cantilever brakes for an old frame

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pliptrot
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Joined: 12 Jan 2007, 2:50am

cantilever brakes for an old frame

Post by pliptrot »

I have a frame built for 27" wheels with cantilever brakes. It's a George Longstaff so I want to keep it going. The set up of brake blocks on the current cantilevers (Dia Compe 987 (front) and Mafac (back)) on 700C wheels (MA40) is difficult in that the blocks do not hit the rims squarely - the studs are too high. The frame and forks are what you may call classic 531 touring design. Does anyone know of cantilevers which may have more vertical adjustment to accommodate this mismatch? V-brakes look worse so that's not the way to go. I would change the levers too, if that is required. Thanks for any advice.
thirdcrank
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Joined: 9 Jan 2007, 2:44pm

Re: cantilever brakes for an old frame

Post by thirdcrank »

Speaking has somebody who faced a version of this long ago, I remember an explanation from CJ which must be archived somewhere. Basically, the brake bosses are pretty much standard, but their positioning isn't and that's not only height (relative to the rim) but position on the fork blades. That article won't cover recent brake models but I doubt if there's been many.
iandusud
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Re: cantilever brakes for an old frame

Post by iandusud »

You could fit these: https://www.paulcomp.com/shop/component ... /motolite/ but at around £180 per brake it's not the cheapest option! In fact probably cheaper to get the frame and fork modified with new bosses.
iandusud
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Re: cantilever brakes for an old frame

Post by iandusud »

These look like they go a lot lower than most https://www.tredz.co.uk/.Shimano-105-Ca ... cbEALw_wcB
MartinC
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Location: Bredon

Re: cantilever brakes for an old frame

Post by MartinC »

Altus CT91 canti brakes - Shimano's bog standard and still available. They have a lot of possible adjustment. I used these to solve the braking on a BSO where the bosses seemed to have been welded on at random and no standard v brakes could strike the rims correctly.
slowster
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Re: cantilever brakes for an old frame

Post by slowster »

iandusud wrote: 24 May 2022, 10:34am These look like they go a lot lower than most https://www.tredz.co.uk/.Shimano-105-Ca ... cbEALw_wcB
It does look like the slots on those brakes might give the adjustability the OP is seeking, but I think there are two potential issues the OP would need to check.

Firstly, the pads on those brakes require one of three different lengths of spacer and corresponding length bolt, depending upon the boss centre measurement and the upon the rim width. An older frame is likely to have a narrower boss centre measurement, and consequently need the small size spacers. Very often those brakes are sold with only the large or large plus medium spacers and bolts, not all three sizes (possibly because what the retailer is selling is an OEM part). See the diagram here - http://www.sjscycles.com/Drawings/Shima ... ch_Doc.pdf. Shimano's chart specifying which spacer size is required for a given boss spacing and rim widths is on page 17 of this link https://si.shimano.com/pdfs/dm/DM-RCBR001-00-ENG.pdf.

Note that the pads are specific/unique to that brake, and being a moulded pad the adjustement/toe in must be set up from scratch every time the pads are replaced. The more expensive CX70 version of the brake came with a cartridge which accepts standard Shimano road pads, but has been discontinued.

Secondly, lowering the height of the brake pads will affect the brake's mechanical advantage. An added complication is that the CX50 brakes are designed for NSSLR levers.
jimlews
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Re: cantilever brakes for an old frame

Post by jimlews »

IMHO you are looking at the problem from the wrong end.

By changing to 700c you are only making more problems and expense for yourself.
Stick with the 27" rims the frameset was designed for; such rims ARE available:

https://www.hubjub.co.uk/kinlin-t10-all ... 2891-p.asp

https://bankruptbikeparts.co.uk/collect ... rigida-new

https://www.sjscycles.co.uk/rims-tape/a ... r-36-hole/

Any of the above rims can be built into a sturdy wheel suitable for touring use
and in my opinion the 27" gives the nicest ride of any wheel size.

If you are worried about future proofing your ride, buy several pairs.

Tyres are also available; Schwalbe, Paneracer and other manufacturers produce tyres for 27s
Tyres can be stored indefinitely in a cool dark place, so future proofing is also possible here.
hamster
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Joined: 2 Feb 2007, 12:42pm

Re: cantilever brakes for an old frame

Post by hamster »

You could try fitting U-Brakes (early 90s MTB), as they have a very different (higher) canti pivot position.
Carlton green
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Re: cantilever brakes for an old frame

Post by Carlton green »

With regard to Jim’s suggestion above. One of my bikes still runs on 27 x 1&1/4” tyres and another was converted to run on 700c tyres. The one with 27s on has wheels that I built with the Rigida rims and I buy tyres for it when the opportunity arises and my store is running low. I don’t use that bike a lot so being stuck in the middle of nowhere and not being able to buy another tyre or rim isn’t a concern (*), the arrangement will likely be good for a couple more decades so whilst moving it to 700s too might be ideal I’m not rushing to change things - if it ain’t broke then don’t fix it.

