shimano cx-70 canti question

[drew beckmeyer]

ok, i feel like this is going to end with me missing something obvious. i just got the cx-70 brakes to avoid having to deflate/squeeze my 700x50 tires everytime i want to take the wheels off. im not so new to cantilever brakes but somewhat new to big tires that prevent easy on and off. 

riv's site sort of implies that they open up easy enough and this video shows a guy doing it....

https://www.youtube.com/watch?v=rA7f-v3Rmts (skip to 1:04)  

here is the description and pics of it opened up

http://www.rivbike.com/product-p/brc3.htm

in my reality, when set up and adjusted correctly, it doesnt seem possible to slip the hanger cable from the brake. there isnt enough slack to get the cable to slide out of that little slot, it seems. if the brakes are super wide, i can get it to go, but it has to be uncomfortably far from the rim. adjusting the inline barrel to it's slackest doesnt really work either. 

so... am i missing something, and if so, what?  id like to avoid deflating or loosening the other side of the cable hanger and then readjusting the brakes all over again. i couldve done that with the old brakes.

many thanks

[Michael Hechmer]

I have no experience with this brake.  But your problem is reminiscent of a problem I had with an earlier Shimano Canti (550?) and Ultegra brifters.  The brifters couldn't pull enough cable, before bottoming out,  to allow me to release the straddle cable.  Switching to the Cane Creek / Tectro levers fixed that problem, but not the poor stopping quality of those brakes.  Now I always match canti brakes with a lever that has a built in quick release, and I avoid Shimano cantis.

Michael

[Takashi]

You might need levers with built-in quick release, depending on how you like your brakes set up.
Or, in-line adjuster / quick releaser might help you.
http://www.amazon.com/gp/product/B008USE9LU/ref=pd_lpo_sbs_dp_ss_1?pf_rd_p=1944687602&pf_rd_s=lpo-top-stripe-1&pf_rd_t=201&pf_rd_i=B00BGBRZZK&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=0VTW9SXT6TAS0SYK429H

Takashi


2014年12月20日土曜日 11時33分17秒 UTC+9 drew beckmeyer:

[Dan McNamara]

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[Dan McNamara]

I have had good luck using the release on Tektro brakes with the CX-70. Not sure I could get the straddle off without that slack. 

Dan

On Dec 19, 2014, at 6:33 PM, drew beckmeyer <drewbe...@gmail.com> wrote:

--

[Aaron Young]

http://store.velo-orange.com/index.php/dia-compe-cable-stop-with-quick-release.html

Here's another option that adds a quick release function to the brake line.  I have one of these installed on a bike with center pulls and it works great.  I like non-aero brakes so the Tektro levers aren't my first choice.

BTW, I just bought the CX-70's for the same reason as you, Drew.  I'm glad you brought this up as I imagine I will have the same problem you mentioned.  I think I will buy one of these dia compe cable stops right now in anticipation.

Can anyone who is actively using these brakes speak to how well they work?  Usually, if Riv is selling something I just trust that it will work well enough.  I'm expecting the same from these CX-70's but I read an Amazon review saying skip 'em and go for the cheaper Tektro 720's.  Can anyone weigh in?  Thanks.

Aaron Young

The Dalles, OR

[Kurt Manley]

I have those brakes and they are awesome but it is hard to release the straddle cable. Most cantis you can easily unhook the cable end from the brake arm. On CX70's it's hard to get the end to release from the canti arm. I have to push on the cable end through the hole in the front of the arm to get it to release. I use a key or an allen or whatever's handy with a small point. After that they open plenty far to clear 700x60 tires on my Hunq.

[Michael Hechmer]

I haven't seen one of those QRs since my wife's 1978 Raleigh mixed bike.!  It did work fine.  I'll bet they went out with CPs but may be poised for a comeback with CPs.

Michael

[Garth]

3 things

1. what frame is it for ?   There is no one standard for how exactly a canti mounts as every frame has different stays and different designs . For example, a cross/road frame is not the same as say a Bombadil/Atlantis etc. , they are intended for much different tires .

