myner... great tips and personal experience for 120bpm onwards..
just to add and for the benefit of softies, i've often asked drummers what speed they practice at cos i've been searching for answers myself.
its a occupational hazard being an educator, u would like to ask every single drummer out there the same question so you get a really wide frequency sample.
one of the things i try to always do when playing a groove, is to get a "pocket".
this means, when im in the pocket, it doesnt take me much effort for the notes to fall in place perfectly.
now, for funk, blues and the like.. finding pocket is pretty common.
thing is, for rock, metal, pocket is also possible.
for very slow, double pedal grooves. getting the pocket is difficult. to quote myner's experience, at faster speeds one can "jog", but at slow speeds.. it becomes quite difficult and often uneven.
what i shared at the last xchange was, at certain intervals of bpm speeds, there is a sweet spot and combination of technique/muscles/joints that works perfectly for it.
so.. to practice double pedal slowly (<80bpm) is no indication that you can play it stably faster later on.
hence, my advice to practice say, at intervals of say, 10bpm increments from 80-200.
every interval has that perfect combination. find it and you should easily achieve that "pocket" to play without much effort.
cheers