Burning on dvd+r dl

i have just starting using dvd+r dl to burn on so i am new to this my question is the dvd says it is 240 min 8.5 gb but i have tried to put a 96min and a 92 min movie on it but it tells me there is not enough space why i have even done just main movie but it wont do is there something i am not doing right or what thank you for any help

Only the bitrate & resolution is really important in this case.

Check videohelp.com/dvd