V-Brake and Canti...

[greenteadrinkers]

Anyone ever use a Canti brake up front and V-brake in the back? I know I'd need different pull levers, which complicates things, but I've noticed up front, the V-brake can sometimes be a little more than I need, it's great in the back though. I have two sets of Paul neo-retro canti's sitting around and was thinking the combination might be something weird worth looking into.

Thx! 

Scott

[Patrick Moore]

What would you hope to gain by this sort of combination? Is it that you've found cantilevers less effective in the rear than desired? 

I've found this, at least using drop bar levers -- probably due to my ineptitude in installing them; but I've also found that a good canti design -- I like "high profile" arms -- properly set up gives good braking front and rear; as I never get tired of saying but I'm sure you get tired of hearing, the best brakes of all the very many types I've used over the years were the IRD wide-profile cantilevers with salmon pads set up by Rivendell staff on the drop-bar'd Sam Hillborne I bought back circa 2013 or so -- nothing better both for power, feel, and modulation; really wonderful. 

Short answer: "No, and I don't see why it would be worth looking into." But please explain your purpose, maybe there is a good reason to do this.

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Patrick Moore

Alburquerque, Nuevo Mexico, Etats Unis d'Amerique, Orbis Terrarum

[greenteadrinkers]

With the v-brake up front, I tend to get this fork vibration I've never really experienced with a cantilever. The headset is nice and tight and nothing else seems to be problematic, just thinking if that vibration might be due to the different stopping power of v brakes, would the canti up front help reduce fork vibration and over more subtle braking modulation? Hopefully, this makes sense.

[Patrick Moore]

So, you've got a pair of Paul cantilevers, one for the front and one for the back ....? Is not Bob your uncle?

And would you care to discuss selling your extra pair of Paul cantis ...? (Silver only ...)

Patrick Moore, slumming with Tektro CR720s in ABQ, NM.

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[greenteadrinkers]

Hahaha, they are black. I actually bought them from a list member last spring, which included moon units. Also, bought a black 56cm Sam from a list member around that time. At the time, thinking was to go with the Pauls, but, happily was introduced to V-brakes. The fork vibration issue really only happens on fast descents, but, I never experienced that issue on other bikes with canti's. From what I gather, V-brakes have more stopping power, which I have found to be the case. The Canti's seem to have a less, which might be great for braking in the front?

[Patrick Moore]

Seriously: Install the Pauls right: get someone to do it for you if you can't do it yourself. That will solve your shuddering problem, give you good braking front and rear, save you from having to find a different brake lever, and absolve you of the aesthetic sin of mismatched levers and brakes front and rear.

Or not, it's your bike. But well set up cantis really ought to solve your problem and look good doing it, besides.

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[greenteadrinkers]

Sounds good, thanks for the input!

[Joel S]

I found a good mechanic up your way in Amherst if you need.  

[Daniel M]

If you're getting shudder with a V-brake then I suspect you're just as likely, if not more, to get it with cantis, because as the fork flexes, the distance between the cable hanger and the brake itself changes, which leads to a feedback loop of exacerbated shudder.

I'm a loudmouth V-brake evangelist, but if you've already gone to the trouble of a long-pull setup, I think you will find cantis a downgrade.

Do you have a particularly flexible fork, BTW?

Daniel M
Berkeley, CA

[Daniel M]

Oh I see it's a Hillborne. My Hillborne had run-of-the-mill Deore V-brakes and it was one of the best braking bikes I've ever had.

DM

[Garth]

    Try the Tektro fork mounted cable hanger as the front brake cable is then direct to it just above the yoke cable. It's a common thing for shudder in the Cyclocross world. Also make sure your headset is properly adjusted.

   

   

[Nick Payne]

I have the opposite on my Appaloosa - V-brake in front and canti on the rear. I used that combination because I found that cantis on the front get in the way of front panniers - I prefer touring with front panniers and no rear panniers.

The brake levers are TRP and with a travel agent on the front to match the V-brake to the lever cable pull.

Nick

[Philip Williamson]

I’d be more likely to put the V on the front, like Nick. His travel agent trick is a smart way to match the levers with the different brakes, too.

