POTENTIAL CONFLICT AND LTSS WHEN A CL65 FLC UNDERESTIMATES THE PERFORMANCE CAPABILITY OF THEIR ACFT IN CLB AND CONFLICT WITH XING TFC ON FREQ WITH ZOB; OH.

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WE WERE IN THE PROCESS OF CLBING TO FL330 ASSIGNED. AT APPROX FL315 THE CTLR ASKED US TO BE AT FL330 IN 1 MIN (LEVEL IN 1 MIN). BOTH THE CAPT AND I BELIEVED WE COULD DO IT BECAUSE WE HAD PLENTY OF EXTRA AIRSPD. THE CL65 ACFT THAT WE FLY IS LIMITED TO 250 KIAS OR MACH 0.70 MINIMUM AIRSPD DURING A CLB ABOVE 10000 FT. WE; UPON RECEIVING THE CLB RATE INSTRUCTION; IMMEDIATELY BEGAN A CLB OF 1500 FPM TO COMPLY WITH THE ASSIGNED RATE. AFTER 15-20 SECONDS OUR AIRSPD BEGAN TO FALL SIGNIFICANTLY; RAPIDLY APCHING THE MINIMUM 250 KTS/0.70 MACH MINIMUM CLB SPD LIMITATION. AT THAT TIME CTR CTLR WAS BUSY TALKING TO ANOTHER FLT(S). AT THE FIRST AVAILABLE BREAK IN THE CTLR'S RADIO XMISSIONS; I TOLD CTR; BEFORE THE EXPIRATION OF 1 MIN; THAT WE WERE UNABLE TO MAKE THE ASSIGNED CLB RATE FOR THE REMAINDER OF OUR CLB. WE WERE VIGILANTLY MONITORING OUR TCASII AND LOOKING OUTSIDE FOR ANY POTENTIAL ACFT. WE ASKED THE CTLR IF WE NEEDED TO TURN AND HE SAID IT WAS TOO LATE FOR THAT. WE RPTED OUR ALT AT; I BELIEVE; FL326 AND AN ACFT 2000 FT BELOW US SBOUND RPTED AN ALT APPROX 2000 FT BELOW US. THERE WAS NO RA OR TA ON TCASII. IN THE FUTURE I WILL BE VERY CAUTIOUS ABOUT AGREEING TO HIGH ALT CLB RATE RESTRS WHEN ASKED BY ATC; AS CLB PERFORMANCE CAN DROP OFF SHARPLY IN THIS ACFT.