I just bought this old school brazilian mountain bike, and it has this little hook thing near the brakes, front and rear. Anyone knows what these are for?
4Cable catcher. Should the brake cable break, the straddle cable would drop down and catch in the tread of the tire, causing a head-over. At least this is what is claimed. However, the picture shows the newer straddle cable scheme which should (in most cases) disassemble itself should the cable break.– Daniel R HicksJun 14, 2017 at 19:04
Yeah, that's why I got confused... When my other cantilever cable broke, it just opened, nothing dangerous. I will just trash them, to save some weight and be super fast.– Emílio Dolgener CantúJun 14, 2017 at 19:10
4And being kinda new to the site, can you explain me why did you write it as a comment, not an answer, @DanielRHicks? Thanks!– Emílio Dolgener CantúJun 14, 2017 at 19:12
2Don't remove safety items - even if you think you won't need them. With knobbly MTB tyres that bike will never be super fast, sorry.– Criggie ♦Jun 14, 2017 at 19:37
Perhaps the original owner experienced the head-over maneuver and ruined the bike then added the hook to the new bike to prevent it from happening again even though it isn't needed.– mikesJun 14, 2017 at 20:27
This is a cable-catcher, but using the brake in the picture it doesn´t work, as the cable coming from the handlebar goes straight to the brake body. If the cable breaks, the whole system will snap open, with loose cables, not interfering with the tires.
A cable catcher is useful if you have a brake that uses the configuration shown in the picture below. In the event of the main cable snapping, the cable that goes accross the break arms stays in the hook, not interfering with the tires. At speed, with no cable catcher, this could cause quite a crash.