve.
Phil Brown

 

[G.T.]

[email protected] wrote:
> sal bass wrote:
>
>>that was my next question....why were the return spring preload soooo
>>strong? was the old housing not lined? compared with a modern
>>caliper, the things are like workout equipment.
>
>
> I believe brake springs used to be much stronger because of friction in
> the cables, and because the levers had no springs.
>
> Friction in the cables was higher before lined cables became popular.
> Brake caliper springs needed to drag that cable back, and drag the
> lever with them. The friction made a strong spring necessary.
>
> But the lack of brake lever springs may have been more important.
> Contrary to the old saying "you can't push a rope," it can help greatly
> if you do.

But you can push a rope when it is constrained by a housing.

Greg

--
"All my time I spent in heaven
Revelries of dance and wine
Waking to the sound of laughter
Up I'd rise and kiss the sky" - The Mekons

 

[[email protected]]

Sal Bass writes:

> http://i15.photobucket.com/albums/a386/ipodusersmustdie/Mvc-045f.jpg

> has this been done before? is this a common fix?

All dual pivot brakes that I have looked at have such a plastic
sleeve. Don't worry, that will also get full of road grit and cause a
non-centered caliper return. The real solution is to make a return
spring that doesn't have the stoooopid elephant ears, but rather coils
around the center-bolt. Then there is no cosine error and sliding at
the retention lug. I've designed such a spring but because I am not
in the brake manufacturing business, you can't buy them.

Spring articulation is approximately at the center of the elephant ear.

Jobst Brandt

 

[Ron Ruff]

sal bass wrote:
> did you bend them down by the tips or up higher?

I'm not sure what part of the spring actually yielded... maybe part of
the coil or near there. I think I just grabbed the wire about half way
from the coil to the tab and forced in each side until it yielded a
little bit.

Old levers didn't have their own return springs, so the brake caliper
had to do that on it's own. The lined housing I'm not certain about...
I suspect that they weren't lined, though.

I used my old Campy calipers with "modern" Shimano levers and housing,
and they seemed to work fine... good feel and plenty of stopping power.
I have Ultegra calipers now (the Campys went when I sold all my bikes),
but I don't see the point in having the extra leverage.

 

[sal bass]

but won't the oil attract road grit/grime?


philcycles wrote:
> [email protected] wrote:
> > sal bass wrote:
> > > that was my next question....why were the return spring preload soooo
> > > strong? was the old housing not lined? compared with a modern
> > > caliper, the things are like workout equipment.
> >
> > I believe brake springs used to be much stronger because of friction in
> > the cables, and because the levers had no springs.
> >
> > - Frank Krygowski
>
> The second, not the first. And a drop of oil does the trick without a
> plastic sleeve.
> Phil Brown

 

[John Forrest Tomlinson]

On 21 Apr 2006 19:10:27 GMT, [email protected] wrote:

>Sal Bass writes:
>
>> http://i15.photobucket.com/albums/a386/ipodusersmustdie/Mvc-045f.jpg
>
>> has this been done before? is this a common fix?
>
>All dual pivot brakes that I have looked at have such a plastic
>sleeve. Don't worry, that will also get full of road grit and cause a
>non-centered caliper return. The real solution is to make a return
>spring that doesn't have the stoooopid elephant ears, but rather coils
>around the center-bolt. Then there is no cosine error and sliding at
>the retention lug. I've designed such a spring but because I am not
>in the brake manufacturing business, you can't buy them.
>
>Spring articulation is approximately at the center of the elephant ear.

I think the brakes on one of my bikes is like that -- a Suntour
Superbe Pro, like these sold at Yellow Jersey:
http://www.yellowjersey.org/brax2.html

I've got another set that were mounted on a bike and ridden less than
40 minutes (ie baarely used) that I'd sell for a price like that, if
anyone is interested.

JT

****************************
Remove "remove" to reply
Visit http://www.jt10000.com
****************************

 

[David L. Johnson]

On Fri, 21 Apr 2006 12:20:56 -0700, Ron Ruff wrote:

> Old levers didn't have their own return springs, so the brake caliper
> had to do that on it's own. The lined housing I'm not certain about...
> I suspect that they weren't lined, though.

That's right. No nylon or teflon linings in the old days, just grease.
I imagine the development of the lined cable housing was what allowed the
weaker springs. But the springs on the levers themselves don't help the
cable return significantly. They are very weak, and the cable is not held
to the lever in a way that enables any push; the end of the cable would
just stick out.

--

David L. Johnson

__o | As far as the laws of mathematics refer to reality, they are not
_`\(,_ | certain, and as far as they are certain, they do not refer to
(_)/ (_) | reality. -- Albert Einstein

 

[john]

Sal wrote:

>so i removed the liner from a brake cable and slipped it over the
>spring tips. still fits in the retainer...almost frictionless
>movement...and no more grinding feel at the lever.

