U brake on my rat bike.

[Chainsnapper]

Hi all,

First post on here and wondering whether anyone can help out. I picked up this 1989 Kona Fire Mountain from the "recycling centre" for a fiver for use as a commuter. Tyres perished, frame a mess so decided to "rat bike" (I hate to use that term but it is what I'm doing) it, Cream Schwalbes from Charlie, stumpy stem, black electrical tape on frame, etc. The thing is, the rear seatstay mounted U-brake seems to be missing a spring as it's next to useless and doesn't return fully when the brake lever is released. I was wondering what I could use in it's place? Don't shoot me but could I get away with a bmx brake on the rear? The old U-brake bosses are larger in diameter than canti bosses so would they be larger dia than bmx brake bosses as well? If so what would my best options be?

Also the rear noodle for the brake cable is all rusty inside and it's nigh on impossible to run a cable through cleanly, are there any decent clip on guides for brake cables out there?

Apologies for coming across as technically incompetent (even though I am, a bit) but any help/tips would be gratefully received, cheers.

 

[zigzag]

BMX U-brake will work just fine - I fitted one to my old Rockhopper - Pics here

 

[was8v]

Use a cheap BMX U brake on there!

alternatively post up the make and model / picture of the U brake on here someone may have the required part lurking in a tool box.

 

[Chainsnapper]

Chaps, thank you. Oh and zigzag, nice bike!

 

[Raging_Bulls]

If you really want to rat it out, think like a ratbike rider :

A strategically placed rubber band might do the trick. Or perhaps a spring from a cheap ballpoint pen would be enough.
The optimal position and length depends on the exact model of brake though.

On this one, for instance, I'd put my bands/springs between the bolts on the end of the arms and those that mount the opposite brake arm onto the frame. So the arm that sticks out on the left to the arm that is mounted on the left, springs in a nearly vertical position really.
Tension between those two points will pull the brake open.

 

[lrh]

The thing is, the rear seatstay mounted U-brake seems to be missing a spring as it's next to useless and doesn't return fully when the brake lever is released.

Sounds like the arms are simply not bolted down tight to the frame. Undo the bolts, hold the arms in their "rest" position (wide enough to let the tyre through) then bolt them down tight to the bosses. Then when you rotate them towards the rim you'll feel the resistance of the internal springs.

The springs are internal and don't just pop out or go missing.

Oh and get some pics up of your £5 Kona

 

[Chainsnapper]

IRH, thanks for the advice, I will take a look. It's far from "finished" and she's hardly gonna be a work of art when she is but I might get some pics up at some point

 

[drcarlos]

The thing is, the rear seatstay mounted U-brake seems to be missing a spring as it's next to useless and doesn't return fully when the brake lever is released.

Sounds like the arms are simply not bolted down tight to the frame. Undo the bolts, hold the arms in their "rest" position (wide enough to let the tyre through) then bolt them down tight to the bosses. Then when you rotate them towards the rim you'll feel the resistance of the internal springs.

The springs are internal and don't just pop out or go missing.

Oh and get some pics up of your £5 Kona

20 Years since I last set up a U and I found the same thing on my courier comp, the Exage mountain brake with a set of Aztec pads in is just like I remember them, super powerful and it's going to be my winter bike/road rider.

Carl.