Bike Forums

Bike Forums (https://www.bikeforums.net/forum.php)
-   Classic & Vintage (https://www.bikeforums.net/classic-vintage/)
-   -   What would you do with this rear brake? (https://www.bikeforums.net/classic-vintage/1137560-what-would-you-do-rear-brake.html)

hokiefyd 03-06-18 07:27 AM

What would you do with this rear brake?
 
...besides putting brake blocks in the caliper... :-)

This is on an '84 Schwinn, low-step frame.

https://farm5.staticflickr.com/4771/...26d2d1e7_h.jpg

The original brake caliper was a Dia-Compe single pivot with reversed cable stop/anchor, typical of brakes used with these types of frames, where the brake cable comes up from the bottom in a large radius curve (also pictured below). I didn't care for that approach too much, as it seemed to restrict me to older single pivot brake calipers. I got these center-pull calipers for free from my LBS from a bike they were disassembling, and I've ran the rear brake cable through both:

(1) the noodle-and-hanger you see in the picture above, and
(2) through a small pulley attached to the seat clamp bolt with a bolt-on cable stop on the seat tube.

Neither one of these solutions seems to be ideal, either. The primary problem I'm having now is the yoke is not centered on the straddle cable, so I get uneven pull from each brake arm. The yoke appears centered in the picture above, but after a number of pulls on the lever, it eventually works its way over to the right side, pulled by the off-centered cable hanger. Neither solution seems all that elegant to me.

I know these low-step frames can be troublesome in setting up a rear brake. Is the stock setup, shown below, about the most elegant way possible for a frame like this? I appreciate any thoughts, comments, or ideas.

https://farm5.staticflickr.com/4577/...530d3838_h.jpg

Bianchigirll 03-06-18 07:33 AM

Are you set on having that center pull style brake? I think unless you can get the hanger between the lug ears you’ll always be off to the side.

hokiefyd 03-06-18 08:05 AM


Originally Posted by Bianchigirll (Post 20207552)
Are you set on having that center pull style brake? I think unless you can get the hanger between the lug ears you’ll always be off to the side.

No, I'm not married to one type over another. Which is why I started this thread -- I've come to the same conclusion that you have -- it seems to me that a center pull will always be compromised as a rear brake due to the cable routing problem here. But you guys work with and build a ton more bikes than I do, at least collectively, so I'm looking for advise on the most elegant approach. The off-center pull on these center pull brakes isn't appealing to me. But the large loop of cable to a rear single pivot wasn't very appealing either.

Maybe that's the lesser of the two evils on a frame type such as this?

Are there any clever ways of using a modern dual pivot brake? I guess the cable would have to snake up the seat tube (like it is now) and then loop back down towards the caliper. Is there a good way to keep that cable secured/mounted? Or would such an S-curve not work well in the first place?

SJX426 03-06-18 08:26 AM

There are cable hanger that will center the cable.

Universal CP Hanger:
[IMG]https://farm6.staticflickr.com/5550/...674dd08a_z.jpg075_PaTrek, on Flickr[/IMG]

Front brakes typically have shorter calipers. Your rear one looks like one as well so you might not have an option other than to swap to 700 rims, if that will be enough.

Upon further examination, there may be CP's with less distance between the mounting bolt and pivot mounts. Here is a front Universal that my be shorter than yours:

[IMG]https://farm8.staticflickr.com/7310/...d13d5d81_z.jpg085_PaTrek_front brake and tire saver, on Flickr[/IMG]

JohnDThompson 03-06-18 08:51 AM

1 Attachment(s)

Originally Posted by Bianchigirll (Post 20207552)
Are you set on having that center pull style brake? I think unless you can get the hanger between the lug ears you’ll always be off to the side.

That style of hanger is actually intended to be mounted between the lug ears:


http://www.os2.dhs.org/~john/DC-hanger.jpg

hokiefyd 03-06-18 09:00 AM


Originally Posted by SJX426 (Post 20207638)
Front brakes typically have shorter calipers. Your rear one looks like one as well so you might not have an option other than to swap to 700 rims, if that will be enough.

I'm sorry that I wasn't clear -- these calipers are what I think used to be referred to as "mid reach" calipers -- they have enough slot so that I can reach the 27" rims with these (but I can also swap to 700s if I need to). These calipers do work with the wheels on the bike -- I'm just looking for a better cable routing.


