Cantilever brakes help needed.

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Brucey
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Re: Cantilever brakes help needed.

Postby Brucey » 16 Aug 2017, 10:39am

Hobbs1951 wrote:Thanks for that Brucey.

So more thought needed, it may encourage me, later in the year when I have the frameset restored (it's an oldie but from a highly respected builder), to remove the canti' bosses and fit caliper brakes...

John.


I wouldn't do that. I'd be more likely to add bosses to a touring frame that didn't have them.... :wink:

Gaz's suggestion of shorter brake blocks side-steps the issue of brake blocks possibly fouling wheel removal entirely. IIRC there are short-pattern post-mount cartridge brake shoes if you look hard enough.

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Hobbs1951
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Re: Cantilever brakes help needed.

Postby Hobbs1951 » 16 Aug 2017, 10:57am

What I find interesting is comparing the oldie (Roberts), with my 2002 Yates, I see the Yates's bosses are pretty much in line with the stays/forks, whereas on the Roberts the bosses are angled inwards toward the rim.

John.

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gaz
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Re: Cantilever brakes help needed.

Postby gaz » 16 Aug 2017, 11:47am

DSCN1458.JPG
Brucey Scenario 1

24mm external rim width, about 8mm space between it and each fork blade. The Koolstop Cross pads linked earlier (recommended to me by 531Colin) avoid the issue.

DSCN1457.JPG
Brucey Scenario 3

Works just fine with either the Koolstop or Clarks V-brake variety.
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elPedro666
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Re: Cantilever brakes help needed.

Postby elPedro666 » 16 Aug 2017, 12:38pm

gaz wrote:
531colin wrote:Nothing at all wrong with these....

Image

+1
Arguably the best cantis ever produced, agree with the recommendation of KoolStop pads though, excellent stuff!

If you do swap them please don't bin them, I'd be happy to give them a new home! PlanetX - amongst others - do a copy of FrogLegs that are very similar and good value.

There is also a set of mini-Vs for sale on here at the moment, not something I've tried personally but the full-size ones are exceptionally powerful. Just mention them as something else to consider in case it suits you vis-à-vis heel clearance, luggage and mudguard compatibility etc.

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gaz
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Re: Cantilever brakes help needed.

Postby gaz » 16 Aug 2017, 12:42pm

I'm not sure that mini Vs will work with the boss spacing on Hobbs1951's frame.
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elPedro666
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Re: Cantilever brakes help needed.

Postby elPedro666 » 16 Aug 2017, 12:48pm

gaz wrote:I'm not sure that mini Vs will work with the boss spacing on Hobbs1951's frame.
Quite possibly not! I must confess that I didn't convert those measurements into mm so they don't mean much to me...

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old_windbag
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Re: Cantilever brakes help needed.

Postby old_windbag » 16 Aug 2017, 1:24pm

elPedro666 wrote: I didn't convert those measurements


Many web browsers have a calculator and conversions built in. So you could type 2*log(57) into the browser line and get an answer, one browser I use pops up a calculator when it returns the answer. Also conversion wise typing "2.25 inches to mm" will give a conversion. As per dozens of other conversions. It is quite useful.

It's handy if you need to do a quick calc whilst on internet without resorting to microsoft calculator or a pocket calculator( or slide rule ). For estimates using imperial to metric and vice versa I just do them in my head. I was fortunate to straddle both systems and be taught both and work with both even in present day, there is still use of imperial in engineering.

* representing multiply operator

conversions wise may have to state us in fluid measurements

Brucey
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Re: Cantilever brakes help needed.

Postby Brucey » 16 Aug 2017, 1:59pm

25.4mm (exactly) = 1"

'old' boss spacing is typically ~2-1/2" (~63mm)
'new' boss spacing is typically ~3-1/4" (~83mm)

the new boss spacing was required for MTBs and other bikes with fat tyres. With narrow spaced bosses a tyre more than ~40mm needs to be deflated in order not to foul on the part of the brake covering the brake bosses. Very many brakes have been made that only work on wide boss spacing. However unless you need to squeeze fat tyres between the brakes arguably narrow boss spacing is better, because the brake block is more likely to hit the rim acceptably as the brake block wears.

