Where is the wear limit on my brake pad?
 

My brake pad looks like the image below. There are grooves in the pad but there is material recessed inside those grooves. The pad is Shimano M70R2.

At which point is the pad considered worn out?

1. When the grooves are even with the recessed materail
2. When the grooves are gone
3. At this molded line. I am fairly certain it is not 3 because the pad will very close to the backing plate if it is worn to this line.

The area below line 3 is inserted into the backing plate; it is not visible when the pad is installed.

https://cimg1.ibsrv.net/gimg/bikefor...55251bf53b.png

1, 2, or if the performance has degraded from contamination or severe glazing.

They are brake pads $10 tops. Why mess around if you think they are even near the end of useful life. I think the cost have zero to do with function when you need to stop

I am asking because I don't know where is the end of useful life and there is no marking on the pad other than marking for orientation of the pad.

When the pad's metal parts touch the rim it's just past worn out. Monitor daily and note when this happens. Andy

The real answer is you can use them until they are about to hit the pad holders. If it was my bike I'd use them close to 3, if its a friends or family member's bike I'd replace around 2 because you don't know how long they will continue to use the bike before its inspected.

JS: I think most people are just trying to say that the brake pad is ready for replacement when it no longer stops the bike.

If you suspect that the performance of your pads has deteriorated beyond safe limits, and if you are sure they are not just out of adjustment, spend a couple of bucks and replace them. They are some of the most important components of your bike, but also some of the least expensive.

I gave you your best suggested answer. It'll just be reworded repeated from here on out by others.

Pretty much my philosophy too.

Honestly, unless you are real single track mountain biking, maybe commuting a lot in the rain, you'll probably never wear them out. More likely age will eventually turn them to stone so they won't work very effectively.

Since its on your mind, replace them Now..