Great macro & lighting! What sort of equipment did you use? (I'm not
inferring that the equipment is responsible for the great quality
photo, just curious)

As for your Record upgrade, have you ridden it yet? Do you think it
will stay in place, or work it's way off the stud?

I think I'll try that too, John

 

[[email protected]]

David L. Johnson wrote:
> On Fri, 21 Apr 2006 12:20:56 -0700, Ron Ruff wrote:
>
> > Old levers didn't have their own return springs, so the brake caliper
> > had to do that on it's own. The lined housing I'm not certain about...
> > I suspect that they weren't lined, though.
>
> That's right. No nylon or teflon linings in the old days, just grease.
> I imagine the development of the lined cable housing was what allowed the
> weaker springs. But the springs on the levers themselves don't help the
> cable return significantly. They are very weak, and the cable is not held
> to the lever in a way that enables any push; the end of the cable would
> just stick out.

The levers on at least a couple of our bikes are held in such a way
that the brake lever springs push the cable. They have plastic clips
that snap over the cable end, where it's anchored to the arm.

Try the experiment I described upthread. It's easy - I just did it in
five minutes in my basement, using a 3/4" dowel, a string, and some
large nuts as weights. The difference is easy to feel. Even easier if
you do a 540 degree wrap angle, rather than just 180 degrees.

- Frank Krygowski

 

[sal bass]

in this case...probably not...it's a base model Mavica (the ones that
use 3.5" disks...i'm waiting for it to die so i can buy a new one) and
the shade of my front porch.

for my needs...it's worked out so well....it's hard to justify getting
a new one.

this is going on a bike that won't be done until Oct. 07. right now,
i'm collecting parts to save the builder the time of having to track
some of this stuff down.



john wrote:
> Sal wrote:
>
> >so i removed the liner from a brake cable and slipped it over the
> >spring tips. still fits in the retainer...almost frictionless
> >movement...and no more grinding feel at the lever.
>
> Great macro & lighting! What sort of equipment did you use? (I'm not
> inferring that the equipment is responsible for the great quality
> photo, just curious)
>
> As for your Record upgrade, have you ridden it yet? Do you think it
> will stay in place, or work it's way off the stud?
>
> I think I'll try that too, John

 

[Helmut Springer]

John Forrest Tomlinson <[email protected]> wrote:
> I think the brakes on one of my bikes is like that -- a Suntour
> Superbe Pro, like these sold at Yellow Jersey:
> http://www.yellowjersey.org/brax2.html

Happen to have the SunTour GPX that features the same internal coil
springs (each arm has its coil spring fixed to the center
bolt)...always wondered why noone offers something like that these
days..


--
MfG/Best regards
helmut springer

 

[john]

Sal wrote:
>in this case...probably not...it's a base model Mavica (the ones that
>use 3.5" disks...i'm waiting for it to die so i can buy a new one) and
>the shade of my front porch.

In any case great sharpness & depth of field. Using shade certainly did
the job of delivering good lighting for your purpose. I wish most ebay
& other net photography were as good. My daughter & her hubby both have
Sony Digital cameras. I don't know squat about digital. I'm still using
Canon film cameras & lenses. One of my lenses is a 50mm close up. I
really enjoy doing macro photography.

Regards, John

 

[Ron Ruff]

I'm thinking about getting some old calipers now... but my memory is
foggy...

Are there any issues with leverage ratios using modern levers... and
how do you deal with the nutted pivot bolt?

 

[Bob]

On 22 Apr 2006 21:25:28 -0700, "Ron Ruff" <[email protected]>
wrote:

>I'm thinking about getting some old calipers now... but my memory is
>foggy...
>
>Are there any issues with leverage ratios using modern levers... and
>how do you deal with the nutted pivot bolt?

The nutted pivot bolt ? Why you just bolt it down on your vintage
frame, of course. It's those recessed allen bolts that cause the real
dilemma... they just don't work on a vintage frame! (Actually, I've
swapped them with comparable brakes from the same period when there
were both types. You can use bolts from an older set and just polish
them a little. )

If you use the sleeve *and* oil, won't the sleeve tend to work it's
way off ?

 

[sal bass]

i inwuired about the same thing and it seems there are no leverage
issues....

i just bought some original bolts and nuts that are for reccesed and
replaced the existing ones.


Ron Ruff wrote:
> I'm thinking about getting some old calipers now... but my memory is
> foggy...
>
> Are there any issues with leverage ratios using modern levers... and
> how do you deal with the nutted pivot bolt?