fitting modern type recessed brakes, to a vintage frame

Discussion in 'Bicycle Mechanics and Repairs' started by fr188, 12 May 2017.

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  1. fr188

    fr188 Active Member

    Location:
    Aberdeenshire
    hello I'm looking for any pointers/ tips, with drilling out the rear brake bridge, I was going to try to hand drill with a 8mm drill bit and mole grips to fit recessed brakes, the forks look straight forward enough to do
    thanks
     
  2. TheDoctor

    TheDoctor Resistance is futile! Moderator

    Location:
    Stevenage
    The easiest way round this is to fit a front brake there using a nut, or buy a nut fitting brakeset.
    I'd be wary of taking a drill to an old frame.
     
  3. Yellow Saddle

    Yellow Saddle Veteran

    Location:
    Loch side.
    Drilling a straight and centre crosswise hole through a tube is notoriously difficult. You have one additional challenge on the brake bridge and that's getting the angle right too. Create a little jig for the job and make sure of your angles first. Start with a pilot hole and then progress with a step drill. A standard twist drill creates a triangular hole slightly bigger than nominal size.

    The fork is easier, provided you have meat there to work with. That hole is perpendicular to the steerer but should be perfectly in plane. Remove the fork and clamp it securely and squarely and use a drill press, not handheld drill.

    Measure twice, drill once.

    Edit: Since the brake caliper will more than likely come with a flat seat at the mount bolt, you will have to find a suitable half-round converter washer/spacer in order to get the brake to seat nicely on the round bridge tube.
     
    Last edited: 12 May 2017
  4. OP
    OP
    fr188

    fr188 Active Member

    Location:
    Aberdeenshire
    Thanks for the replies, I'm still just thinking my options, I wont be home to have a good look at it until 3 weeks from now,its a 531 db frame
     
  5. raleighnut

    raleighnut Guru

    Location:
    On 3 Wheels
    Exactly correct, the front brake caliper is identical to a rear, they just have a longer bolt.
    Drilling the fork out to 8mm ( from 5) is easy but remember just drill the back of the fork to accept the sleeve nut (DO NOT Drill Right Through) and I make sure the drill is the right size to give a snug fit to the sleeve nut. I always choose one that doesn't quite 'bottom out' at the front of the fork crown but has plenty of engagement on the thread.
     
  6. Drago

    Drago Flouncing Nobber

    Location:
    Valhalla
    Right angled chuck. Piece of pith.
     
  7. S-Express

    S-Express Guest

    Unlikely to be possible on the rear, as the seat tube will be in the way. Most brake bridges are drilled before brazing.
     
  8. Yellow Saddle

    Yellow Saddle Veteran

    Location:
    Loch side.
    I don't understand.
     
  9. S-Express

    S-Express Guest

    He wants to adapt the rear brake bridge to accept a sleeve nut - but things are going to get in the way, given the angle, the available space and the direction of drilling.
     
  10. raleighnut

    raleighnut Guru

    Location:
    On 3 Wheels
    Not to mention that they generally don't have enough 'meat' to allow drilling without becoming weak if they're just a piece of tube, then there is the fact that ideally you need a pair of concave washers to fit them securely.
     
    S-Express likes this.
  11. Yellow Saddle

    Yellow Saddle Veteran

    Location:
    Loch side.
    I see. I'm slow today. Drago's right angle drill now also makes sense.
     
    Drago likes this.
  12. raleighnut

    raleighnut Guru

    Location:
    On 3 Wheels
    Here is the ideal set-up on a Surly

    clip002.jpg

    EDIT - The picture is also a link, it shows the differences between the 2 types of rear bridge.
     
    Last edited: 12 May 2017
    Gravity Aided likes this.
  13. Tim Hall

    Tim Hall Guest

    Location:
    Crawley
    I had the exact same problem on a frame I was converting. I drilled the bridge all the way through from the 'wrong' side. It worked fine for me.
     
  14. Dogtrousers

    Dogtrousers Kilometre nibbler

    When faced with a similar problem ... I purchased a set of nut-fit brakes. They weren't expensive and they work a treat.

    So I have no useful advice for you.
     
    gbb likes this.
  15. OP
    OP
    fr188

    fr188 Active Member

    Location:
    Aberdeenshire
    thanks for the replies, the rear bridge is flat on both sides I wont need a concave washer but a lock type one, if I use the front brake on the rear is there something about turning the brake pads.heres a picture of the same type of rear bridge
     

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