Brake calipers fixing type - single versus dual-pivot

wafter

Über Member
Location
Oxford
My current irrational fetish is to build up an old lugged steel frame with modern components. One of the potential pitfalls is the brake caliper mounting type; with earlier calipers having a stud that passes all the way through the fork / brake bridge in a close-fitting hole, to be secured with a traditional hex-nut at the rear.. while later / current calipers have a shorter stud that terminates inside the fork / bridge and is held on with a recessed, socket / hex nut that protrudes inside the frame / fork to some extent.

This means that the frames and forks are different for each mounting type; with the constant stud-diameter holes in earlier bikes requiring their rear / nut side drilling out to accomodate the larger OD of the recessed nut of the later calipers - something I'd very much like to avoid if possible..

In an effort to easily identify the brake mounting type on the frame and fork, are fixing types as simple to identify as single-pivot calipers having normal nuts and dual-pivot items using recessed nuts, or would that be too easy?

Ta :smile:
 
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fossyant

Ride It Like You Stole It!
Location
South Manchester
Nope too easy.

Both my road bikes are single pivot with recessed nuts. This came in from around 1986 (shimano 600) or earlier, so they would take dual pivots if I wanted.

You probably be limited by the frame if it's older than mid 80's
 
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wafter

wafter

Über Member
Location
Oxford
Nope too easy.

Both my road bikes are single pivot with recessed nuts. This came in from around 1986 (shimano 600) or earlier, so they would take dual pivots if I wanted.

You probably be limited by the frame if it's older than mid 80's
Thanks - I appreciate the reply. I guess on the whole that's good news as it opens up range of suitable frames to those earlier than I'd though. I suppose now it comes down to identifying the groupsets fitted and the fixing types associated with each. While will be fun :blink: :laugh:
 
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wafter

wafter

Über Member
Location
Oxford
You may have a little drilling if using recessed nuts, but you can get longer recessed nuts from SJS if the fork crown is too deep.
Ahh... so you're saying that the recess in the frame / fork might not be deep enough to accommodate shorter studs on more modern calipers? Hadn't thought of that :rolleyes:

Surely frames and forks should all be of an approximately similar depth..?
 

si_c

Veteran
Location
Wirral
It's not that easy unfortunately - but generally speaking a new dual pivot brake will have a recessed nut.

One way to generally avoid this problem on the rear by using a front brake instead of a rear brake as the bolt is long enough usually to pass through the brake bridge.
 

rogerzilla

Legendary Member
The fork is easy to drill out to 8mm (you only do the rear of the crown) for a recessed nut.

The brake bridge is much harder to drill as you can't get a normal drill between the seat tube and the bridge. A 90 degree drill adapter can work but would be expensive to buy for this one job. Any framebuilder could do it.
 

fossyant

Ride It Like You Stole It!
Location
South Manchester
Ahh... so you're saying that the recess in the frame / fork might not be deep enough to accommodate shorter studs on more modern calipers? Hadn't thought of that :rolleyes:

Surely frames and forks should all be of an approximately similar depth..?
No, you'll find older 'square' fork crowns are deeper. I have what were called 'aero' crowns, and they were designed for the shorted recessed nuts.

The good news is you can get longer nuts.

My crown looks like this - one bike was an external lug, but the other is smooth with an internal lug like below.

546349
 

Milkfloat

An Peanut
Location
Midlands
I have drilled the fork before and used a front brake on the rear and both methods worked very well.
 
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wafter

wafter

Über Member
Location
Oxford
Thanks guys - again I don't want to drill anything if I can help it as it's a ballache, one more thing to go wrong, an irreversible mod to the frame and an invitation for corrosion if I'm not having the frame refinished.. nice tip about the front caliper on the rear though - didn't think of that :smile:

No, you'll find older 'square' fork crowns are deeper. I have what were called 'aero' crowns, and they were designed for the shorted recessed nuts.

The good news is you can get longer nuts.

My crown looks like this - one bike was an external lug, but the other is smooth with an internal lug like below.

View attachment 546349
Cool - thanks. I guess it's potentially more likely with steel that the section of the fork that the stud passes through will be hollow, so hole depth won't really be a thing (the only bike I've paid attention to when replacing calipers was my Boardman, its brake bridge and fork being composite so solid and with a definite hole depth).

If it's just a case of using different recessed nuts that's certainly no big deal - I have a bag left over from fitting the 105 calipers to my Team Carbon as it happens :smile:
 

rogerzilla

Legendary Member
You can convert a front brake to a rear brake, or a nutted brake to an a/k brake, by extending the thread with an M6 die and cutting the bolt short. It is hard work if the bolt is chromed, which it generally is.
 

raleighnut

Legendary Member
Location
On 3 Wheels
Thanks guys - again I don't want to drill anything if I can help it as it's a ballache, one more thing to go wrong, an irreversible mod to the frame and an invitation for corrosion if I'm not having the frame refinished.. nice tip about the front caliper on the rear though - didn't think of that :smile:


Cool - thanks. I guess it's potentially more likely with steel that the section of the fork that the stud passes through will be hollow, so hole depth won't really be a thing (the only bike I've paid attention to when replacing calipers was my Boardman, its brake bridge and fork being composite so solid and with a definite hole depth).

If it's just a case of using different recessed nuts that's certainly no big deal - I have a bag left over from fitting the 105 calipers to my Team Carbon as it happens :smile:
As others have posted on here (and I posted on your other thread) it's easy to fit modern brakes to a classic frame.
 
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wafter

wafter

Über Member
Location
Oxford
Thanks guys - will just look to buy an appropriate frame from the off though ;)

You can buy nutted brake calipers that are dual pivot for an older frame. Tektro do them.
Cheers for the thought, although I've not had positive experiences with Tektro brakes tbh so will probably look towards a set of 105s ;)
 
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