Paul Netro-Retro Cantilevers & Straddle Cable Height: where is your happy place?

[John Phillips]

Hi, my question is:

   If, and only if, you are happy with your Paul Neo-Retros, what is the height of your straddle cable / cable carrier in relation to the pivots of your brakes?

 

   I'm trying on adjust my Neo-Retro canti's to brake as well, or close to as well, as the Paul Touring cant's I have on the back of my Hunqapillar.  I'm using Paul Canti levers with both. I've read through the info on the Black Mountain Cycles blog, and the pdf document Mike Varley has a link to, but I'm still not getting the braking I'm hoping for. I'd like to keep the straddle cable at least high enough to clear the hole in my fork crown, and the Nitto front rack mounted there, if only for safety's sake.

   I've read here that some people found Neo-Retro's frustrating, but some people love them. So, I'm hoping your anecdotes and testimonials will point me in the right direction, 'cause I'm puzzled.

Thanks for your help,

John

[Scott G.]

The neo-retros are cable length insensitive,.

The tourings are the ones that the straddle length varies the mechanical advantage.

You can turn them into virtual v-brakes with a really short straddle, more power,

less pad to rim distance. Leave the brake cable long, and fiddle with hanger height

height, and straddle length. Educational.

[Bill Lindsay]

The math indicates that all wide profile cantilevers have a very flat response to straddle height.  In other words straddle height doesn't matter with Paul Neo-Retros.  If that's the only variable you change you'll probably get frustrated because the result won't change much.  If they feel great, lucky you because small changes in straddle height will leave them feeling great.  If they feel lousy, bummer, because you may feel like you are "fiddling" all day and nothing is changing.  

The math indicates that all narrow profile cantilevers have a very steep response to straddle height.  In other words straddle height is super important with Paul Touring Cantilevers.  If you change straddle height to avoid your front rack you may get frustrated because the resulting brake feel will change completely.  

I've got lots of set up experience with both, but neither is in my current stable.  I also find that the rim/brakepad interaction is terribly underrated.  Too many people think koolstop salmon solves all problems, and I've found that is not necessarily the case.  Virtually nobody talks about the rim as a contributor, save as a consumable wear-item.  I think some rims make poor brake rotors, and I know some rim/brakepad combos are not good.  

My anectdote, which is no more than an anectdote, is my 650B Atlantis.  I chose to run black Cliffhangers (from Riv) because Riv runs them on alot of builds and I trust them.  I blindly upgraded the stock Shimano pads in CX70 brakes to KoolStop salmon inserts and the braking sucked (for lack of a better word).  They went from nothing to grabby, and the only thing that modulated was the pitch of the howl.  Please take my word for it, I know how to set up brakes.  I blamed in part the black anodized non-machined sidewalls of the Cliffhanger rims.  Rather than buy new rims to prove my own diagnosis, I switched back to the stock Shimano pads and everything was remarkably improved.  From howling to silent, from grabby to controllable modulation.  Now the braking is among the best I've used.  So for that machine, KoolStop salmons were the wrong choice.  Your mileage may vary.  

Bill Lindsay

El Cerrito, CA

[lconley]

My understanding of the math is that the shorter and straighter the transverse cable, the more mechanical advantage for both wide angle (Neo-Retro) and medium angle (Touring) cantilevers, just more so for the medium angle, but it still helps the wide angle. If you have both, put the Touring cantilevers on the front where most of the braking is done and the Neo-Retros on the rear.

The distance between the arm and the pad is also important, make sure that the narrow spacers are on the inside between the pad and arm and the wide spacers are on the outside of the arm, I believe that this is more important on the Neo-Retro wide angle models. This rotates the wide angle arm up so that its geometry is ever so slightly closer to the medium angle arm geometry.

Laing

Delray Beach FL

[John Phillips]

So maybe the question I should be asking is, if you're happy with your Paul Neo-Retro's, what rims and brake pads are you using???

   I could be completely confused by the math, but it looks to me as though there is a curve to the response of wider profile canti's to straddle height, but that curve in the response is so low, I would have to put the straddle cable though the middle of my tire, at least if I'm trying to match the braking of my Touring Cant's in the rear. And I don't believe this solution would work out for me in my situation.

   Thanks Bill, I'm guessing the stock Shimano pads were black compound pads? I'm also using Cliffhanger rims, mine are the plain silver ones, but I was also thinking about trying out either the black or the dual black/salmon Kool-Stops to see if they exorcised the shrieking banshees in my bike.

 

John

[Bill Lindsay]

The black Shimano slide in inserts that improved the braking on my black Cliffhangers were that standard Shimano compound.  The compound  almost looks very dark brown.

You understand the MA math correctly.  there's a steep part of the curve for wide cantilevers, but it exists inside the volume of the tire, and you can't get there.   :(

Bill Lindsay

El Cerrito, CA

[John Phillips]

Thanks Laing,  I will check out changing the spacers & washers up like you suggest. I don't know if I have much more range to move the pads higher to make this work. The Touring Canti's on my back wheel look like they may have a bit more range for that kind of tweaking, but definitely worth a try.

What everyone's said so far is confirming my nagging suspicion that I need to fork out for a set of Touring Cant's for the front wheel.

