What is the function of the little machine screw?

[Boyntonstu]

 

[PaulD]

To adjust return spring tension so that you can get left and right sides even. That way one side isn't rubbing.

Sent from my Nexus 5X using Tapatalk

 

[Warren]

On inexpensive, stamped sheet metal brakes, adjusting the screws may not be enough to correct brake drag. The springs on these brakes are not made from quality spring steel, but soft wire. Also, tolerances in the brake pivots are not good, so one arm may bind on its pivot more than the other. One work-around is to bend the wire springs themselves.

Also, on brakes, like the one shown, the adjustable end of the spring is anchored to the plastic part with the screw in it. Over time, the plastic piece cracks, making adjustment impossible.

 

[spinningmagnets]

Quite often (dependant on which model brakes you have) there is a small "tang" at the root of this "hairpin" spring. If you have that, then there are sometimes several holes (maybe 3?) that you can insert the tang into, to select a tension "range" within which to adjust with the screw. This is also valuable if the spring weakens over time, so you can re-set the tang in a hole that provides more tension.

Of course, as stated by the posters above, the screw provides a finer control over the final tension, so both sides are even.

 

[d8veh]

It adjusts the tension in the spring. Turn it one way makes the spring stiffer and the other way for less stiff. The idea is to adjust them so that both levers move evenly. If you have different tensions on each side, they won't both move to the rim together.

 

[dogman dan]

First thing I usually do, especially on back brakes, is re mount the brakes so they use the hole with the most spring tension. This way the brakes snap back open despite some problems with sticky cables. Then if still not even, start adjusting the screws.

As said above, the goal is to have them touch the rim at the same time. Not always riding the same distance from the rim to get that.

 

[Boyntonstu]

First thing I usually do, especially on back brakes, is re mount the brakes so they use the hole with the most spring tension. This way the brakes snap back open despite some problems with sticky cables. Then if still not even, start adjusting the screws.

As said above, the goal is to have them touch the rim at the same time. Not always riding the same distance from the rim to get that.

Thanks,

Nice!