A C182 PLT LANDS WITH A TAILWIND WHICH HE DOES NOT REALIZE UNTIL UNABLE TO SLOW THE LNDG ROLL. ACFT ROLLED OFF THE END OF THE RWY AND INTO A DITCH.

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I HAD BEEN FLYING IN AND OUT OF DUANESBURG MANY TIMES. GOOD SHORT FIELD PRACTICE. WINDS ALOFT WERE 270 DEGS AT 10 KTS. WINDS ON THE SURFACE WERE LIGHT AND VARIABLE. I HAD TAKEN OFF RWY 28 TO CATCH THE PREVAILING WINDS ON CLBOUT. I HAD LANDED 1 HR EARLIER ON RWY 28 WITH NO PROBS; TOOK A BREAK; AND DEPARTED 30 MINS PRIOR ON RWY 28. NORMAL ACCELERATION AND CLBOUT. BUT THE WINDS WERE PICKING UP AND SHIFTING FROM N TO NE AND WHEN I RETURNED 30 MINS OR LESS FROM THE PREVIOUS TKOF I LANDED IN MY NORMAL SPOT AND AT MY NORMAL SPD (INDICATED) YET I SEEMED TO HAVE A GREATER GND SPD; SO I RAISED THE FLAPS AND STARTED IMMEDIATE BRAKE APPLICATION. DUANESBURG'S RWY 10/28 IS CONCAVE AND SLOPES UP AT THE VERY END OF THE RWY 28 AND SLOPES DOWN GRADUALLY THE FIRST HALF OF RWY 28. MY IMMEDIATE BRAKE APPLICATION DIDN'T DO MUCH TO SLOW ME DOWN ON THE SLIGHT DOWNHILL WITH A TAILWIND I WASN'T FULLY AWARE OF. WHEN I GOT TO THE END OF THE RWY WHERE I NORMALLY DO ALL MY BRAKING; THE BRAKES HAD OVERHEATED AND I ROLLED OVER THE EDGE OF THE RWY AND DOWN THE OTHER SIDE OF THE SLOPE INTO A DITCH. MINIMAL DAMAGE. THE TROUBLING THING IS NOT ONLY HOW QUICK THE WINDS AT THE SURFACE CHANGED; BUT THAT THEY WERE OPPOSITE THE WINDS ALOFT. ALSO; MY TECHNIQUE FOR MAX BRAKING -- TO RAISE FLAPS -- HURT ME BECAUSE I LANDED MANY TIMES ON THIS 2800 FT RWY AND USED ALMOST ONLY THE AERODYNAMIC BRAKING TO STOP THE PLANE IN TIME. THE EXTRA WT ON THE WHEELS WAS MEANINGLESS BECAUSE OF LOOSE GRAVEL AND GRASS GROWING OUT OF THE RWY.