I have had some big cubes for quite a long time but I haven't improved much. I average around 2.5min on 4x4x4 and 7min on 5x5x5. I don't know about 6x6x6 and 7x7x7 because I can't be bothered to time them (they take me too long.)
Is there a way to get fast quickly on big cubes??
Thanks.