? about recessed brake nut length

[dustyrider]

I can't seem to figure these suckers out. I've done a lot of reading, and I've looked through sale items, in the hopes that I'd find some close to my measurements. All to no avail!

I've got two measurements. Total length and recessed length (measuring just the recess).

Total length for front is 30mm, rear is 19. The front is about 3mm too long and the rear is 4mm too long. So I get 27mm front and 15mm rear?

I've seen the 27mm, but not the 15mm...

Length of the recess/flange is 27mm front and 16mm rear, which means 24mm front and 12mm rear. None of which line up to anything I've seen.

My reading suggests the rear should be a 10mm due to the age of the frame, yet I can't seem to find anything related to a "standard" for the front.

So my question is how the heck do I measure these things?
Is there a way to measure the frame?

I'd go to a LBS, but the locals are into MTBs and are quirky when it comes to road bikes if they even support them!

[sales guy]

Tell me what sizes you want, I have tons in different length.

Give me the total length.

[cmbicycles]

There are a bunch of different sizes for these. Are you handy with a file/dremel/hacksaw? If you are only over by 3-4mm you can shave a little off the brake nuts you have. Conversely you could put a spacer/washer between the brake & fork/bridge to take up the extra length.

[oldpotatoe]

I can't seem to figure these suckers out. I've done a lot of reading, and I've looked through sale items, in the hopes that I'd find some close to my measurements. All to no avail!

I've got two measurements. Total length and recessed length (measuring just the recess).

Total length for front is 30mm, rear is 19. The front is about 3mm too long and the rear is 4mm too long. So I get 27mm front and 15mm rear?

I've seen the 27mm, but not the 15mm...

Length of the recess/flange is 27mm front and 16mm rear, which means 24mm front and 12mm rear. None of which line up to anything I've seen.

My reading suggests the rear should be a 10mm due to the age of the frame, yet I can't seem to find anything related to a "standard" for the front.

So my question is how the heck do I measure these things?
Is there a way to measure the frame?

I'd go to a LBS, but the locals are into MTBs and are quirky when it comes to road bikes if they even support them!

That's too bad, where in Colorado are you?..shimano and Campagnolo brakes come with a bag of different lengths....call Jim at Vecchio's or go by(Colorado), he has a drawer full of these..he'll give you a size run for free...

[dustyrider]

Thanks for the support! 200+ miles away from vecchios

It sounds like trial and error is the only way to figure this out.
Gotta love the bike industry's standards", and of course campi has got it dialed in....

[ultraman6970]

Ultra generally try to get long ones and then cut them if necessary, then put some nails paint over the cut area just for corrosion protection.

[weisan]

I ran into a slightly different issue: how to use modern-day DA dual pivot caliper brakes in an older Bianchi frame, which I am building up as a commuter, that does not accept recessed nut.

I did some research and once again Sheldon Brown, bless his soul, came to the rescue. :banana:

You drilled the hole bigger. Who would have thought? :rolleyes:

http://sheldonbrown.com/calipers.html
Mounting recessed-mounting calipers on older frames
Rear: Here are three options:
You might mount a rear brake for recessed mounting ahead of the seatstays, as long as the back side of the brake bridge can be safely drilled out. This is more likely to work with a single-pivot or dual-pivot brake, due to the difficulty of routing the cable with a centerpull. Use an 8 mm or USA letter-size O drill bit. A 5/16"drill bit is slightly smaller, and you may have to ream the hole slightly. Radiused washers (as shown on the nutted-style brake in the photo above) must be used if the brake bridge has no flat mounting surfaces. The washer that goes under the nut must be drilled out, and so must athe brace of a baggage rack, if it attaches to the brake bolt.
Drilling out the brake bridge from the front is possible on most frames using a right-angle electric drill: the seat tube would get in the way of a normal. drill. Even Dremel makes a right-angle attachment.
Front brakes for recessed mounting have bolts that are long enough to use them as rear brakes, if you substitute the appropriate washers and a 6 mm nut.
Front: Here are 3 options:

Drill out the back of the fork crown, just as is described above for the rear brake.
That's it if you can get two front calipers. Sometimes, you may have to deal with a pair of brakes, with one long and one short bolt. If you used the long one in back, you can use the short one in front two different ways:

Drill out the back of the fork crown and use an extra-long recessed nut. These nuts are commonly available for use in carbon-fiber forks.
Use the short recessed nut, but don't put it through the back of the fork. Instead, push it up into the inside of the steerer from the bottom. You can reach a 5 mm Allen wrench in through the hole in the back of the fork, and poke the short caliper bolt in from the front.
You may need to shorten the recessed nut slightly to get it to fit inside your steerer.


For some reason, i found the picture of putting the caliper ahead of the seat stay is way too cool. http://sheldonbrown.com/images/IMG_8671Brakefrontcropped300.JPG