I’ve had two bikes that needed Paul minimotos to cure the brake judder. The light forks and long steerers did the flexing trick under hard braking, slackening the brake pressure. Because the cable stop is on the brake, Vs and Minimotos aren’t affected by the flex in the system.

I’d look at the V-brakes pads, sand them and make sure they hit square, and make sure there are no dents or high spots in your rim. If you have another wheel that fits, I’d swap that in and see if the judder remains.

Philip

Santa Rosa, CA

[Daniel M]

I will also throw out there that finding a long-pull lever you can live with is a preferable solution than Travel Agents. I'd sooner go with a short-arm V-brake than use a Travel Agent, but there are significant benefits to long-pull brakes, both rim and mechanical disc, in that the cable is under less tension so the cable stretches less and the housing compresses less as a result.

Daniel M
Berkeley, CA

[Victor Hanson]

This is (i think) is easy.   1) are your v-brake bushings too loose.  2) brake boosters are ugly but the bees’ knees for stopping power.  $35 i know but with careful installation they work great.

Victor

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VIctor R. Hanson

Gen Mgr

Schmier Industrial Properties

o:  510-652-0800

c:  510-207-8593

[Victor Hanson]

scott,

If you have ‘short pull levers’ Problem Slovers makes essentially a cam to get the extra cable pull for v brakes.  However,  Patrick raises a better point, why? In the first place,  with less than 42mm tire width cantilevers set up properly stop plenty good

Vtw

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[Michael Baquerizo]

i'm not a pro mechanic by any means but i've used the standard shimano lever on a tektro canti front and shimano v brake rear and didn't really have beef with the stopping power (casual use, not performance at all, in NYC)

[fug...@gmail.com]

There are real problems with Travel Agents, including safety. I just changed levers.

[Ash]

Here's a related thread 

https://groups.google.com/g/rbw-owners-bunch/c/a0uWpfDl6Ss/m/G7bKwJ8XCAAJ

After experimenting with various setups, I finally settled with Avid shorty ultimates, setup with wide profile in the rear and narrow in the front.  Been riding the Susie this way for over a month.  Very happy with break power distribution and modulation. 

[greenteadrinkers]

Thanks for all the info, everyone! I'll need to take a deeper dive into the comments shortly.

[Victor Hanson]

Please expand?   I have used travel agents for years, even replaced cables on them..   I have had no issues. 

VTW

[fug...@gmail.com]

Twice I had frayed cables even when installed by LBS. I was told by 2 different bike mechanics frayed cables were not uncommon - also I remember the feel was not as good as direct. YMMV 

[Kainalu V. -Brooklyn NY]

Daniel's statement makes some sense- "but there are significant benefits to long-pull brakes, both rim and mechanical disc, in that the cable is under less tension so the cable stretches less and the housing compresses less as a result."

That's enough of a reason to never use cantilevers again. I use Avid Speed Dial levers for the adjustable pull built in to the lever. Currently all set on long pull and that's how they'll stay. Glad the last time I spent a lot on cantilevers was 1990

-Kai

[Benz Ouyang, Sunnyvale, CA]

Travel Agents need to be set up correctly so the cable has no relative motion with respect to the pulley, especially around the bridging hole. Otherwise, the sharp kink and repeated motion may possibly cause the cable to fray. The key is to ensure the bridging hole is set correctly within the rotation range of the pulley. Here's Park Tool's tutorial on Travel Agent setup.

Given that there are people with good experiences with Travel Agents, I don't believe the mechanism is always inherently bad. OK, maybe if you consider being sensitive to setup as bad. Furthermore, having a shop do it doesn't guarantee that the job was properly done. I can't tell you how many times I've been aghast at "professional" work that I could have done better, if I had their tools (which I didn't because it's too expensive for one-time use).

Finally, the leverage/cable displacement change provided by the Travel Agent is not adjustable. It's kind of hit-or-miss whether you like the feel. For many people, having a spongy feel isn't great, and they prefer a solid feel. However, if the brake is set up and adjusted correctly, those two feel types only indicate how much leverage the brake system has – the spongy feel is high leverage, and the solid feel is low leverage. See St. Sheldon for more info (applies equally to canti and V-brakes). Some brake levers have adjustable leverage though, and with those, one can customize the leverage to vary the feel to one's liking (again, trading power for "solidness").