2. in the shimano vid, notice how high the straddle hanger is centered above the tire, the center point .   On the riv photo, notice how low it is.  Notice in the shimano vid it does not appear the tire would come off easily or is very very close to it , because the hanger is centered so high. 
Try lowering it's center as much as possible.

3. I am not a fan of the fixed cable hangers .   I prefer the classic ones that you can remove the cable completely from the carrier , it's just so much easier . http://www.rivbike.com/product-p/ca21.htm .   I've never had any problem with them staying centered, even on brakes that have no tension adjustment like the original Deore's .   If the other hanger doesn't work for you, just get some of the basic one from a local shop or a friend , as almost everyone who does their own bike work has some in the misc. bin. 

[drew beckmeyer]

thanks everyone. it appears i am not that much of an idiot/this problem is not uncommon, which is both good and bad news.  it seems like some sort of qr or in line adjuster thing is needed to get them to do what i want

aaron, 

i had the tektro 720s previously installed. they worked just fine. they were a little harder to set up and adjust than the shimanos and they werent finished as nicely. shimanos seem to modulate a bit better. still, totally adequate brakes. i would be curious about combining that dia compe quick release with them. could be much cheaper and better working alternative to what we are trying to do... but then there is the back wheel too...

garth,

i have them on a hunqapillar. your points are well taken and get to the science of what i was trying to understand. that makes a lot of sense. 

On Friday, December 19, 2014 6:33:17 PM UTC-8, drew beckmeyer wrote:

[Shoji Takahashi]

I've been using CX-70 cantis for at least the past 6 months on my Hunqapillar. I don't use the Shimano link-wire thing, and instead use a regular straddle hanger yoke.

RE: how well they work

For me, the CX-70s are easy to set up and provide powerful braking. They replaced CR-720, which were fine. I like the feel of the CX-70s better, and I think they are not as finicky to set up for good braking. I used the OEM brake pads, which were surprisingly good. I've since switched to Yokozuna's as the OEMs have worn down. (Very easy swap.)

RE: quick release

I have nonaero brake levers with quick release, and the brake hangers both have barrel adjusters. I can pull the straddle cable from the brake or remove the yoke from the straddle cable. It does take a little adjusting; first time I set it up, there wasn't enough slack.

BTW: I saw Bill's offer to trade CX-70 for his Pauls. I thought about it for a little bit, but I really like the CX-70s. If I get another canti-equipped bike, I'd definitely get these again.

Best, shoji

 

On Friday, December 19, 2014 11:54:41 PM UTC-5, AaronY wrote:

[mikel...@juno.com]

i have my eye on the CX 70 brakes but im curious if the entire pad and holder can be replaced or are you confined to using that particular holder and replace pads when needed
____________________________________________________________
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[stonehog]

I use the CX-70 as the front brake on my Miyata commuter.  Two observations:

1. fit/finish, and feel is good in my opinion - better modulation than the CR720s or V-Brakes I've used (Deore, XT).

2. the hanger and cable attachment on these are more complicated than they need to be.

I replaced the fixed hanger cable (it wasn't long enough to clear my rack) with a cheap dia-compe hanger and regular old canti hanger cable.  Works great.  What isn't great is the silly release built into the brake arm.  To fit the button in, you have to have extra slack in the cable to angle one end of it into the closed hole (https://flic.kr/p/qceReY).  Much more work than the simple open half-circle on a brake like the CR720 (https://flic.kr/p/qtBQ9n).  Seems like a badly designed attempt to avoid lawsuits.  Brake "lawyer lips"?  I'm tempted to dremel the circle into a half circle at some point...

Brian Hanson

Seattle, WA

[Tim Gavin]

I have similar issues with the vintage Shimano XT-M730 cantilevers on my KOM--if I have the pads as close as I like for nice, strong braking, I can't pull enough slack on the straddle cable to remove the QR end from the canti arm.  

For me, the QR button on the Tektro TRP RRL levers gives me the right amount of slack, and it re-sets automatically the next time you squeeze the lever.

