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Re: When did Centre-pull brakes take over from Side-pull ?

Posted: 11 Oct 2020, 10:53am
by Brucey
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

https://forum.cyclinguk.org/viewtopic.php?t=123862

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.

Image

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.]

cheers

Re: When did Centre-pull brakes take over from Side-pull ?

Posted: 11 Oct 2020, 10:53am
by peetee
Brucey wrote:I only recently became aware of this spanner from Park Tool

Image

the left end of which is meant to help centre old side pull brakes; the pegs go into the spring loops. AFAICT it is only slightly less horrible than any of the other ad-hoc ways folk use to move these brakes around; the pegs are (literally) square, going into round holes.... :roll: :roll:

cheers

I have had one of these for some time. They are somewhat dependant on there being enough room to hook them in. It’s not uncommon for a lack of spacing washers limiting the gap or the headset to get in the way.

Re: When did Centre-pull brakes take over from Side-pull ?

Posted: 11 Oct 2020, 11:06am
by Brucey
I mainly just find it a horrible idea that you would stick a tool with sharp edges on it to bear against the spring; if you need the tool presumably you need to lean on it pretty hard (otherwise you would be centring the brake one of several other ways) and creating notches in springs seems both likely and very likely to cause the spring to break subsequently. If I couldn't get it in the gap I might be grateful for small mercies!

cheers

Re: When did Centre-pull brakes take over from Side-pull ?

Posted: 11 Oct 2020, 11:09am
by NATURAL ANKLING
Hi,
Centering vs Centring?
https://wikidiff.com/centring/centering
Side pull brakes with no Mechanical centring, Suffer the same problem as "V" brakes.
The inner cable is connected to one arm, the outer cable is connected to the other arm, so the outer cable moves.
Because the outer cable moves You have an undesirable situation where the outer cable may become more stiff and less flexible / have bias thus affecting balanced movement of the brake arms before touching the rim. enter mechanical centring.
Just think single cable car handbrake...ugh.
Just like all brakes where you have independent springs if you have to rely on the balance of the arms with individual springs which includes single pivot side pull The worst of the bunch.
They can be prone to constant fettling.
To be pedantic the only brakes I'm using currently are V & canti brakes, Which will still require you to keep an eye on centring And adjust arm springs periodically.
My road bike centre pull brakes also suffer the same non mechanical centring, even though they use a cam.
There have been many attempts to use mechanical means to operate and balance brake arms, but allowing the outer and inner cable to balance as well is not very clever.

Unless full balance is mechanical you will always have this problem using springs to give you balance.
But mechanical means quite often makes the brakes less efficient, This is why V brakes Which are direct Pull Work so well.

To me it's more about anaesthetics which is why I prefer centre pull brakes.
Though going back to the OP's post, The question is what will look right what is correct looking side or centre pull IIRC.

Re: When did Centre-pull brakes take over from Side-pull ?

Posted: 11 Oct 2020, 7:02pm
by scottg
Dave Moulton on centering side pulls, like most good fixes it involves a Birmingham screw driver. :)


http://davesbikeblog.squarespace.com/bl ... rakes.html
Also Daves' blog is very worthwhile.

Re: When did Centre-pull brakes take over from Side-pull ?

Posted: 12 Oct 2020, 8:58am
by Mick F
Not unlike the method I suggest.
Nowt to do with the spring.

Re: When did Centre-pull brakes take over from Side-pull ?

Posted: 12 Oct 2020, 10:36am
by 9494arnold
One or two sidepull manufacturers did think about 'centering' a sidepull brake.
Here is an image of a Weinman 605 (quite an upmarket brake) but I know they used it on their 'lower end' brakes too , you needed a special tool with an allen key head in it that just slips in at the front ideally, although you can prise the plastic bit off and use an adjustable or very small spanner on it ) (annoyingly the Hex was a different size on the cheapies) to keep the front where you want it when tightening it up at the back . You can also just see that the rear yoke of the brake has room for a thin spanner too.
Ignore the fitting it's on a Trike on an extended nose brazed to the fork crown, and there's a Mafac Cantilever on braze on form mounts behind it.
I seem to recall Shimano Sidepull Brakes had provision fo a thin spanner on the yoke too.

Re: When did Centre-pull brakes take over from Side-pull ?

Posted: 12 Oct 2020, 11:02am
by Brucey
scottg wrote:Dave Moulton on centering side pulls, like most good fixes it involves a Birmingham screw driver. :)
http://davesbikeblog.squarespace.com/bl ... rakes.html
.


it is exactly the method used by bike mechanics (especially ones in a hurry) the world over.

Mick F wrote:Nowt to do with the spring.


Everything to do with the spring.... :roll:

Re: When did Centre-pull brakes take over from Side-pull ?

Posted: 12 Oct 2020, 11:23am
by Brucey
9494arnold wrote:One or two sidepull manufacturers did think about 'centering' a sidepull brake.
Here is an image of a Weinman 605 (quite an upmarket brake) but I know they used it on their 'lower end' brakes too , you needed a special tool with an allen key head in it that just slips in at the front ideally, although you can prise the plastic bit off and use an adjustable or very small spanner on it ) (annoyingly the Hex was a different size on the cheapies) ....