[Mark Roland]

I question the notion that these attributes represent a "significant advantage." My Trek 830 still has the original basic cantilever brakes from 1984. I don't think the pads, cables, or housing have been changed. Stops like a charm. Even after being under all that averse tension and compression for the past 36 years. Also cantilevers have been stopping tandems, loaded touring bikes, and racing bikes for many years. I get that people don't like working with them, But it's just another personal technology decision, like whether you want to use indexing, or electronic shifting, or friction. Cantilever brakes are effective when they are set up the way they are supposed to be set up.

[lconley]

Sorry, but that article is full of misinformation as are many articles on cantilever brakes. The brake pad rim contact point to cantilever pivot point is constant regardless of where the pad washers are - it is a fixed distance. It is fixed by the relative position of the cantilever braze on to the rim surface and does not change by changing the pad washers or even brand of brake - the relative motion of the pad to rim is constant regardless of the shape of the metal in between. Changing the pad washers only changes:

 1. the the relative location of the straddle cable attachment points to each other and to the straddle hanger

 2. the amount of flex between the brake pad and the pivot point.

Laing

Delray Beach FL

On Wednesday, October 21, 2020 at 2:06:56 PM UTC-4, S wrote:

Although I have switched to using V-brakes, I agree that cantis work well when set up properly. Has anyone linked this article yet? Good tips:

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

I also agree with Ash that the model of canti can make a big difference.

I think technique may sometimes play a part in fork judder or perceived lack of modulation when using V-brakes. Because of the greater mechanical advantage, they require a much lighter touch on the levers than cantis or calipers. When I first switched to Vs, until I learned to lighten up, I nearly sent myself over the bars several times. Now I have no problems. I find the feel of Vs very similar to mechanical disc brakes

[lconley]

and 

 3. the relative location of the straddle cable cable attachment points to the brake pad rim contact point.

[Ash]

This might be tangential, but here's an observation I made recently while playing with Canti brakes.  When the cable stop is mounted on the stem (ie farther from the brakes), the setup becomes more squeak-prone as compared to a fork mounted cable stop.   I was intrigued and changed around the cable stop a couple of times without changing anything else with the brakes.  It squeaked repeatedly more with stem-mounted.  I can probably reduce the sound or even eliminate with better toe-in pad adjustment, but the bottom line is fork-mounted cable stop setup is more forgiving.

On Wednesday, 21 October 2020 at 13:03:06 UTC-7 S wrote:

I don't see how this general idea is wrong or "misinformation":

"I try to make this slotted part of the arm be perpendicular to the brake pad post when the pad contacts the rim.  Why?  Because this lets the pad hit the rim as squarely as possible.  Too far past 90 degrees and the brake loses power (especially true with v-brakes) and when the arm is past 90 degrees, it’s on its way to promoting the pad diving under the rim."

And the relative position of the straddle cable is key to making cantis work. So anything that affects that, including washers, is important.

[Eric Daume]

Yeah, but Mark you like DC750 brakes as well, so your views are pretty suspect :)

Eric

V brake fan

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[lconley]

"I try to make this slotted part of the arm be perpendicular to the brake pad post when the pad contacts the rim.  Why?  Because this lets the pad hit the rim as squarely as possible.  Too far past 90 degrees and the brake loses power (especially true with v-brakes) and when the arm is past 90 degrees, it’s on its way to promoting the pad diving under the rim."

Geometrically this is just plain false. The brake pads have spherical washers that allow, within limits, the brake pad to be perpendicular to the rim whether the arm is slanted in or out or perpendicular. The geometry of the pad to the rim to the pivot point is constant. The pad is ALWAYS headed in a downward arc relative to the rim because braze on pivot point is outward of and below the rim surface, even when the brake pad post to brake arm attachment point is moving up.

Pretend the braze on pivot point is the hub of a very tiny wheel to the right and down from the braking surface. As the tiny wheel rotates counterclockwise, the spokes on the left rotate down as the spokes on the right rotate up.

