[John Brown]

The real reason that you would what to use a lighter driveshaft is the critical speed for the length of the shaft. Mild steel is good to a certain length where critical speed makes it impractical or dangerous to use in a racing application. Some racers complain about unbalanced slicks when it really is a driveshaft that has exceeded critical speed and has started to whip and bend while going down the track.

My son (a driveshaft engineer for one of the big three) has always told me that you need the lightest, shortest (hard to do), largest diameter driveshaft made from the stiffest material when building a shaft for racing. When you do all these things you raise the critical speed which will add to reliability and increase performance (if you were exceeding critical speed in the first place).

Stockers that have aluminum shafts already can be improved with larger diameter MMC material which again raises critical speed. Stockers with steel shafts can use larger diameter alloy shaft material.

Super Stockers should always adhere to what was stated in paragraph two.

Note: If you want a larger tube make sure that it fits in the tunnel and driveshaft loops before having it made.

If you want more information go here http://www.markwilliams.com/driveshafttech.aspx .

I am by no means an expert on the subject but I can sure talk to one any time when there is a question.