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

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

Postby rogerzilla » 10 Oct 2020, 11:40am

tatanab wrote:
rogerzilla wrote:Centrepulls were the best option on lightweights until Campag made a sidepull that worked better. They have a lot of theoretical and practical problems but they look good on vintage frames (dual-pivots look horrendous) and may be your best option if reach is very long.

What, even period correct dual pivots such as GB Synchron and Weinmann Dynamic?
pwa wrote:I suspect, now, that I probably needed an impossibly slim spanner to access a slim nut between the arms and the fork / frame rather than the nut on the face of the arms?
As an impoverished schoolboy, to centre cheap steel sidepulls on my 3 speed roadster I would set a screwdriver against the spring and hit it with hammer to shock the whole lot to rotate so that the brake was centralised.

I think that was SOP for cheap sidepulls, and in most bike maintenance books of the time.

Yes, period DP brakes would look ok, if you can find any. Don't just whack Tektro or Acor long-reach DPs on there, though - I have done that and they look really nasty. If you're on a tight budget, Dia-Compe 750 centre-pulls look pretty timeless (although they're not as stiff as the ones that use plain-post pads).

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

Postby Brucey » 10 Oct 2020, 3:26pm

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

Postby Brucey » 10 Oct 2020, 3:41pm

Mick F wrote:Mine on Hercules were basic chromed steel side-pulls.
I had that bike from 1964 to 1982 and never had an issue with them pulling off to the side.


they would have been 'proper' side pulls, with a single pivot. Often such brakes at that time used curved spacers that couldn't be moved on the brake bridge or the fork crown; the same piece had a slot in it for the brake spring too. This meant that once the brake was centred, it stayed centred. To adjust it, spring bending was required.

I am aware that people had that problem, but in my experience, I never had or have had since on a couple of bikes with side-pulls. Moulton is on it's second set of side-pulls - first Tektro, and now Shimano. Never an issue with pulling to the side.


they would have been dual pivots; they don't have the same centring issues.

From building Mercian though, it was always Campag.


BITD they would have been SP side pulls. When you look at them it is not difficult to see why they became popular; they were considerably better made than most other caliper brakes. Like any other SP brake they still to be set up carefully.

FWIW the arrival of aero brake levers effectively sounded the death knell for SP side-pulls; the front brake often wouldn't centre properly once it was connected to a short (and stiff) housing run on a small racing frame.

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

Postby Mick F » 10 Oct 2020, 5:00pm

Dual pivots and single pivots?
Not made any difference to me.

I have Campag Athena on Mercian. Single pivot rear and dual pivot front.
No issues whatsoever ............... and none of my single pivots over the years either.

Set 'em up right, and they're fine.
Mick F. Cornwall

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

Postby rogerzilla » 10 Oct 2020, 7:10pm

One known disadvantage of DP brakes is that the pads are basically fixed and only move if the lever moves. This means (a) a slightly out of true rim will push against one pad, then the other and (b) frame/wheel flex when climbing can give significant drag because the pad can't get out of the way and will resist the rim. Normal side-pulls (and centre-pulls, and cantis and V-brakes) don't suffer from either of these as they have no fixed centre point and the whole brake can swing from side to side.

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

Postby Brucey » 10 Oct 2020, 7:18pm

Mick F wrote:Dual pivots and single pivots?
Not made any difference to me...


they are very different brakes; single pivots are only centred by the spring, but DPs arms are interlinked i.e. the movement of the arms is synchronised by a mechanical linkage. The issues with keeping the two types centred are completely different.

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robert17
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Re: When did Centre-pull brakes take over from Side-pull ?

Postby robert17 » 10 Oct 2020, 10:43pm

Brucey wrote:when MAFAC centre pulls were introduced they were widely acknowledged as the best caliper brake available and quickly took a big slice of the lightweight market. There had been many other brakes which one could call 'centre pull' type previously but none were as well thought out or became as popular as MAFAC. Almost any handbuilt lightweight machine between the early 1950s and the 1980s could legitimately be fitted with MAFACs and still be 'period correct'. Standard models fit brake drops from ~50mm to ~75mm but less common ones can go shallower and deeper respectively.

There is a nice article about MAFAC in the classic lightweights website but this hasn't yet reappeared in the revamped site. Fortunately the internet archive has a copy of part 1

https://web.archive.org/web/20200106172821/http://www.classiclightweights.co.uk/components/mafac1-comp.html

there are also parts 2 and 3 IIRC.

There were many other half- decent brakes available including various side pulls but it was arguably the introduction of the Campagnolo brake in the late 1960s which provided the first real competition for 'top spot' in the brake market. MAFAC even brought out their own side pull brakes in response. Nonetheless MAFAC centre pulls were still used to win the TdF in the 1970s.

Image

If you are faithfully restoring a 'production model' bike then it should arguably have the correct model of brake fitted to it, whatever that might be. However if it was a lightweight which would have been sold as a frameset only, it would have been built as the owner desired BITD, so anything you fancy that is 'period correct' and fits is probably fair game.