Plus, the RRL levers are just the most comfy, ergonomic levers I've ever used.  Quite handsome as well.  Very highly recommended if you use drops or stache bars.  And, you can find the black/black ones for pretty cheap if you prefer non-blingy.

[Garth]

Replace just the pads Mike, Shimano road pads or *any* other brand Shimano road compatible pad .   The lesser CX-50 does not use cartridge pads fwiw and are specific to that brake only .

[Aaron Young]

Shoji and Kurt - which size spacer did you use on your Hunqas?  I'm putting these on my Atlantis right now, but the chart on the directions sheet doesn't extrapolate out far enough.  It seems like the mid-sized ones would be best. 

Thanks,

Aaron   

--

[Tom Harrop]

Hi Aaron,

I can't believe I'm admitting this in public, but last winter I wrote a little calculator to optimise my canti setup using the formulas suggested by Benno Belhumeur (circleacycles.com). I made some changes to the formula to take into account changes in canti angle caused by changing the spacer setup on the brake pad attachment.

To sum up, on my Bombadil with CX-70 brakes and wide rims (30 mm OD) the medium spacers gave the most mechanical advantage. To adjust the brakes, I set the yoke as low as it would go. This gave me too much MA so I gradually raised the yoke until it felt right.

Excuse the dorkery...!

Tom

[Aaron Young]

Wow, that is a serious case of dorkery.  You may want to get that checked.  :)  Thanks for the info.  I'll go with the mediums and feel it out.  Changing the spacers later on if need be won't be too big of a job any way.  

Thanks,

Aaron

--

[Paul Brodek]

So, I'm just a bozo on this bus, was never in love with cantis, but they seem to be a necessary evil to allow fatter tire clearance, esp with vintage steel. Picked up lightly-used CX70s to convert a 27" narrow-mount canti bike to 700C wheels, reading online that CX70s had lots of adjustability and good geometry to do that. Overall the operation was successful, so I can recommend trying this setup to ya'll in similar situations. Possibly pertinent/useless on-topic observations:

1. IME the CX70s stop really, really well. Solid feel, good modulation, quick stops. No performance negatives to report. The narrow mounts on this particular bike might help; the shoes, I'm sure, contribute (see below).
2. Dense I am, but AFAICT the "CX70s open wide" Riv thing is only due to the short stock brake blocks? Is there anything else special with the CX70 that they open wider than other cantis regardless of brake block length? O/W, use any canti you like & just switch to short brake blocks? And if the blocks hitting the stays/blades is what prevents wide opening, regardless of brake brand/type, if short shoes hit metal before the calipers fully spread their wings, well, you're hosed.
3. I always ditch one-piece/weirdo straddle link thingies for good ol' cable & straddle.
4. The CX70 cable-end receptor and cable anchor device is needlessly complex/weird. You do need a little more cable slack to extract the cable end.
5. I use almost exclusively aero brake levers, and lotsa brifters, so extracting the cable end is always difficult when brakes are adjusted to taste. I have two general workarounds:
*Curse and swear mightily, and be OK with light finger laceration.
*Adjust cable just a little loose enough to remove cable without cussing/laceration, and take up that little bit o' slack w/adjuster barrels. Helps to have a setup with adjuster barrels somewhere in the cable path. Gets the cable out w/o too much squishiness.
*Tektro, especially TRP levers w/QR buttons, are very helpful, that's what I use w/bar-cons.
6. I tend to favor longer brake shoes, for better braking, so even removing the straddle cable often doesn't clear the tire, especially with vintage narrow-mount setups.
*Canti bikes that might need to go into the car often might get short blocks up front, preventing my fellow club riders from hearing me swearing mightily, in public.
*Recently a big fan of Kool-Stop thinline dual-compound ATB shoes: thin, non-replaceable, but long and curved to follow the rim arc; have to be OK with a large screened ATB logo on your non-ATB machine.
*More recently found Kool-Stop thinline dual-compound BMX shoes seem identical to their ATB cousins, but are cheaper; the price you pay for saving $$$ is the even-more-declasse "BMX" screened on the shoes.
*The brake shoe length/type stuff above also applies, for me, to non-canti centerpull calipers that use canti shoes. I'm primarily talking Paul Components here. Short blocks up front for car bikes, long Kool-Stop thinline dual-compound ATBs in the back.
7. I think this is all....
8. I will attempt to attach a piccie of the non-Riv vintage steed w/CX-70 calipers.

