Uh-oh. I am going to have to remove the tires when I reassemble the 
Bombadil to adjust the brakes now!

Laing

On Wednesday, March 1, 2023 at 8:58:46 AM UTC-5 JohnS wrote:

> I agree with Laing, I spend way too much time setting up canti brakes. I 
> usually remove the tires and even the fenders when installing them. This 
> allows me to see how well aligned the brake pad is to the rim as Laing has 
> noted. I prefer to use brake pad holders for this reason, set them up once 
> and when the pads wear out, slide out the old pads and slide in the new. No 
> adjustments necessary.
>
> JohnS
>
> On Wednesday, March 1, 2023 at 8:46:30 AM UTC-5 lconley wrote:
>
>> That is a pretty good video - he uses the tool to show the 90 degree 
>> angle. He points out that lowering the straddle (making the straddle cable 
>> flatter) results in better braking. He even talks about getting the pads as 
>> close to the arm as possible with the Neo-Retro (wide profile) style 
>> cantilevers. To steal a phrase from someone - Approve!
>>
>> Laing
>>
>> On Wednesday, March 1, 2023 at 8:19:44 AM UTC-5 maxcr wrote:
>>
>>> I found this Path Less Pedaled video useful when I installed the Paul 
>>> Touring Cantis on my Atlantis: 
>>> https://www.youtube.com/watch?v=CDdWIq4cLLo
>>>
>>> Thanks everyone for your responses and particularly to  Laing for that 
>>> masterclass on how to set up cantis!
>>>
>>> Max who's still rethinking handlebar and drivetrain choices for the 
>>> upcoming Bombadil
>>>
>>> On Wednesday, March 1, 2023 at 8:13:39 AM UTC-5 lconley wrote:
>>>
>>>> Remember that flat at the straddle and 90 deg at the arms fight each 
>>>> other - it is always a compromise.
>>>>
>>>> Laing
>>>>
>>>> On Tuesday, February 28, 2023 at 8:41:13 PM UTC-5 Patrick Moore wrote:
>>>>
>>>>> Laing: Thanks for this detailed and informing overview; I have read it 
>>>>> through and will read it again slowly, but I think I get it: 90* to brake 
>>>>> arm pivots + as flat as possible at straddle, as little toe-in as you can 
>>>>> get by with to prevent squeal, and make sure that the pads meet the rim 
>>>>> brake tracks squarely. I've already done the last 2, must go back and 
>>>>> look 
>>>>> at the first 2. The single rear rack strut to seatstay bridge may limit 
>>>>> my 
>>>>> options in the rear. My pads are old Kool Stop salmons, the short, blocky 
>>>>> sort. I did make various shim tools for toe in, must seek those out again.
>>>>>
>>>>> Thanks again!
>>>>>
>>>>> On Tue, Feb 28, 2023 at 3:52 PM lconley <lco...@brph.com> wrote:
>>>>>
>>>>>> Geometry is all important with cantilevers. I will use Paul models 
>>>>>> for reference. Note that at a certain level, V-brakes are just optimized 
>>>>>> cantilevers, so much so that they have too much braking force that must 
>>>>>> be 
>>>>>> reduced at the levers. If maximizing braking force is the be-all, end 
>>>>>> all 
>>>>>> of braking, then why use levers that reduce the braking force? But there 
>>>>>> is 
>>>>>> something to be said for V-brakes having less tension (and therefore 
>>>>>> stretch) on the brake cable.
>>>>>>
>>>>>> 1. You want the straddle cable operating at, or as close as possible 
>>>>>> to a 90 degree angle to a line drawn from the brake arm pivot axis (the 
>>>>>> post brazed/welded to the frame) to the straddle cable connection to the 
>>>>>> arm. This is much easier on a Paul Touring than a Paul Neo-Retro. 