IME long reach side pulls from the 1960s are mostly a pretty sorry bunch, but a well fettled set of MAFAC centre pulls can be a pretty good brake even by modern standards. So I'm building a 1960's lightweight at present (not slavishly 'period correct' BTW) and it may have had 'Universal' centre pull brakes on it BITD. But I don't have any of those, and I do have some MAFACs, and I think the MAFACs are better brakes too, so that is what will probably go on the bike.

cheers

My father purchased the bike as frameset only in 1965. The only things left on it when pulled from his garage were the following;

Campagnolo cable guide, Stronglight BB and a GB rear centre pull. Pictures below, plus one of the Mafac brakes I've purchased.

He sadly cannot really remember the full spec. His next bike after this was a bespoke Holdsworth Italia which he requested with Mafac cantilevers.

Therefore, a true restoration is a little tricky, I'm just trying to be near enough.

Robert.
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NATURAL ANKLING
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Re: When did Centre-pull brakes take over from Side-pull ?

Postby NATURAL ANKLING » 10 Oct 2020, 11:14pm

Hi,
Thank heavens for a bit of sanity.
I had a viking in early seventies, it had side pull brakes and the rear derailleur worked back to front, forward for ist gear :?
It got nicked, even today I think about the thing.
To this day its been centre pull brakes with the exception of V brakes, even these suffer from and stiffness in the outer cable can affect centring of arms.
I had some junk steel single pivots and did not centre well.
My weinmann gb brakes would pull a stopee with no problem, you just had to get those soft rubber brake blocks to last more than two weeks :P
NA Thinks Just End 2 End Return + Bivvy
You'll Still Find Me At The Top Of A Hill
Please forgive the poor Grammar I blame it on my mobile and phat thinkers.

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

Postby Mick F » 11 Oct 2020, 8:55am

Brucey wrote: ............. single pivots are only centred by the spring ........
Wrong.
It depends on what you mean by "centred" though.

Single pivots in my experience are centred by the clamp/nut/bolt etc and they are adjustable left/right.

If the spring isn't the same pull on both sides, you have to centre off to one side so when the brakes are applied, the blocks touch the rim together.

Having sufficient brake cable suitably fitted in length makes the two arms work better too. Nothing worse than the cable outer forcing the issue being too long or too short.
Mick F. Cornwall

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

Postby Brucey » 11 Oct 2020, 8:59am

Mick F wrote:
Brucey wrote: ............. single pivots are only centred by the spring ........
Wrong.
....


no. Only the spring. When you move the centrebolt, you move the spring.

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

Postby Mick F » 11 Oct 2020, 9:02am

Exactly! :D
When you move the centre-bolt, you move the whole lot!
Nothing to do with the spring by itself.

As I said, it depends what you mean by "centred".
Mick F. Cornwall

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

Postby Brucey » 11 Oct 2020, 9:34am

the brake also goes 'off centre' wrt to the wheel if the wheel is put in the fork sideways.... :roll: :wink:

The point I was trying to make is that some caliper brakes have a mechanical connection between the arms, so that they cannot go 'off centre' in normal use, or be subject to being easily tugged about by the brake cable. In this respect DPs are completely different from SP side pulls; SP side pull arms are free to pivot independently and are only held centred by the spring. Failing to distinguish between the two and then further muddying the waters is helping no-one.

Brakes which have a (centring) connection between the arms include

- All DP brakes
- Altenburger/GB 'Synchron' brakes
- Current Shimano SLR-EV brakes
- a few other side pull brakes with a linkage
- Weinmann Centre pull brakes (apart from the very first (none) and very last (different linkage) versions)
- Dia Compe (610/750) centre pull brakes (which are nigh-on identical to weinmann ones)

The last two have a 'pip' that slides in a groove in the other brake arm; this stops the arms from getting out of sync, even if the springs/pivots change on one side only.

The 'beborex' brake

Image

has a linkage between the arms but it doesn't affect the brake centring; the arms are still free to rotate around the centrebolt and are only held in position (centred) by the spring, just like any other SP brake.

BTW the latest SLR-EV brakes are (in principle of operation, if not appearance) an even more faithful knock-off of the Altenburger/GB design than older DPs were.

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

Postby Mick F » 11 Oct 2020, 9:52am

Brucey.
Go back to the first page and look at my reply to PW.

By rotating the whole thing, you can get the blocks even on both sides.

The spring is a return spring that works on both arms, but the unit is centred by dint of it's locked position on the brake bridge.
If the wheel is in a different left/right position, re-centre the brake using the bolt.
Mick F. Cornwall

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

Postby thirdcrank » 11 Oct 2020, 10:23am

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?

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

Postby Brucey » 11 Oct 2020, 10:35am

Mick F wrote:Brucey.
Go back to the first page ....


that is b.obvious to anyone that knows what they are doing and misses the point that in a SP brake the arms are ONLY coupled to the rest of the brake via the spring and in a DP brake that is not the case. You may not have noticed but in practice the centring qualities of SP and DP brakes are completely different.

cheers
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