Originally Posted by JohnDThompson (Post 20207701)
That style of hanger is actually intended to be mounted between the lug ears.

Thanks -- yes, I agree. In order to do that, I think I'd have to run a length of cable up so that the cable itself would be stopped by the hanger, rather than use a linear pull brake noodle. I was hoping to avoid an S-curve in the cable like this, but I'd have to do it if I were using a dual pivot brake anyway...so I could try it with my existing center pull.

Thanks for the reminder on this -- it may be my best solution with the existing hardware.

obrentharris 03-06-18 09:58 AM

I think the pulley and cable stop method may be the best solution if you can center the pulley between the ears of the seat lug and mount the cable stop on the back of the seat tube:
http://1.bp.blogspot.com/_hf6_g-DH_P...0/IMG_0998.JPG
Photo from an image search.

Otherwise, ditch the noodle and try a loop in the cable housing:
http://www.classiclightweights.co.uk...ns-frames4.jpg
Another copied image.
Brent

Ghrumpy 03-06-18 11:29 AM


Originally Posted by obrentharris (Post 20207845)
I think the pulley and cable stop method may be the best solution if you can center the pulley between the ears of the seat lug and mount the cable stop on the back of the seat tube:
http://1.bp.blogspot.com/_hf6_g-DH_P...0/IMG_0998.JPG
Photo from an image search.

Look closely and you'll notice there's no need for the added stop on the seat tube. The pulley bracket has a stop built in. All that's needed is a step-down ferrule.


Originally Posted by obrentharris (Post 20207845)
Otherwise, ditch the noodle and try a loop in the cable housing:
http://www.classiclightweights.co.uk...ns-frames4.jpg
Another copied image.
Brent

Agree. No need for the noodle.

hokiefyd 03-06-18 11:50 AM

Thanks for the ideas, everyone. I thought the noodle would reduce flex/compression in the system and figured that any loop of cable that I could eliminate, or at least replace with a non-compressible piece, would be worth doing. It obviously didn't work as well as I wanted it to. I will also concede that the pulley I used was pretty small in diameter, and the cable just sort of "bent" around it rather than wrapped around it smoothly, if that makes any sense.

I definitely have some things to try.

79pmooney 03-06-18 12:35 PM

The really easy fix is to replace the OEM yoke with any of the yokes that have set screws for the bridle cable. I use the popular black ones on several bikes. You may well find you have to set it off center to get the brake pads centered but everything stays put and requires no attention.

Harris Cyclery Tektro Deluxe Yoke Silver BRH05 $6.95 (There are several other similar yokes. I've never used these but they should do just fine.)
Ben

Fahrenheit531 03-06-18 08:27 PM

1 Attachment(s)
Here's another shot of probably your best option, which is the stock Schwinn pulley; it ain't pretty but it works like a champ. This one's on a Mesa Runner, brakes are cantilever. I'd wager you can find one at your local co-op for a buck or two.

SkyDog75 03-07-18 01:27 AM

It may be hard to see in this picture, but my daughter's Bianchi Advantage is set up with one of those pulleys. Works great for her cantilever brakes and I don't see why it wouldn't work just as well for centerpulls.

https://www.bikeforums.net/attachmen...hmentid=597702

hokiefyd 03-07-18 06:01 AM

I did reposition the hanger to between the seat post clamp lugs (centered), and that definitely centers the yoke, but the cable's route to get there isn't ideal. I agree that a larger diameter pulley may be best. I like the option of having the cable stop built in to the pulley. I live in the country, and the nearest bike co-op is over an hour and a half away. Next time I go to the big city, I'll check it out.

Does anyone happen to have one of these Schwinn/similar pulleys unused you'd be willing to sell? If so, please PM me. Thanks, all.

SkyDog75 03-07-18 10:14 AM


Originally Posted by hokiefyd (Post 20209338)
I live in the country, and the nearest bike co-op is over an hour and a half away.

Understood. I'm in the same boat. There's only one within a few hours' drive of here and there's no way I'd be able to show up during their limited hours.


Originally Posted by hokiefyd (Post 20209338)
Does anyone happen to have one of these Schwinn/similar pulleys unused you'd be willing to sell?

