Just looked at a set that came out of a calliper that was dragging a bit. Piston wasn’t returning properly. I thought they look like they need changing so I compared them to a new set.

2mm of material on a new set, 1mm on the old set.

Done over 1000 miles on them so happy to change but when do you change? Run them down to the metal?

If you run them down to the metal you will damage the disc.

Keep a regular eye on them and change out once the friction material is getting too thin.

I wouldn’t actually run to the metal but 50% worn instinctively seems too soon.

Other problem I find when they wear down is the Pistons get shitty and stop returning properly.

When the pad material has dropped off and you wondering why your bike sounds awful when you brake. Hopefully the scored disc will still be fine. Am I the only one who has no luck with aftermarket pads? Do they attach the pads to the backing plate with Nutella?

Just before they’re down to the metal.

I usually hear the springs touching the disc, and know it’s time for a change.
About half a mm.

When they have worn right down. Unless you run them to the metal for a protracted period you shouldn’t write off the discs. Throwing away when they are half worn? No chance.

I’m with dibbs, the twanging springs usually signal a change…

Yep- that’s what the springs are for 😆

When they stop working or are making a right racket. I’ve been down to the metal before, discs fine. As said the springs start catching when it’s about time anyway.

If you take them down to metal on metal, the discs will be rough and eat through your next set of pads. False economy.

The springy things escaped, causing a continuous chirrup on the disc. I would have ignored them otherwise as they had only been on for a little while…