arewolfe

In my attempt to upgrade my 1982 Fuji team I bought a Tektro r315 rear brake and quickly realized the cylindrical piece that receives the screw (to attach the brake to the frame on the crossbar between the seat stays) is too large for the frame. The diameter of the cylinder is larger than the brake mount hole drilled into the frame. Is the cylinder size a modern component that fits most frames built after a certain year? It seems my choices are:

A) replace the bolt that attaches the brake to the frame with something a lot longer, and get a makeshift hex bolt to secure it.

B) find some type of adapter so the cylindrical peice can serve its function in attaching the brake to the frame... though the stock Tektro screw is very short (barely reaches through the brake mount hole on the Fuji).

C) get a new frame 😂

Am I missing something? Any advice welcome. The old Diacomp brakes (I believe they were original) are terrible.

HillRider

What you now have are "recessed nut" brakes and that elongated nut needs an 8mm hole to fit in but only at the front of the brake bridge. It's a bit tricky to drill out only the front side of the bridge because the seat tube blocks it. It can be done using a very short 8mm or 5/16" drill bit, clamping the bit in a pair of vise-grips and rotating the bit by hand a fraction of a turn at a time. It's laborious but it works.

arewolfe

Thanks. Are "non-recessed nut" brakes easy to find? That'd be my first choice before drilling the frame.

EDIT: Found 'em Thanks again!

dedhed

"Nutted" vs "Recessed" mounts.

You're probably going to want something like these as well, unless the brakes come with them, and/or the back of the fork is flat.

​​​​​​https://www.porkchopbmx.com/dia-comp...spacer-fo.html

​​​​​​https://www.porkchopbmx.com/dia-comp...-46156262.html

FBinNY 

ANY 6mm (6x1) nut will do. It's just a plain nut.

However, that style brake bridge needs 2 hemispheral washers to properly support the tube so it doesn't get squashed flat.

oldbobcat

It also needs a longer mounting bolt because the ones that use recessed nuts don't reach all the way through the bridge/fork crown.

Mr. 66

I would use the front brake on the rear nut mounted, and replace the short bolt with a longer for nut mount on front.

I did just that on a brake swap for a '77 Nishiki

HillRider

A variation on this is to use the front brake on the rear with. a nut as mentioned above. For the front, drill out the rear of the fork to 8mm/5/16" and use the rear brake with a long recessed nut (they are available up to 30 mm) or just use the rear brake and a regular nut inserted under the fork crown into the open bottom of the steerer.

Here is a Youtube video:
I realize this is moot as you already found real nutted calipers but it may help someone else.

arewolfe

Wow, great responses. Thanks.

I ordered a Tektro 539 rear brake that supposedly has a 1-3/8" bolt which will reach through the frame.

As for the front brake swap idea, I don't have one. I'm a brakelss BMX guy who just wants an around-town cruiser (bought the Fuji for $100 and have been upgrading it slowly) so one rear brake is plenty.

ShannonM

70% of your braking power comes from the front wheel. So, if you insist on having only one brake on a road-ridden bike, (and if you do, you are always and eternally wrong,) that brake must be on the front.

Unless you have a large life insurance policy, the beneficiary of which you want to make wealthy very soon. In which case, have at.

Bicycles have two brakes for very, very, very good reasons.

--Shannon

Jeff Neese

You found the answer - you need brakes with a nutted mount. I had the same problem replacing brakes on an '85 Fuji, and ended up buying those Tektro R539s that you linked to. Those are fantastic dual-pivot brakes, much better than the stock calipers.

ShannonM

Which model Fuji? My' 85 League is recessed. 1985 seems a couple of years late to me for nutted brakes on a bike shop bike.

--Shannon

Jeff Neese

It was an '85 Sagres. I no longer have that bike but interestingly, I just acquired an '86 Sagres almost by accident and I got it for free. I'm restoring it because it has the same quad-butted Valite frame that other bikes higher in the food chain had, and I like the way Fuji's "sport touring" bikes ride and handle. It has the same brake setup, nutted. Also 27" wheels which is also kind of late in the game.

Andrew R Stewart 

Since I like to be able to stop quickly I don't ride bikes without front brakes. If I were to only be restricted to only one brake it would be the front, again because of stopping ability. Andy (who is right handed and operates the front brake with this dominate hand)