[RallySport Direct]

Yield strength is based on the materials Youngs modulus of elasticity and correlates to stress and strain that a material can withstand before yield strength is reached. Yield strength is the materials proper to withstand loading prior to deformation occurring and be able to return back to its original yield property and shape. Going beyond this point will result in work hardening of the material, beyond that you have your ultimate yeild where the materials property is gone out the window. That right there is a quick and dirty overview of 2 Material Science and Strength of Materials college level classes hahaha.

Ill do my best to put it into simple terms for easy understanding. For instance ceramics (think of your coffee cup) are very strong, however they are very brittle. When high load is applied rapidly it will fracture easily (dropping the cup) into many different pieces, but if you apply a large load over a small time frame the cup will hold up quite a bit of weight.
Now take the example you provided, simple rubber (rubber band, as we can get into polymers and would be beyond the scope of easy understanding unless you have a good background in material science at which point this explanation wouldn't be needed). It will deform and stretch over 3 times its size, when it does fracture you have a nice even break and very little shrapnel. As you can imagine if you have a rubber shaft it would twist and twist and twist, you have a ceramic shaft and it will fracture easily.

Now......think of carbon shafts as a very very very good rubber band that will have higher amount of twist then aluminum of up to 30 degrees if I remember correctly (this depending on resin used, carbon lay direction, and layers of carbon) along with having a higher resistance to fracture as a result. Where as aluminum shaft is a lower angle of only about 5-8 degrees, showing that is has a lower Proportionality limit. Yet Carbons ability in this application to transfer energy, have a higher critical speed as a result of the harmonics that it can withstand before hitting natural frequency, and its ability to be manufactured in various sizes easier make it ideal for this application. Problem with aluminum is you can only get it in industry standard sizes, 2", 3", ect for instance, and with certain wall thickness. To be able to withstand torsion and deformation it needs a wall thickness that can support that, and to get that wall thickness you need to go to a larger pipe size.

So I hope you can see the benefit of these units. Nissan has been using them on 350Z's sense day one, they are used on GTR's and many other sports cars for these reasons.

Is a carbon shaft a product for everyone? No. Same way that a body kit, or knock off wheels, and LED's are not for everyone. But this product works great and is for a consumer who can appreciate fine tuning the car and increasing response (quality over quantity). Ive used them on my personal car, we have them on both our shop cars, and I have many customers who use them on everything from street cars to 600+ HP Time attack cars. They simply work due to the carbon fibers vast benefits as a material, compact design, and the safety factor.


If you guys really want more info about material properties and loading I can blow the dust off the books at my house on these subjects and go a bit more in depth. Only problem is it might confuse more people instead of educate them unless they have a background of previous exposure in chemicals, material science, and strength of materials.

Kirill
RallySportDirect.com

PS. Dont get me wrong Aluminum shafts have their place in the market, its just that technology advances of carbon materials being used make it much more desirable is many applications. About the only draw back to carbon is Cost. If carbon was made cheaper it would be used on production car chassis, there is a reason why most modern day super cars use carbon and exotic metals for construction. If carbon didnt have an advantage race teams, major manufactures (not just in the automotive industry), and millitary would not be spending billions uppon billions on research.