The new Shimano disc brake calipers claim a 10% wider gap between the pads and rotor. The older R8070 caliper's spec is 0.50 mm so the new R8170 caliper spec is 0.55 mm.
I have not been able to find this spec for the latest SRAM AXS Red, Force, or Rival brakes. Checking to see if anyone knows this or better yet can point me to where SRAM has these spec's. TIA!
That would be interesting to know for sure. I had to laugh when I saw Shimano say that. Don't get me wrong, more clearance is always nice, but the actual difference is so minuscule it's hard to believe it changes much of anything.
Excuse my naivete, but isn't an even thinner gap automatically provided by the back-pressure of the rotor against the piston's fluid-pressure, ala all automotive disc brake iterations? If so, why is a gap spec'ed...and why would a bigger one be better, if a longer (even if slight) lever-pull would be required?
A larger gap minimizes pad wear in muddy/gritty conditions. SRAM has a pretty minimal gap and tend to have much higher pad wear than Shimano in gritty conditions because of it. I think Shimano compensates for the larger gap by using “servo wave” on the levers so you don’t have a large lever throw, (I’m an SRAM user so that may be wrong.)
I don’t know the actual amount, but my GRX800 setup seems to have more clearance than my SRAM Red AXS XpLR setup. It could be a negligible amount, but I find my SRAM setup grinding with crap more often. I do seem to have to bleed my GRX setup more often though compared to my SRAM setup.
The “new” SRAM groups coming out will have redesigned calipers with more pad to rotor gap. But they are getting rid of the pad contact adjustment on the lever.
