Cycling UK Forum

Rear of a 1980s Dawes Super Galaxy tandem.

What is this type called, and what would you recommend as replacement?

Thankyou

Jonathan

I had those same weinmann cantilever brakes on my Dawes super galaxy 3x6 speed tandem bought from sjsc in 1989 or thereabouts. I always found them very good brakes. The main issue being replacement brake blocks. I can't be certain but I found some Shimano road brake shoes for side pull calipers which used a bolt. Reusing the hardware helped them fit. V brake pads may also fit. Long term I would change them for V brakes and get compatible levers. I may even still have them in my parts bin as I found them easy to set up and firm in operation.
viewtopic.php?t=51266#p426173

What is the length of the threaded post? It looks like it may be the same as the length on those replacement pads which use two sets of concave and convex washers. If it is, then there are plenty of those that you should be able to choose from, e.g. this symmetrical short length pad https://www.sjscycles.co.uk/brake-block ... ks-salmon/, as well as longer pads designed for V brakes, most of which are asymmetric. The longer V brake pads may offer better braking, but the length means they are likely to extend behind the fork blades, potentially making it necesssary to partially deflate the tyre to remove the wheel. NB I am assuming the actual thread is standard (whatever that is, M5?)

I've just checked some old Shimano V brake pads that use the concave and convex washers, and the threaded post on those is 25mm long.

I presume you would not be able to fit a more modern brake, whether V brakes or cantilevers, on a 1980s frame, because the frame cantilever boss spacings then were much narrower, i.e. around 55mm(?) vs. 70mm-80mm on modern frames.

Thankyou, both. That's very helpful.

It's a bolt into a metal receiver in the block, M6, thread length 34.5 mm

Jonathan

Convert to stud mount: https://www.ebay.co.uk/itm/305177743601 (no knowledge of seller or item beyond description in listing).

slowster wrote: ↑8 Oct 2023, 3:04pm ...
I've just checked some old Shimano V brake pads that use the concave and convex washers, and the threaded post on those is 25mm long.
...

I've just checked some Shimano BR-M770. 23 mm threaded post. With the original pair of washers to fit the cylindrical mount that needs another 10mm.

Jonathan

I suspect you will not be able to find a replacement block or cartridge with a 34.5mm threaded post.

gaz's link looks interesting. I wonder why the allen key fitting is at 90 degrees to the hex nut. Normally smooth post cantilevers are designed to accept an allen key in the opposite end of the housing from the the hex nut. I even wonder if an unmodified Weinmann cantilever would accept a smooth post pad (the posts are 7mm diameter) - the obvious difficulty would be tightening the hex nut, but it might be possible to hold the pad and stop it turning or moving by wrapping in a rag and gripping it with vise-grip pliers.

I suggest you measure the cantilever boss spacings. It might be that you could fit replacement modern brakes. Even if, as I suspect, you could not fit V brakes, a modern low or medium profile cantilever might work, because the narrower boss spacing would make them work as medium or wide profile cantilevers respectively (I think this is something which I recall Brucey suggesting - I've not tried it myself).

Another possible option is the Shimano BR-CX50 cantilever, which is available with diffferent length bolts and spacers to allow for different boss spacings and rim widths. See page 17 of the manual here for details - https://si.shimano.com/en/pdfs/dm/RCBR0 ... 00-ENG.pdf. The downside of the CX50 is that the moulded pads are specific to that brake, although there was a previous thread which discussed how the cartridge units of other brands might fit - viewtopic.php?t=83367.

By way of comparison, this thread shows an older bike both with an old spacing pattern Shimano cantilever and with a modern wide profile cantilever designed for wider boss spacing - viewtopic.php?p=1367218#p1367218

gaz wrote: ↑8 Oct 2023, 3:46pm Convert to stud mount: https://www.ebay.co.uk/itm/305177743601 (no knowledge of seller or item beyond description in listing).

slowster wrote: ↑8 Oct 2023, 4:19pm gaz's link looks interesting. I wonder why the allen key fitting is at 90 degrees to the hex nut. Normally smooth post cantilevers are designed to accept an allen key in the opposite end of the housing from the the hex nut. I even wonder if an unmodified Weinmann cantilever would accept a smooth post pad (the posts are 7mm diameter) - the obvious difficulty would be tightening the hex nut, but it might be possible to hold the pad and stop it turning or moving by wrapping in a rag and gripping it with vise-grip pliers.

Thanks, both.

It wouldn't be a problem to put the pliers on it occasionally.

Jonathan

slowster wrote: ↑8 Oct 2023, 4:19pm...
...
I suggest you measure the cantilever boss spacings. It might be that you could fit replacement modern brakes. Even if, as I suspect, you could not fit V brakes, a modern low or medium profile cantilever might work, because the narrower boss spacing would make them work as medium or wide profile cantilevers respectively (I think this is something which I recall Brucey suggesting - I've not tried it myself).
...

73mm between centres.

And a single lever pulls both rear and front rim brakes...

