Possible the friction coefficient?
When I compare photos I sense the 06435MAJG41 (ST1100A*) being darker (graphite gray), vs the 06435MCSG03 (ST1300A*) having a light tone (the "Windows gray")
That is an excellent thought. I hadn't thought of that !
I compared them togther. One had slightly darker grey friction material ! The other three were just a tiny bit lighter - but the same as each other. But under the light I noticed something else - the sheen on the pad surface. So without working out which was which I angled them all to catch the light at the same angle. Then took this photo.
Guess which two pair together ?
Counting from the back, the first (back) and third have decidedly more stuff in there that refelect light. The sintering, I presume. The other two reflect the light a little bit, but not nearly as much.
The 4th, front one is the one that I marked as being the ST1300 pad. It has the blue dots on the bottom edge of the backing plate. I've taken another shot of that pad at a better angle to show the blue dots. The other one that has the blue dots is the 2nd form the top - the other dull pad.
So - and this is a guess - the ST1100 pads are more highly sintered than the ST1300 pads ? The texture of the pads looks coarser on the refelcted surfaces - but viewed from the tops side, under an extremely bright police torch** - there is no visible difference.
Other differences. The backing plates is lighter on both of the two ST1300 pads (2nd and 4th), and
there is a cross between the pair of middle pads friction blocks onto the ST1300 pads. I hadn't noticed that until I looked at the photo. Yeah - that would have saved a lot of time !!!
Still - not one to shy away from getting as much info as I can from this, I continued.
Put backing plate to backing plate (without the heat shield and anti-squeal plate in position - I can detect no difference between the ST1100 and ST1300 plates.
Whatever - I am happy that I have got the two pairs sorted out.
For info - micrometer measurements.
All backing plates - 4.00mm
Thickness including antisqeal and heat shield - ST1300 = 11.14mm & 11.38mm - ST1100 = 11.25mm & 11.20mm
Thickness without antisqueal and heat shield - ST1300 = 9.75mm & 9.97mm - ST1100 = 9.81mm & 9.74mm
The heat shield and antisqueal plate are subject to being squeezed together - more or less - so measurements are approximate.
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** Police torch. The present that I never knew that I wanted. Protec T2000L - 2000 Lumen 36W LED search torch and power bank.
3 light levels. Ridiculously bright, Extremely bright and severe retina damage. WIth a viscious strobe setting, and a setting that repeatedly flashes out SOS. (Presumably for use after looking at the torch in its highest setting and you need help to find your way home.)
