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A Specific Cantilever Brake Design

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A Specific Cantilever Brake Design

Old 11-20-11, 09:20 PM
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xenologer
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A Specific Cantilever Brake Design

Hello
Im looking for my dream brake, but the current distributor catalogs don't seem to offer anything that fits. Maybe someone here has seen it?

Medium profile cantilever brake -allows fender clearance w/o sacrificing power

threaded brake pads -so you can use cartridge pads

barrel adjusting straddle wire -allows compensation for pad wear w/o raising straddle wire height

pivot mounted cable anchor -avoids sharp cable bending/fraying over time

independently adjustable return springs

Imagine all the features of the tektro cr720, but in a medium instead of wide profile, so it has better mechanical advantage
has anyone seen such a brake?
Thanks
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Old 11-20-11, 09:35 PM
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any avid shorty, but use the tektro 1246A yoke, which is the same yoke that comes with the CR720.

barrel adjusting straddle wire -allows compensation for pad wear w/o raising straddle wire height
I've never seen such a device before. The yoke needs to remain in the same position, otherwise the arms won't return an equal distance, and that's why at least one side of the straddle cable has a fixed length.

Imagine all the features of the tektro cr720, but in a medium instead of wide profile, so it has better mechanical advantage
if I remember correctly, wide profile has more mechanical advantage compared to medium profile
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Last edited by AEO; 11-20-11 at 09:40 PM.
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Old 11-20-11, 09:46 PM
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Paul's touring version. they use independently adjustable return springs.
you preload the spring tension with an open end wrench,
and tightening the fixing 6mm allen bolt sets it in place.

Neo Retro is the wide profile version, touring has the arms angled upward.
and gains a bit more leverage than the L shaped sibling.

Last edited by fietsbob; 11-20-11 at 10:26 PM.
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Old 11-20-11, 11:45 PM
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re AEO
you're probably thinking of shimano 'link wire' style straddles, where one side is a housing of fixed length and the brake cable runs down it to one arm. older style yoke carriers use a second wire for the straddle, and the brake line terminates at the carrier in the center, this means you can have a barrel adjuster on the horizontal straddle wire and let any changes in length freely slide between the left and right arms.

having a variable length horizontal straddle wire is important for me because:
consider as pads wear down the distance to rim increases, typially we compensate for this by adjusting the barrel adjuster on the brake lever (at handlebar), this decreases the distane but also moves the pivot point of the straddle wire higher, resulting is less mechanical advantage
a better solution is the have a barrel adjuster on the transverse cable, this directly pulls the arms in closer, but the pivot point stays at the same height, thus the same leverage is preserved throughout pad life

a number of expensive brakes use this mechanism... but most don't meet all the other requirements in my list or have some other flaw...

re: fietsbob
the Paul touring canti is close to what I want, except the cable anchor doesn't pivot
i should also clarify that i don't like the type of springs it uses, i'm looking for the type with a hex bolt adjuster on the side as found in most common v-brakes



The Avid Shorty Ultimate Cantileveris close to what i want, (AEO: note the barrel adjuster at the tip of one arm) however it's flaw is that it has a 'folding' gimmik where the arms can be folded to either a wide profile or medium profile brake, which I just don't trust, also it has the inconvenient frontside adjustment springs

Thanks for suggestions so far
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Old 11-21-11, 08:43 AM
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I swear I've seen a straddle cable made with a built in adjustment barrel, but I'm having trouble finding it just now. I think it was an old Velo Orange product, maybe if you email them they can give you a lead on tracking it down.

Having the barrel adjuster straddle cable as a separate component would ease your search a bit.
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Old 11-21-11, 09:05 AM
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Originally Posted by xenologer View Post
re AEO
you're probably thinking of shimano 'link wire' style straddles, where one side is a housing of fixed length and the brake cable runs down it to one arm. older style yoke carriers use a second wire for the straddle, and the brake line terminates at the carrier in the center, this means you can have a barrel adjuster on the horizontal straddle wire and let any changes in length freely slide between the left and right arms.

having a variable length horizontal straddle wire is important for me because:
consider as pads wear down the distance to rim increases, typially we compensate for this by adjusting the barrel adjuster on the brake lever (at handlebar), this decreases the distane but also moves the pivot point of the straddle wire higher, resulting is less mechanical advantage
a better solution is the have a barrel adjuster on the transverse cable, this directly pulls the arms in closer, but the pivot point stays at the same height, thus the same leverage is preserved throughout pad life

a number of expensive brakes use this mechanism... but most don't meet all the other requirements in my list or have some other flaw...

re: fietsbob
the Paul touring canti is close to what I want, except the cable anchor doesn't pivot
i should also clarify that i don't like the type of springs it uses, i'm looking for the type with a hex bolt adjuster on the side as found in most common v-brakes



The Avid Shorty Ultimate Cantileveris close to what i want, (AEO: note the barrel adjuster at the tip of one arm) however it's flaw is that it has a 'folding' gimmik where the arms can be folded to either a wide profile or medium profile brake, which I just don't trust, also it has the inconvenient frontside adjustment springs

Thanks for suggestions so far
Jagwire makes the adjusters like those on the Avid brakes. They could probably be made to work with just about any brake.

That said, I think you are making too much out of the pivot point issue. The difference in mechanical advantage would be minimal given the small amount of adjustment that is being made. You could also adjust the anchor bolt on the cable to take up the slack developed in the system with pad wear so that the anchor point stays in the same place. The lack of a pivot on the anchor bolt isn't going to cause and excessive amount if wear on the cable either. All of the frayed cables I've seen on cantilever brakes (or any brake for that matter) is due to over tightening of the cable at the anchor point.

As for the spring adjustment on brakes, I find the type of adjustment that Paul (and some others) use to be superior to those found on v-brakes. They have a greater range of adjustment and allow for a finer tuning of the springs.
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Old 11-21-11, 09:10 AM
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Shimano CX series of brakes?

M
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Old 11-21-11, 11:12 AM
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Avid Ultimate, if it is so by definition , ultimate, apex, top of the heap.?

Or just go for Magura's HS33, the hydraulic rim brake.

they fit on cantilever/V bosses.

Last edited by fietsbob; 11-21-11 at 11:18 AM.
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Old 12-03-11, 07:55 PM
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New Update;

Tektro has just created my impossible to find dream brake
http://www.tektro.com/_english/01_pr...e&sort=1&fid=2

Now the long wait for it to get through distribution....
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