On Friday, December 19, 2014 9:33:17 PM UTC-5, drew beckmeyer wrote:

[Aaron Young]

Paul, you are a bozo, too?  I thought I was the only one! :)

Yes, the CX-70's differ in more than just pad length.  The vertical slot that the pads sit in are on the front end of the brake.  Many other canti's are designed in the reverse way with the pad slot nearer to the fork legs (see this here on the Tektro 720's: http://www.rivbike.com/product-p/brc15153.htm).  This design element is what allows the CX-70's to open so widely.  At least that's what it looks like to me.

-Aaron Young

The Dalles, OR

--

[Garth]

The canti's which I still prefer are all the "vintage" Shimano's that use the good ol' smooth post pads .  On these the pad mounts in front of the arm .  With Kool Stop "dura" type pads, which are needlessly long , they do not clear the stays .  However, the pads are easily trimmed of the trailing end, where the first "notch" in the pad is.  Voilla !  Now the pads clear the stays :)   You can also buy road type replaceable post type holders/pads in their place, but you don't save anything on replacement pads.

I love these canti's because they are so easily adjusted and offer a huge range of fit .   They are great brakes, regardless of the era they were made. 

[Dave Johnston]

On the front wheel sometimes you can flip the hub quick release and remove the hub axle from the dropout and push the wheel up so the brake pads are under the rims near the spokes. This will give you enough slack to pop the straddle out. I've used this technique with center pulls to remove the stradle button. I haven't tried it on the rear.

-Dave

On Friday, December 19, 2014 9:33:17 PM UTC-5, drew beckmeyer wrote:

[Kurt Nowak]

I was pulling my hair out with this one too. Its much easier than we think. Apparently the metal cable end just a little stuck, preventing it from sliding out when grabbing onto the cable handle thingy. Just take something like a small screwdriver or allen wrench (or a little stick if you're out on the road/trail) and push the cable end (flat surface) within its hole. This will free it up and allow you to pull the cable out nicely (with the cable grab handle) while squeezing both brake pads against the rim with your hand. I hope I explained this well enough.

[JohnS]

This winter my CX-70's seemed to be dragging against the rim. Upon closer inspection I found that the bushing was binding on the brake arm. It is a non-serviceable part since it is pressed together, no options to re-grease. They came on my QB that I bought used, so I don't know how old they are. Could be rust or grit, who knows? Can't take them apart to find out. I replaced with Tektro 720's. At least they open and close like they are suppose to.

JohnS

[Paul Brodek]

First off, great resurrection of a 01/2015 thread!

Were the CX70s binding only when the bolt was tightened, or without the bolt being torqued down?

There are a couple of reasons for cantis to bind.
One is if the bushing inner diameter is too narrow. I don't think that's common.

On Mon, Jun 4, 2018 at 9:45 AM, JohnS <shar...@gmail.com> wrote:

This winter my CX-70's seemed to be dragging against the rim. Upon closer inspection I found that the bushing was binding on the brake arm. It is a non-serviceable part since it is pressed together, no options to re-grease. They came on my QB that I bought used, so I don't know how old they are. Could be rust or grit, who knows? Can't take them apart to find out. I replaced with Tektro 720's. At least they open and close like they are suppose to.

JohnS

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[Paul Brodek]

First off, great resurrection of a 01/2015 thread!

Were the CX70s binding only when the bolt was tightened, or without the bolt being torqued down?

There are a couple of reasons for cantis to bind.

One is if the bushing inner diameter is too narrow. I don't think that's common.

On Mon, Jun 4, 2018 at 9:45 AM, JohnS <shar...@gmail.com> wrote:

This winter my CX-70's seemed to be dragging against the rim. Upon closer inspection I found that the bushing was binding on the brake arm. It is a non-serviceable part since it is pressed together, no options to re-grease. They came on my QB that I bought used, so I don't know how old they are. Could be rust or grit, who knows? Can't take them apart to find out. I replaced with Tektro 720's. At least they open and close like they are suppose to.

