AN MU2B-36A ON TKOF ROLL AT POINT OF ROTATION DECLARED AN EMER AND DIVERTED DUE TO SEVERE NOSE GEAR VIBRATION AND PWR FLUCTUATION ON THE R ENG CAUSED BY A NOSE TIRE THROWN TREAD WHICH BENT THE R PROP.

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I WAS DEPARTING ON RWY 26L AT ATL ARPT; ON THE TKOF ROLL; WHEN AT THE POINT OF ROTATION I GOT A VERY VIOLENT SHIMMY IN THE ACFT. MY INITIAL RESPONSE WAS TO LIFT THE NOSEWHEEL OFF THE GND; FEARING THE SHIMMY DAMPENER WAS NOT WORKING PROPERLY AT THAT POINT. THE NOSE AND ACFT LIFTED OFF THE GND; THE SHIMMY SUBSIDED; BUT WAS STILL APPARENT. I THOUGHT THAT I HAD LOST A NOSEWHEEL TIRE AND CONTINUED THE DEP STRAIGHT OUT. THE CTLR GAVE ME A HDG TO TURN TO AND I TOLD HIM TO STAND BY; I HAD A BAD SHIMMY AFTER TKOF. HE ASKED IF I NEEDED ANY ASSISTANCE AND I STATED NO; BUT I WOULD LIKE TO RETURN FOR LNDG. HE ACKNOWLEDGED AND GAVE ME A HDG. AT THIS POINT I HAD DETERMINED THAT THE R ENG WAS NOT FUNCTIONING PROPERLY AND DECIDED TO PULL BACK MOST OF THE PWR ON THAT ENG TO SLOW THE SHIMMY AND PROCEEDED TO LAND UNEVENTFULLY. UPON ARR; I HAD STILL NOT DETERMINED WHAT THE PROB WAS; SO I LANDED VERY SMOOTHLY AND AS SLOW AS POSSIBLE -- EVERYTHING APPEARED FINE. AFTER SHUTDOWN; A POSTFLT INSPECTION SHOWED THAT A RECAP HAD COME OFF THE TIRE; HIT THE GEAR DOOR AND WENT INTO THE PROP; BENDING 2 PROP BLADES. I THEN CALLED THE TWR AND ADVISED THAT I HAD LOST THE RETREAD ON THE TIRE AND THAT AN OPS CHK OF THAT RWY WOULD BE NEEDED. THEY DID SO RETURNING WITH THE RETREAD AND A RETAINER FOR THE GEAR DOOR THAT HAD ALSO BEEN BROKEN OFF WHEN THE TREAD SEPARATED FROM THE TIRE.