pwa wrote:The spring is what keeps the blocks off the rims when you are not pressing the lever, isn't it?
That's exactly what it's for.
Just done an experiment with Mercian.
Rear brake is single pivot.
Bike on the stand.
Unlatched the spring on both sides so it was free do as it pleased ............. and the brake works just as well as before and remains properly centred. It doesn't release very well of course, but the wheel spun fine.
Because the brake levers are Ergos, the brake lever returns ok by dint of the gear shift paddle being sprung-loaded forwards.
I say again.........
Single pivot brakes are centred by the centre bolt. If the brake is uneven and won't pull the same on both sides, it'll be the cable restricting it. Trial and error will sort it.
Doing it without the spring is a good experiment. I must try that again sometime when and if I need to set up a single pivot brake again.
Mick F. Cornwall