Jonathan

If you are scouring ebay/jumbles those cantis are the Weinmann version of Shimano mid-profile BR-M730/M732 in XT, or BR-MT60/MT62 in Deore.

Low-profile canti's should be fine on those boss spacings, although you may need to set them closer to the rims.

slowster wrote: ↑8 Oct 2023, 4:19pm I even wonder if an unmodified Weinmann cantilever would accept a smooth post pad

Thinking about it, it looks like position of the post in the cyclindrical holder is determined by the nut and washer (in red below) which are wider than the post. I don't know how it might work if a smooth post was used. At minimum it would presumably result in needing a couple of more turns of the hex nut to tighten.

Jdsk wrote: ↑8 Oct 2023, 4:29pm 73mm between centres.

I thought it would be less than that. I think it might still not be enough for V brakes, but the CX50s should work and maybe many other modern cantilevers. I guess cable pull might be an issue, i.e. you would want a brake that was suitable for your lever. That presumably is another thing that would rule out full V brakes. I've used 1980s cantilevers with SLR and SSLR levers, and personally did not notice any difference. I think SLR was essentially just traditional cable pull but with a return spring in the lever, and I presume your lever would have a similar traditional cable pull. So maybe there is enough leeway to use your levers with modern cantilevers (maybe even mini-Vs?). Hopefully someone else with more actual experience can advise.

With regards to buying an old pattern Shimano cantilever, I vaguely recall a thread a couple of years ago in which someone posted a wanted ad asking for one, and another member posted a link to an ebay listing for a copy of the Shimano brake by another small (chinese?) manufacturer. IIRC the seller was in Germany or the Netherlands. I think the thread was on this forum, but unfortuntely if was indeed a wanted ad it would have automatically been deleted.

Jdsk wrote: ↑8 Oct 2023, 4:29pm
73mm between centres.

And a single lever pulls both rear and front rim brakes...

Jonathan

Single lever for both F and R rim brakes.....so what other brake(s) have you got? And does it stop adequately?
For example, if the rim brakes are the main stopping power and you have also got a rear drum brake as a drag brake (eg Arai) I wouldn't give the drag brake one of the captain's regular brake levers....a drag brake can be operated by the stoker, or by a friction/ratchet gear lever (eg left bar end) in the case of a child stoker.

I'm getting mighty hazy on all the historical brake stuff.........
I just measured a couple of Vee brake bikes, they seem to be about 80mm boss spacing. Wasn't there one sort of full size Vee brake which would fit less than 80mm spacing?.....and are F and R spacings the same on this machine?
I have all sorts of stuff in the bits box......i still have this cantilever...

003 by 531colin, on Flickr

Braking on a solo was limited by my ability to keep the rear wheel down, braking from the hoods before my hands became arthritic. Pretty sure I also have an example of the brake it derived from. (note cable adjuster in the straddle wire......much less detriment to the MA than an adjuster in the "main" wire.)

Probably got some of these kicking about as well, they take standard stud fit I think I use KoopStop road pads in the holders.

002 by 531colin, on Flickr

My parents old tandem I used to take my kids out on was immeasurably improved (particularly in the rain) by fitting a Honda 50 front hub brake; These days i might give careful consideration to a Sturmey Archer hub brake....the big (90mm?) one

slowster wrote: ↑8 Oct 2023, 5:34pm

slowster wrote: ↑8 Oct 2023, 4:19pm I even wonder if an unmodified Weinmann cantilever would accept a smooth post pad

Thinking about it, it looks like position of the post in the cyclindrical holder is determined by the nut and washer (in red below) which are wider than the post. I don't know how it might work if a smooth post was used. At minimum it would presumably result in needing a couple of more turns of the hex nut to tighten.

IMG_8790 a.jpg

Not sure that would work.
In my picture of the old Shimano brake there is a very obvious washer that the plain stud bears on....in fact a "wedge" washer which sets the toe-in....in Jonathan's picture it looks like the "bolt with a hole in it" (draw bolt?) nips up against the brake arm, rather than the brake pad stud.....?
...and the bolt which screws into the pad sets the toe-in?

If you do want to replace them, I'd suggest Suntour SE cantilever for the rear, in preference to Shimano CX (v cheap from SJSC). There's a problem though, in that there's no front option available.

531colin wrote: ↑8 Oct 2023, 6:01pm

Jdsk wrote: ↑8 Oct 2023, 4:29pm And a single lever pulls both rear and front rim brakes...

Single lever for both F and R rim brakes.....so what other brake(s) have you got? And does it stop adequately?
For example, if the rim brakes are the main stopping power and you have also got a rear drum brake as a drag brake (eg Arai) I wouldn't give the drag brake one of the captain's regular brake levers....a drag brake can be operated by the stoker, or by a friction/ratchet gear lever (eg left bar end) in the case of a child stoker.
...

Yes, both tandems have Tsunoda rear drum brakes, which I think were made by Arai.

Braking is OK.

And there's a child much more often than an adult on the rear seat, and some of them are much too young to be relied on for braking : - )

Jonathan