Hanlon Dura-Ace rear brake

After some comments on my post in RPotM I thought I would reply to them here.

stevevw":1ztpdgzu said:

Here you go then. My polished first Gen rear Dura-Ace brake caliper, Part of a complete groupset i am using on the Pat Hanlon.

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First point was from Montello regarding having the blocks in back to front.

Well I did answer this with
"No they have none replaceable rubbers, closed both ends so universal fit. What do you Campagnolo boy's know anyway "

Then we had Torqueless

torqueless":1ztpdgzu said:

By way of totally off-topic hijack, I can't help noticing that stevevw's Pat Hanlon has a noticeably off-centre brake-mounting hole. I have a 1975 mystery frame with the same feature, and in the same direction- more than a mm over to driveside. Accident or design? Is this an identifying feature of a certain framebuilder? And/or an attempt at compensating for the lopsided geometry of side-pulls?

This is on a 531db frame that is otherwise true and symmetrical, as I assume stevevw's Hanlon is, so I'd reckon the chances of it being accidental to be small. How common is this? Anyone else got one?

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I did not reply but yes the mount is off set to the drive side by 2mm. As the frame is very well made I can not believe this is a mistake and must of had a reason. Any Ideas?



Then we have Woz

Woz":1ztpdgzu said:

torqueless":1ztpdgzu said:

By way of totally off-topic hijack, I can't help noticing that stevevw's Pat Hanlon has a noticeably off-centre brake-mounting hole. I have a 1975 mystery frame with the same feature, and in the same direction- more than a mm over to driveside. Accident or design? Is this an identifying feature of a certain framebuilder? And/or an attempt at compensating for the lopsided geometry of side-pulls?

This is on a 531db frame that is otherwise true and symmetrical, as I assume stevevw's Hanlon is, so I'd reckon the chances of it being accidental to be small. How common is this? Anyone else got one?

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.....just to add to the close examination of the nice picture, it would be rude not to comment, I would
say that the wheel isn't centered judging by more unworn tyre dimples on the NDS. :facepalm:

PS: Or perhaps the tread is not centered on the tyre casing :?

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torqueless":1ztpdgzu said:

Woz- So are you saying that the tyre might be somehow off-centre and therefore the brake mounting hole is not? I still maintain that, unless stevevw's camera suffers from severe astigmatism, that hole is off-centre, regardless of the tyre!

It's good to know about this stuff. As you can imagine, my frame played merry hell with my attempts at wheel-centering until I realised what was up.

Apologies for my Shimano-free posts..

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Well sorry to disappoint but the tub is fairly well centred, just not as good a picture as I had first thought I guess
The picture below is a bit better showing the tread pattern.
All pictures from my Samsung phone.



And I can assure you the frame is aliened well and rides a treat. I do have a frame checking tool and also a frame building jig although I did build them myself so could be out of bonk The jig during construction with no false axle fitted.

Re:

Thanks for taking the time to do that. I was beginning to doubt my own judgement! Do you know what year your Hanlon was built?

You've heard my ideas on this phenomenon. Another one just occurred to me: Rather than a sidepull thing, it might be a centrepull thing. One spring is always a bit weaker than the other. Maybe this is a way of fine-tuning the brake by putting the weaker spring on the 'long' side? Tbh it's been so long since I had centrepulls that I cannot even remember if it's possible to switch the springs left for right or not?

...But then again it could just be a particular framebuilder's quirk- a sort of identifying feature, a bit like Bates forks or Hetchins stays..

As far as I know the frame was built in 76-77 as a race frame. Therefore I would not of thought it would have been built with centre pulls in mind. Perhaps it is Aero to hide the arms behind the seat stay.

I'll post a pic of the chainstay bridge from my Falcon San Remo taken from the production line of the team frames by Billy Holmes which is decidedly wonky

I have come across quite a few frames where they have been brazed by the Mk I eyeball lol

Shaun

Re:

Fwiw my '75 frame is also a race frame, pretty much identical to yours, geometrically (just seen your Rbotm entry.)

Without any particular attachment to my 'centrepull' theory, it's worth remembering that the '75 and '77 Tours de France were won on a bike using centrepulls. With hindsight, we know that they were the last Tours de France won on centre pulls, but back then there was no guarantee that they were not going to return to fashion, just as sidepulls had in the late '60s.

On the other hand, framebuilders are human too, even the ones building for the top end of the market. How many frames into their career was the person who built my frame? probably hundreds. How many had they built that week?

Another possibility is that a small group of Dadaist cyclists were deliberately commissioning frames with off-centre brake holes, just because they could...

Here's a pic of the chainstay bridge of my Falcon San Remo Equipe as ridden by the 70's Falcon pro team of the day.........looks a bit slanty to me LOL



Shaun

Re:

I'll take your word for it Shaun, but I couldn't possibly comment, unless I see an attempt at a 'dead centre' picture, like steve's, with the seat tube right in the middle of the chainstays.. There's a riot of colours and diagonals in your photo. As a composition, I quite like it. I am less enthusiastic about it's merits as a means of assessing the disposition of your chainstay bridge...

Yep, believe me it's wonky and has bugged me for near on 40 years

Back in the 70's it was my job to unwrap the frames, Raleigh used about 6 feet of paper but the usual culprits (holdsworth, CB, Carlton, Mercian, Bob Jackson, Pennine, etc) wrapped their frames with about 100 feet of brown paper about 4 inches wide, took ages to unwrap as using scissors might scratch the frame.

My job was to check the paint but "Bunny" and the others simply held the frame up to the window to check it was straight

I guess my frame passed the "HOLD IT UP TO THE WINDOW TEST"

Shaun

Re:

Yeah you need a good eye for symmetry, but toleration for those little bits of wonkiness that are mainly cosmetic rather than functional, and to understand the difference..

I would guess from his name that 'Bunny' was one of those ex-RAF men, with Brylcreem, a moustache and a pipe, who seemed to spend their entire post-war existence inside a khaki-coloured warehouse coat....?