Brake posts too long
 

Trying to fit a pair of Tektro dual-pivot brakes to a 1983 Holdsworth professional frame with recessed brakes. The posts are a bit too long, so when I tighten down the nut all the way they flop around with several mm of free play. I assume they were made for aluminum frames with bigger tubes. So possible solutions I can see include putting a spacer on the brake side or cutting down the brake post by about 6mm or so. The spacer is reversible, but I think it will look nicer with the posts trimmed to the appropriate length.

This post is just a reality check. First, am I missing something obvious or a better way? Second I'm leaning towards cutting down the brak post which seems like the better option to me, but if this is a bad idea someone please stop me before I get the hacksaw out.

Do you have enough threads?

You can purchase different lengths of recessed nuts, so if your nuts are bottoming out, you can get shorter ones.

That also means that if someone in the future wants longer bolts, they can just use longer nuts.

I'd probably just cut if it seems safe enough to do.

I have shortened posts and also had to use a die to cut additional threads onto it. Never experienced any problems with those brakes.

Dan

One wants 5ish min thread overlaps with critical fasteners. Adding mounting bolt spacers is an age old solution. Andy

NOT POSTS they are called CENTERBOLTS

Is this being attached to a round seatstay bridge? If so, you should be using the washers with a curved side to match the bridge and a flat side to match the brake and bolt.

Edit: the washers are shown here in the picture with the caption "Traditional Nut Style" https://www.sheldonbrown.com/calipers.html#mounting

I've got the shorter nuts already but the post extends just past the end of the hole, so there isn't such a thing as one that is short enough. I think there is plenty of thread.

The bridge on the Holdsworth has a square block for the mounting hole.
https://cimg7.ibsrv.net/gimg/bikefor...fc45c406eb.jpg

If this is for the rear brake bridge you are using the front brake on the back. Front brakes have a longer threaded bolt than do rear brakes for recessed mounting.

It is for both of them. I am aware the longer one goes on the front.

Are you sure your calipers are for recessed mount?

Yes, quite sure. They are late model Tektro dual-pivot brakes, and the posts extend level with (in front) and just past the surface of the mounting hole in the rear. In both cases with the short nut, there is about 3-4mm of free play when the nut bottoms out.

Found this for nutted

https://m.media-amazon.com/images/I/...L._SS1000_.jpg

Thanks, folks. I think I got my answer in the first few replies. I will have a closer look at them before I take the hacksaw to them and make sure there is enough threads, but I don't think there should be a problem shortening them by 5-6mm each.

TIP:
When cutting/shortening threads it tends to ****er the thread.
Place a nut on the thread before cutting. Then removing the nut will reform the start to the thread.

wow BF would not allow the word g o o b e r?

This is a good idea. Just adding that I would cut the new/additional threads before shortening the post, then put the nut or die on, and then shorten the post. The existing threads can function as guide for the die.

Dan

And after that file a bevel on the end of the stud.

Yes, thanks I was already planning to thread 2 nuts on and then file the bevel before removing the nuts. In addition to fixing the threads on their way off, I figure it will make a nice saw guide.