It's not a great habit to have, but I've braked mostly with the back wheel since I was a kid. Where I grew up, our roads were mostly bad asphalt or decomposed granite, and covered in pine needles & oak leaves in winter with fog or rain all year. If you locked up your front wheel on leaves or gravel or wet asphalt, you might hit some dry asphalt and fly over your bars. I've tried to break the habit for years, but haven't gotten there yet.

Thanks,

John

[John Phillips]

Thanks Bill, you made me feel a little better in that at least I was understanding the math!

Looks like I'm going to have to buy the Touring Canti's and try out some black Kool-Stops.

Thanks,

John

[Jay Lonner]

On my Hunq I went from Neo-Retros to Touring to Motolites. Could never get the cantis dialed in and I’m much happier with the linear pull brakes. If you’re buying new brakes anyway it’s worth thinking about. (Of course you’d have to buy a new lever as well.)

Jay Lonner

Bellingham, WA

Sent from my Atari 400

On Jul 28, 2020, at 2:20 PM, 'John Phillips' via RBW Owners Bunch <rbw-owne...@googlegroups.com> wrote:



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[Paul Brodek]

Not to be automatically contrarian, but from a foot/heel clearance standpoint, usual usage is low-profile Touring in the rear to maximize heel clearance, with the Neo-Retros up front, where clearance isn't an issue. Plus the Neo-Retros in front look much cooler.

I think the low-profile cantis were generally designed to maximize heel clearance, not for performance reasons. In fact, on Paul's website the Touring is described thusly:

"The Touring Canti is a powerful cantilever brake with a similar design to the Neo-Retro, but with the arms angled upward. This gives the brake a much narrower profile without significantly reducing stopping power."

As for the shoe/arm spacing, isn't that also somewhat dependent on the boss-boss spacing? Relatively narrow boss placement means the wide spacers may not work at all behind the shoes, while relatively wide boss spacing may require using the wider spacers to avoid the arms diving under the rims during braking.

Or am I missing something?

Paul Brodek

Hillsdale, NJ USA

[lconley]

I have a Neo-Retro on the front of my Bombadil and a Touring on the rear and they work fine for me (but I live in Florida and I have drop bars & levers - drop bar levers are generally supposed to have more mechanical advantage than mountain bike style levers if I remember my Sheldon Brown correctly), but the OP seemed to be looking for more braking power and reversing the layout should give better braking on the front - all else being equal. The rear tire has less grip and the Neo-Retro should work fine there, even a single pivot sidepull is usually plenty on the rear. I was think of reversing them myself to see if the generalized math translates into reality. I have not measured the two types of Paul cantilevers, there could be dimensional differences that cancel out the "all else being equal."

On a different note, I just got the shipping notice on my large Gus Boots Wilsen frame. I guess they finally got the large 700C forks in! I have unused V brakes and cantilevers sitting around...

Laing

Do as I say and not as I do....

[John Phillips]

Hi Paul,

   As for the Touring Canti's having less braking power than the Neo-Retro's, the math doesn't seem to bear that out. To get more mechanical advantage from my Neo-Retro's, I would need to lower my straddle cable to about 5cm's higher than the pivots, placing the cable just above the rim, in the middle of my tire, and this just won't work with my 55mm Ant' Hill tires. The Touring Canti's will give me the power I need even with the straddle cable 10-11cm's higher than the brake pivots. This also clears my Nitto front rack fork crown support which will keep the straddle cable from snagging knobby tires if my brake cable snaps. The Neo-Retro's might give someone with a strong grip enough braking power, but what if I need to brake my loaded Hunqapillar with two fingers on a steep, bumpy, paved road? Here in Berkeley, we have some really steep streets, and some really scary bad drivers, and combining those has me looking for some better braking on my front wheel.

   And yes, you're right, futzing with the brake pad spacers won't fix this problem.

John

[John Phillips]

Thanks Laing for the suggestion, but I don't think shifting my Neo-Retro's to the rear would give me enough braking power on the rear wheel.

John

[tuolumne bikes]

I'm seeing a lot of mathematicians talking without any math. :-) So far, Paul's comments square with my understanding and experience.

Excepting some of the dumbed down, no choices, 90s low profile Shimanos, I've generally don't find cantis to lack stopping power, and even the worst are fine for the rear where low profile is needed. If the pads are aligned sensibly, the straddle cable makes a roughly 90 deg bend over the saddle, and the straddle cable pulls at right angles to the line through the pivot and straddle attachment point on the arms, they all seem to work. It seems like some of the very long armed low profile brakes are intended to be set up not optimized as I just described to reduce the effective lever arm. In essence part of the cable tension pulls the arms up rather than together which reduces power and increases a sense of modulation.

If braking is poor and the cable/arm geometry is sensible, check the rims and pads. Squealing is the main issue with cantis for me.

Carl

[lconley]

See below for the math

https://www.sheldonbrown.com/cantilever-geometry.html

Laing

[John Phillips]

There is also this article on cantilever brake geometry:

http://www.circleacycles.com/cantilevers/canti-geometry.pdf

John

[masmojo]

I definitely know how to set them up, wants hard is explaining how to do it! :-)

[Mark Allen]

Thanks for sharing this John, it made things click for me much better than my prior lifelong method of randomly adjusting straddle cable lengths and yoke positions until it felt not horrible.

Mark

[John Phillips]

Hi Mark,

    I found this blog post of Mike Varley's to also be a big help:

https://blackmtncycles.com/get-the-most-out-of-your-canti-brake/

John