thirdcrank wrote:That Beborex brake is completely new to me - I don't even remember seeing one in a catalogue.
The one in the pic looks to have a spoke replacing the cable. I presume they would have been more effective than single pivot. Has anybody any experience of using them? I wonder why they never caught on? Too far ahead of their time? A good idea needing tweaking in the land of the rising Sun?
They are discussed in more detail in this thread
and apparently appeared in the late 1940s and were still listed by Ron Kitching as late as 1970.
Superficially they don't look a million miles away from some 'Universal' side pulls (eg mod68) fitted with the 'pillar' QR.
but the extra bits in the universal brake are only connected to one arm so don't alter the way the brake works in normal use.
I was unaware of the beborex brake for years and supposed that I might have casually glanced at them previously on old bikes and taken them for universals. Quite a few of my buddies ran older road equipment on various 'beater/training' machines in the 1980s, so grubby universals were not uncommon.
The beborex brake has a rising rate linkage so the brake will get stronger and stronger as the caliper closes (brake blocks wear) and use more and more cable travel too, until the linkage flips horizontal , at which point the brake will still work (provided the linkage is stopped by the pinch-bolt arm) but the lever may run out of travel and the MA declines suddenly to that of any other SP brake (which could be half what it was previously).
So the beborex brake will only work consistently if the rim width and brake block wear are compatible. If you set the brake up so that the linkage gets to about 45 degrees then there will be a useful increase in MA. However another 2mm of brake block wear and the brake will be dangerously close to the linkage flipping. Post-type brake blocks would ease setup; as it is I would expect you to have to use spacers in the brake block mountings as the brake blocks wear, if you want consistent braking.
[BTW using old spokes to keep brakes together is a good idea; if more people did this you wouldn't see so many brakes at jumbles with their barrel adjusters etc missing. The Follis Beborex uses a (unique?) stepped QR fitting in the housing stop; this is (yet another) small part that is easily lost from a spare brake.]