They turn up on eBay pretty regularly, and if memory serves, I think that's where I got mine. Unfortunately, the only ones listed right now seem to be in the UK, bumping up the shipping charge a few bucks. They're still under $20, though:

https://www.ebay.com/itm/381293125287

hokiefyd 03-13-18 05:10 AM

Through the generosity of a forum member (@3speedslow), I have a rear cable pulley on the bike.

https://farm5.staticflickr.com/4782/...04c33807_h.jpg

The cable is centered over the yoke and I was able to keep using the stock Dia-Compe yoke (that I prefer over the "closed" triangular yokes, as this is essentially my quick release on the brake).

As installed, the pulley doesn't turn -- the cable just slides over it. I think the unit got compressed just slightly when installed on the seat post clamp. The pulley will turn, but with some finger force. I think it's okay for now, and I may just use some dry lube there where the cable slides.

3speedslow 03-13-18 06:01 PM

Glad I could help. A washer placed under the bolt could open up the pulley bracket.
I like the yellow cables which match the decals and fork and go well with the blue.

hokiefyd 03-14-18 05:12 AM


Originally Posted by 3speedslow (Post 20221426)
Glad I could help. A washer placed under the bolt could open up the pulley bracket.
I like the yellow cables which match the decals and fork and go well with the blue.

Yes, I may eventually do this. The seat clamp bolt is fairly short, and there are only a few threads' of engagement right now (with the extra spacing of the pulley bracket). I may eventually replace it with a longer bolt or something like a quick release lever in which the pulley and its bracket would be free to find their own position during use. I will play some more with it over time...and will test it more when it's more pleasant to ride outside (winter just isn't giving up in the Shenandoah Valley).

Thank you for the compliment on the color coordination. I think the bike looks pretty nice. I bought it to try a road bar and road levers, but I just couldn't get into it, so I've got a hodge-podge of mountain/hybrid bike parts on it at the moment. The step-through frame is interesting, though it definitely makes the bike feel a little twitchy at speed. The combination of the "soft" chromoly tubing, the parallelogram of a main "triangle", the already steep(ish) head tube angle ('80s road bike), and the replacement Fuji fork that appears to have more offset than the OEM fork (which should reduce trail) makes for a "whippy" feeling bike when steering at speed. Most of my bikes feel very stable at speed, but this one feels like the front of the frame is only casually connected to the rear. It's a different feeling, but I think this flexibility in the frame/system is also what makes it super comfortable to ride. Despite the relatively narrow tires (compared to what I have on my other bikes) and higher inflation pressure, this bike is one of my softest-riding.

It's been fun to play with and ride around the neighborhood.

Sportivo 05-05-21 06:31 PM

rear cable pulley
 
Hi,

I am looking for a rear cable pulley, for a very similar bike as the one shown in the forum... do you know where I could find one?

Thanks!


Originally Posted by 3speedslow (Post 20221426)
Glad I could help. A washer placed under the bolt could open up the pulley bracket.
I like the yellow cables which match the decals and fork and go well with the blue.


Wildwood 05-05-21 06:59 PM

You just need a design with a braze-on in the proper location for a cleaner brake run of much shorter cable length for a tighter system.
here’s one pic. let me check for a closer-up.
https://cimg0.ibsrv.net/gimg/bikefor...802670fbd.jpeg

3speedslow 05-07-21 06:50 AM


Originally Posted by Sportivo (Post 22046843)
Hi,

I am looking for a rear cable pulley, for a very similar bike as the one shown in the forum... do you know where I could find one?

Thanks!

Welcome to the CV Forum!

Sorry, not at the moment. They are out there, maybe at a close to you bike shop or co-op.

happy hunting!

gaucho777 05-07-21 10:12 AM

@Sportivo. Welcome! If you don’t find what you need at your local bike shop or co-op, there are several options currently available on eBay. Try searching with terms: cable hanger pulley.

sovende 05-08-21 08:26 AM

I know that it has NO effect on function but aesthetically, I would turn the “Dia-Compe” yoke around :rolleyes:. Just looks better that way :thumb:. If you think that the cable routing compromises brake “pull” in any way, I’d definitely keep the centerpulls opposed sidepulls. IMHO, they provide better stopping power. Of course, that’s my opinion :thumb:


All times are GMT -6. The time now is 07:51 PM.


Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.