Deciding what is right for your car can be as simple as finding out what the different materials and yokes cost—or not. Think about this, if you have a heavy B-Body that races every weekend, with a thin wall driveshaft using small 7260 u-joints, you are asking for trouble. To the opposite, a Slant Six–powered Dart doesn't need a carbon fiber shaft with 1350 u-joints. In other words, do your research, and spend only what you need to, or at least what your combination should require. The following is a simple outline of what's available.
Chromoly is a steel tube that is usually drawn over a die or mandrel (D.O.M.). Chromoly steel has chromium and molybdenum added to the metal mix, and is considered the top of the line steel driveshaft. It's mostly used for heavy cars with high horsepower engines. Pros: This metal has a very high torsional strength.
Cons: This is also the most expensive of all steel driveshafts, and is only available in 3-inch diameter. It's also very heavy. This driveshaft uses steel weld-yokes.
D.O.M. 4140 is the most common aftermarket driveshaft used in racing situations. As long as the shaft is sized correctly, according to Dynotech Driveshafts, there's no car that can overpower this shaft.
Pros: This material is much stronger than seam tube and can withstand relatively high critical speed.
Cons: Not many. It's only slightly more expensive than a seam tube driveshaft. Like Chromoly, this is a fairly heavy shaft using steel weld yokes.
Seam Tube is the most common material used for OEM applications. It is perfectly suited for everyday driver or restored cars. Although stretching its limits is a possibility, it could be carefully used in circle track and drag racing applications.
Pros: This is the most cost effective driveshaft you will ever find.
Cons: It's also the weakest of all the steel driveshaft and has the lowest critical speed survivability rating, and is still heavy. Once again, steel weld yokes are used.
6061 T6 is the most common OEM application for an aluminum driveshaft. This type of shaft is best suited for everyday applications or restoration cars, sometimes a nice alternative to the heavy steel shaft, but is only suited for moderate horsepower.
Pros: Light weight, never rusts, and has a higher critical speed than steel shafts.
Cons: The weakest of all driveshafts. Remember, this is the same driveshaft used on applications such as the Astro van and Mustang. Also uses aluminum weld yokes.
Carbon Fiber is technology at its finest. This material is usually wound over a mandrel, while the fiber is soaked with resin. It is very well suited for circle track and drag racing. Pros: Very light weight and ultra strong.
Cons: By far the most expensive of all driveshafts. Can use either steel or aluminum weld yokes.
Aluminum wrapped with Carbon Fiber.
This is when you wrap any aluminum driveshaft with a thin carbon fiber over the outside diameter of the tube.
Pros: Light weight with extra strength and high critical speed. Price is less than a standard carbon fiber, as it is still an aluminum shaft; it's just wrapped with a thin layer of Carbon fiber.
Cons: Still not cheap. Uses aluminum weld yokes.
So now that you have the knowledge you need to decide what type of driveshaft you should get, all you have to do is get a little help from your friendly driveshaft shop, and you can pick the right material for your application and budget. mm