Of course being stuck somewhere and needing spare parts might be a concern and hence I altered the other bike to 700c (so it can be taken on holiday / anywhere away from home), thankfully the brakes (traditional callipers) had enough drop in them to accommodate the difference rim diameter. Whatever, as Jim suggests, running on 27’s is still possible, it just needs a bit of planning and it might be as practical as any other way forward.

* edit. ie. If I broke down miles from home and there was a bike shop available to me then it’s unlikely that they would have any 27 x 1&1/4” rims and tyres; however it is likely that they would have some selection of 700C tyres and maybe even some wheels and rims too. If you don’t take the bike far from home the ready availability or not of parts is irrelevant.
Last edited by Carlton green on 1 Jun 2022, 7:49pm, edited 1 time in total.
Don’t fret, it’s OK to: ride a simple old bike; ride slowly, walk, rest and admire the view; ride off-road; ride in your raincoat; ride by yourself; ride in the dark; and ride one hundred yards or one hundred miles. Your bike and your choices to suit you.
Cyckelgalen
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Joined: 21 Sep 2018, 11:29am

Re: cantilever brakes for an old frame

Post by Cyckelgalen »

Have a look at Tektro CR720 cantis. They allow a lot of vertical adjustment and are a popular cheap option when converting to a larger rim size.

viewtopic.php?t=96386
iandusud
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Re: cantilever brakes for an old frame

Post by iandusud »

hamster wrote: 24 May 2022, 1:59pm You could try fitting U-Brakes (early 90s MTB), as they have a very different (higher) canti pivot position.
As I remember it U-brakes used a boss that was mounted above the rim.
jimlews
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Re: cantilever brakes for an old frame

Post by jimlews »

Being stuck somewhere in need of spare parts is always going to be a problem, whatever the part may be.
But parts can be couriered to most areas of the world, these days.

Also, I suggest that any cycle tourist venturing into remote places should:

A/ Make sure they are equipped with bombproof wheels.

B/ Have a good working knowledge of wheel building.
iandusud
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Re: cantilever brakes for an old frame

Post by iandusud »

jimlews wrote: 24 May 2022, 3:49pm Being stuck somewhere in need of spare parts is always going to be a problem, whatever the part may be.
But parts can be couriered to most areas of the world, these days.

Also, I suggest that any cycle tourist venturing into remote places should:

A/ Make sure they are equipped with bombproof wheels.

B/ Have a good working knowledge of wheel building.
Doesn't A negate B? :D
jimlews
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Joined: 11 Jun 2015, 8:36pm
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Re: cantilever brakes for an old frame

Post by jimlews »

iandusud wrote: 24 May 2022, 4:01pm
jimlews wrote: 24 May 2022, 3:49pm Being stuck somewhere in need of spare parts is always going to be a problem, whatever the part may be.
But parts can be couriered to most areas of the world, these days.

Also, I suggest that any cycle tourist venturing into remote places should:

A/ Make sure they are equipped with bombproof wheels.

B/ Have a good working knowledge of wheel building.
Doesn't A negate B? :D
One would hope so.

But the best laid plans...

Oh, and C/ Be equipped with a reasonably comprehensive array of tools to effect a repair, should that be necessary. :D
Carlton green
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Joined: 22 Jun 2019, 12:27pm

Re: cantilever brakes for an old frame

Post by Carlton green »

jimlews wrote: 24 May 2022, 3:49pm Being stuck somewhere in need of spare parts is always going to be a problem, whatever the part may be.
But parts can be couriered to most areas of the world, these days.

Also, I suggest that any cycle tourist venturing into remote places should:

A/ Make sure they are equipped with bombproof wheels.

B/ Have a good working knowledge of wheel building.
That’s all true. Of course some components are more commonly available than others. I think that I could walk into a localish bike shop (say 15 - 20 miles away) and buy a replacement 700c wheel or tyre but finding something in the old 27” size would be a great surprise.
Don’t fret, it’s OK to: ride a simple old bike; ride slowly, walk, rest and admire the view; ride off-road; ride in your raincoat; ride by yourself; ride in the dark; and ride one hundred yards or one hundred miles. Your bike and your choices to suit you.
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