1/4" square drive socket sets often include both hexagon socket sizes to allow the brakes to be centred.

The appearance of the plastic front covers on weinmann side pulls was shortly followed by the replacement of the spring holder piece (which had been a small die casting, reasonably rigid) with a plastic piece instead. The result was that all weinmann brakes so equipped (which was nearly all of them) went from 'worth using' to 'junk' status overnight.

The plastic spring holder piece has two main problems

a) it wears, so it fails to achieve its intended task, and leaves the brake flopping from side to side and
b) it isn't stiff enough, so the brake arms appear to be about twice as flexible as they should be

the latter problem means that the brake blocks tend to fall off the rim (at the rear) or go into the tyre (at the front) when under load.

In the very final weinmann side pulls, IIRC the arms were not even flat where they bear against one another on the centrebolt. Completely hopeless.

I don't care for the plastic front covers and I will usually substitute a more 'normal' looking domed nut + locknut arrangement. Provided the spring holder is metal (not plastic) and the brake arms are not the final version, the brake is just about OK.

Weinmann made some nice brakes; the 405, 605, and Carrera models were top quality. The basic '500' model was, for a long time, the lightest standard brakeset that could be bought, so found favour with time triallists (who didn't need super brakes).

cheers

Re: When did Centre-pull brakes take over from Side-pull ?

Posted: 12 Oct 2020, 2:02pm
by bgnukem
I remember Weinmann 500 side-pulls being fitted to my childhood bikes, a Raleigh Winner 10-speed then subsequently an Orbit frameset built with parts of my choosing. Powerful they were not! They seemed to be a default choice for cheap BSOs of the day, along with Weinmann-branded hubs.

My dad had a Raleigh Merlin steel roadster at the time and I remember being impressed with the power of the Weinmann centre-pulls, in the dry at least (it had steel rims).

Re: When did Centre-pull brakes take over from Side-pull ?

Posted: 12 Oct 2020, 2:16pm
by rogerzilla
The more expensive Weinmann sidepulls used an alloy bolt. This meant using the special centring tool instantly rounded off the hex. There is a reason they went out of business; they made terrible products.

Re: When did Centre-pull brakes take over from Side-pull ?

Posted: 12 Oct 2020, 4:44pm
by Brucey
rogerzilla wrote:The more expensive Weinmann sidepulls used an alloy bolt....


example?

Re: When did Centre-pull brakes take over from Side-pull ?

Posted: 12 Oct 2020, 8:35pm
by rogerzilla
Carrera, the later model. Fortunately you could swap in the steel spindles from normal 700 calipers.

If they weren't aluminium, they were some kind of monkey metal, which seems unlikely in the top model.

Re: When did Centre-pull brakes take over from Side-pull ?

Posted: 12 Oct 2020, 11:19pm
by Brucey
rogerzilla wrote:Carrera, the later model. Fortunately you could swap in the steel spindles from normal 700 calipers.

If they weren't aluminium, they were some kind of monkey metal, which seems unlikely in the top model.


The final Carrera model was different from the preceding models, with calipers made by Dia Compe. These brakes are vastly superior to previous Carrera models. I've seen your comment on Velobase which refers to the penultimate model, which used Swiss-made parts I think.

Image

I express scepticism about the alloy centrebolt for several reasons, not the least of which is that AFAICT no other manufacturer -no matter how weight obsessed- has been crazy enough to sell brakes with aluminium alloy M6 threaded centrebolts; they simply wouldn't be strong enough. IIRC the steel used in weinmann centrebolts was roughly 8.8 grade, so they would bend (rather than snap like a carrot) in a prang or if badly fitted. Needless to say the centring tool is meant to help hold the caliper in the right place as the nut is tightened at the back, rather than groinch the caliper round when the bolt is still quite tight; you can soon make that fitting strip if you do that.

cheers

Re: When did Centre-pull brakes take over from Side-pull ?

Posted: 13 Oct 2020, 8:52am
by peetee
9494arnold wrote:Here is an image of a Weinman 605 (quite an upmarket brake) but I know they used it on their 'lower end' brakes too , you needed a special tool with an allen key head in it that just slips in at the front ideally,


The 605 might have been more upmarket that the 500 and in terms of performance it was better but still terrible. It lacked any kind of feel at the lever so grabbing a handful of lever in a tricky situation still felt like squeezing a block of cheese. Observation suggested that it was made from the same alloy as the 500 albeit slightly more of it. Weinmann’s true performance brake, the Carrera was visually, at least, a much more convincing product. As for the centring tool, there were at least two sizes. The 500 required one, the 605 another. For no particular reason, as far as I can see. :roll: Bizarre then that getting hold of these tools (and the right one too) was difficult to say the least. Perhaps the retailers didn’t see the need to provide for those that sought to polish the shoes of the donkeys they sold.