i know on F1 cars the redline is different in every gear..i think that redline goes down as the gears go up..not too sure tho..but imagine your max power is 4,000 and redline is around 5,000 for 1st gear.and most of the power/powerband around 3,000-5,000..in 1st u change at 5,000 your revs drop to maybe 3,000..but from 4th at 4,500 to 5th might drop only to 3,500..close enough to your max power to allow more acceleration..if you revved it to 5,000 in 4th you might hit 3,900..right on max power but you would run out of puff in another 300rpm..does any1 understand what im sayin?..caus i dont..lol