JohnS

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[Paul Brodek]

First off, great resurrection of a 01/2015 thread!

Were the CX70s binding only when the bolt was tightened, or without the bolt being torqued down?

There are a couple/few reasons for cantis to bind.
1. The bushing inner diameter is too narrow. I don't think that's common.

2. The canti boss outer diameter is oversized. I don't think tt's common for the overall boss diameter to be oversized, but sometimes the very end of the boss becomes mushroomed.

3. The canti boss is too short, so the arm binds when the bolt is tightened.

4. I suppose you could have enough grit between the boss & bushing to cause binding.

5. What'd I miss?

Paul Brodek

Hillsdale, NJ USA

On Mon, Jun 4, 2018 at 9:45 AM, JohnS <shar...@gmail.com> wrote:

This winter my CX-70's seemed to be dragging against the rim. Upon closer inspection I found that the bushing was binding on the brake arm. It is a non-serviceable part since it is pressed together, no options to re-grease. They came on my QB that I bought used, so I don't know how old they are. Could be rust or grit, who knows? Can't take them apart to find out. I replaced with Tektro 720's. At least they open and close like they are suppose to.

JohnS

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[Philip Williamson]

My only question about CX-70s is, “I can haz?”

Philip
Santa Rosa, CA

[Brad]

I had a similar problem with my CX-50's (which I bought new last fall).  They weren't binding, but by the end of the winter, I could feel a distinct grinding sensation when I pulled the brake levers. I flushed the bushing with oil and the problem went away. I also wasn't impressed with the serviceability, but I'm not planning on replacing them quite yet. I'll try to flush them out a little more regularly over the winter.

Brad

Queens

[Brad]

Paul,

I'm not sure how to articulate this, but the Shimano CX cantis have a floating bushing that's held by the bolt. So the friction is between the bushing and the cantilever body, not the bushing and the canti boss. To lube the system, you need to drip oil between the bushing and the cantilever body. 

My CX50s didn't bind, but felt rough. If I let them go long enough I'm pretty sure they would have frozen eventually. Note: I commute on the bike all winter in the salty northeast and don't wash & lube as often as I should.

Brad

Queens

On Wednesday, June 20, 2018 at 8:37:52 PM UTC-4, Paul Brodek wrote:

First off, great resurrection of a 01/2015 thread!

Were the CX70s binding only when the bolt was tightened, or without the bolt being torqued down?

There are a couple/few reasons for cantis to bind.
1. The bushing inner diameter is too narrow. I don't think that's common.

2. The canti boss outer diameter is oversized. I don't think tt's common for the overall boss diameter to be oversized, but sometimes the very end of the boss becomes mushroomed.

3. The canti boss is too short, so the arm binds when the bolt is tightened.

4. I suppose you could have enough grit between the boss & bushing to cause binding.

5. What'd I miss?

Paul Brodek

Hillsdale, NJ USA

On Mon, Jun 4, 2018 at 9:45 AM, JohnS <shar...@gmail.com> wrote:

This winter my CX-70's seemed to be dragging against the rim. Upon closer inspection I found that the bushing was binding on the brake arm. It is a non-serviceable part since it is pressed together, no options to re-grease. They came on my QB that I bought used, so I don't know how old they are. Could be rust or grit, who knows? Can't take them apart to find out. I replaced with Tektro 720's. At least they open and close like they are suppose to.

JohnS

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[Shoji Takahashi]

Hi Brad,

Yes. My CX70 rusted at the bushing-- and I, too, used them through the winter/snow/slush. 

When I tried to service them, I noticed you can't! Too bad, because I thought their set up and braking performance was great. 

Shoji

Arlington MA

[JohnS]

Same problem for me. I was commuting in the Baltimore region this winter when the bushings started to bind. They use a LOT of salt here! They don't get a lot of snow, but there is ice/slush. Inner bushing is binding to the outer brake arm.

JohnS