>>>>>> Motolites 
>>>>>> are basically taking the progression to it's conclusion (Neo-Retro -> 
>>>>>> Touring -> Motolite). Note that when working with Neo-Retros, this 
>>>>>> generally means rotating the arms as far towards the rim as possible, 
>>>>>> using 
>>>>>> the fewest, narrowest spacers between the pad and arm as possible (and 
>>>>>> that 
>>>>>> is allowed by your tires). This is where some "experts" get it all 
>>>>>> wrong, 
>>>>>> they seem to think that the rotation of the arm changes the direct of 
>>>>>> travel of the pad at the rim - i.e. the arm carrying the pad should be 
>>>>>> straight up, which is untrue. The direction of travel of the pad at the 
>>>>>> rim 
>>>>>> is fixed by where the relative location of the pivot is to the rim-pad 
>>>>>> interface - only a welder can be used to adjust this. The pivot is below 
>>>>>> and outside the rim -> the pad will ALWAYS be traveling in a downward 
>>>>>> arc 
>>>>>> relative to the rim. Note that because V-brakes use the same pivots as 
>>>>>> cantilevers, the cheapest POS cantilevers that you can find vs. Paul 
>>>>>> Motolites - on a given bike, the pads are traveling in exactly the same 
>>>>>> arc, this is a function of the frame and wheel, not the brakes nor the 
>>>>>> brake adjustment.
>>>>>>
>>>>>> 2. Ideally, you want the straddle cable as close to straight as 
>>>>>> possible where it goes through straddle cable carrier -> the straddle 
>>>>>> cable 
>>>>>> as short as possible. This is a very unappreciated part of the equation. 
>>>>>> When you apply a perpendicular pressure at the center of a straight 
>>>>>> cable, 
>>>>>> you would actually get an infinite tension in the cable if it did not 
>>>>>> stretch. This a very handy thing to use in many instances - you can move 
>>>>>> a 
>>>>>> car with only a rope and this principal. The cosine of 90 degrees is 0. 
>>>>>> When you divide by 0, you get infinity. If you want to prove this to 
>>>>>> yourself - make a straddle cable between the ends of a V-brake and use a 
>>>>>> straddle cable hanger connected to the brake cable cantilever/centerpull 
>>>>>> style.
>>>>>>
>>>>>> 3. There is an interaction between 1 and 2 - as you make the straddle 
>>>>>> cable straighter (#2), you lose the 90 degree angle (#1). On top of that 
>>>>>> as 
>>>>>> the cables, straddle hanger, and brake arms move, and the cables 
>>>>>> stretch; 
>>>>>> the geometry changes. With Neo-Retros, getting the arm as close to the 
>>>>>> rim 
>>>>>> as possible also raises the straddle cable arm interface up, getting the 
>>>>>> arm-cable angle closer to 90 degrees. Note that means having your wheels 
>>>>>> extremely true and minimizing the pad gap and toe-in. As the brake arm 
>>>>>> rotates under application of the brake, this angle improves - gets 
>>>>>> closer 
>>>>>> to 90 degrees again. As the straddle hanger rises under brake 
>>>>>> application, 
>>>>>> this also gets the brake arm - straddle cable angle closer to 90 degrees 
>>>>>> and increasing your braking force. But as all of this is going on, the 
>>>>>> straddle cable at the straddle hanger is getting less straight, reducing 
>>>>>> your braking force. With precise measurements of the actual relative 
>>>>>> geometries on your bike, you can calculate all of this, or you can 
>>>>>> experiment with lengthening and shortening the straddle cable.
>>>>>>
>>>>>> 4. I think that a far bigger item with braking is the pad interface 
>>>>>> with the rim. Getting the pad centered on the rim, or actually just a 
>>>>>> little bit above centerline of the braking surface is advised (remember 
>>>>>> that the pad is traveling in a downward arc with the pivot below the rim 
>>>>>> with cantilevers - with centerpulls, the pad is traveling in an upward 
>>>>>> arc). You also want the pad flat to the rim (up-down flat when it 
>>>>>> contacts). If you don't want squealing brakes, you must toe them in. The 
>>>>>> better your pads, the more you must toe them in. The more you toe your 
>>>>>> pads 
>>>>>> in, the worse your braking is because less of your pad is is touching 
>>>>>> the 
>>>>>> rim. I think the long pads in fashion at the moment make this worse. I 
>>>>>> prefer shorter pads with less toe-in. I have not experimented with 
>>>>>> cutting/filing/grinding a bevel on the leading edge of the brake pads, 
>>>>>> yet, 
>>>>>> but I think that hold promise.
