Cycling UK Forum

I have a nice old British Eagle frame, 531 and converted from staight bar to drops.
The Dia Compe cantilevers have never meshed easily with the stud spacing which seems to me to be too close, even with the narrow Mavic MA2 rims. I have to choose blocks with minimal braking surface to brake mech. distance.
The spacing of the studs is 60mm rear and 50 mm front.
The current levers are STI Shimano STX 3x7, which I would like to keep.

Does anyone have thoughts and advice on more suitable brakes, please?

.

What model are the Dia Compe cantilevers?

The following *might* be suitable alternatives:

Shimano BR-CX50

As shown in the tech doc below these use three different bolt and spacer sizes to cope with varying rim width and boss spacing. See page 17 of the Shimano dealer's manual below for a chart detailing the spacers required for different combinations of rim width and boss spacing.

NB 1 It appears that some (many?) retailers selling these brakes are supplying them with only one or two of the three different spacers and bolts, probably because they are OEM stock. I think you would need to make certain which spacers and bolts are included before making a purchase.

NB 2 The CX50 brakes are supplied with moulded pads, which are specific to that model. The cartridge version supplied with the CX70 version, which uses the more widely available standard Shimano pattern rim brake pad, is no longer available. There have been a number of previous threads about this, including the suggestion that the cartridges of some other aftermarket manufacturers, e.g. Ashima, *might* be compatible with the CX50 bolts and spacers and so likewise allow Shimano pattern rim brake pads to be used.

http://www.sjscycles.com/Drawings/Shima ... ch_Doc.pdf

https://si.shimano.com/pdfs/dm/DM-RCBR001-00-ENG.pdf

Smooth post cantilevers

It's possible that some of the current models of smooth post cantilevers can cope with traditional boss spacing, but I think you would need to check the specifications carefully. The comments/answers on SJS's website suggests the Shimano Altus would be compatible, but that the Dia Compe 999 might only work with a narrow rim (although 'narrow' is not defined).

https://www.sjscycles.co.uk/brakes/fron ... es-silver/

https://www.sjscycles.co.uk/brakes/dia- ... ver-brake/

The Shimano CX50 are very good cantilever brakes and other brake shoes will fit. Due to the longer nut in the shoe of Aztec ones I just drilled the rececess in the spacer slightly deeper. I could have choosen the file a bit of the nut instead I suppose.
I would try and buy sets with the three different spacers as it would be difficult to calculate before hand which to use. A bit of trial and error to arrive at the correct one.

Dia comp will not work with the stud spacings you have in my opinion. I tried them and the set up angle ends up wrong.
I also was unable to get enough pressure on the lever to do more than slightly slow my speed.

Thanks for your thoughts and recommendations.
I think that the Dia Compes are 980s.

Dia comp will not work with the stud spacings you have in my opinion. I tried them and the set up angle ends up wrong.
I also was unable to get enough pressure on the lever to do more than slightly slow my speed.

That is my problem.

I presume that modern spacing is greater. What is standard now?