BTW frogslegs are a wide-arm canti that only works very well on modern wide-spaced bosses. The arms end up below horizontal on narrow-boss frames.

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Steve
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Re: Cantilever brakes help needed.

Postby Steve » 19 Aug 2017, 2:22pm

Hmmm... seems like the CX70s are so good everywhere has sold out of them. Does that mean Shimano have stopped making them? Anyone know how they would compare with the cheaper (but in stock) CX50?

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elPedro666
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Re: Cantilever brakes help needed.

Postby elPedro666 » 19 Aug 2017, 3:30pm

I think there's minimal difference between the two, mechanically they're the same just slightly less refined in finish.

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gaz
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Re: Cantilever brakes help needed.

Postby gaz » 19 Aug 2017, 3:46pm

CX50/CX70 aside from finish and possibly weight they have different brake shoes.
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Gattonero
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Re: Cantilever brakes help needed.

Postby Gattonero » 19 Aug 2017, 3:57pm

elPedro666 wrote:
gaz wrote:
531colin wrote:Nothing at all wrong with these....

Image

+1
Arguably the best cantis ever produced, agree with the recommendation of KoolStop pads though, excellent stuff!

...


Maybe for touring use.
In the early days of Mtb, we gladly put them away as soon as low-profile came, and especially when V-brakes were introduced: those very wide canti's were prone to catch to brambles and branches (another reason to stop using Lycra when going offroad), and especially could get damaged when crashing.
Not to mention that you would need 5 hands to set them up with old suspension forks :lol:

I guess on a Touring bike, with bags and other stuff, there isn't any problem of clearance, Avid cantilevers are super-easy to setup and work well.
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tatanab
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Re: Cantilever brakes help needed.

Postby tatanab » 19 Aug 2017, 4:06pm

^^^^ I remember those cantis coming into the country something like 1982. At the time, MAFACs had disappeared and there really was nothing. Then the Deore arrived with toe-in adjustment. Fabulous and quite effective. Mainstream MTBs arrived somewhat after this and so the further development of cantis (good and bad) and then V brakes.

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elPedro666
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Re: Cantilever brakes help needed.

Postby elPedro666 » 19 Aug 2017, 7:02pm

Never heard of anyone having problems with cantis snagging on brambles! Lo-pro were a reaction to the ever decreasing length of chainstays causing heels to overlap the brakes and catch, functionally they are far less effective, bloomin' abysmal in many cases. I think it's Paul who's superb modern cantis (touring? cyclocross?) use a wide front and low profile rear for the best compromise of stopping power and heel clearance.

Agree that toe-in set up is a really nice bit of simple/effective engineering

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Gattonero
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Re: Cantilever brakes help needed.

Postby Gattonero » 19 Aug 2017, 7:19pm

elPedro666 wrote:Never heard of anyone having problems with cantis snagging on brambles! Lo-pro were a reaction to the ever decreasing length of chainstays causing heels to overlap the brakes and catch, functionally they are far less effective, bloomin' abysmal in many cases. I think it's Paul who's superb modern cantis (touring? cyclocross?) use a wide front and low profile rear for the best compromise of stopping power and heel clearance.

Agree that toe-in set up is a really nice bit of simple/effective engineering

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Well we never saw anyone having problem of heel clearance with the rear brakes, but more than once those things sticking out 1" or more out the forks would catch here&there on the singletracks. Surely, not a problem for a touring bike.

Lack of power for lo-pro canti's? It all depends how the cantilever is engineered.
Ever tried the Avid Ultimates? Yes, they cost a lot of money, but they have stopping power in spades! :D
Oh, they happen to have maximum stopping power when set in narrow mode, go figure

Image
It is by riding a bicycle that you learn the contours of a country best,
since you have to sweat up the hills and coast down them.
Thus you remember them as they actually are...