Laing

On Wednesday, October 21, 2020 at 4:03:06 PM UTC-4, S wrote:

I don't see how this general idea is wrong or "misinformation":

"I try to make this slotted part of the arm be perpendicular to the brake pad post when the pad contacts the rim.  Why?  Because this lets the pad hit the rim as squarely as possible.  Too far past 90 degrees and the brake loses power (especially true with v-brakes) and when the arm is past 90 degrees, it’s on its way to promoting the pad diving under the rim."

And the relative position of the straddle cable is key to making cantis work. So anything that affects that, including washers, is important.

On Wednesday, October 21, 2020 at 12:16:49 PM UTC-7 lconley wrote:

[Nick Payne]

On Thursday, 22 October 2020 07:03:06 UTC+11, S wrote:

I don't see how this general idea is wrong or "misinformation":

"I try to make this slotted part of the arm be perpendicular to the brake pad post when the pad contacts the rim.  Why?  Because this lets the pad hit the rim as squarely as possible.  Too far past 90 degrees and the brake loses power (especially true with v-brakes) and when the arm is past 90 degrees, it’s on its way to promoting the pad diving under the rim."

The second part of this description (that the angle of the arm can somehow promote the pad diving under the rim) is garbage. The geometry of the pad/rim interface relative to the brake pivot point doesn't change regardless of what path you follow between the two. It's just as much woolly thinking as the PMP cranks from the 1980s, that were supposed to eliminate TDC and BDC when pedalling:

Nick

[lconley]

The article claims that the relative motion of the pad to the rim can be changed by altering the distance of the pad to the brake arm with washers. This is false. The relative motion of the pad to the rim is fixed by the fixed relative location of the brake pivot to the rim. It does not matter how many washers are used, nor whether the brake is a V-brake or a cantilever. The changes that result from adding or subtracting washers or changing from V-brake to cantilever are real, but they are not because the relative motion of the pad to the rim is changed, because it cannot changed without moving the braze on. 

The frame design/build can greatly alter the effectiveness of the brakes - the closer the brake pivot is to the rim, the greater the mechanical advantage can be, up to the point that the brake post bottoms out in the slot. 

Laing

On Wednesday, October 21, 2020 at 5:02:40 PM UTC-4, S wrote:

Maybe we are talking past each other or interpreting that passage differently? To me, the point is not about pad angle, but arm/wire angle. You want a good arm/wire angle at the point where the pad contacts the rim and washers can help you achieve this. For instance, keeping all else equal, if you use fewer washers, the pad starts farther away from the rim, hence the arm needs to swing farther in for the pad to contact the rim, increasing the arm/wire angle and decreasing mechanical advantage. I think this is easiest to visualize with V-brakes, as the wire remains horizontal.

[S]

Actually, wow, re-reading it, I am misrepresenting that quote, I thought he was saying something different and overlayed my own point on top of it. That's what I get for responding too quickly. Ugh. I apologize.

On Wednesday, October 21, 2020 at 2:08:41 PM UTC-7 S wrote:

Anyway, I should have just linked Sheldon, whose descriptions and advice are always the best: https://www.sheldonbrown.com/cantilever-geometry.html

On Wednesday, October 21, 2020 at 2:02:40 PM UTC-7 S wrote:

Maybe we are talking past each other or interpreting that passage differently? To me, the point is not about pad angle, but arm/wire angle. You want a good arm/wire angle at the point where the pad contacts the rim and washers can help you achieve this. For instance, keeping all else equal, if you use fewer washers, the pad starts farther away from the rim, hence the arm needs to swing farther in for the pad to contact the rim, increasing the arm/wire angle and decreasing mechanical advantage. I think this is easiest to visualize with V-brakes, as the wire remains horizontal.

On Wednesday, October 21, 2020 at 1:29:38 PM UTC-7 lconley wrote:

[Mark Roland]

Yes, using a cable stop mounted at the fork is a very well known fix to eliminate the "bow" affect of a long cable run from the stem cable stop to the cable hanger that can be a source of judder.