>>>>>>
>>>>>> I spend a lot more time adjusting brake pads than anything else in 
>>>>>> the braking system (that goes for discs also). The location of the 
>>>>>> brakes 
>>>>>> makes it hard to observe the pad-rim interface which is where everything 
>>>>>> important happens.
>>>>>>
>>>>>> I use bent pieces of old credit and business cards of different 
>>>>>> thicknesses at the leading edge of the pads to set toe-in (this does not 
>>>>>> apply to the Rene Herse centerpulls).  A velcro strap at the brake lever 
>>>>>> on 
>>>>>> non-Paul brakes to apply tension. My almost half-century old 3rd hand 
>>>>>> brake 
>>>>>> tool is too narrow for todays brakes - still works on the Campagnolo 
>>>>>> side 
>>>>>> pulls though. 
>>>>>>
>>>>>> Laing
>>>>>>
>>>>>> On Tuesday, February 28, 2023 at 4:04:46 PM UTC-5 Patrick Moore wrote:
>>>>>>
>>>>>>> 1. Cantilevers too work better with tires no more than about 60 +/- 
>>>>>>> mm wide; getting a 3" knobby between the canti bosses (unused; the 
>>>>>>> Monocog 
>>>>>>> 29er has disc brakes and is set up for both) is a hassle, even when 
>>>>>>> they 
>>>>>>> are soft at 13-15 psi.
>>>>>>>
>>>>>>> 2. While I can get decent (my definition may not be yours) braking 
>>>>>>> from good cantilevers, at least I personally have found it much harder 
>>>>>>> to 
>>>>>>> get "powerful" -- = strong retardation with moderate hand pressure -- 
>>>>>>> braking with cantis than with V brakes. I do like other things -- 
>>>>>>> adjustability, modulation, looks -- better about cantis than Vs.
>>>>>>>
>>>>>>> I recall the miserable power from Mafac cantis, both single-bike 
>>>>>>> shorter-arm version and longer-arm tandem version, on my Herse, pulled 
>>>>>>> by 
>>>>>>> Mafac levers. I daresay I could have shortened the straddle cables, but 
>>>>>>> sold the bike before I got around to doing so (sold, not because of the 
>>>>>>> brakes).
>>>>>>>
>>>>>>> Laing: How do you get strong cantilever braking, particularly with 
>>>>>>> drop bar levers? I guess that one preliminary factor is to match the 
>>>>>>> pull 
>>>>>>> of your lever to the needs of the cantilever; my Dura Ace 7410-era drop 
>>>>>>> levers probably don't have as much MA as my Paul Neo Retros and Touring 
>>>>>>> cantis need for best operation, but I love the shape of those levers.
>>>>>>>
>>>>>>> I'd be interested in others' *apercus *about this.
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> On Tuesday, 28 February 2023 at 05:29:32 UTC-8 lconley wrote:
>>>>>>> > Big tires, big fenders with clearance to the tires and V-brakes 
>>>>>>> tend not to play well together. I have V-brakes on several of my bikes 
>>>>>>> and 
>>>>>>> I don't really 
>>>>>>> > see any real advantage to them over cantilevers, unless you 
>>>>>>> consider ugly an advantage. The cantilevers work just as well and have 
>>>>>>> all 
>>>>>>> the fender
>>>>>>> > clearance that you could want. I am waiting for Rene Herse to get 
>>>>>>> their cable hangers back in stock to get one for the Bombadil.
>>>>>>>
>>>>>>> Laing
>>>>>>>  
>>>>>>>
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>>>>>>  
>>>>>> <https://groups.google.com/d/msgid/rbw-owners-bunch/be53cfff-12c4-47bc-9f24-05a63dee80bfn%40googlegroups.com?utm_medium=email&utm_source=footer>
>>>>>> .
>>>>>>
>>>>>
>>>>>
>>>>> -- 
>>>>>
>>>>> -----------------------------------------------------------------------
>>>>> Patrick Moore
>>>>> Alburquerque, Nuevo Mexico, Etats Unis d'Amerique, Orbis Terrarum
>>>>>
>>>>>

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